wikidoc - User contributions [en]

Avian influenza

2009-07-14T17:00:35Z

Michaelagibson:

{{flu}}
{{SI}}
__NOTOC__
{{CMG}}

{{Editor Help}}

For Patient Information on Avian Influenza (Bird Flu), click [[Avian Influenza (Patient Information)|here]]

:''For the H5N1 subtype of Avian influenza see [[H5N1]].''

'''Avian influenza''', sometimes '''Avian flu''', and commonly '''Bird flu''' refers to "[[influenza]] caused by [[virus]]es adapted to birds."<ref name=ECDPC> "Avian influenza strains are those well adapted to birds"[http://72.14.207.104/search?q=cache:72mkmIQKbIQJ:www.ecdc.eu.int/documents/AF050930/AF3_13_Actions_taked_in_connection_with_Avian_Flu.doc+%22Avian+influenza%22+%22adapted+to+birds%22&hl=en&gl=us&ct=clnk&cd=3 EUROPEAN CENTRE FOR DISEASE PREVENTION AND CONTROL]. </ref><ref name=influenzareport> [http://www.influenzareport.com/ir/ai.htm Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner] in ''Influenza Report 2006''</ref><ref>[http://www.nature.com/nature/journal/v437/n7062/full/nature04239.html Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution] Nature magazine presents a summary of what has been discovered in the [[Influenza Genome Sequencing Project]].</ref><ref>[http://content.nejm.org/cgi/content/full/353/13/1374 Avian Influenza A (H5N1) Infection in Humans] by The Writing Committee of the [[World Health Organization]] (WHO) Consultation on Human Influenza A/H5 in the September 29, 2005 [[New England Journal of Medicine]]</ref><ref>[http://darwin.nap.edu/books/0309095042/html The Threat of Pandemic Influenza: Are We Ready? Workshop Summary (2005)] Full text of online book by INSTITUTE OF MEDICINE OF THE NATIONAL ACADEMIES</ref><ref>[http://www.cdc.gov/ncidod/EID/vol11no10/05-0644-G1.htm] CDC has a [[phylogenetic tree]] showing the relationship between dozens of highly [[pathogenic]] varieties of the Z genotype of avian flu virus H5N1 and ancestral strains.</ref><ref>[http://vir.sgmjournals.org/cgi/content/full/81/5/1293 Evolutionary characterization of the six internal genes of H5N1 human influenza A virus]</ref>

"Bird flu" is a phrase similar to "Swine flu", "Dog flu", "Horse flu", or "[[Human flu]]" in that it refers to an illness caused by any of many different strains of influenza viruses that have adapted to a specific host. All known viruses that cause influenza in birds belong to the species: ''[[Influenzavirus A|Influenza A virus]]''. All subtypes (but not all strains of all subtypes) of Influenza A virus are adapted to birds, which is why for many purposes avian flu virus ''is'' the Influenza A virus (note that the "A" does ''not'' stand for "avian").

Adaption is non-exclusive. Being adapted towards a particular species does not preclude adaptions, or partial adaptions, towards infecting different species. In this way strains of influenza viruses are adapted to multiple species, though may be preferential towards a particular host. For example, viruses responsible for [[influenza pandemics]] are adapted to both humans and birds. Recent [[influenza research]] into the genes of the [[Spanish Flu]] virus shows it to have genes adapted to both birds and humans; with more of its genes from birds than less deadly later pandemic strains.

==Genetics==
Genetic factors in distinguishing between "[[human flu]] viruses" and "avian flu viruses" include:
:'''PB2''': ([[RNA polymerase]]): [[Amino acid]] (or [[residue]]) position 627 in the PB2 protein encoded by the PB2 [[RNA]] gene. Until [[H5N1]], all known avian influenza viruses had a [[Glutamic acid|Glu]] at position 627, while all human influenza viruses had a [[lysine]].
:'''HA''': ([[hemagglutinin]]): Avian influenza HA bind alpha 2-3 [[sialic acid]] receptors while human influenza HA bind alpha 2-6 sialic acid receptors. Swine influenza viruses have the ability to bind both types of sialic acid receptors.

==Influenza pandemic==
{{details more|Influenza pandemic}}
Pandemic flu viruses have some avian flu virus genes and usually some [[human flu]] virus genes. Both the [[H2N2]] and [[H3N2]] pandemic strains contained genes from avian influenza viruses. The new subtypes arose in pigs coinfected with avian and human viruses and were soon transferred to humans. Swine were considered the original "intermediate host" for influenza, because they supported reassortment of divergent subtypes. However, other hosts appear capable of similar coinfection (e.g., many poultry species), and direct transmission of avian viruses to humans is possible.<ref name=Blanchard>Blanchard, Ben. "China says son likely infected father with bird flu." Reuters 10 Jen 2008 10 Jen 2008 <http://www.reuters.com/article/healthNews/idUSPEK27288320080110>.</ref> The Spanish flu virus strain may have been transmitted directly from birds to humans.<ref>[http://www.influenzareport.com/ir/ai.htm Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner]</ref>

In spite of their pandemic connection, avian influenza viruses are noninfectious for most species. When they are infectious they are usually asymptomatic, so the carrier does not have any disease from it. Thus while infected with an avian flu virus, the animal doesn't have a "[[flu]]". Typically, when illness (called "flu") from an avian flu virus ''does'' occur, it is the result of an avian flu virus strain adapted to one species spreading to another species (usually from one bird species to another bird species). So far as is known, the most common result of this is an illness so minor as to be not worth noticing (and thus little studied). But with the domestication of chickens and turkeys, humans have created species subtypes (domesticated poultry) that can catch an avian flu virus adapted to waterfowl and have it rapidly mutate into a form that kills in days over 90% of an entire flock and spread to other flocks and kill 90% of ''them'' and can only be stopped by killing every domestic bird in the area. Until [[H5N1]] infected humans in the 1990s, this was the only reason avian flu was considered important. Since then, avian flu viruses have been intensively studied; resulting in changes in what is believed about flu pandemics, changes in poultry farming, changes in flu vaccination research, and changes in flu pandemic planning.

[[H5N1]] has evolved into a flu virus strain that infects more species than any previously known flu virus strain, is deadlier than any previously known flu virus strain, and continues to evolve becoming both more widespread and more deadly causing [[Robert Webster]], a leading expert on avian flu, to publish an article titled "The world is teetering on the edge of a pandemic that could kill a large fraction of the human population" in ''[[American Scientist]]''. He called for adequate resources to fight what he sees as a major world threat to possibly billions of lives.<ref name=webster>

{{cite journal
| author=[[Robert Webster|Webster, R. G.]] and Walker, E. J. | title=The world is teetering on the edge of a pandemic that could kill a large fraction of the human population | journal=American Scientist | year=2003 | pages=122 | volume=91 | issue=2 |url=http://www.americanscientist.org/template/AssetDetail/assetid/17221?fulltext=true | id={{DOI|10.1511/2003.2.122}}

}} </ref> Since the article was written, the world community has spent billions of dollars fighting this threat with limited success.

==H5N1==
{{H5N1}}
{{details more|H5N1|Transmission and infection of H5N1}}
The highly pathogenic Influenza A virus subtype [[H5N1]] virus is an emerging avian influenza virus that has been causing global concern as a potential [[pandemic]] threat. It is often referred to simply as "bird flu" or "avian influenza" even though it is only one subtype of avian influenza causing virus.

H5N1 has killed millions of poultry in a growing number of countries throughout Asia, Europe and Africa. Health experts are concerned that the co-existence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal to humans.<ref name=FSRIO>Food Safety Research Information Office. [http://fsrio.nal.usda.gov/document_fsheet.php?product_id=207 "A Focus on Avian Influenza"]. Created May 2006, Updated November 2007.</ref>

Since the first H5N1 outbreak occurred in 1997, there has been an increasing number of HPAI H5N1 bird-to-human transmissions leading to clinically severe and fatal human infections. However, because there is a significant species barrier that exists between birds and humans, the virus does not easily cross over to humans, though some cases of infection are being researched to discern whether human to human transmission is occurring.<ref name=Blanchard/> More research is necessary to understand the pathogenesis and epidemiology of the H5N1 virus in humans. Exposure routes and other disease transmission characteristics such as genetic and immunological factors, that may increase the likelihood of infection, are not clearly understood. <ref name=WHO>World Health Organization. (2006). [http://www.who.int/mediacentre/factsheets/avian_influenza/en/#humans Avian influenza (" bird flu") – The Disease in Humans.] Retrieved April 6, 2006.</ref>

Although millions of birds have become infected with the virus since its discovery, 206 humans have died from the H5N1 in twelve countries according to [[WHO]] data as of November 2007.
(View the most current WHO Data regarding [http://www.who.int/csr/disease/avian_influenza/country/en/ Cumulative Number of Human Cases].)

The Avian Flu claimed at least 200 humans in Romania, Greece, Turkey and Russia. Epidemioloigists are afraid that the next time such a virus mutates, it could pass from human to human. If this form of transmission occurs, another big pandemic could result. However, disease-control centers around the world are making avian flu their top priority.

==See also==
*[[H5N1]]
*[[Global spread of H5N1]]
*[[Transmission and infection of H5N1]]
*[[:Category:Subtypes of Influenza A virus|Subtypes of Influenza A virus]]
*[[Influenzavirus A]]
*[[Influenza pandemic]]
*[[Influenza Genome Sequencing Project]]
*[[Influenza research]]
*[[Influenza vaccine]]
*[[OIE/FAO Network of Expertise on Avian Influenza]]
*[[International Partnership on Avian and Pandemic Influenza]]
*[[Pandemic Preparedness and Response Act]]

==References==
{{reflist|2}}

==External links==
;International
;;World Health Organisation (WHO)
;*[http://www.who.int/csr/disease/avian_influenza/en/ WHO Avian influenza resource (updated)]
;*[http://www.who.int/csr/disease/avian_influenza/avianinfluenza_factsheetJan2006/en/index.html The United Nation's World Health Organization's Avian Flu Facts Sheet for 2006]
;;Food and Agriculture Organization of the UN (FAO)
;*[http://www.fao.org/ag/avian.html FAO Avian Influenza portal] Information resources, animations, videos, photos
;*[http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/avian.html FAO Bird Flu disease card]
;;World Organisation for Animal Health (OIE)
;*[http://www.oie.int/downld/AVIAN%20INFLUENZA/A_AI-Asia.htm Official outbreak reports by country]
;*[http://www.oie.int/eng/info/hebdo/a_isum.htm Official outbreak reports by week]

;United States
*[http://www.pandemicflu.gov PandemicFlu.Gov] U.S. Government avian and pandemic flu information
*[http://www.usaid.gov/our_work/global_health/home/News/news_items/avian_influenza.html US Avian Influenza Response] U.S. Agency for International Development (USAID)

;Europe
*[http://library.wur.nl/frontis/avian_influenza/ Avian Influenza: Prevention and Control] Proceedings of the Frontis workshop on Avian Influenza: Prevention and Control, Wageningen, The Netherlands

;Other
*[http://www.fluwikie.com/ Flu Wiki]
*[http://www.flupandemicalert.com Bird Flu Pandemic Alert and Breaking News]
*[http://declanbutler.info/blog/?p=58 The spread of avian flu with time; new maps exploiting Google Earth’s time series function] updated Google Earth maps of bird flu spread by [[Nature (journal)|Nature]] reporter Declan Butler
*[http://www.birdfluthreat.org/essentials/main_info.php birdfluthreat.org information page]

{{Influenza}}
{{Viral diseases}}

[[af:Voëlgriep]]
[[ar:إنفلونزا الطيور]]
[[zh-min-nan:Khîm-liû-kám]]
[[bg:Птичи грип]]
[[ca:Grip aviària]]
[[cs:Ptačí chřipka]]
[[cy:Ffliw adar]]
[[da:Fugleinfluenza]]
[[de:Vogelgrippe]]
[[es:Gripe aviaria]]
[[eo:Birda gripo]]
[[fr:Grippe aviaire]]
[[gl:Gripe aviaria]]
[[ko:조류 인플루엔자]]
[[hi:बर्ड फ़्लू]]
[[hr:Ptičja gripa]]
[[id:Flu burung]]
[[is:Fuglaflensa]]
[[it:Influenza aviaria]]
[[he:שפעת העופות]]
[[ku:Arsima balindeyan]]
[[ln:Gilípi ya ndɛkɛ]]
[[mk:Птичји грип]]
[[ms:Selsema burung]]
[[nl:Vogelpest]]
[[ja:トリインフルエンザ]]
[[no:Fugleinfluensa]]
[[nn:Fugleinfluensa]]
[[nds:Vagelgripp]]
[[pt:Gripe aviária]]
[[ro:Gripă aviară]]
[[ru:Птичий грипп]]
[[sq:Gripi i shpendëve]]
[[simple:Bird flu]]
[[sk:Vtáčia chrípka]]
[[sl:Ptičja gripa]]
[[sr:Птичји грип]]
[[fi:Lintuinfluenssa]]
[[sv:Fågelinfluensa]]
[[tl:Avian influenza]]
[[th:ไข้หวัดนก]]
[[vi:Cúm gia cầm]]
[[uk:Грип пташиний]]
[[wa:Pesse des oujheas]]
[[zh:禽流感]]
[[ta:பறவைக் காய்ச்சல்]]
[[te:బర్డ్ ఫ్లూ]]

{{SIB}}

[[Category:Occupational safety and health]]
[[Category:Bird diseases]]
[[Category:Avian influenza]]
[[Category:Infectious disease]]

[[pl:Ptasia grypa]]
[[tr:Kuş gribi]]
{{WikiDoc Help Menu}}
{{WikiDoc Sources}}

Avian influenza

2009-07-14T16:59:29Z

Michaelagibson:

{{flu}}
{{SI}}
__NOTOC__
{{CMG}}

{{Editor Help}}

For Patient Information on Avian Influenza (Bird Flu), click [[|Avian Influenza Patient Information|here]]

:''For the H5N1 subtype of Avian influenza see [[H5N1]].''

'''Avian influenza''', sometimes '''Avian flu''', and commonly '''Bird flu''' refers to "[[influenza]] caused by [[virus]]es adapted to birds."<ref name=ECDPC> "Avian influenza strains are those well adapted to birds"[http://72.14.207.104/search?q=cache:72mkmIQKbIQJ:www.ecdc.eu.int/documents/AF050930/AF3_13_Actions_taked_in_connection_with_Avian_Flu.doc+%22Avian+influenza%22+%22adapted+to+birds%22&hl=en&gl=us&ct=clnk&cd=3 EUROPEAN CENTRE FOR DISEASE PREVENTION AND CONTROL]. </ref><ref name=influenzareport> [http://www.influenzareport.com/ir/ai.htm Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner] in ''Influenza Report 2006''</ref><ref>[http://www.nature.com/nature/journal/v437/n7062/full/nature04239.html Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution] Nature magazine presents a summary of what has been discovered in the [[Influenza Genome Sequencing Project]].</ref><ref>[http://content.nejm.org/cgi/content/full/353/13/1374 Avian Influenza A (H5N1) Infection in Humans] by The Writing Committee of the [[World Health Organization]] (WHO) Consultation on Human Influenza A/H5 in the September 29, 2005 [[New England Journal of Medicine]]</ref><ref>[http://darwin.nap.edu/books/0309095042/html The Threat of Pandemic Influenza: Are We Ready? Workshop Summary (2005)] Full text of online book by INSTITUTE OF MEDICINE OF THE NATIONAL ACADEMIES</ref><ref>[http://www.cdc.gov/ncidod/EID/vol11no10/05-0644-G1.htm] CDC has a [[phylogenetic tree]] showing the relationship between dozens of highly [[pathogenic]] varieties of the Z genotype of avian flu virus H5N1 and ancestral strains.</ref><ref>[http://vir.sgmjournals.org/cgi/content/full/81/5/1293 Evolutionary characterization of the six internal genes of H5N1 human influenza A virus]</ref>

"Bird flu" is a phrase similar to "Swine flu", "Dog flu", "Horse flu", or "[[Human flu]]" in that it refers to an illness caused by any of many different strains of influenza viruses that have adapted to a specific host. All known viruses that cause influenza in birds belong to the species: ''[[Influenzavirus A|Influenza A virus]]''. All subtypes (but not all strains of all subtypes) of Influenza A virus are adapted to birds, which is why for many purposes avian flu virus ''is'' the Influenza A virus (note that the "A" does ''not'' stand for "avian").

Adaption is non-exclusive. Being adapted towards a particular species does not preclude adaptions, or partial adaptions, towards infecting different species. In this way strains of influenza viruses are adapted to multiple species, though may be preferential towards a particular host. For example, viruses responsible for [[influenza pandemics]] are adapted to both humans and birds. Recent [[influenza research]] into the genes of the [[Spanish Flu]] virus shows it to have genes adapted to both birds and humans; with more of its genes from birds than less deadly later pandemic strains.

==Genetics==
Genetic factors in distinguishing between "[[human flu]] viruses" and "avian flu viruses" include:
:'''PB2''': ([[RNA polymerase]]): [[Amino acid]] (or [[residue]]) position 627 in the PB2 protein encoded by the PB2 [[RNA]] gene. Until [[H5N1]], all known avian influenza viruses had a [[Glutamic acid|Glu]] at position 627, while all human influenza viruses had a [[lysine]].
:'''HA''': ([[hemagglutinin]]): Avian influenza HA bind alpha 2-3 [[sialic acid]] receptors while human influenza HA bind alpha 2-6 sialic acid receptors. Swine influenza viruses have the ability to bind both types of sialic acid receptors.

==Influenza pandemic==
{{details more|Influenza pandemic}}
Pandemic flu viruses have some avian flu virus genes and usually some [[human flu]] virus genes. Both the [[H2N2]] and [[H3N2]] pandemic strains contained genes from avian influenza viruses. The new subtypes arose in pigs coinfected with avian and human viruses and were soon transferred to humans. Swine were considered the original "intermediate host" for influenza, because they supported reassortment of divergent subtypes. However, other hosts appear capable of similar coinfection (e.g., many poultry species), and direct transmission of avian viruses to humans is possible.<ref name=Blanchard>Blanchard, Ben. "China says son likely infected father with bird flu." Reuters 10 Jen 2008 10 Jen 2008 <http://www.reuters.com/article/healthNews/idUSPEK27288320080110>.</ref> The Spanish flu virus strain may have been transmitted directly from birds to humans.<ref>[http://www.influenzareport.com/ir/ai.htm Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner]</ref>

In spite of their pandemic connection, avian influenza viruses are noninfectious for most species. When they are infectious they are usually asymptomatic, so the carrier does not have any disease from it. Thus while infected with an avian flu virus, the animal doesn't have a "[[flu]]". Typically, when illness (called "flu") from an avian flu virus ''does'' occur, it is the result of an avian flu virus strain adapted to one species spreading to another species (usually from one bird species to another bird species). So far as is known, the most common result of this is an illness so minor as to be not worth noticing (and thus little studied). But with the domestication of chickens and turkeys, humans have created species subtypes (domesticated poultry) that can catch an avian flu virus adapted to waterfowl and have it rapidly mutate into a form that kills in days over 90% of an entire flock and spread to other flocks and kill 90% of ''them'' and can only be stopped by killing every domestic bird in the area. Until [[H5N1]] infected humans in the 1990s, this was the only reason avian flu was considered important. Since then, avian flu viruses have been intensively studied; resulting in changes in what is believed about flu pandemics, changes in poultry farming, changes in flu vaccination research, and changes in flu pandemic planning.

[[H5N1]] has evolved into a flu virus strain that infects more species than any previously known flu virus strain, is deadlier than any previously known flu virus strain, and continues to evolve becoming both more widespread and more deadly causing [[Robert Webster]], a leading expert on avian flu, to publish an article titled "The world is teetering on the edge of a pandemic that could kill a large fraction of the human population" in ''[[American Scientist]]''. He called for adequate resources to fight what he sees as a major world threat to possibly billions of lives.<ref name=webster>

{{cite journal
| author=[[Robert Webster|Webster, R. G.]] and Walker, E. J. | title=The world is teetering on the edge of a pandemic that could kill a large fraction of the human population | journal=American Scientist | year=2003 | pages=122 | volume=91 | issue=2 |url=http://www.americanscientist.org/template/AssetDetail/assetid/17221?fulltext=true | id={{DOI|10.1511/2003.2.122}}

}} </ref> Since the article was written, the world community has spent billions of dollars fighting this threat with limited success.

==H5N1==
{{H5N1}}
{{details more|H5N1|Transmission and infection of H5N1}}
The highly pathogenic Influenza A virus subtype [[H5N1]] virus is an emerging avian influenza virus that has been causing global concern as a potential [[pandemic]] threat. It is often referred to simply as "bird flu" or "avian influenza" even though it is only one subtype of avian influenza causing virus.

H5N1 has killed millions of poultry in a growing number of countries throughout Asia, Europe and Africa. Health experts are concerned that the co-existence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal to humans.<ref name=FSRIO>Food Safety Research Information Office. [http://fsrio.nal.usda.gov/document_fsheet.php?product_id=207 "A Focus on Avian Influenza"]. Created May 2006, Updated November 2007.</ref>

Since the first H5N1 outbreak occurred in 1997, there has been an increasing number of HPAI H5N1 bird-to-human transmissions leading to clinically severe and fatal human infections. However, because there is a significant species barrier that exists between birds and humans, the virus does not easily cross over to humans, though some cases of infection are being researched to discern whether human to human transmission is occurring.<ref name=Blanchard/> More research is necessary to understand the pathogenesis and epidemiology of the H5N1 virus in humans. Exposure routes and other disease transmission characteristics such as genetic and immunological factors, that may increase the likelihood of infection, are not clearly understood. <ref name=WHO>World Health Organization. (2006). [http://www.who.int/mediacentre/factsheets/avian_influenza/en/#humans Avian influenza (" bird flu") – The Disease in Humans.] Retrieved April 6, 2006.</ref>

Although millions of birds have become infected with the virus since its discovery, 206 humans have died from the H5N1 in twelve countries according to [[WHO]] data as of November 2007.
(View the most current WHO Data regarding [http://www.who.int/csr/disease/avian_influenza/country/en/ Cumulative Number of Human Cases].)

The Avian Flu claimed at least 200 humans in Romania, Greece, Turkey and Russia. Epidemioloigists are afraid that the next time such a virus mutates, it could pass from human to human. If this form of transmission occurs, another big pandemic could result. However, disease-control centers around the world are making avian flu their top priority.

==See also==
*[[H5N1]]
*[[Global spread of H5N1]]
*[[Transmission and infection of H5N1]]
*[[:Category:Subtypes of Influenza A virus|Subtypes of Influenza A virus]]
*[[Influenzavirus A]]
*[[Influenza pandemic]]
*[[Influenza Genome Sequencing Project]]
*[[Influenza research]]
*[[Influenza vaccine]]
*[[OIE/FAO Network of Expertise on Avian Influenza]]
*[[International Partnership on Avian and Pandemic Influenza]]
*[[Pandemic Preparedness and Response Act]]

==References==
{{reflist|2}}

==External links==
;International
;;World Health Organisation (WHO)
;*[http://www.who.int/csr/disease/avian_influenza/en/ WHO Avian influenza resource (updated)]
;*[http://www.who.int/csr/disease/avian_influenza/avianinfluenza_factsheetJan2006/en/index.html The United Nation's World Health Organization's Avian Flu Facts Sheet for 2006]
;;Food and Agriculture Organization of the UN (FAO)
;*[http://www.fao.org/ag/avian.html FAO Avian Influenza portal] Information resources, animations, videos, photos
;*[http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/avian.html FAO Bird Flu disease card]
;;World Organisation for Animal Health (OIE)
;*[http://www.oie.int/downld/AVIAN%20INFLUENZA/A_AI-Asia.htm Official outbreak reports by country]
;*[http://www.oie.int/eng/info/hebdo/a_isum.htm Official outbreak reports by week]

;United States
*[http://www.pandemicflu.gov PandemicFlu.Gov] U.S. Government avian and pandemic flu information
*[http://www.usaid.gov/our_work/global_health/home/News/news_items/avian_influenza.html US Avian Influenza Response] U.S. Agency for International Development (USAID)

;Europe
*[http://library.wur.nl/frontis/avian_influenza/ Avian Influenza: Prevention and Control] Proceedings of the Frontis workshop on Avian Influenza: Prevention and Control, Wageningen, The Netherlands

;Other
*[http://www.fluwikie.com/ Flu Wiki]
*[http://www.flupandemicalert.com Bird Flu Pandemic Alert and Breaking News]
*[http://declanbutler.info/blog/?p=58 The spread of avian flu with time; new maps exploiting Google Earth’s time series function] updated Google Earth maps of bird flu spread by [[Nature (journal)|Nature]] reporter Declan Butler
*[http://www.birdfluthreat.org/essentials/main_info.php birdfluthreat.org information page]

{{Influenza}}
{{Viral diseases}}

[[af:Voëlgriep]]
[[ar:إنفلونزا الطيور]]
[[zh-min-nan:Khîm-liû-kám]]
[[bg:Птичи грип]]
[[ca:Grip aviària]]
[[cs:Ptačí chřipka]]
[[cy:Ffliw adar]]
[[da:Fugleinfluenza]]
[[de:Vogelgrippe]]
[[es:Gripe aviaria]]
[[eo:Birda gripo]]
[[fr:Grippe aviaire]]
[[gl:Gripe aviaria]]
[[ko:조류 인플루엔자]]
[[hi:बर्ड फ़्लू]]
[[hr:Ptičja gripa]]
[[id:Flu burung]]
[[is:Fuglaflensa]]
[[it:Influenza aviaria]]
[[he:שפעת העופות]]
[[ku:Arsima balindeyan]]
[[ln:Gilípi ya ndɛkɛ]]
[[mk:Птичји грип]]
[[ms:Selsema burung]]
[[nl:Vogelpest]]
[[ja:トリインフルエンザ]]
[[no:Fugleinfluensa]]
[[nn:Fugleinfluensa]]
[[nds:Vagelgripp]]
[[pt:Gripe aviária]]
[[ro:Gripă aviară]]
[[ru:Птичий грипп]]
[[sq:Gripi i shpendëve]]
[[simple:Bird flu]]
[[sk:Vtáčia chrípka]]
[[sl:Ptičja gripa]]
[[sr:Птичји грип]]
[[fi:Lintuinfluenssa]]
[[sv:Fågelinfluensa]]
[[tl:Avian influenza]]
[[th:ไข้หวัดนก]]
[[vi:Cúm gia cầm]]
[[uk:Грип пташиний]]
[[wa:Pesse des oujheas]]
[[zh:禽流感]]
[[ta:பறவைக் காய்ச்சல்]]
[[te:బర్డ్ ఫ్లూ]]

{{SIB}}

[[Category:Occupational safety and health]]
[[Category:Bird diseases]]
[[Category:Avian influenza]]
[[Category:Infectious disease]]

[[pl:Ptasia grypa]]
[[tr:Kuş gribi]]
{{WikiDoc Help Menu}}
{{WikiDoc Sources}}

Avian influenza

2009-07-14T16:56:01Z

Michaelagibson:

{{flu}}
{{SI}}
__NOTOC__
{{CMG}}

{{Editor Help}}

For Patient Information on Avian Influenza (Bird Flu), click [[here|Avian Influenza Patient Information]]

:''For the H5N1 subtype of Avian influenza see [[H5N1]].''

'''Avian influenza''', sometimes '''Avian flu''', and commonly '''Bird flu''' refers to "[[influenza]] caused by [[virus]]es adapted to birds."<ref name=ECDPC> "Avian influenza strains are those well adapted to birds"[http://72.14.207.104/search?q=cache:72mkmIQKbIQJ:www.ecdc.eu.int/documents/AF050930/AF3_13_Actions_taked_in_connection_with_Avian_Flu.doc+%22Avian+influenza%22+%22adapted+to+birds%22&hl=en&gl=us&ct=clnk&cd=3 EUROPEAN CENTRE FOR DISEASE PREVENTION AND CONTROL]. </ref><ref name=influenzareport> [http://www.influenzareport.com/ir/ai.htm Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner] in ''Influenza Report 2006''</ref><ref>[http://www.nature.com/nature/journal/v437/n7062/full/nature04239.html Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution] Nature magazine presents a summary of what has been discovered in the [[Influenza Genome Sequencing Project]].</ref><ref>[http://content.nejm.org/cgi/content/full/353/13/1374 Avian Influenza A (H5N1) Infection in Humans] by The Writing Committee of the [[World Health Organization]] (WHO) Consultation on Human Influenza A/H5 in the September 29, 2005 [[New England Journal of Medicine]]</ref><ref>[http://darwin.nap.edu/books/0309095042/html The Threat of Pandemic Influenza: Are We Ready? Workshop Summary (2005)] Full text of online book by INSTITUTE OF MEDICINE OF THE NATIONAL ACADEMIES</ref><ref>[http://www.cdc.gov/ncidod/EID/vol11no10/05-0644-G1.htm] CDC has a [[phylogenetic tree]] showing the relationship between dozens of highly [[pathogenic]] varieties of the Z genotype of avian flu virus H5N1 and ancestral strains.</ref><ref>[http://vir.sgmjournals.org/cgi/content/full/81/5/1293 Evolutionary characterization of the six internal genes of H5N1 human influenza A virus]</ref>

"Bird flu" is a phrase similar to "Swine flu", "Dog flu", "Horse flu", or "[[Human flu]]" in that it refers to an illness caused by any of many different strains of influenza viruses that have adapted to a specific host. All known viruses that cause influenza in birds belong to the species: ''[[Influenzavirus A|Influenza A virus]]''. All subtypes (but not all strains of all subtypes) of Influenza A virus are adapted to birds, which is why for many purposes avian flu virus ''is'' the Influenza A virus (note that the "A" does ''not'' stand for "avian").

Adaption is non-exclusive. Being adapted towards a particular species does not preclude adaptions, or partial adaptions, towards infecting different species. In this way strains of influenza viruses are adapted to multiple species, though may be preferential towards a particular host. For example, viruses responsible for [[influenza pandemics]] are adapted to both humans and birds. Recent [[influenza research]] into the genes of the [[Spanish Flu]] virus shows it to have genes adapted to both birds and humans; with more of its genes from birds than less deadly later pandemic strains.

==Genetics==
Genetic factors in distinguishing between "[[human flu]] viruses" and "avian flu viruses" include:
:'''PB2''': ([[RNA polymerase]]): [[Amino acid]] (or [[residue]]) position 627 in the PB2 protein encoded by the PB2 [[RNA]] gene. Until [[H5N1]], all known avian influenza viruses had a [[Glutamic acid|Glu]] at position 627, while all human influenza viruses had a [[lysine]].
:'''HA''': ([[hemagglutinin]]): Avian influenza HA bind alpha 2-3 [[sialic acid]] receptors while human influenza HA bind alpha 2-6 sialic acid receptors. Swine influenza viruses have the ability to bind both types of sialic acid receptors.

==Influenza pandemic==
{{details more|Influenza pandemic}}
Pandemic flu viruses have some avian flu virus genes and usually some [[human flu]] virus genes. Both the [[H2N2]] and [[H3N2]] pandemic strains contained genes from avian influenza viruses. The new subtypes arose in pigs coinfected with avian and human viruses and were soon transferred to humans. Swine were considered the original "intermediate host" for influenza, because they supported reassortment of divergent subtypes. However, other hosts appear capable of similar coinfection (e.g., many poultry species), and direct transmission of avian viruses to humans is possible.<ref name=Blanchard>Blanchard, Ben. "China says son likely infected father with bird flu." Reuters 10 Jen 2008 10 Jen 2008 <http://www.reuters.com/article/healthNews/idUSPEK27288320080110>.</ref> The Spanish flu virus strain may have been transmitted directly from birds to humans.<ref>[http://www.influenzareport.com/ir/ai.htm Chapter Two : Avian Influenza by Timm C. Harder and Ortrud Werner]</ref>

In spite of their pandemic connection, avian influenza viruses are noninfectious for most species. When they are infectious they are usually asymptomatic, so the carrier does not have any disease from it. Thus while infected with an avian flu virus, the animal doesn't have a "[[flu]]". Typically, when illness (called "flu") from an avian flu virus ''does'' occur, it is the result of an avian flu virus strain adapted to one species spreading to another species (usually from one bird species to another bird species). So far as is known, the most common result of this is an illness so minor as to be not worth noticing (and thus little studied). But with the domestication of chickens and turkeys, humans have created species subtypes (domesticated poultry) that can catch an avian flu virus adapted to waterfowl and have it rapidly mutate into a form that kills in days over 90% of an entire flock and spread to other flocks and kill 90% of ''them'' and can only be stopped by killing every domestic bird in the area. Until [[H5N1]] infected humans in the 1990s, this was the only reason avian flu was considered important. Since then, avian flu viruses have been intensively studied; resulting in changes in what is believed about flu pandemics, changes in poultry farming, changes in flu vaccination research, and changes in flu pandemic planning.

[[H5N1]] has evolved into a flu virus strain that infects more species than any previously known flu virus strain, is deadlier than any previously known flu virus strain, and continues to evolve becoming both more widespread and more deadly causing [[Robert Webster]], a leading expert on avian flu, to publish an article titled "The world is teetering on the edge of a pandemic that could kill a large fraction of the human population" in ''[[American Scientist]]''. He called for adequate resources to fight what he sees as a major world threat to possibly billions of lives.<ref name=webster>

{{cite journal
| author=[[Robert Webster|Webster, R. G.]] and Walker, E. J. | title=The world is teetering on the edge of a pandemic that could kill a large fraction of the human population | journal=American Scientist | year=2003 | pages=122 | volume=91 | issue=2 |url=http://www.americanscientist.org/template/AssetDetail/assetid/17221?fulltext=true | id={{DOI|10.1511/2003.2.122}}

}} </ref> Since the article was written, the world community has spent billions of dollars fighting this threat with limited success.

==H5N1==
{{H5N1}}
{{details more|H5N1|Transmission and infection of H5N1}}
The highly pathogenic Influenza A virus subtype [[H5N1]] virus is an emerging avian influenza virus that has been causing global concern as a potential [[pandemic]] threat. It is often referred to simply as "bird flu" or "avian influenza" even though it is only one subtype of avian influenza causing virus.

H5N1 has killed millions of poultry in a growing number of countries throughout Asia, Europe and Africa. Health experts are concerned that the co-existence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal to humans.<ref name=FSRIO>Food Safety Research Information Office. [http://fsrio.nal.usda.gov/document_fsheet.php?product_id=207 "A Focus on Avian Influenza"]. Created May 2006, Updated November 2007.</ref>

Since the first H5N1 outbreak occurred in 1997, there has been an increasing number of HPAI H5N1 bird-to-human transmissions leading to clinically severe and fatal human infections. However, because there is a significant species barrier that exists between birds and humans, the virus does not easily cross over to humans, though some cases of infection are being researched to discern whether human to human transmission is occurring.<ref name=Blanchard/> More research is necessary to understand the pathogenesis and epidemiology of the H5N1 virus in humans. Exposure routes and other disease transmission characteristics such as genetic and immunological factors, that may increase the likelihood of infection, are not clearly understood. <ref name=WHO>World Health Organization. (2006). [http://www.who.int/mediacentre/factsheets/avian_influenza/en/#humans Avian influenza (" bird flu") – The Disease in Humans.] Retrieved April 6, 2006.</ref>

Although millions of birds have become infected with the virus since its discovery, 206 humans have died from the H5N1 in twelve countries according to [[WHO]] data as of November 2007.
(View the most current WHO Data regarding [http://www.who.int/csr/disease/avian_influenza/country/en/ Cumulative Number of Human Cases].)

The Avian Flu claimed at least 200 humans in Romania, Greece, Turkey and Russia. Epidemioloigists are afraid that the next time such a virus mutates, it could pass from human to human. If this form of transmission occurs, another big pandemic could result. However, disease-control centers around the world are making avian flu their top priority.

==See also==
*[[H5N1]]
*[[Global spread of H5N1]]
*[[Transmission and infection of H5N1]]
*[[:Category:Subtypes of Influenza A virus|Subtypes of Influenza A virus]]
*[[Influenzavirus A]]
*[[Influenza pandemic]]
*[[Influenza Genome Sequencing Project]]
*[[Influenza research]]
*[[Influenza vaccine]]
*[[OIE/FAO Network of Expertise on Avian Influenza]]
*[[International Partnership on Avian and Pandemic Influenza]]
*[[Pandemic Preparedness and Response Act]]

==References==
{{reflist|2}}

==External links==
;International
;;World Health Organisation (WHO)
;*[http://www.who.int/csr/disease/avian_influenza/en/ WHO Avian influenza resource (updated)]
;*[http://www.who.int/csr/disease/avian_influenza/avianinfluenza_factsheetJan2006/en/index.html The United Nation's World Health Organization's Avian Flu Facts Sheet for 2006]
;;Food and Agriculture Organization of the UN (FAO)
;*[http://www.fao.org/ag/avian.html FAO Avian Influenza portal] Information resources, animations, videos, photos
;*[http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/avian.html FAO Bird Flu disease card]
;;World Organisation for Animal Health (OIE)
;*[http://www.oie.int/downld/AVIAN%20INFLUENZA/A_AI-Asia.htm Official outbreak reports by country]
;*[http://www.oie.int/eng/info/hebdo/a_isum.htm Official outbreak reports by week]

;United States
*[http://www.pandemicflu.gov PandemicFlu.Gov] U.S. Government avian and pandemic flu information
*[http://www.usaid.gov/our_work/global_health/home/News/news_items/avian_influenza.html US Avian Influenza Response] U.S. Agency for International Development (USAID)

;Europe
*[http://library.wur.nl/frontis/avian_influenza/ Avian Influenza: Prevention and Control] Proceedings of the Frontis workshop on Avian Influenza: Prevention and Control, Wageningen, The Netherlands

;Other
*[http://www.fluwikie.com/ Flu Wiki]
*[http://www.flupandemicalert.com Bird Flu Pandemic Alert and Breaking News]
*[http://declanbutler.info/blog/?p=58 The spread of avian flu with time; new maps exploiting Google Earth’s time series function] updated Google Earth maps of bird flu spread by [[Nature (journal)|Nature]] reporter Declan Butler
*[http://www.birdfluthreat.org/essentials/main_info.php birdfluthreat.org information page]

{{Influenza}}
{{Viral diseases}}

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Template:WikiPatient - Patient Resources

2009-07-07T22:25:28Z

Michaelagibson:

Template:WikiPatient - Patient Resources

2009-07-07T22:23:09Z

Michaelagibson:

Leukemia Patient Information

2009-07-07T22:18:09Z

Michaelagibson: Leukemia Patient Information moved to Leukemia (Patient Information)

#REDIRECT [[Leukemia (Patient Information)]]

Leukemia (patient information)

2009-07-07T22:18:09Z

Michaelagibson: Leukemia Patient Information moved to Leukemia (Patient Information)

{{MAG}}

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

'''Common symptoms''' of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

'''Radiation Therapy:'''

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation therapy]]

'''Chemotherapy:'''

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

'''Biological Therapy:'''

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

'''Targeted Therapy:'''

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

'''Stem Cell Transplant:'''

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

''Physical exam:'' Your doctor checks for swollen lymph nodes, spleen, or liver.

''Blood tests:'' The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

''Biopsy:'' Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

''Cytogenetics:'' The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

''Spinal tap:'' Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

''Chest x-ray:'' An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

====Where to Get Medical Care====
[http://maps.google.com/maps?f=q&hl=en&geocode=&q={{urlencode:{{#if:{{{1|}}}|{{{1}}}|Leukemia}}}}&sll=37.0625,-95.677068&sspn=65.008093,112.148438&ie=UTF8&ll=37.0625,-95.677068&spn=91.690419,149.414063&z=2&source=embed Directions to Hospitals Treating Leukemia]

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]

[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]

[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

{{WH}}
{{WS}}

AIDS Patient Information

2009-07-07T22:17:08Z

Michaelagibson: AIDS Patient Information moved to AIDS (Patient Information)

#REDIRECT [[AIDS (Patient Information)]]

AIDS (patient information)

2009-07-07T22:17:08Z

Michaelagibson: AIDS Patient Information moved to AIDS (Patient Information)

{{MAG}}

==What is AIDS?==
AIDS - The '''A'''cquired '''I'''mmuno'''d'''eficiency '''S'''yndrome - is a disease you get when HIV destroys your body’s immune system. Normally, your immune system helps you fight off illness. When your immune system fails you can become very sick and can die.
HIV - The '''H'''uman '''I'''mmunodeficiency '''V'''irus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body fight off infection and disease.
===What is the Difference Between AIDS and HIV?===
AIDS is the disease which results from HIV's destruction of the T-helper cells. The HIV virus causes AIDS.

===Symptoms===
The symptoms of AIDS are primarily the result of infections that do not normally develop in individuals with healthy immune systems. These are called opportunistic infections.

People with AIDS have had their immune system weakened by HIV and are very susceptible to these opportunistic infections. Common symptoms are fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss.

Note: Initial infection with HIV can produce no symptoms. Some people, however, do experience flu-like symptoms with fever, rash, sore throat, and swollen lymph nodes, usually 2 weeks after contracting the virus. Some people with HIV infection remain without symptoms for years between the time the are exposed to the virus and when they develop AIDS

===How HIV/AIDS Is Spread===
Anyone can get HIV. The most important thing to know is how you can get the virus.

You '''can''' get HIV:

-By having unprotected sex- sex without a condom- with someone who has HIV. The virus can be in an infected person’s blood, semen, or vaginal secretions and can enter your body through tiny cuts or sores in your skin, or in the lining of your vagina, penis, rectum, or mouth.

-By sharing a needle and syringe to inject drugs or sharing drug equipment used to prepare drugs for injection with someone who has HIV.

-From a blood transfusion or blood clotting factor that you got before 1985. (But today it is unlikely you could get infected that way because all blood in the United States has been tested for HIV since 1985.)

-Babies born to women with HIV also can become infected during pregnancy, birth, or breast-feeding.

You '''cannot''' get HIV:

-By working with or being around someone who has HIV.

-From sweat, spit, tears, clothes, drinking fountains, phones, toilet seats, or through everyday things like sharing a meal.

-From insect bites or stings.

-From donating blood.

-From a closed-mouth kiss (but there is a very small chance of getting it from open-mouthed or "French" kissing with an infected person because of possible blood contact).

==Treatment Options==
There is no cure for HIV. It is a lifelong condition. Although HIV is a very serious infection, many people with HIV and AIDS are living longer, healthier lives today, thanks to new and effective treatments. It is very important to make sure you have a doctor who knows how to treat HIV. If you don’t know which doctor to use, talk with a health care professional or trained HIV counselor. If you are pregnant or are planning to become pregnant, this is especially important.

There also are other things you can do for yourself to stay healthy. Here are a few:
-Follow your doctor’s instructions. Keep your appointments. Your doctor may prescribe medicine for you. Take the medicine just the way he or she tells you to because taking only some of your medicine gives your HIV infection more chance to grow.
-Get immunizations (shots) to prevent infections such as pneumonia and flu. Your doctor will tell you when to get these shots.
-If you smoke or if you use drugs not prescribed by your doctor, quit.
-Eat healthy foods. This will help keep you strong, keep your energy and weight up, and help your body protect itself.
-Exercise regularly to stay strong and fit.
-Get enough sleep and rest.

===How to know you have AIDS (Diagnosis)===
You might have HIV and still feel perfectly healthy. The only way to know for sure if you are infected or not is to be tested. Talk with a knowledgeable health care provider or counselor both before and after you are tested. You can go to your doctor or health department for testing. To find out where to go in your area for HIV counseling and testing, call your local health department or the CDC INFO, at 1-800-CDC-INFO (232-4636).

Your doctor or health care provider can give you a confidential HIV test. The information on your HIV test and test results are confidential, as is your other medical information. This means it can be shared only with people authorized to see your medical records. You can ask your doctor, health care provider, or HIV counselor at the place you are tested to explain who can obtain this information. For example, you may want to ask whether your insurance company could find out your HIV status if you make a claim for health insurance benefits or apply for life insurance or disability insurance.

The CDC recommends that everyone know their HIV status. How often you should an HIV test depends on your circumstances. If you have never been tested for HIV, you should be tested. If you have high-risk behaviors, then you should get tested more often. The CDC recommends testing once a year for people with high risk behaviors.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===
SInce HIV weakens the immune system, people with AIDS should be consult with a doctor and get tested if they believe they have it. If you are diagnosed with AIDS, you should be in constant contact with your doctor. People with AIDS are susceptible to infections and cancers that most healthy adults would not get and so they must be very aware of any new diseases which their bodies acquire, and report them to their physicians as they occur.

==Prevention==
-Don’t share needles and syringes used to inject drugs, steroids, vitamins, or for tattooing or body piercing. Also, don’t share equipment ("works") used to prepare drugs to be injected. Many people have been infected with HIV, hepatitis, and other germs this way. Germs from an infected person can stay in a needle and then be injected directly into the next person who uses the needle.
-The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a longterm mutually monogamous relationship with a partner who has been tested and you know is uninfected.
-For persons whose sexual behaviors place them at risk for STDs, correct and consistent use of the male latex condom can reduce the risk of STD transmission. However, no protective method is 100 percent effective, and condom use cannot guarantee absolute protection against any STD. The more sex partners you have, the greater your chances are of getting HIV or other diseases passed through sex.
-Condoms used with a lubricant are less likely to break. However, condoms with the spermicide nonoxynol-9 are not recommended for STD/HIV prevention. Condoms must be used correctly and consistently to be effective and protective. Incorrect use can lead to condom slippage or breakage, thus diminishing the protective effect. Inconsistent use, e.g., failure to use condoms with every act of intercourse, can result in STD transmission because transmission can occur with a single act of intercourse.
-Don’t share razors or toothbrushes because of they may have the blood of another person on them.
-If you are pregnant or think you might be soon, talk to a doctor or your local health department about being tested for HIV. If you share HIV, drug treatments are available to help you and they can reduce the chance of passing HIV to your baby.

==What to Expect (Outook/Prognosis)==
Right now, there is no cure for AIDS. It is always fatal if no treatment is provided. In the US, most patients survive many years after diagnosis because of the availability of medicines such as HAART. HAART and medicines like it have dramatically increased the amount of time people with HIV remain alive.

Research continues in the areas of drug treatments and vaccine development. Unfortunately, HIV medications are not always available in the developing world, where the bulk of cases now occur.

==Copyleft Sources==
http://www.cdc.gov/hiv/resources/brochures/at-risk.htm

http://www.nlm.nih.gov/medlineplus/ency/article/000594.htm

{{WH}}

{{WS}}

AIDS (patient information)

2009-07-07T22:16:37Z

Michaelagibson:

Leukemia (patient information)

2009-07-07T22:10:48Z

Michaelagibson:

Leukemia (patient information)

2009-07-07T22:06:17Z

Michaelagibson:

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

'''Common symptoms''' of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

'''Radiation Therapy:'''

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation therapy]]

'''Chemotherapy:'''

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

'''Biological Therapy:'''

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

'''Targeted Therapy:'''

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

'''Stem Cell Transplant:'''

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

''Physical exam:'' Your doctor checks for swollen lymph nodes, spleen, or liver.

''Blood tests:'' The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

''Biopsy:'' Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

''Cytogenetics:'' The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

''Spinal tap:'' Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

''Chest x-ray:'' An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

====Where to Get Medical Care====
[http://maps.google.com/maps?f=q&hl=en&geocode=&q={{urlencode:{{#if:{{{1|}}}|{{{1}}}|Leukemia}}}&sll=37.0625,-95.677068&sspn=65.008093,112.148438&ie=UTF8&ll=37.0625,-95.677068&spn=91.690419,149.414063&z=2&source=embed Directions to Hospitals Treating Leukemia]

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]

[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]

[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

{{WH}}
{{WS}}

Leukemia (patient information)

2009-07-07T21:57:03Z

Michaelagibson:

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

'''Common symptoms''' of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

'''Radiation Therapy:'''

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation therapy]]

'''Chemotherapy:'''

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

'''Biological Therapy:'''

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

'''Targeted Therapy:'''

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

'''Stem Cell Transplant:'''

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

''Physical exam:'' Your doctor checks for swollen lymph nodes, spleen, or liver.

''Blood tests:'' The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

''Biopsy:'' Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

''Cytogenetics:'' The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

''Spinal tap:'' Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

''Chest x-ray:'' An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

====Where to Get Medical Care====
[http://maps.google.com/maps?f=q&hl=en&geocode=&q={{urlencode:{{#if:{{{1|}}}|{{{1}}}|Leukemia}}}&sll=37.0625,-95.677068&sspn=65.008093,112.148438&ie=UTF8&ll=37.0625,-95.677068&spn=91.690419,149.414063&z=2&source=embed Directions to Hospitals Treating Leukemia]

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]
[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]
[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

Leukemia (patient information)

2009-07-07T21:54:33Z

Michaelagibson:

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

'''Common symptoms''' of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

'''Radiation Therapy:'''

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation therapy]]

'''Chemotherapy:'''

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

'''Biological Therapy:'''

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

'''Targeted Therapy:'''

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

'''Stem Cell Transplant:'''

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

''Physical exam:'' Your doctor checks for swollen lymph nodes, spleen, or liver.

''Blood tests:'' The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

''Biopsy:'' Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

''Cytogenetics:'' The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

''Spinal tap:'' Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

''Chest x-ray:'' An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

====Where to Get Medical Care====
[http://maps.google.com/maps?f=q&hl=en&geocode=&q={{urlencode:{{#if:{{{1|}}}|{{{1}}}|{{Leukemia}}}}}&sll=37.0625,-95.677068&sspn=65.008093,112.148438&ie=UTF8&ll=37.0625,-95.677068&spn=91.690419,149.414063&z=2&source=embed Directions to Hospitals Treating {{Leukemia}}]

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]
[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]
[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

Leukemia (patient information)

2009-07-07T21:52:51Z

Michaelagibson:

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

'''Common symptoms''' of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

'''Radiation Therapy:'''

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation therapy]]

'''Chemotherapy:'''

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

'''Biological Therapy:'''

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

'''Targeted Therapy:'''

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

'''Stem Cell Transplant:'''

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

''Physical exam:'' Your doctor checks for swollen lymph nodes, spleen, or liver.

''Blood tests:'' The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

''Biopsy:'' Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

''Cytogenetics:'' The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

''Spinal tap:'' Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

''Chest x-ray:'' An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

====Where to Get Medical Care====
[http://maps.google.com/maps?f=q&hl=en&geocode=&q={{urlencode:{{#if:{{{1|}}}|{{{1}}}|{{PAGENAME}}}}}}&sll=37.0625,-95.677068&sspn=65.008093,112.148438&ie=UTF8&ll=37.0625,-95.677068&spn=91.690419,149.414063&z=2&source=embed Directions to Hospitals Treating {{PAGENAME}}]

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]
[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]
[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

Template:WikiPatient - Patient Resources

2009-07-07T21:50:38Z

Michaelagibson:

Leukemia (patient information)

2009-07-07T21:46:46Z

Michaelagibson:

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

'''Common symptoms''' of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

'''Radiation Therapy:'''

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation therapy]]

'''Chemotherapy:'''

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

'''Biological Therapy:'''

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

'''Targeted Therapy:'''

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

'''Stem Cell Transplant:'''

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

''Physical exam:'' Your doctor checks for swollen lymph nodes, spleen, or liver.

''Blood tests:'' The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

''Biopsy:'' Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

''Cytogenetics:'' The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

''Spinal tap:'' Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

''Chest x-ray:'' An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]
[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]
[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

Leukemia (patient information)

2009-07-07T21:43:47Z

Michaelagibson:

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

Common symptoms of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

Radiation Therapy:

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation therapy]]

Chemotherapy:

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

Biological Therapy:

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

Targeted Therapy:

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

Stem Cell Transplant:

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

Physical exam: Your doctor checks for swollen lymph nodes, spleen, or liver.

Blood tests: The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

Biopsy: Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

Cytogenetics: The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

Spinal tap: Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

Chest x-ray: An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]
[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]
[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

Leukemia (patient information)

2009-07-07T21:42:14Z

Michaelagibson:

==What is Leukemia?==
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form. Most blood cells develop from cells in the bone marrow called stem cells. Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a special job:
White blood cells help fight infection. There are several types of white blood cells.
Red blood cells carry oxygen to tissues throughout the body.
Platelets help form blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as the body needs them. When cells grow old or get damaged, they die, and new cells take their place.

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells. Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
===Types of Leukemia===

The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):

''Chronic leukemia'': Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup - before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.

''Acute leukemia'': The leukemia cells can't do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.

The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. See the picture of these cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.

There are four common types of leukemia:

''Chronic lymphocytic leukemia (CLL)'': CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.

''Chronic myeloid leukemia (CML)'': CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.

''Acute lymphocytic (lymphoblastic) leukemia (ALL)'': ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.

''Acute myeloid leukemia (AML)'': AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.

===Symptoms===

Like all blood cells, leukemia cells travel through the body. The symptoms of leukemia depend on the number of leukemia cells and where these cells collect in the body.

People with chronic leukemia may not have symptoms. The doctor may find the disease during a routine blood test.

People with acute leukemia usually go to their doctor because they feel sick. If the brain is affected, they may have headaches, vomiting, confusion, loss of muscle control, or seizures. Leukemia also can affect other parts of the body such as the digestive tract, kidneys, lungs, heart, or testes.

Common symptoms of chronic or acute leukemia may include:

-Swollen lymph nodes that usually don't hurt (especially lymph nodes in the neck or armpit)

-Fevers or night sweats

-Frequent infections

-Feeling weak or tired

-Bleeding and bruising easily (bleeding gums, purplish patches in the skin, or tiny red spots under the skin)

-Swelling or discomfort in the abdomen (from a swollen spleen or liver)

-Weight loss for no known reason

-Pain in the bones or joints

==Treatment Options==
Unlike other types of cancer, leukemia isn't a tumor that your doctor can surgically remove. Leukemia cells are produced in the bone marrow and travel throughout the body.
There are several treatment options for leukemia. Every treatment option has side effects and drawbacks. Be sure to consult with your doctor about which one is right for you.

Radiation Therapy:

Radiation therapy (also called radiotherapy) uses high-energy rays to kill leukemia cells. People receive radiation therapy at a hospital or clinic. Some people receive radiation from a large machine that is aimed at the spleen, the brain, or other parts of the body where leukemia cells have collected. For more information see [[Radiation Therapy]]

Chemotherapy:

Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells. For more information see [[Chemotherapy]].

Biological Therapy:

Biological therapy uses special substances that improve the body's natural defenses against cancer. Some patients with chronic lymphocytic leukemia receive monoclonal antibodies, which are man-made proteins that can identify leukemia cells. Monoclonal antibodies bind to the cells and assist the body in killing them.

Targeted Therapy:

People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy.Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.

Stem Cell Transplant:

Some people with leukemia receive a stem cell transplant. A stem cell transplant allows you to be treated with high doses of drugs, radiation, or both. The high doses destroy both leukemia cells and normal blood cells in the bone marrow. After you receive highdose chemotherapy, radiation therapy, or both, you receive healthy stem cells through a large vein. (It's like getting a blood transfusion.) New blood cells develop from the transplanted stem cells. The new blood cells replace the ones that were destroyed by treatment.

===How to know you have Leukemia (Diagnosis)===
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what's causing the problems. Your doctor may ask about your personal and family medical history.

You may have one or more of the following tests:

Physical exam: Your doctor checks for swollen lymph nodes, spleen, or liver.

Blood tests: The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.

Biopsy: Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.

The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other, less common tests:

Cytogenetics: The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.

Spinal tap: Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.

Chest x-ray: An x-ray can show swollen lymph nodes or other signs of disease in your chest.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

==Prevention==

There are certain activities and events which can lead to an increased risk for leukemia. Try to avoid:

-Smoking

-Exposure to the chemical Benzene

-Exposure to large amounts of radiation

Other factors that point to a higher risk for leukemia include:
-Chemotherapy
-Down syndrome and certain other inherited diseases
-Myelodysplastic syndrome and certain other blood disorders
-Family history of leukemia
-Infection with the Human T-cell leukemia virus type I (HTLV-I)

==What to Expect (Outook/Prognosis)==
Leukemia is a very serious disease which can have many complications. Complications can come from the disease itself and the treatments. Acute leukemia has a much quicker and more dramatic onset, but can sometimes be cured. Chronic Leukiemia has a slower onset and can often be put off for years. However, chronic leukemia is very rarely cured.

==Copyleft Sources==
[http://nihseniorhealth.gov/leukemia/whatisleukemia/01.htm]
[http://www.cancer.gov/cancertopics/wyntk/leukemia/page1]
[http://www.nlm.nih.gov/medlineplus/leukemiaadultacute.html]

AIDS (patient information)

2009-07-07T20:34:30Z

Michaelagibson:

==What is AIDS?==
AIDS - The '''A'''cquired '''I'''mmuno'''d'''eficiency '''S'''yndrome - is a disease you get when HIV destroys your body’s immune system. Normally, your immune system helps you fight off illness. When your immune system fails you can become very sick and can die.
HIV - The '''H'''uman '''I'''mmunodeficiency '''V'''irus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body fight off infection and disease.
===What is the Difference Between AIDS and HIV?===
AIDS is the disease which results from HIV's destruction of the T-helper cells. The HIV virus causes AIDS.

===Symptoms===
The symptoms of AIDS are primarily the result of infections that do not normally develop in individuals with healthy immune systems. These are called opportunistic infections.

People with AIDS have had their immune system weakened by HIV and are very susceptible to these opportunistic infections. Common symptoms are fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss.

Note: Initial infection with HIV can produce no symptoms. Some people, however, do experience flu-like symptoms with fever, rash, sore throat, and swollen lymph nodes, usually 2 weeks after contracting the virus. Some people with HIV infection remain without symptoms for years between the time the are exposed to the virus and when they develop AIDS

===How HIV/AIDS Is Spread===
Anyone can get HIV. The most important thing to know is how you can get the virus.

You '''can''' get HIV:

-By having unprotected sex- sex without a condom- with someone who has HIV. The virus can be in an infected person’s blood, semen, or vaginal secretions and can enter your body through tiny cuts or sores in your skin, or in the lining of your vagina, penis, rectum, or mouth.

-By sharing a needle and syringe to inject drugs or sharing drug equipment used to prepare drugs for injection with someone who has HIV.

-From a blood transfusion or blood clotting factor that you got before 1985. (But today it is unlikely you could get infected that way because all blood in the United States has been tested for HIV since 1985.)

-Babies born to women with HIV also can become infected during pregnancy, birth, or breast-feeding.

You '''cannot''' get HIV:

-By working with or being around someone who has HIV.

-From sweat, spit, tears, clothes, drinking fountains, phones, toilet seats, or through everyday things like sharing a meal.

-From insect bites or stings.

-From donating blood.

-From a closed-mouth kiss (but there is a very small chance of getting it from open-mouthed or "French" kissing with an infected person because of possible blood contact).

==Treatment Options==
There is no cure for HIV. It is a lifelong condition. Although HIV is a very serious infection, many people with HIV and AIDS are living longer, healthier lives today, thanks to new and effective treatments. It is very important to make sure you have a doctor who knows how to treat HIV. If you don’t know which doctor to use, talk with a health care professional or trained HIV counselor. If you are pregnant or are planning to become pregnant, this is especially important.

There also are other things you can do for yourself to stay healthy. Here are a few:
-Follow your doctor’s instructions. Keep your appointments. Your doctor may prescribe medicine for you. Take the medicine just the way he or she tells you to because taking only some of your medicine gives your HIV infection more chance to grow.
-Get immunizations (shots) to prevent infections such as pneumonia and flu. Your doctor will tell you when to get these shots.
-If you smoke or if you use drugs not prescribed by your doctor, quit.
-Eat healthy foods. This will help keep you strong, keep your energy and weight up, and help your body protect itself.
-Exercise regularly to stay strong and fit.
-Get enough sleep and rest.

===How to know you have AIDS (Diagnosis)===
You might have HIV and still feel perfectly healthy. The only way to know for sure if you are infected or not is to be tested. Talk with a knowledgeable health care provider or counselor both before and after you are tested. You can go to your doctor or health department for testing. To find out where to go in your area for HIV counseling and testing, call your local health department or the CDC INFO, at 1-800-CDC-INFO (232-4636).

Your doctor or health care provider can give you a confidential HIV test. The information on your HIV test and test results are confidential, as is your other medical information. This means it can be shared only with people authorized to see your medical records. You can ask your doctor, health care provider, or HIV counselor at the place you are tested to explain who can obtain this information. For example, you may want to ask whether your insurance company could find out your HIV status if you make a claim for health insurance benefits or apply for life insurance or disability insurance.

The CDC recommends that everyone know their HIV status. How often you should an HIV test depends on your circumstances. If you have never been tested for HIV, you should be tested. If you have high-risk behaviors, then you should get tested more often. The CDC recommends testing once a year for people with high risk behaviors.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===
SInce HIV weakens the immune system, people with AIDS should be consult with a doctor and get tested if they believe they have it. If you are diagnosed with AIDS, you should be in constant contact with your doctor. People with AIDS are susceptible to infections and cancers that most healthy adults would not get and so they must be very aware of any new diseases which their bodies acquire, and report them to their physicians as they occur.

==Prevention==
-Don’t share needles and syringes used to inject drugs, steroids, vitamins, or for tattooing or body piercing. Also, don’t share equipment ("works") used to prepare drugs to be injected. Many people have been infected with HIV, hepatitis, and other germs this way. Germs from an infected person can stay in a needle and then be injected directly into the next person who uses the needle.
-The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a longterm mutually monogamous relationship with a partner who has been tested and you know is uninfected.
-For persons whose sexual behaviors place them at risk for STDs, correct and consistent use of the male latex condom can reduce the risk of STD transmission. However, no protective method is 100 percent effective, and condom use cannot guarantee absolute protection against any STD. The more sex partners you have, the greater your chances are of getting HIV or other diseases passed through sex.
-Condoms used with a lubricant are less likely to break. However, condoms with the spermicide nonoxynol-9 are not recommended for STD/HIV prevention. Condoms must be used correctly and consistently to be effective and protective. Incorrect use can lead to condom slippage or breakage, thus diminishing the protective effect. Inconsistent use, e.g., failure to use condoms with every act of intercourse, can result in STD transmission because transmission can occur with a single act of intercourse.
-Don’t share razors or toothbrushes because of they may have the blood of another person on them.
-If you are pregnant or think you might be soon, talk to a doctor or your local health department about being tested for HIV. If you share HIV, drug treatments are available to help you and they can reduce the chance of passing HIV to your baby.

==What to Expect (Outook/Prognosis)==
Right now, there is no cure for AIDS. It is always fatal if no treatment is provided. In the US, most patients survive many years after diagnosis because of the availability of medicines such as HAART. HAART and medicines like it have dramatically increased the amount of time people with HIV remain alive.

Research continues in the areas of drug treatments and vaccine development. Unfortunately, HIV medications are not always available in the developing world, where the bulk of cases now occur.

==Copyleft Sources==
http://www.cdc.gov/hiv/resources/brochures/at-risk.htm
http://www.nlm.nih.gov/medlineplus/ency/article/000594.htm

AIDS (patient information)

2009-07-07T20:31:30Z

Michaelagibson:

==What is AIDS?==
AIDS - The '''A'''cquired '''I'''mmuno'''d'''eficiency '''S'''yndrome - is a disease you get when HIV destroys your body’s immune system. Normally, your immune system helps you fight off illness. When your immune system fails you can become very sick and can die.
HIV - The '''H'''uman '''I'''mmunodeficiency '''V'''irus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body fight off infection and disease.
===What is the Difference Between AIDS and HIV?===
AIDS is the disease which results from HIV's destruction of the T-helper cells. The HIV virus causes AIDS.

===Symptoms===
The symptoms of AIDS are primarily the result of infections that do not normally develop in individuals with healthy immune systems. These are called opportunistic infections.

People with AIDS have had their immune system weakened by HIV and are very susceptible to these opportunistic infections. Common symptoms are fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss.

Note: Initial infection with HIV can produce no symptoms. Some people, however, do experience flu-like symptoms with fever, rash, sore throat, and swollen lymph nodes, usually 2 weeks after contracting the virus. Some people with HIV infection remain without symptoms for years between the time the are exposed to the virus and when they develop AIDS

===How HIV/AIDS Is Spread===
Anyone can get HIV. The most important thing to know is how you can get the virus.

You can get HIV:

-By having unprotected sex- sex without a condom- with someone who has HIV. The virus can be in an infected person’s blood, semen, or vaginal secretions and can enter your body through tiny cuts or sores in your skin, or in the lining of your vagina, penis, rectum, or mouth.

-By sharing a needle and syringe to inject drugs or sharing drug equipment used to prepare drugs for injection with someone who has HIV.

-From a blood transfusion or blood clotting factor that you got before 1985. (But today it is unlikely you could get infected that way because all blood in the United States has been tested for HIV since 1985.)

-Babies born to women with HIV also can become infected during pregnancy, birth, or breast-feeding.

You cannot get HIV:

-By working with or being around someone who has HIV.
-From sweat, spit, tears, clothes, drinking fountains, phones, toilet seats, or through everyday things like sharing a meal.
-From insect bites or stings.
-From donating blood.
-From a closed-mouth kiss (but there is a very small chance of getting it from open-mouthed or "French" kissing with an infected person because of possible blood contact).

==Treatment Options==
There is no cure for HIV. It is a lifelong condition. Although HIV is a very serious infection, many people with HIV and AIDS are living longer, healthier lives today, thanks to new and effective treatments. It is very important to make sure you have a doctor who knows how to treat HIV. If you don’t know which doctor to use, talk with a health care professional or trained HIV counselor. If you are pregnant or are planning to become pregnant, this is especially important.

There also are other things you can do for yourself to stay healthy. Here are a few:
-Follow your doctor’s instructions. Keep your appointments. Your doctor may prescribe medicine for you. Take the medicine just the way he or she tells you to because taking only some of your medicine gives your HIV infection more chance to grow.
-Get immunizations (shots) to prevent infections such as pneumonia and flu. Your doctor will tell you when to get these shots.
-If you smoke or if you use drugs not prescribed by your doctor, quit.
-Eat healthy foods. This will help keep you strong, keep your energy and weight up, and help your body protect itself.
-Exercise regularly to stay strong and fit.
-Get enough sleep and rest.

===How to know you have AIDS (Diagnosis)===
You might have HIV and still feel perfectly healthy. The only way to know for sure if you are infected or not is to be tested. Talk with a knowledgeable health care provider or counselor both before and after you are tested. You can go to your doctor or health department for testing. To find out where to go in your area for HIV counseling and testing, call your local health department or the CDC INFO, at 1-800-CDC-INFO (232-4636).

Your doctor or health care provider can give you a confidential HIV test. The information on your HIV test and test results are confidential, as is your other medical information. This means it can be shared only with people authorized to see your medical records. You can ask your doctor, health care provider, or HIV counselor at the place you are tested to explain who can obtain this information. For example, you may want to ask whether your insurance company could find out your HIV status if you make a claim for health insurance benefits or apply for life insurance or disability insurance.

The CDC recommends that everyone know their HIV status. How often you should an HIV test depends on your circumstances. If you have never been tested for HIV, you should be tested. If you have high-risk behaviors, then you should get tested more often. The CDC recommends testing once a year for people with high risk behaviors.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===
SInce HIV weakens the immune system, people with AIDS should be consult with a doctor and get tested if they believe they have it. If you are diagnosed with AIDS, you should be in constant contact with your doctor. People with AIDS are susceptible to infections and cancers that most healthy adults would not get and so they must be very aware of any new diseases which their bodies acquire, and report them to their physicians as they occur.

==Prevention==
-Don’t share needles and syringes used to inject drugs, steroids, vitamins, or for tattooing or body piercing. Also, don’t share equipment ("works") used to prepare drugs to be injected. Many people have been infected with HIV, hepatitis, and other germs this way. Germs from an infected person can stay in a needle and then be injected directly into the next person who uses the needle.
-The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a longterm mutually monogamous relationship with a partner who has been tested and you know is uninfected.
-For persons whose sexual behaviors place them at risk for STDs, correct and consistent use of the male latex condom can reduce the risk of STD transmission. However, no protective method is 100 percent effective, and condom use cannot guarantee absolute protection against any STD. The more sex partners you have, the greater your chances are of getting HIV or other diseases passed through sex.
-Condoms used with a lubricant are less likely to break. However, condoms with the spermicide nonoxynol-9 are not recommended for STD/HIV prevention. Condoms must be used correctly and consistently to be effective and protective. Incorrect use can lead to condom slippage or breakage, thus diminishing the protective effect. Inconsistent use, e.g., failure to use condoms with every act of intercourse, can result in STD transmission because transmission can occur with a single act of intercourse.
-Don’t share razors or toothbrushes because of they may have the blood of another person on them.
-If you are pregnant or think you might be soon, talk to a doctor or your local health department about being tested for HIV. If you share HIV, drug treatments are available to help you and they can reduce the chance of passing HIV to your baby.

==What to Expect (Outook/Prognosis)==
Right now, there is no cure for AIDS. It is always fatal if no treatment is provided. In the US, most patients survive many years after diagnosis because of the availability of medicines such as HAART. HAART and medicines like it have dramatically increased the amount of time people with HIV remain alive.

Research continues in the areas of drug treatments and vaccine development. Unfortunately, HIV medications are not always available in the developing world, where the bulk of cases now occur.

==Copyleft Sources==
http://www.cdc.gov/hiv/resources/brochures/at-risk.htm
http://www.nlm.nih.gov/medlineplus/ency/article/000594.htm

AIDS (patient information)

2009-07-07T20:29:11Z

Michaelagibson:

==What is AIDS?==
AIDS - The '''A'''cquired '''I'''mmuno'''d'''eficiency '''S'''yndrome - is a disease you get when HIV destroys your body’s immune system. Normally, your immune system helps you fight off illness. When your immune system fails you can become very sick and can die.
HIV - The '''H'''uman '''I'''mmunodeficiency '''V'''irus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body fight off infection and disease.
===What is the Difference Between AIDS and HIV?===
AIDS is the disease which results from HIV's destruction of the T-helper cells. The HIV virus causes AIDS.

===Symptoms===
The symptoms of AIDS are primarily the result of infections that do not normally develop in individuals with healthy immune systems. These are called opportunistic infections.

People with AIDS have had their immune system weakened by HIV and are very susceptible to these opportunistic infections. Common symptoms are fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss.

Note: Initial infection with HIV can produce no symptoms. Some people, however, do experience flu-like symptoms with fever, rash, sore throat, and swollen lymph nodes, usually 2 weeks after contracting the virus. Some people with HIV infection remain without symptoms for years between the time the are exposed to the virus and when they develop AIDS

===How HIV/AIDS Is Spread===
Anyone can get HIV. The most important thing to know is how you can get the virus.

You can get HIV:

-By having unprotected sex- sex without a condom- with someone who has HIV. The virus can be in an infected person’s blood, semen, or vaginal secretions and can enter your body through tiny cuts or sores in your skin, or in the lining of your vagina, penis, rectum, or mouth.
-By sharing a needle and syringe to inject drugs or sharing drug equipment used to prepare drugs for injection with someone who has HIV.
-From a blood transfusion or blood clotting factor that you got before 1985. (But today it is unlikely you could get infected that way because all blood in the United States has been tested for HIV since 1985.)
-Babies born to women with HIV also can become infected during pregnancy, birth, or breast-feeding.

You cannot get HIV:

-By working with or being around someone who has HIV.
-From sweat, spit, tears, clothes, drinking fountains, phones, toilet seats, or through everyday things like sharing a meal.
-From insect bites or stings.
-From donating blood.
-From a closed-mouth kiss (but there is a very small chance of getting it from open-mouthed or "French" kissing with an infected person because of possible blood contact).

==Treatment Options==
There is no cure for HIV. It is a lifelong condition. Although HIV is a very serious infection, many people with HIV and AIDS are living longer, healthier lives today, thanks to new and effective treatments. It is very important to make sure you have a doctor who knows how to treat HIV. If you don’t know which doctor to use, talk with a health care professional or trained HIV counselor. If you are pregnant or are planning to become pregnant, this is especially important.

There also are other things you can do for yourself to stay healthy. Here are a few:
-Follow your doctor’s instructions. Keep your appointments. Your doctor may prescribe medicine for you. Take the medicine just the way he or she tells you to because taking only some of your medicine gives your HIV infection more chance to grow.
-Get immunizations (shots) to prevent infections such as pneumonia and flu. Your doctor will tell you when to get these shots.
-If you smoke or if you use drugs not prescribed by your doctor, quit.
-Eat healthy foods. This will help keep you strong, keep your energy and weight up, and help your body protect itself.
-Exercise regularly to stay strong and fit.
-Get enough sleep and rest.

===How to know you have AIDS (Diagnosis)===
You might have HIV and still feel perfectly healthy. The only way to know for sure if you are infected or not is to be tested. Talk with a knowledgeable health care provider or counselor both before and after you are tested. You can go to your doctor or health department for testing. To find out where to go in your area for HIV counseling and testing, call your local health department or the CDC INFO, at 1-800-CDC-INFO (232-4636).

Your doctor or health care provider can give you a confidential HIV test. The information on your HIV test and test results are confidential, as is your other medical information. This means it can be shared only with people authorized to see your medical records. You can ask your doctor, health care provider, or HIV counselor at the place you are tested to explain who can obtain this information. For example, you may want to ask whether your insurance company could find out your HIV status if you make a claim for health insurance benefits or apply for life insurance or disability insurance.

The CDC recommends that everyone know their HIV status. How often you should an HIV test depends on your circumstances. If you have never been tested for HIV, you should be tested. If you have high-risk behaviors, then you should get tested more often. The CDC recommends testing once a year for people with high risk behaviors.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===
SInce HIV weakens the immune system, people with AIDS should be consult with a doctor and get tested if they believe they have it. If you are diagnosed with AIDS, you should be in constant contact with your doctor. People with AIDS are susceptible to infections and cancers that most healthy adults would not get and so they must be very aware of any new diseases which their bodies acquire, and report them to their physicians as they occur.

==Prevention==
-Don’t share needles and syringes used to inject drugs, steroids, vitamins, or for tattooing or body piercing. Also, don’t share equipment ("works") used to prepare drugs to be injected. Many people have been infected with HIV, hepatitis, and other germs this way. Germs from an infected person can stay in a needle and then be injected directly into the next person who uses the needle.
-The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a longterm mutually monogamous relationship with a partner who has been tested and you know is uninfected.
-For persons whose sexual behaviors place them at risk for STDs, correct and consistent use of the male latex condom can reduce the risk of STD transmission. However, no protective method is 100 percent effective, and condom use cannot guarantee absolute protection against any STD. The more sex partners you have, the greater your chances are of getting HIV or other diseases passed through sex.
-Condoms used with a lubricant are less likely to break. However, condoms with the spermicide nonoxynol-9 are not recommended for STD/HIV prevention. Condoms must be used correctly and consistently to be effective and protective. Incorrect use can lead to condom slippage or breakage, thus diminishing the protective effect. Inconsistent use, e.g., failure to use condoms with every act of intercourse, can result in STD transmission because transmission can occur with a single act of intercourse.
-Don’t share razors or toothbrushes because of they may have the blood of another person on them.
-If you are pregnant or think you might be soon, talk to a doctor or your local health department about being tested for HIV. If you share HIV, drug treatments are available to help you and they can reduce the chance of passing HIV to your baby.

==What to Expect (Outook/Prognosis)==
Right now, there is no cure for AIDS. It is always fatal if no treatment is provided. In the US, most patients survive many years after diagnosis because of the availability of medicines such as HAART. HAART and medicines like it have dramatically increased the amount of time people with HIV remain alive.

Research continues in the areas of drug treatments and vaccine development. Unfortunately, HIV medications are not always available in the developing world, where the bulk of cases now occur.

==Copyleft Sources==
http://www.cdc.gov/hiv/resources/brochures/at-risk.htm
http://www.nlm.nih.gov/medlineplus/ency/article/000594.htm

Leukemia (patient information)

2009-07-07T20:28:31Z

Michaelagibson: New page: ==What is Leukemia== ===Symptoms=== ===How Leukemia Is Spread=== ==Treatment Options== ===How to know you have Leukemia (Diagnosis)=== ====Diseases With Similar Symptoms==== ===Whe...

==What is Leukemia==

===Symptoms===

===How Leukemia Is Spread===

==Treatment Options==

===How to know you have Leukemia (Diagnosis)===

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

==Prevention==

==What to Expect (Outook/Prognosis)==

==Copyleft Sources==

AIDS (patient information)

2009-07-07T20:26:10Z

Michaelagibson:

==What is AIDS?==
AIDS - The '''A'''cquired '''I'''mmuno'''d'''eficiency '''S'''yndrome - is a disease you get when HIV destroys your body’s immune system. Normally, your immune system helps you fight off illness. When your immune system fails you can become very sick and can die.
HIV - The '''H'''uman '''I'''mmunodeficiency '''V'''irus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body fight off infection and disease.
===What is the Difference Between AIDS and HIV?===
AIDS is the disease which results from HIV's destruction of the T-helper cells. The HIV virus causes AIDS.

===Symptoms===
The symptoms of AIDS are primarily the result of infections that do not normally develop in individuals with healthy immune systems. These are called opportunistic infections.

People with AIDS have had their immune system weakened by HIV and are very susceptible to these opportunistic infections. Common symptoms are fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss.

Note: Initial infection with HIV can produce no symptoms. Some people, however, do experience flu-like symptoms with fever, rash, sore throat, and swollen lymph nodes, usually 2 weeks after contracting the virus. Some people with HIV infection remain without symptoms for years between the time the are exposed to the virus and when they develop AIDS

===How HIV/AIDS Is Spread===
Anyone can get HIV. The most important thing to know is how you can get the virus.

You can get HIV:

-By having unprotected sex- sex without a condom- with someone who has HIV. The virus can be in an infected person’s blood, semen, or vaginal secretions and can enter your body through tiny cuts or sores in your skin, or in the lining of your vagina, penis, rectum, or mouth.
-By sharing a needle and syringe to inject drugs or sharing drug equipment used to prepare drugs for injection with someone who has HIV.
-From a blood transfusion or blood clotting factor that you got before 1985. (But today it is unlikely you could get infected that way because all blood in the United States has been tested for HIV since 1985.)
-Babies born to women with HIV also can become infected during pregnancy, birth, or breast-feeding.

You cannot get HIV:

-By working with or being around someone who has HIV.
-From sweat, spit, tears, clothes, drinking fountains, phones, toilet seats, or through everyday things like sharing a meal.
-From insect bites or stings.
-From donating blood.
-From a closed-mouth kiss (but there is a very small chance of getting it from open-mouthed or "French" kissing with an infected person because of possible blood contact).

==Treatment Options==
There is no cure for HIV. It is a lifelong condition. Although HIV is a very serious infection, many people with HIV and AIDS are living longer, healthier lives today, thanks to new and effective treatments. It is very important to make sure you have a doctor who knows how to treat HIV. If you don’t know which doctor to use, talk with a health care professional or trained HIV counselor. If you are pregnant or are planning to become pregnant, this is especially important.

There also are other things you can do for yourself to stay healthy. Here are a few:
-Follow your doctor’s instructions. Keep your appointments. Your doctor may prescribe medicine for you. Take the medicine just the way he or she tells you to because taking only some of your medicine gives your HIV infection more chance to grow.
-Get immunizations (shots) to prevent infections such as pneumonia and flu. Your doctor will tell you when to get these shots.
-If you smoke or if you use drugs not prescribed by your doctor, quit.
-Eat healthy foods. This will help keep you strong, keep your energy and weight up, and help your body protect itself.
-Exercise regularly to stay strong and fit.
-Get enough sleep and rest.

===How to know you have AIDS (Diagnosis)===
You might have HIV and still feel perfectly healthy. The only way to know for sure if you are infected or not is to be tested. Talk with a knowledgeable health care provider or counselor both before and after you are tested. You can go to your doctor or health department for testing. To find out where to go in your area for HIV counseling and testing, call your local health department or the CDC INFO, at 1-800-CDC-INFO (232-4636).

Your doctor or health care provider can give you a confidential HIV test. The information on your HIV test and test results are confidential, as is your other medical information. This means it can be shared only with people authorized to see your medical records. You can ask your doctor, health care provider, or HIV counselor at the place you are tested to explain who can obtain this information. For example, you may want to ask whether your insurance company could find out your HIV status if you make a claim for health insurance benefits or apply for life insurance or disability insurance.

The CDC recommends that everyone know their HIV status. How often you should an HIV test depends on your circumstances. If you have never been tested for HIV, you should be tested. If you have high-risk behaviors, then you should get tested more often. The CDC recommends testing once a year for people with high risk behaviors.

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===
SInce HIV weakens the immune system, people with AIDS should be consult with a doctor and get tested if they believe they have it. If you are diagnosed with AIDS, you should be in constant contact with your doctor. People with AIDS are susceptible to infections and cancers that most healthy adults would not get and so they must be very aware of any new diseases which their bodies acquire, and report them to their physicians as they occur.

==Prevention==
-Don’t share needles and syringes used to inject drugs, steroids, vitamins, or for tattooing or body piercing. Also, don’t share equipment ("works") used to prepare drugs to be injected. Many people have been infected with HIV, hepatitis, and other germs this way. Germs from an infected person can stay in a needle and then be injected directly into the next person who uses the needle.
-The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a longterm mutually monogamous relationship with a partner who has been tested and you know is uninfected.
-For persons whose sexual behaviors place them at risk for STDs, correct and consistent use of the male latex condom can reduce the risk of STD transmission. However, no protective method is 100 percent effective, and condom use cannot guarantee absolute protection against any STD. The more sex partners you have, the greater your chances are of getting HIV or other diseases passed through sex.
-Condoms used with a lubricant are less likely to break. However, condoms with the spermicide nonoxynol-9 are not recommended for STD/HIV prevention. Condoms must be used correctly and consistently to be effective and protective. Incorrect use can lead to condom slippage or breakage, thus diminishing the protective effect. Inconsistent use, e.g., failure to use condoms with every act of intercourse, can result in STD transmission because transmission can occur with a single act of intercourse.
-Don’t share razors or toothbrushes because of they may have the blood of another person on them.
-If you are pregnant or think you might be soon, talk to a doctor or your local health department about being tested for HIV. If you share HIV, drug treatments are available to help you and they can reduce the chance of passing HIV to your baby.

==What to Expect (Outook/Prognosis)==
Right now, there is no cure for AIDS. It is always fatal if no treatment is provided. In the US, most patients survive many years after diagnosis because of the availability of medicines such as HAART. HAART and medicines like it have dramatically increased the amount of time people with HIV remain alive.

Research continues in the areas of drug treatments and vaccine development. Unfortunately, HIV medications are not always available in the developing world, where the bulk of cases now occur.

==Copyleft Sources==
http://www.cdc.gov/hiv/resources/brochures/at-risk.htm
http://www.nlm.nih.gov/medlineplus/ency/article/000594.htm

AIDS (patient information)

2009-07-07T19:50:56Z

Michaelagibson:

AIDS (patient information)

2009-07-07T19:44:28Z

Michaelagibson:

==What is AIDS?==

===What is the Difference Between AIDS and HIV?===

===Symptoms===

===How HIV/AIDS Is Spread===

==Treatment Options==

===How to know you have AIDS (Diagnosis)===

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

==Prevention==

==What to Expect (Outook/Prognosis)==

==Copyleft Sources==

AIDS (patient information)

2009-07-07T19:43:48Z

Michaelagibson: Replacing page with '==What is AIDS?== ===What is the Difference Between AIDS and HIV?=== ===Symptoms=== ===How " " Is Spread=== ==Treatment Options== ===How to know you have " " (Diagnosis)...'

==What is AIDS?==

===What is the Difference Between AIDS and HIV?===

===Symptoms===

===How " " Is Spread===

==Treatment Options==

===How to know you have " " (Diagnosis)===

====Diseases With Similar Symptoms====

===When to Seek Urgent Medical Care===

==Prevention==

==What to Expect (Outook/Prognosis)==

==Copyleft Sources==

Template:WikiPatient - Patient Resources

2009-07-07T19:40:35Z

Michaelagibson:

Template:WikiPatient - Patient Resources

2009-07-07T19:08:25Z

Michaelagibson:

AIDS (patient information)

2009-07-07T19:04:07Z

Michaelagibson: New page: ==What is HIV and how can I get it?== HIV - the human immunodeficiency virus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body figh...

==What is HIV and how can I get it?==

HIV - the human immunodeficiency virus - is a virus that kills your body’s "CD4 cells." CD4 cells (also called T-helper cells) help your body fight off infection and disease. HIV can be passed from person to person if someone with HIV infection has sex with or shares drug injection needles with another person. It also can be passed from a mother to her baby when she is pregnant, when she delivers the baby, or if she breastfeeds her baby.

What is AIDS?

AIDS - the acquired immunodeficiency syndrome - is a disease you get when HIV destroys your body’s immune system. Normally, your immune system helps you fight off illness. When your immune system fails you can become very sick and can die.

What do I need to know about HIV?

The first cases of AIDS were identified in the United States in 1981, but AIDS most likely existed here and in other parts of the world for many years before that time. In 1984 scientists proved that HIV causes AIDS.

Anyone can get HIV. The most important thing to know is how you can get the virus.

You can get HIV:

By having unprotected sex- sex without a condom- with someone who has HIV. The virus can be in an infected person’s blood, semen, or vaginal secretions and can enter your body through tiny cuts or sores in your skin, or in the lining of your vagina, penis, rectum, or mouth.
By sharing a needle and syringe to inject drugs or sharing drug equipment used to prepare drugs for injection with someone who has HIV.
From a blood transfusion or blood clotting factor that you got before 1985. (But today it is unlikely you could get infected that way because all blood in the United States has been tested for HIV since 1985.)
Babies born to women with HIV also can become infected during pregnancy, birth, or breast-feeding.

You cannot get HIV:

By working with or being around someone who has HIV.
From sweat, spit, tears, clothes, drinking fountains, phones, toilet seats, or through everyday things like sharing a meal.
From insect bites or stings.
From donating blood.
From a closed-mouth kiss (but there is a very small chance of getting it from open-mouthed or "French" kissing with an infected person because of possible blood contact).
How can I protect myself?

Don’t share needles and syringes used to inject drugs, steroids, vitamins, or for tattooing or body piercing. Also, don’t share equipment ("works") used to prepare drugs to be injected. Many people have been infected with HIV, hepatitis, and other germs this way. Germs from an infected person can stay in a needle and then be injected directly into the next person who uses the needle.
The surest way to avoid transmission of sexually transmitted diseases is to abstain from sexual intercourse, or to be in a longterm mutually monogamous relationship with a partner who has been tested and you know is uninfected.
For persons whose sexual behaviors place them at risk for STDs, correct and consistent use of the male latex condom can reduce the risk of STD transmission. However, no protective method is 100 percent effective, and condom use cannot guarantee absolute protection against any STD. The more sex partners you have, the greater your chances are of getting HIV or other diseases passed through sex.
Condoms used with a lubricant are less likely to break. However, condoms with the spermicide nonoxynol-9 are not recommended for STD/HIV prevention. Condoms must be used correctly and consistently to be effective and protective. Incorrect use can lead to condom slippage or breakage, thus diminishing the protective effect. Inconsistent use, e.g., failure to use condoms with every act of intercourse, can result in STD transmission because transmission can occur with a single act of intercourse.
Don’t share razors or toothbrushes because of they may have the blood of another person on them.
If you are pregnant or think you might be soon, talk to a doctor or your local health department about being tested for HIV. If you share HIV, drug treatments are available to help you and they can reduce the chance of passing HIV to your baby.
How do I know if I have HIV or AIDS?

You might have HIV and still feel perfectly healthy. The only way to know for sure if you are infected or not is to be tested. Talk with a knowledgeable health care provider or counselor both before and after you are tested. You can go to your doctor or health department for testing. To find out where to go in your area for HIV counseling and testing, call your local health department or the CDC INFO, at 1-800-CDC-INFO (232-4636).

Your doctor or health care provider can give you a confidential HIV test. The information on your HIV test and test results are confidential, as is your other medical information. This means it can be shared only with people authorized to see your medical records. You can ask your doctor, health care provider, or HIV counselor at the place you are tested to explain who can obtain this information. For example, you may want to ask whether your insurance company could find out your HIV status if you make a claim for health insurance benefits or apply for life insurance or disability insurance.

CDC recommends that everyone know their HIV status. How often you should an HIV test depends on your circumstances. If you have never been tested for HIV, you should be tested. CDC recommends being tested at least once a year if you do things that can transmit HIV infection, such as:

injecting drugs or steroids with used injection equipment
having sex for money or drugs
having sex with an HIV infected person
having more than one sex partner since your HIV test
having a sex partner who has had other sex partners since your last HIV test.
If you have been tested for HIV and the result is negative and you never do things that might transmit

In many states, you can be tested anonymously. These tests are usually given at special places known as anonymous testing sites. When you get an anonymous HIV test, the testing site records only a number or code with the test result, not your name. A counselor gives you this number at the time your blood, saliva, or urine is taken for the test, then you return to the testing site (or perhaps call the testing site, for example with home collection kits) and give them your number or code to learn the results of your test.

If you have been tested for HIV and the result is negative and you never do things that might transmit HIV infection, then you and your health care provider can decide whether you need to get tested again.

You are more likely to test positive for (be infected with) HIV if you

Have ever shared injection drug needles and syringes or "works."
Have ever had sex without a condom with someone who had HIV.
Have ever had a sexually transmitted disease, like chlamydia or gonorrhea.
Received a blood transfusion or a blood clotting factor between 1978 and 1985.
Have ever had sex with someone who has done any of those things
What can I do if the test shows I have HIV?

Although HIV is a very serious infection, many people with HIV and AIDS are living longer, healthier lives today, thanks to new and effective treatments. It is very important to make sure you have a doctor who knows how to treat HIV. If you don’t know which doctor to use, talk with a health care professional or trained HIV counselor. If you are pregnant or are planning to become pregnant, this is especially important.

There also are other things you can do for yourself to stay healthy. Here are a few

Follow your doctor’s instructions. Keep your appointments. Your doctor may prescribe medicine for you. Take the medicine just the way he or she tells you to because taking only some of your medicine gives your HIV infection more chance to grow.
Get immunizations (shots) to prevent infections such as pneumonia and flu. Your doctor will tell you when to get these shots.
If you smoke or if you use drugs not prescribed by your doctor, quit.
Eat healthy foods. This will help keep you strong, keep your energy and weight up, and help your body protect itself.
Exercise regularly to stay strong and fit.
Get enough sleep and rest.
How can I find out more about HIV and AIDS?

You can call CDC-INFO at 1-800-CDC-INFO (232-4636); TTY access 1-888-232-6348. CDC-INFO is staffed with people trained to answer your questions about HIV and AIDS in a prompt and confidential manner in English or Spanish, 24 hours per day. Staff at CDC-INFO can offer you a wide variety of written materials and put you in touch with organizations in your area that deal with HIV and AIDS.

HIV AIDS

2009-07-07T19:02:28Z

Michaelagibson:

{{Infobox_Disease |
Name = Acquired immunodeficiency syndrome (AIDS) |
Image = Red_Ribbon.svg |
Caption = The Red ribbon is a symbol for solidarity with HIV-positive people and those living with AIDS. |
Width = 200 |
DiseasesDB = 5938 |
ICD10 = {{ICD10|B|24||b|20}} |
ICD9 = {{ICD9|042}} |
ICDO = |
OMIM = |
MedlinePlus = 000594 |
eMedicineSubj = emerg |
eMedicineTopic = 253 |
MeshID = D000163 |
}}
{| style="float: right; clear:right; margin: 0 0 0.5em 1em; padding: 0.5em; background: #fffff4; border: 1px solid #ddb; width: 250px; font-size:90%;"
|-
|List of abbreviations used in this article 
'''AIDS''': Acquired immune deficiency syndrome 
'''HIV''': [[Human immunodeficiency virus]] 
'''CD4+''': [[T helper cells]] 
'''CCR5''': [[Chemokine (C-C motif) receptor 5]] 
'''CDC''': [[Centers for Disease Control and Prevention]] 
'''WHO''': [[World Health Organization]] 
'''PCP''': [[Pneumocystis pneumonia]] 
'''TB''': [[Tuberculosis]] 
'''MTCT''': Mother-to-child transmission 
'''HAART''': [[Highly active antiretroviral therapy]] 
'''STI/STD''': [[Sexually transmitted infection]]/disease
|}
{{SI}}
{{CMG}}

{{Editor Help}}

For AIDS Patient Information click [[AIDS Patient Information|here]]

'''Acquired immune deficiency syndrome ''' or '''acquired immunodeficiency syndrome''' ('''AIDS''' or '''Aids''') is a [[syndrome|collection of symptoms and infections]] resulting from the specific damage to the [[immune system]] caused by the [[HIV|human immunodeficiency virus]] (HIV) in humans,<ref>{{cite web
|url=http://www.niaid.nih.gov/Publications/hivaids/hivaids.htm
|title=The Relationship Between the Human Immunodeficiency Virus and the Acquired Immunodeficiency Syndrome |publisher= NIAID
|accessdate=2008-03-10}}</ref> and similar viruses in other species ([[Simian immunodeficiency virus|SIV]], [[Feline immunodeficiency virus|FIV]], etc.). The late stage of the condition leaves individuals susceptible to [[opportunistic infection]]s and [[tumor]]s. Although treatments for AIDS and HIV exist to decelerate the [[virus]]'s progression, there is currently no known cure. HIV is [[Transmission (medicine)|transmitted]] through direct contact of a [[mucous membrane]] or the bloodstream with a [[bodily fluid]] containing HIV, such as [[blood]], [[semen]], [[vaginal fluid]], [[preseminal fluid]], and [[breast milk]].<ref name=CDCtransmission>{{

cite web
| author=[[Divisions of HIV/AIDS Prevention]]
| publisher=[[Centers for Disease Control & Prevention]] | year= 2003
| url=http://www.cdc.gov/HIV/pubs/facts/transmission.htm
| title=HIV and Its Transmission
| accessdate = 2006-05-23
}}</ref><ref name=sfaf>{{

cite web
| author=[[San Francisco AIDS Foundation]]
| publisher=
| year= [[2006-04-14]]
| url=http://www.sfaf.org/aids101/transmission.html
| title=How HIV is spread | accessdate = 2006-05-23

}}</ref> This transmission can come in the form of [[anal sex|anal]], [[vaginal sex|vaginal]] or [[oral sex|oral]] [[Sexual intercourse|sex]], [[blood transfusion]], contaminated [[hypodermic needle]]s, exchange between mother and baby during [[pregnancy]], [[childbirth]], or [[breastfeeding]], or other exposure to one of the above bodily fluids.

Most researchers believe that HIV originated in sub-Saharan Africa during the twentieth century.<ref name=Gao>

{{ cite journal
| author=Gao F, Bailes E, Robertson DL, et al
| title=Origin of HIV-1 in the Chimpanzee Pan troglodytes troglodytes
| journal=Nature
| year=1999
| pages=436–441
| volume=397
| issue=6718
| pmid=9989410 |doi=10.1038/17130

}}</ref> It is now a [[pandemic]]. In 2007, an estimated 33.2 million people lived with the disease worldwide, and it claimed the lives of an estimated 2.1 million people, including 330,000 children.<ref name=UNAIDS2007/> Over three-fourths of these deaths occurred in sub-Saharan Africa,<ref name=UNAIDS2007/> retarding economic growth and destroying human capital.<ref name=Bell-et-al-2003/> [[antiretroviral drug|Antiretroviral]] treatment reduces both the [[Mortality rate|mortality]] and the morbidity of HIV infection, but routine access to antiretroviral [[medication]] is not available in all countries.<ref name=Palella>{{

cite journal
| author=Palella FJ Jr, Delaney KM, Moorman AC, et al
| title=Declining morbidity and mortality among patients with advanced human immunodeficiency virus infection. HIV Outpatient Study Investigators
| journal=N. Engl. J. Med | year=1998 | pages=853–860 | volume=338 | issue=13
| pmid=9516219

}}</ref>

HIV/AIDS [[social stigma|stigma]] is more severe than that associated with some other life-threatening conditions and extends beyond the disease itself to providers and even volunteers involved with the care of people living with HIV.<ref name=Snyder>{{

cite journal |
author=Snyder M, Omoto AM, Crain AL |
title=Punished for their good deeds: stigmatization for AIDS volunteers |
journal=American Behavioral Scientist | year=1999 | pages=1175–1192 | volume=42 | issue=7 | doi=10.1177/0002764299042007009

}}</ref>

==History==
{{main|AIDS origin}}

AIDS was first reported June 5, 1981, when the U.S. Centers for Disease Control and Prevention recorded a cluster of [[Pneumocystis pneumonia (PCP)|''Pneumocystis carinii'' pneumonia]] (now still classified as PCP but known to be caused by [[Pneumocystis pneumonia (PCP)|''Pneumocystis jirovecii'']]) in five homosexual men in Los Angeles.<ref name=MMWR2>{{cite journal
|author=Gottlieb MS
|title=Pneumocystis pneumonia--Los Angeles. 1981
|journal=Am J Public Health
|volume=96
|issue=6
|pages=980–1; discussion 982–3
|year=2006
|pmid=16714472
|url=http://www.cdc.gov/mmwr/preview/mmwrhtml/june_5.htm
|doi=
}}</ref>

Three of the earliest known instances of HIV infection are:
#A plasma sample taken in 1959 from an adult male living in Kinshasa, today part of the Democratic Republic of the Congo.<ref name=Zhu>{{

cite journal
| author=Zhu T, Korber BT, Nahmias AJ, et al | title=An African HIV-1 Sequence from 1959 and Implications for the Origin of the Epidemic
| journal=Nature | year=1998 | pages=594–597 | volume=391 | issue=6667
| pmid=9468138 | doi=10.1038/35400

}}</ref>
#HIV found in tissue samples from "Robert R.", a 15 year old African-American teenager who died in St. Louis in 1969.<ref name=Kolata>

{{cite news
| author=Kolata G
| url=http://query.nytimes.com/gst/fullpage.html?res=9B0DEFD6173AF93BA15753C1A961948260&sec=&pagewanted=all
| title=Boy's 1969 death suggests AIDS invaded U.S. several times
| work=The New York Times
| date=1987-10-28
| accessdate = 2006-06-19
}}
</ref>
#HIV found in tissue samples from Arvid Noe, a Norwegian sailor who died around 1976.<ref name=HooperBMJ>{{

cite journal
| author=Hooper E
| title=Sailors and star-bursts, and the arrival of HIV
| url=http://bmj.bmjjournals.com/cgi/content/full/315/7123/1689
| journal=BMJ | year=1997 | pages=1689–1691 | volume=315 | issue=7123
| pmid=9448543

}}</ref>

Two species of HIV infect humans: [[HIV-1]] and [[HIV-2]]. HIV-1 is more virulent and more easily transmitted. HIV-1 is the source of the majority of HIV infections throughout the world, while HIV-2 is not as easily transmitted and is largely confined to West Africa.<ref name=Reeves>{{

cite journal
| author=Reeves JD, Doms RW
| title=Human Immunodeficiency Virus Type 2
| journal=J. Gen. Virol. | year=2002 | pages=1253–1265 | volume=83 | issue=Pt 6
| pmid=12029140

}}</ref> Both HIV-1 and HIV-2 are of [[primate]] origin. The origin of HIV-1 is the Central Common Chimpanzee (''Pan troglodytes troglodytes'') found in southern Cameroon.<ref name=Keele>{{

cite journal
| author=Keele BF, van Heuverswyn F, Li YY, et al | title=Chimpanzee Reservoirs of Pandemic and Nonpandemic HIV-1
| journal=Science | year=2006 |volume=313 |issue=5786 |pages=523–6
| url= http://www.sciencemag.org/cgi/content/abstract/1126531
| pmid=16728595 | doi=10.1126/science.1126531

}}</ref> It is established that HIV-2 originated from the Sooty Mangabey (''Cercocebus atys''), an Old World monkey of Guinea Bissau, Gabon, and Cameroon.

Most experts believe that HIV probably transferred to humans as a result of direct contact with primates, for instance during hunting or butchery.<ref name=CohenOrigns>{{

cite journal
| author=Cohen J
| title=Vaccine Theory of AIDS Origins Disputed at Royal Society
| journal=Science | year=2000 | pages=1850–1851 | volume= 289| issue=5486 |
pmid=11012346 | doi=10.1126/science.289.5486.1850

}}</ref>
A more controversial theory known as the [[OPV AIDS hypothesis]] suggests that the AIDS epidemic was inadvertently started in the late 1950s in the Belgian Congo by [[Hilary Koprowski]]'s research into a [[poliomyelitis]] [[vaccine]].<ref name=Curtis>{{

cite news |
author=Curtis T |
title=The origin of AIDS|
work=Rolling Stone | year=1992 | pages=54–59, 61, 106, 108 | issue=626 | url=http://www.uow.edu.au/arts/sts/bmartin/dissent/documents/AIDS/Curtis92.html|accessdate=2008-03-10

}}</ref><ref name=Hooper>{{

cite book
| author = Hooper E
| year = 1999
| title = The River : A Journey to the Source of HIV and AIDS
| edition = 1st
| pages = 1–1070
| publisher = Little Brown & Co
| location = Boston, MA
| id = ISBN 0-316-37261-7

}}</ref>
According to scientific consensus, this scenario is not supported by the available evidence.<ref name=refuted>{{

cite journal
| author = Worobey M, Santiago ML, Keele BF, et al |title = Origin of AIDS: contaminated polio vaccine theory refuted
|journal=Nature | year=2004 | pages=820 | volume=428| issue=6985 | pmid=15103367 | doi=10.1038/428820a}}</ref><ref name=Berry>{{

cite journal
| author = Berry N, Jenkins A, Martin J, et al |title = Mitochondrial DNA and retroviral RNA analyses of archival oral polio vaccine (OPV CHAT) materials: evidence of macaque nuclear sequences confirms substrate identity
|journal=Vaccine | year=2005 | pages=1639–1648 | volume=23 | pmid=15705467 | doi=10.1016/j.vaccine.2004.10.038}}</ref><ref name=VaccineQA>{{

cite web
| publisher=[[Centers for Disease Control and Prevention]]
| date= 2004-03-23
| url=http://www.cdc.gov/nip/vacsafe/concerns/aids/poliovac-hiv-aids-qa.htm
| title= Oral Polio Vaccine and HIV / AIDS: Questions and Answers | accessdate = 2006-11-20

}}</ref>

A recent study states that HIV probably moved from Africa to Haiti and then entered the United States around 1969.<ref>{{cite journal
|author=Gilbert MT, Rambaut A, Wlasiuk G, Spira TJ, Pitchenik AE, Worobey M
|title=The emergence of HIV/AIDS in the Americas and beyond
|journal=Proc. Natl. Acad. Sci. U.S.A.
|volume=104
|issue=47
|pages=18566–70
|year=2007
|pmid=17978186
|doi=10.1073/pnas.0705329104
}}
</ref>

==Epidemiology==

{{main|AIDS pandemic}}

[[Image:HIV Epidem.png|290px|thumb|left|Percentage of adult HIV prevalence per country at the end of 2005]]

The AIDS pandemic can also be seen as several epidemics of separate subtypes; the major factors in its spread are sexual transmission and vertical transmission from mother to child at birth and through breast milk.<ref name=Kallings/> Despite recent, improved access to antiretroviral treatment and care in many regions of the world, the AIDS pandemic claimed an estimated 2.1 million (range 1.9–2.4 million) lives in 2007 of which an estimated 330,000 were children under 15 years.<ref name=UNAIDS2007>{{
cite web
| author =[[Joint United Nations Programme on HIV/AIDS|UNAIDS]], [[World Health Organization|WHO]]
| date = December 2007
| title = 2007 AIDS epidemic update
| url= http://data.unaids.org/pub/EPISlides/2007/2007_epiupdate_en.pdf
| accessdate = 2008-03-12
| format= PDF
}}</ref>
Globally, an estimated 33.2 million people lived with HIV in 2007, including 2.5 million children. An estimated 2.5 million (range 1.8–4.1 million) people were newly infected in 2007, including 420,000 children.<ref name=UNAIDS2007/>

[[AIDS pandemic#Sub-Saharan Africa|Sub-Saharan Africa]] remains by far the worst affected region. In 2007 it contained an estimated 68% of all people living with AIDS and 76% of all AIDS deaths, with 1.7 million new infections bringing the number of people living with HIV to 22.5 million, and with 11.4 million AIDS orphans living in the region. Unlike other regions, most people living with HIV in sub-Saharan Africa in 2007 (61%) were women. Adult prevalence in 2007 was an estimated 5.0%, and AIDS continued to be the single largest cause of mortality in this region.<ref name=UNAIDS2007/> South Africa has the largest population of HIV patients in the world, followed by Nigeria and India.<ref>
{{cite news
| date = 2007-11-20
| title= U.N. agency to say it overstated extent of H.I.V. cases by millions
| url= http://query.nytimes.com/gst/fullpage.html?res=9C01EEDF103BF933A15752C1A9619C8B63
| work= New York Times | accessdate=2008-03-18
| author= McNeil DG Jr
}}</ref> [[AIDS pandemic#South and South-East Asia|South & South East Asia]] are second worst affected; in 2007 this region contained an estimated 18% of all people living with AIDS, and an estimated 300,000 deaths from AIDS.<ref name=UNAIDS2007/> India has an estimated 2.5 million infections and an estimated adult prevalence of 0.36%.<ref name=UNAIDS2007/> [[Life expectancy]] has fallen dramatically in the worst-affected countries; for example, in 2006 it was estimated that it had dropped from 65 to 35 years in Botswana.<ref name=Kallings>{{cite journal |journal= J Intern Med |date=2008 |volume=263 |issue=3 |pages=218–43 |title= The first postmodern pandemic: 25 years of HIV/AIDS |author= Kallings LO |doi=10.1111/j.1365-2796.2007.01910.x |pmid=18205765}}</ref>

==Demographics==
[http://www.unaids.org UNAIDS] and the [http://www.who.int/en/ WHO] estimate that AIDS has killed more than 25 million people since it was first recognized in 1981, making it one of the most destructive epidemics in recorded history.

Despite recent, improved access to antiretroviral treatment and care in many regions of the world, the AIDS epidemic claimed an estimated 3.1 million (between 2.8 and 3.6 million) lives in 2005 of which more than half a million (570,000) were children.
Globally, between 36.7 and 45.3 million people are currently living with HIV.

In 2005, between 4.3 and 6.6 million people were newly infected and between 2.8 and 3.6 million people with AIDS died, an increase from 2004 and the highest number since 1981(UNAIDS, 2005).

Sub-Saharan Africa remains by far the worst-affected region, with an estimated 23.8 to 28.9 million people currently living with HIV. More than 60% of all people living with HIV are in sub-Saharan Africa, as are more than three quarters (76%) of all women living with HIV. [15] South & South East Asia are second most affected with 15%. AIDS accounts for the deaths of 500,000 children.

The latest evaluation report of the World Bank's Operations Evaluation Department assesses the development effectiveness of the World Bank's country-level HIV/AIDS assistance defined as policy dialogue, analytic work, and lending with the explicit objective of reducing the scope or impact of the AIDS epidemic. This is the first comprehensive evaluation of the World Bank's HIV/AIDS support to countries, from the beginning of the epidemic through mid-2004. Because the Bank's assistance is for implementation of government programs by government, it provides important insights on how national AIDS programs can be made more effective.

==Pathophysiology==

The pathophysiology of AIDS is complex, as is the case with all [[syndrome]]s.<ref name="pmid8040596">{{cite journal
|author=Guss DA
|title=The acquired immune deficiency syndrome: an overview for the emergency physician, Part 1
|journal=J Emerg Med
|volume=12
|issue=3
|pages=375-84
|year=1994
|pmid=8040596
|doi=
}}</ref>

=== The major pulmonary illnesses ===

=== Pneumocystis jiroveci pneumonia ===
[[Image:Pneumocystis_jiroveci.jpg|thumb|left|Pneumocystis jiroveci is present in this lung impression smear, using Giemsa stain]]
Pneumocystis jiroveci pneumonia (originally known as Pneumocystis carinii pneumonia, often abbreviated PCP) is relatively rare in normal, immunocompetent people but common among HIV-infected individuals. Before the advent of effective treatment and diagnosis in Western countries it was a common immediate cause of death.
In developing countries, it is still one of the first indications of AIDS in untested individuals, although it does not generally occur unless the CD4 count is less than 200 per µl (Feldman, 2005).

==== Tuberculosis ====
[[Image:Tuberculosis_SEM.jpg|thumb|left|Scanning electron micrograph (SEM) of a number of Gram-positive Mycobacterium tuberculosis bacteria]]
Among infections associated with HIV, [[Tuberculosis]] (TB) is unique in that it may be transmitted to immunocompetent persons via the respiratory route, is easily treatable once identified, may occur in early-stage HIV disease, and is preventable with drug therapy. However, multi-drug resistance is a potentially serious problem. Even though its incidence has declined because of the use of directly observed therapy and other improved practices in Western countries, this is not the case in developing countries where HIV is most prevalent. In early-stage HIV infection (CD4 count >300 cells per µl), TB typically presents as a pulmonary disease.
In advanced HIV infection, TB may present atypically and extrapulmonary TB is common infecting bone marrow, bone, urinary and gastrointestinal tracts, liver, regional lymph nodes, and the central nervous system (Decker and Lazarus, 2000).

=== The major gastro-intestinal illnesses ===

==== Esophagitis ====

Esophagitis is an inflammation of the lining of the lower end of the esophagus (gullet or swallowing tube leading to the stomach). In HIV infected individuals, this could be due to fungus (candidiasis), virus (herpes simplex-1 or cytomegalovirus). In rare cases, it could be due to mycobacteria (Zaidi and Cervia, 2002).

==== Unexplained chronic diarrhea ====

In HIV infection, there are many possible causes of diarrhea, including common bacterial (Salmonella, Shigella, Listeria, Campylobacter, or Escherichia coli) and parasitic infections, and uncommon opportunistic infections such as cryptosporidiosis, microsporidiosis, Mycobacterium avium complex (MAC) and cytomegalovirus (CMV) colitis. Diarrhea may follow a course of antibiotics (common for Clostridium difficile). It may also be a side effect of several drugs used to treat HIV, or it may simply accompany HIV infection, particularly during primary HIV infection. In the later stages of HIV infection, diarrhea is thought to be a reflection of changes in the way the intestinal tract absorbs nutrients, and may be an important component of HIV-related wasting (Guerrant et al., 1990).

=== The major neurological illnesses ===

==== Toxoplasmosis ====
[[Image:Toxoplasmosi_AIDS.jpg|thumb|left|Toxoplasmosis of heart in AIDS]]
Toxoplasmosis is a disease caused by the single-celled parasite called Toxoplasma gondii. T. gondii usually infects the brain causing toxoplasma encephalitis. It can also infect and cause disease in the eyes and lungs (Luft and Chua, 2000).

==== Progressive multifocal leukoencephalopathy ====

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease, in which the myelin sheath covering the axons of nerve cells is gradually destroyed, impairing the transmission of nerve impulses. It is caused by a virus called JC virus which occurs in 70% of the population in latent form, causing disease only when the immune system has been severly weakened, as is the case for AIDS patients. It progresses rapidly, usually causing death within months of diagnosis (Sadler and Nelson, 1997).

==== HIV-associated dementia ====

HIV-1 associated dementia (HAD) is a metabolic encephalopathy induced by HIV infection and fueled by immune activation of brain macrophages and microglia (Gray et al., 2001). These cells are actively infected with HIV and secrete neurotoxins of both host and viral origin. Specific neurologic impairments are manifested by cognitive, behavioral, and motor abnormalities that occur after years of HIV infection and is associated with low CD4+ T cell levels and high plasma viral loads. Prevalence is between 15-30% in Western countries (Heaton et al., 1995; White et al., 1995) and has only been seen in 1-2% of India based infections (Satischandra et al., 2000; Wadia et al., 2001).

=== HIV-associated malignancies ===

Patients with HIV infection are susceptible to a number of malignancies (Yarchoan et al., 2005). The most common is Kaposi's sarcoma, and the appearance of this tumor in young gay men in New York in 1981 was one of the first signals of the AIDS epidemic. In addition, patients with HIV infection have a higher incidence of certain high grade B cell lymphomas, especially Burkitt-like and large cell lymphomas. These tumors, as well as aggressive cervical cancer in women, confer a diagnosis of AIDS in patients with HIV infection.

==Symptoms==

[[Image:Hiv-timecourse.png|450px|thumb|right|A generalized graph of the relationship between HIV copies (viral load) and CD4 counts over the average course of untreated HIV infection; any particular individual's disease course may vary considerably.
{{legend-line|blue solid 2px|CD4+ T Lymphocyte count (cells/mm³)}}
{{legend-line|red solid 2px|HIV RNA copies per mL of plasma}}
]]

The symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy [[immune system]]s. Most of these conditions are infections caused by [[bacteria]], [[virus]]es, [[fungus|fungi]] and [[parasite]]s that are normally controlled by the elements of the immune system that HIV damages. [[Opportunistic infection]]s are common in people with AIDS.<ref name=Holmes>{{

cite journal
| author=Holmes CB, Losina E, Walensky RP, Yazdanpanah Y, Freedberg KA
| title=Review of human immunodeficiency virus type 1-related opportunistic infections in sub-Saharan Africa
| journal=Clin. Infect. Dis. | year=2003 | pages=656–662 | volume=36 | issue=5
| pmid=12594648

}}</ref> HIV affects nearly every [[organ system]]. People with AIDS also have an increased risk of developing various cancers such as [[Kaposi's sarcoma]], [[cervical cancer]] and cancers of the immune system known as [[lymphoma]]s.

Additionally, people with AIDS often have systemic symptoms of infection like [[fever]]s, [[sweat]]s (particularly at night), swollen glands, chills, weakness, and [[weight loss]].<ref name=Guss>{{

cite journal
| author=Guss DA
| title=The acquired immune deficiency syndrome: an overview for the emergency physician, Part 1
| journal=J. Emerg. Med. | year=1994 | pages=375–384 | volume=12 | issue=3
| pmid=8040596

}}</ref><ref name=Guss2>{{

cite journal
| author=Guss DA
| title=The acquired immune deficiency syndrome: an overview for the emergency physician, Part 2
| journal=J. Emerg. Med. | year=1994 | pages=491–497 | volume=12 | issue=4
| pmid=7963396

}}</ref> After the diagnosis of AIDS is made, the current average survival time with antiretroviral therapy (as of 2005) is estimated to be more than 5 years,<ref name=Schneider>{{

cite journal
| author=Schneider MF, Gange SJ, Williams CM, Anastos K, Greenblatt RM, Kingsley L, Detels R, Munoz A
| title=Patterns of the hazard of death after AIDS through the evolution of antiretroviral therapy: 1984–2004
| journal=AIDS | year=2005 | pages=2009–2018 | volume=19 | issue=17
| pmid=16260908

}}</ref> but because new treatments continue to be developed and because HIV continues to [[Evolution|evolve]] resistance to treatments, estimates of survival time are likely to continue to change. Without antiretroviral therapy, death normally occurs within a year.<ref name=Morgan2 /> Most patients die from opportunistic infections or [[malignancies]] associated with the progressive failure of the immune system.<ref name=Lawn>{{

cite journal
| author=Lawn SD
| title=AIDS in Africa: the impact of coinfections on the pathogenesis of HIV-1 infection
| journal=J. Infect. Dis. | year=2004 | pages=1–12 | volume=48 | issue=1
| pmid=14667787

}}</ref>

The rate of clinical disease progression varies widely between individuals and has been shown to be affected by many factors such as host susceptibility and immune function<ref name=Clerici /><ref name=Morgan /><ref name=Tang /> health care and co-infections,<ref name=Morgan2 /><ref name=Lawn /> as well as factors relating to the viral strain.<ref name=Campbell /><ref name=Campbell2>{{

cite journal
| author=Campbell GR, Watkins JD, Esquieu D, Pasquier E, Loret EP, Spector SA
| title=The C terminus of HIV-1 Tat modulates the extent of CD178-mediated apoptosis of T cells
| journal=J. Biol. Chem. | year=2005 | pages=38376–39382 | volume=280 | issue=46
| pmid=16155003

}}</ref><ref name=Senkaali>{{

cite journal
| author=Senkaali D, Muwonge R, Morgan D, Yirrell D, Whitworth J, Kaleebu P
| title=The relationship between HIV type 1 disease progression and V3 serotype in a rural Ugandan cohort
| journal=AIDS Res. Hum. Retroviruses. | year=2005 | pages=932–937 | volume=20 | issue=9
| pmid=15585080

}}</ref> The specific opportunistic infections that AIDS patients develop depend in part on the prevalence of these infections in the geographic area in which the patient lives.

===Pulmonary infections===
[[Image:PCPxray.jpg|thumb|right|150px|X-ray of [[Pneumocystis pneumonia (PCP)|''Pneumocystis jirovecii'']] caused pneumonia. There is increased white (opacity) in the lower lungs on both sides, characteristic of ''Pneumocystis'' pneumonia]]
[[Pneumocystis pneumonia (PCP)|Pneumocystis pneumonia]] (originally known as ''Pneumocystis carinii'' pneumonia, and still abbreviated as PCP, which now stands for '''P'''neumo'''c'''ystis '''p'''neumonia) is relatively rare in healthy, [[immunocompetent]] people, but common among HIV-infected individuals. It is caused by [[Pneumocystis pneumonia (PCP)|''Pneumocystis jirovecii'']]. Before the advent of effective diagnosis, treatment and routine [[prophylaxis]] in Western countries, it was a common immediate cause of death. In developing countries, it is still one of the first indications of AIDS in untested individuals, although it does not generally occur unless the CD4 count is less than 200 per µL.<ref name=Feldman>{{

cite journal
| author=Feldman C | title=Pneumonia associated with HIV infection
| journal=Curr. Opin. Infect. Dis. | year=2005 | pages=165–170 | volume=18 | issue=2
| pmid=15735422

}}</ref>

[[Tuberculosis]] (TB) is unique among infections associated with HIV because it is transmissible to immunocompetent people via the respiratory route, is easily treatable once identified, may occur in early-stage HIV disease, and is preventable with drug therapy. However, [[multidrug resistance]] is a potentially serious problem. Even though its incidence has declined because of the use of directly observed therapy and other improved practices in Western countries, this is not the case in developing countries where HIV is most prevalent. In early-stage HIV infection (CD4 count >300 cells per µL), TB typically presents as a pulmonary disease. In advanced HIV infection, TB often presents atypically with extrapulmonary (systemic) disease a common feature. Symptoms are usually constitutional and are not localized to one particular site, often affecting [[bone marrow]], [[bone]], urinary and [[gastrointestinal tract]]s, [[liver]], regional [[lymph node]]s, and the [[central nervous system]].<ref name=Decker>{{

cite journal
| author=Decker CF, Lazarus A
| title=Tuberculosis and HIV infection. How to safely treat both disorders concurrently
| journal=Postgrad Med. | year=2000 | pages=57–60, 65–68 | volume=108 | issue=2
| pmid=10951746

}}</ref>

===Gastrointestinal infections===

[[Esophagitis]] is an inflammation of the lining of the lower end of the [[esophagus]] (gullet or swallowing tube leading to the [[stomach]]). In HIV infected individuals, this is normally due to fungal ([[candidiasis]]) or viral ([[Herpes simplex virus|herpes simplex-1]] or [[cytomegalovirus]]) infections. In rare cases, it could be due to [[mycobacteria]].<ref name=Zaidi>{{

cite journal
| author=Zaidi SA, Cervia JS
| title=Diagnosis and management of infectious esophagitis associated with human immunodeficiency virus infection
| journal=J. Int. Assoc. Physicians AIDS Care (Chic Ill) | year=2002 | pages=53–62 | volume=1 | issue=2
| pmid=12942677

}}</ref>

Unexplained chronic [[diarrhea]] in HIV infection is due to many possible causes, including common bacterial (''[[Salmonella]]'', ''[[Shigella]]'', ''[[Listeria]]'', ''[[Campylobacter]]'', or ''[[Escherichia coli]]'') and parasitic infections; and uncommon opportunistic infections such as [[cryptosporidiosis]], [[microsporidiosis]], ''[[Mycobacterium avium]]'' complex (MAC) and [[cytomegalovirus]] (CMV) [[colitis]]. In some cases, diarrhea may be a side effect of several drugs used to treat HIV, or it may simply accompany HIV infection, particularly during primary HIV infection. It may also be a side effect of [[antibiotic]]s used to treat bacterial causes of diarrhea (common for ''[[Clostridium difficile]]''). In the later stages of HIV infection, diarrhea is thought to be a reflection of changes in the way the [[intestinal tract]] absorbs nutrients, and may be an important component of HIV-related [[wasting]].<ref name=Guerrant>{{

cite journal
| author=Guerrant RL, Hughes JM, Lima NL, Crane J
| title=Diarrhea in developed and developing countries: magnitude, special settings, and etiologies
| journal=Rev. Infect. Dis. | year=1990 | pages=S41–S50 | volume=12 | issue=Suppl 1
| pmid=2406855

}}</ref>

===Neurological diseases===

[[Toxoplasmosis]] is a disease caused by the single-celled [[parasite]] called ''Toxoplasma gondii''; it usually infects the brain causing toxoplasma [[encephalitis]] but it can infect and cause disease in the [[eye]]s and lungs.<ref name=Luft>{{

cite journal
| author=Luft BJ, Chua A
| title=Central Nervous System Toxoplasmosis in HIV Pathogenesis, Diagnosis, and Therapy
| journal=Curr. Infect. Dis. Rep. | year=2000 | pages=358–362 | volume=2 | issue=4
| pmid=11095878

}}</ref>

[[Progressive multifocal leukoencephalopathy]] (PML) is a [[demyelinating disease]], in which the gradual destruction of the [[myelin]] sheath covering the [[axon]]s of nerve cells impairs the transmission of nerve impulses. It is caused by a virus called [[JC virus]] which occurs in 70% of the population in [[Virus latency|latent]] form, causing disease only when the immune system has been severely weakened, as is the case for AIDS patients. It progresses rapidly, usually causing death within months of diagnosis.<ref name=Sadler>{{

cite journal
| author=Sadler M, Nelson MR
| title=Progressive multifocal leukoencephalopathy in HIV
| journal=Int. J. STD AIDS | year=1997 | pages=351–357 | volume=8 | issue=6
| pmid=9179644

}}</ref>
[[AIDS dementia complex]] (ADC) is a metabolic [[encephalopathy]] induced by HIV infection and fueled by immune activation of HIV infected brain [[macrophage]]s and [[microglia]] which secrete [[neurotoxin]]s of both host and viral origin.<ref name=Gray>{{

cite journal
| author=Gray F, Adle-Biassette H, Chrétien F, Lorin de la Grandmaison G, Force G, Keohane C
| title=Neuropathology and neurodegeneration in human immunodeficiency virus infection. Pathogenesis of HIV-induced lesions of the brain, correlations with HIV-associated disorders and modifications according to treatments
| journal=Clin. Neuropathol. | year=2001 | pages=146–155 | volume=20 | issue=4
| pmid=11495003

}}</ref> Specific neurological impairments are manifested by cognitive, behavioral, and motor abnormalities that occur after years of HIV infection and is associated with low CD4+ T cell levels and high plasma viral loads. Prevalence is 10–20% in Western countries<ref name=Grant>{{

cite book
| author = Grant I, Sacktor H, McArthur J
| year = 2005
| title = The Neurology of AIDS
| chapter = HIV neurocognitive disorders
| chapterurl = http://www.hnrc.ucsd.edu/publications_pdf/2005grant1.pdf
| editor = H. E. Gendelman, I. Grant, I. Everall, S. A. Lipton, and S. Swindells. (ed.)
| edition = 2nd
| pages = 357–373
| publisher = Oxford University Press
| location = London, UK
| format= PDF
| id = ISBN 0-19-852610-5

}}</ref> but only 1–2% of HIV infections in India.<ref name=Satischandra>{{

cite journal
| author=Satishchandra P, Nalini A, Gourie-Devi M, et al | title=Profile of neurologic disorders associated with HIV/AIDS from Bangalore, South India (1989–1996)
| journal=Indian J. Med. Res. | year=2000 | pages=14–23 | volume=11 | issue=
| pmid=10793489

}}</ref><ref name=Wadia>{{

cite journal
| author=Wadia RS, Pujari SN, Kothari S, Udhar M, Kulkarni S, Bhagat S, Nanivadekar A
| title=Neurological manifestations of HIV disease
| journal=J. Assoc. Physicians India | year=2001 | pages=343–348 | volume=49 | issue=
| pmid=11291974

}}</ref> This difference is possibly due to the HIV subtype in India.

Cryptococcal meningitis is an infection of the [[meninges|meninx]] (the membrane covering the brain and [[spinal cord]]) by the fungus ''[[Cryptococcus]] neoformans''. It can cause fevers, [[headache]], [[Fatigue (medical)|fatigue]], [[nausea]], and [[vomiting]]. Patients may also develop [[seizure]]s and confusion; left untreated, it can be lethal.

===Tumors and malignancies===

[[Image:Kaposi's Sarcoma.jpg|thumb|right|150px|Kaposi's sarcoma]]

Patients with HIV infection have substantially increased incidence of several malignant [[cancer]]s. This is primarily due to co-infection with an [[oncogene|oncogenic]] [[DNA virus]], especially [[Epstein-Barr virus]] (EBV), Kaposi's sarcoma-associated herpesvirus ([[KSHV]]), and human [[papillomavirus]] (HPV).<ref name=Boshoff>{{

cite journal
| author=Boshoff C, Weiss R
| title=AIDS-related malignancies
| journal=Nat. Rev. Cancer | year=2002 | pages=373–382 | volume=2 | issue=5
| pmid=12044013

}}</ref><ref name=Yarchoan>{{

cite journal
| author=Yarchoan R, Tosatom G, Littlem RF
| title=Therapy insight: AIDS-related malignancies — the influence of antiviral therapy on pathogenesis and management
| journal=Nat. Clin. Pract. Oncol. | year=2005 | pages=406–415 | volume=2 | issue=8
| pmid=16130937

}}</ref>

Kaposi's sarcoma (KS) is the most common tumor in HIV-infected patients. The appearance of this tumor in young homosexual men in 1981 was one of the first signals of the AIDS epidemic. Caused by a [[Gammaherpesvirinae|gammaherpes]] virus called [[Kaposi's sarcoma-associated herpes virus]] (KSHV), it often appears as purplish [[Nodule (medicine)|nodules]] on the skin, but can affect other organs, especially the [[mouth]], gastrointestinal tract, and lungs.

High-grade [[B cell]] [[lymphoma]]s such as [[Burkitt's lymphoma]], Burkitt's-like lymphoma, diffuse large B-cell lymphoma (DLBCL), and [[primary central nervous system lymphoma]] present more often in HIV-infected patients. These particular cancers often foreshadow a poor prognosis. In some cases these lymphomas are AIDS-defining. [[Epstein-Barr virus]] (EBV) or KSHV cause many of these lymphomas.

[[Cervical cancer]] in HIV-infected women is considered AIDS-defining. It is caused by [[human papillomavirus]] (HPV).<ref>{{cite journal
|author=Palefsky J
|title=Human papillomavirus infection in HIV-infected persons
|journal=Top HIV Med
|volume=15
|issue=4
|pages=130–3
|year=2007
|pmid=17720998
|doi=
}}</ref>

In addition to the AIDS-defining tumors listed above, HIV-infected patients are at increased risk of certain other tumors, such as [[Hodgkin's disease]] and [[Anal cancer|anal]] and [[rectal carcinoma]]s. However, the incidence of many common tumors, such as [[breast cancer]] or [[colon cancer]], does not increase in HIV-infected patients. In areas where [[HAART]] is extensively used to treat AIDS, the incidence of many AIDS-related malignancies has decreased, but at the same time malignant cancers overall have become the most common cause of death of HIV-infected patients.<ref name=Bonnet>{{

cite journal
| author=Bonnet F, Lewden C, May T, et al | title=Malignancy-related causes of death in human immunodeficiency virus-infected patients in the era of highly active antiretroviral therapy
| journal=Cancer | year=2004 | pages=317–324 | volume=101 | issue=2
| pmid=15241829

}}</ref>

===Other opportunistic infections===

AIDS patients often develop opportunistic infections that present with non-specific symptoms, especially [[low-grade fever]]s and weight loss. These include infection with ''[[Mycobacterium avium]]-intracellulare'' and [[cytomegalovirus]] (CMV). CMV can cause colitis, as described above, and [[Cytomegalovirus retinitis|CMV retinitis]] can cause [[blindness]]. [[Penicilliosis]] due to ''[[Penicillium marneffei]]'' is now the third most common opportunistic infection (after extrapulmonary tuberculosis and [[cryptococcosis]]) in HIV-positive individuals within the endemic area of Southeast Asia.<ref name=Skoulidis>{{

cite journal
| author=Skoulidis F, Morgan MS, MacLeod KM
| title=Penicillium marneffei: a pathogen on our doorstep?
| journal=J. R. Soc. Med.| year=2004 | pages=394–396 | volume=97 | issue=2
| pmid=15286196

}}</ref>

==Cause==
{{details|HIV}}
[[Image:HIV-budding.jpg|right|thumbnail|300px|[[Scanning electron microscope|Scanning electron micrograph]] of HIV-1 budding from cultured [[lymphocyte]].]]

AIDS is the most severe acceleration of [[infection]] with HIV. HIV is a [[retrovirus]] that primarily infects vital organs of the human [[immune system]] such as [[T helper cell|CD4+ T cells]] (a subset of [[T cell]]s), [[macrophage]]s and [[dendritic cell]]s. It directly and indirectly destroys CD4+ T cells.<ref name=Alimonti>{{

cite journal
| author=Alimonti JB, Ball TB, Fowke KR
| title=Mechanisms of CD4+ T lymphocyte cell death in human immunodeficiency virus infection and AIDS.
| journal=J. Gen. Virol. | year=2003 | pages=1649–1661 | volume=84 | issue=7 | pmid=12810858 | doi=10.1099/vir.0.19110-0

}}</ref> CD4+ T cells are required for the proper functioning of the immune system. When HIV kills CD4+ T cells so that there are fewer than 200 CD4+ T cells per [[microliter]] (µL) of [[blood]], [[cellular immunity]] is lost. In some countries, such as the United States, this leads to a diagnosis of AIDS. In other jurisdictions, such as in Canada, AIDS is only diagnosed when a person infected with HIV is diagnosed with one or more of several AIDS-related opportunistic infections or cancers.<ref>[http://www.phac-aspc.gc.ca/publicat/haest-tesvs/a_e.html#AIDS_DIAGNOSIS Public Health Agency of Canada] (Note that this source is mistaken in its assertion that the U.S. definition of AIDS requires a CD4 count of <200.)</ref><ref>McGovern, Theresa and Smith, Raymond (1998). [http://www.thebody.com/content/art14002.html AIDS, Case Definition of.] TheBody.com. Retrieved on 2008-03-10.</ref><ref>[http://www.aegis.com/topics/definition.html AEGIS]</ref> [[Acute (medicine)|Acute]] HIV infection progresses over time to clinical latent HIV infection and then to early [[symptomatic]] HIV infection and later to AIDS, which is identified either on the basis of the amount of CD4+ T cells in the blood, and/or the presence of certain infections, as noted above.

In the absence of [[Antiretroviral drug|antiretroviral therapy]], the median [[HIV Disease Progression Rates|time of progression from HIV infection to AIDS]] is nine to ten years, and the median survival time after developing AIDS is only 9.2 months.<ref name=Morgan2>{{

cite journal
| author=Morgan D, Mahe C, Mayanja B, Okongo JM, Lubega R, Whitworth JA
| title=HIV-1 infection in rural Africa: is there a difference in median time to AIDS and survival compared with that in industrialized countries?
| journal=AIDS | year=2002 | pages=597–632 | volume=16 | issue=4 | pmid=11873003

}}</ref> However, the rate of clinical disease progression varies widely between individuals, from two weeks up to 20 years. Many factors affect the rate of progression. These include factors that influence the body's ability to defend against HIV such as the infected person's general immune function.<ref name=Clerici>{{

cite journal
| author=Clerici M, Balotta C, Meroni L, et al | title=Type 1 cytokine production and low prevalence of viral isolation correlate with long-term non progression in HIV infection
| journal=AIDS Res. Hum. Retroviruses. | year=1996 | pages=1053–1061 | volume=12 | issue=11
| pmid=8827221

}}</ref><ref name=Morgan>{{

cite journal
| author=Morgan D, Mahe C, Mayanja B, Whitworth JA
| title=Progression to symptomatic disease in people infected with HIV-1 in rural Uganda: prospective cohort study
| journal=BMJ | year=2002 | pages=193–196 | volume=324 | issue=7331
| pmid=11809639 | doi=10.1136/bmj.324.7331.193

}}</ref> Older people have weaker immune systems, and therefore have a greater risk of rapid disease progression than younger people. Poor access to [[health care]] and the existence of coexisting infections such as [[tuberculosis]] also may predispose people to faster disease progression.<ref name=Morgan2 /><ref name=Gendelman>{{

cite journal
| author=Gendelman HE, Phelps W, Feigenbaum L, et al | title=Transactivation of the human immunodeficiency virus long terminal repeat sequences by DNA viruses
| journal=Proc. Natl. Acad. Sci. U. S. A. | year=1986 | pages=9759–9763 | volume=83 | issue=24
| pmid=2432602

}}</ref><ref name=Bentwich>{{

cite journal
| author=Bentwich Z, Kalinkovich, A, Weisman Z
| title=Immune activation is a dominant factor in the pathogenesis of African AIDS.
| journal=Immunol. Today | year=1995 | pages=187–191 | volume=16 | issue=4
| pmid=7734046

}}</ref> The infected person's [[genetics|genetic inheritance]] plays an important role and some people are resistant to certain strains of HIV. An example of this is people with the [[homozygous]] [[CCR5-Δ32]] variation are resistant to infection with certain [[strain (biology)|strains]] of HIV.<ref name=Tang>{{

cite journal
| author=Tang J, Kaslow RA
| title=The impact of host genetics on HIV infection and disease progression in the era of highly active antiretroviral therapy
| journal=AIDS | year=2003 | pages=S51–S60 | volume=17 | issue=Suppl 4
| pmid=15080180

}}</ref> HIV is genetically variable and exists as different strains, which cause different rates of clinical disease progression.<ref name=Quinones>{{

cite journal
| author=Quiñones-Mateu ME, Mas A, Lain de Lera T, Soriano V, Alcami J, Lederman MM, Domingo E
| title=LTR and tat variability of HIV-1 isolates from patients with divergent rates of disease progression
| journal=Virus Research | year=1998 | pages=11–20 | volume=57 | issue=1
| pmid=9833881

}}</ref><ref name=Campbell>{{

cite journal
| author=Campbell GR, Pasquier E, Watkins J, et al | title=The glutamine-rich region of the HIV-1 Tat protein is involved in T-cell apoptosis
| journal=J. Biol. Chem. | year=2004 | pages=48197–48204 | volume=279 | issue=46
| pmid=15331610 | doi=10.1074/jbc.M406195200

}}</ref><ref name=Kaleebu>{{

cite journal
| author=Kaleebu P, French N, Mahe C, et al | title=Effect of human immunodeficiency virus (HIV) type 1 envelope subtypes A and D on disease progression in a large cohort of HIV-1-positive persons in Uganda | journal=J. Infect. Dis. | year=2002 | pages=1244–1250 | volume=185 | issue=9
| pmid=12001041

}}</ref> The use of highly active antiretroviral therapy prolongs both the median time of progression to AIDS and the median survival time.

===Alternative hypotheses===
{{main|AIDS reappraisal}}

A small minority of scientists and activists question the connection between HIV and AIDS,<ref name=Duesberg>{{cite journal
| author=Duesberg PH
| title=HIV is not the cause of AIDS
| journal=Science | year=1988 | pages=514, 517 | volume=241 | issue=4865
| pmid=3399880 | doi=10.1126/science.3399880
}}</ref> the existence of HIV itself,<ref name=Papadopulos>{{
cite journal
| author=Papadopulos-Eleopulos E, Turner VF, Papadimitriou J, et al
| title=A critique of the Montagnier evidence for the HIV/AIDS hypothesis
| journal=Med Hypotheses | year=2004 | pages=597–601 | volume=63 | issue=4
| pmid=15325002 | doi=10.1016/j.mehy.2004.03.025
}}</ref> or the validity of current testing and treatment methods. Though these claims have been examined and widely rejected by the scientific community,<ref name=consensus>For evidence of the [[scientific consensus]] that HIV is the cause of AIDS, see (for example):
*{{cite journal |title=The Durban Declaration |journal=Nature |volume=406 |issue=6791 |pages=15–6 |year=2000 |pmid=10894520 |doi=10.1038/35017662}} – full text [http://www.nature.com/nature/journal/v406/n6791/full/406015a0.html here].
*{{cite journal
| author=Cohen J
| title=The Controversy over HIV and AIDS
| journal=Science | year=1994 | pages=1642–1649 | volume=266 | issue=5191
| url=http://www.sciencemag.org/feature/data/cohen/266-5191-1642a.pdf|format=PDF}}
*{{cite web
| publisher=[[National Institute of Allergy and Infectious Diseases]] | year=
| url=http://www3.niaid.nih.gov/news/focuson/hiv/resources/
| title=Focus on the HIV-AIDS Connection: Resource links
| accessdate = 2006-09-07
}}
*{{cite journal |author=O'Brien SJ, Goedert JJ |title=HIV causes AIDS: Koch's postulates fulfilled |journal=Curr. Opin. Immunol. |volume=8 |issue=5 |pages=613-8 |year=1996 |pmid=8902385 |doi=}}
*{{cite journal |author=Galéa P, Chermann JC |title=HIV as the cause of AIDS and associated diseases |journal=Genetica |volume=104 |issue=2 |pages=133–42 |year=1998 |pmid=10220906 |doi=}}</ref> they continue to be promulgated through the Internet<ref>{{cite journal |author=Smith TC, Novella SP |title=HIV denial in the Internet era |journal=PLoS Med. |volume=4 |issue=8 |pages=e256 |year=2007 |pmid=17713982 |doi=10.1371/journal.pmed.0040256}}</ref> and have had a significant political impact, particularly in South Africa, where until late 2006 the Thabo Mbeki government did not accept that AIDS was caused by HIV, lead to an ineffective response to that country's AIDS epidemic.<ref>{{cite journal |author=Watson J |title=Scientists, activists sue South Africa's AIDS 'denialists' |journal=Nat. Med. |volume=12 |issue=1 |pages=6 |year=2006 |pmid=16397537 |doi=10.1038/nm0106-6a}}</ref><ref>{{cite journal |author=Baleta A |title=S Africa's AIDS activists accuse government of murder |journal=Lancet |volume=361 |issue=9363 |pages=1105 |year=2003 |pmid=12672319 |doi=10.1016/S0140-6736(03)12909-1}}</ref><ref>{{cite journal |author=Cohen J |title=South Africa's new enemy |journal=Science |volume=288 |issue=5474 |pages=2168-70 |year=2000 |pmid=10896606 |doi=10.1126/science.288.5474.2168}}</ref><ref>Andrew Meldrum. [http://www.guardian.co.uk/world/2006/oct/27/aids.southafrica South African government ends Aids denial], guardian.co.uk, 27 October 2006</ref>

===Misconceptions===
{{main|HIV and AIDS misconceptions}}
A number of misconceptions have arisen surrounding HIV/AIDS. Three of the most common are that AIDS can spread through casual contact, that sexual intercourse with a virgin will cure AIDS, and that HIV can infect only homosexual men and drug users. Other misconceptions are that any act of anal intercourse between gay men can lead to AIDS infection, and that open discussion of homosexuality and HIV in schools will lead to increased rates of homosexuality and AIDS.<ref>{{cite book
|author=Blechner MJ
|title=Hope and mortality: psychodynamic approaches to AIDS and HIV
|publisher=Analytic Press
|location=Hillsdale, NJ
|year=1997
|isbn=0-88163-223-6
}}</ref>

==Diagnosis==
[[Image:TEM HIV.jpg|thumb|200px|Thin-section transmission electron micrograph (TEM) depicting the ultrastructural details of two ”human immunodeficiency virus” (HIV) virions]]
[[Image:Kaposi's_sarcoma.jpg|thumb|Kaposi's sarcoma lesion commonly found in patients with stage IV AIDS]]
Since June 5, 1981, many definitions have been developed for [[epidemiology|epidemiological]] surveillance such as the Bangui definition and the 1994 expanded World Health Organization AIDS case definition. However, clinical staging of patients was not an intended use for these systems as they are neither sensitive, nor specific. In developing countries, the [[World Health Organization]] staging system for HIV infection and disease, using clinical and laboratory data, is used and in developed countries, the [[Centers for Disease Control and Prevention|Centers for Disease Control]] (CDC) Classification System is used.

===WHO disease staging system for HIV infection and disease===
{{main|WHO Disease Staging System for HIV Infection and Disease}}

In 1990, the [[World Health Organization]] (WHO) grouped these infections and conditions together by introducing a staging system for patients infected with HIV-1.<ref name=WHO>{{

cite journal
| author=World Health Organization
| title=Interim proposal for a WHO staging system for HIV infection and disease
| journal=WHO Wkly Epidem. Rec. | year=1990 | pages=221–228 | volume=65 | issue=29
| pmid=1974812

}}</ref> An update took place in September 2005. Most of these conditions are [[opportunistic infection]]s that are easily treatable in healthy people.
* Stage I: HIV infection is [[asymptomatic]] and not categorized as AIDS
* Stage II: includes minor [[Mucous membrane|mucocutaneous]] manifestations and recurrent [[upper respiratory tract]] infections
* Stage III: includes unexplained [[Chronic (medical)|chronic]] [[diarrhea]] for longer than a month, severe bacterial infections and [[pulmonary]] tuberculosis
* Stage IV: includes [[toxoplasmosis]] of the [[brain]], [[candidiasis]] of the [[esophagus]], [[Vertebrate trachea|trachea]], [[bronchi]] or [[lung]]s and [[Kaposi's sarcoma]]; these diseases are indicators of AIDS.

===CDC classification system for HIV infection===

{{main|CDC Classification System for HIV Infection}}

In the beginning, the [[Centers for Disease Control and Prevention]] (CDC) did not have an official name for the disease, often referring to it by way of the diseases that were associated with it, for example, [[lymphadenopathy]], the disease after which the discoverers of HIV originally named the virus.<ref name=MMWR1982a>{{

cite journal
| author=Centers for Disease Control (CDC)
| title=Persistent, generalized lymphadenopathy among homosexual males.
| journal=MMWR Morb Mortal Wkly Rep. | year=1982 | pages=249–251 | volume=31| issue=19
| pmid=6808340

}}</ref><ref name=Barre>{{cite journal | author=Barré-Sinoussi F, Chermann JC, Rey F, et al | title=Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS) | journal=Science | year=1983 | pages=868–871 | volume=220 | issue=4599 | pmid=6189183 | doi=10.1126/science.6189183 | format=
}}</ref> They also used ''Kaposi's Sarcoma and Opportunistic Infections'', the name by which a task force had been set up in 1981.<ref name=MMWR1982b>{{

cite journal
| author=Centers for Disease Control (CDC)
| title=Opportunistic infections and Kaposi's sarcoma among Haitians in the United States
| journal=MMWR Morb Mortal Wkly Rep. | year=1982 | pages=353–354; 360–361 | volume=31 | issue=26
| pmid=6811853

}}</ref> In the general press, the term ''GRID'', which stood for [[Gay-related immune deficiency]], had been coined.<ref name=Altman>{{

cite news
| author=Altman LK
| title=New homosexual disorder worries officials
| work=The New York Times | date=1982-05-11

}}</ref> However, after determining that AIDS was not isolated to the homosexual community,<ref name=MMWR1982b/> the term GRID became misleading and ''AIDS'' was introduced at a meeting in July 1982.<ref name=Kher>{{

cite news
| author=Kher U
| title=A Name for the Plague
| work=Time | date=1982-07-27 | url=http://www.time.com/time/80days/820727.html |accessdate=2008-03-10

}}</ref> By September 1982 the CDC started using the name AIDS, and properly defined the illness.<ref name=MMWR1982c>{{

cite journal
| author=Centers for Disease Control (CDC)
| title=Update on acquired immune deficiency syndrome (AIDS)—United States.
| journal=MMWR Morb Mortal Wkly Rep. | year=1982 | pages=507–508; 513–514 | volume=31 | issue=37
| pmid=6815471

}}</ref> In 1993, the CDC expanded their definition of AIDS to include all HIV positive people with a CD4+ T cell count below 200 per µL of blood or 14% of all [[lymphocyte]]s.<ref name=MMWR>{{

cite web | publisher=[[Centers for Disease Control and Prevention|CDC]] | publisher=CDC | year=1992
| url=http://www.cdc.gov/mmwr/preview/mmwrhtml/00018871.htm
| title=1993 Revised Classification System for HIV Infection and Expanded Surveillance Case Definition for AIDS Among Adolescents and Adults
| accessdate = 2006-02-09

}}</ref> The majority of new AIDS cases in developed countries use either this definition or the pre-1993 CDC definition. The AIDS diagnosis still stands even if, after treatment, the CD4+ T cell count rises to above 200 per µL of blood or other AIDS-defining illnesses are cured.

===HIV test===
{{main|HIV test}}

Many people are unaware that they are infected with HIV.<ref name=Kumaranayake>

{{cite journal
| author=Kumaranayake L, Watts C | title=
Resource allocation and priority setting of HIV/AIDS interventions: addressing the generalized epidemic in sub-Saharan Africa | journal=J. Int. Dev. | year=2001 | pages=451–466 | volume=13 | issue=4 | id={{DOI|10.1002/jid.798}}

}}</ref> Less than 1% of the sexually active urban population in Africa has been tested, and this proportion is even lower in rural populations. Furthermore, only 0.5% of pregnant women attending urban health facilities are counseled, tested or receive their test results. Again, this proportion is even lower in rural health facilities.<ref name=Kumaranayake>

{{cite journal
| author=Kumaranayake L, Watts C | title=
Resource allocation and priority setting of HIV/AIDS interventions: addressing the generalized epidemic in sub-Saharan Africa | journal=J. Int. Dev. | year=2001 | pages=451–466 | volume=13 | issue=4 | id={{DOI|10.1002/jid.798}}

}}</ref> Therefore, donor blood and blood products used in medicine and medical research are screened for HIV.

HIV tests are usually performed on venous blood. Many laboratories use ''fourth generation'' screening tests which detect anti-HIV antibody (IgG and IgM) and the HIV p24 antigen. The detection of HIV antibody or antigen in a patient previously known to be negative is evidence of HIV infection. Individuals whose first specimen indicates evidence of HIV infection will have a repeat test on a second blood sample to confirm the results. The window period (the time between initial infection and the development of detectable antibodies against the infection) can vary since it can take 3–6 months to [[seroconversion|seroconvert]] and to test positive. Detection of the virus using polymerase chain reaction ([[PCR]]) during the window period is possible, and evidence suggests that an infection may often be detected earlier than when using a fourth generation EIA screening test. Positive results obtained by PCR are confirmed by antibody tests.<ref name="pmid16706742">{{cite journal
|author=Weber B
|title=Screening of HIV infection: role of molecular and immunological assays
|journal=Expert Rev. Mol. Diagn.
|volume=6
|issue=3
|pages=399-411
|year=2006
|pmid=16706742
|doi=10.1586/14737159.6.3.399
|url=http://dx.doi.org/10.1586/14737159.6.3.399
}}</ref>
Routinely used HIV tests for infection in [[neonates]], born to HIV-positive mothers, have no value because of the presence of maternal antibody to HIV in the child's blood. HIV infection can only be diagnosed by PCR, testing for HIV pro-viral DNA in the children's [[lymphocyte]]s.<ref name="pmid11791341">{{cite journal
|author=Tóth FD, Bácsi A, Beck Z, Szabó J
|title=Vertical transmission of human immunodeficiency virus
|journal=Acta Microbiol Immunol Hung
|volume=48
|issue=3-4
|pages=413-27
|year=2001
|pmid=11791341
}}</ref>

==Transmission and prevention==

{| class="prettytable" style="float:right; font-size:85%; margin-left:15px;"
|- bgcolor="#efefef"
|+ Estimated per act risk for acquisition of HIV by exposure route<ref name=MMWR3>{{

cite journal | author=Smith DK, Grohskopf LA, Black RJ, et al | title=Antiretroviral Postexposure Prophylaxis After Sexual, Injection-Drug Use, or Other Nonoccupational Exposure to HIV in the United States | journal=MMWR | year=2005 | pages=1–20 | volume=54 | issue=RR02 | url=http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5402a1.htm#tab1

}}</ref>
|- bgcolor="#efefef"
! style="width: 100px" abbr="Route" | Exposure Route
! style="width: 130px" abbr="Infections" | Estimated infections per 10,000 exposures to an infected source
|-
! style="text-align:left"| Blood Transfusion
| 9,000<ref name=Donegan>{{

cite journal | author=Donegan E, Stuart M, Niland JC, et al | title=Infection with human immunodeficiency virus type 1 (HIV-1) among recipients of antibody-positive blood donations | journal=Ann. Intern. Med. | year=1990 | pages=733–739 | volume=113 | issue=10
| pmid=2240875

}}</ref>
|-
! style="text-align:left"| Childbirth
| 2,500<ref name=Coovadia>{{

cite journal | author=Coovadia H | title=Antiretroviral agents—how best to protect infants from HIV and save their mothers from AIDS | journal=N. Engl. J. Med. | year=2004 | pages=289–292 | volume=351 | issue=3 | pmid=15247337

}}</ref>
|-
! style="text-align:left"| Needle-sharing injection drug use
| 67<ref name=Kaplan>{{

cite journal | author=Kaplan EH, Heimer R | title=HIV incidence among New Haven needle exchange participants: updated estimates from syringe tracking and testing data | journal=J. Acquir. Immune Defic. Syndr. Hum. Retrovirol. | year=1995 | pages=175–176 | volume=10 | issue=2
| pmid=7552482

}}</ref>
|-
! style="text-align:left"| Percutaneous needle stick
| 30<ref name=Bell>{{

cite journal | author=Bell DM | title=Occupational risk of human immunodeficiency virus infection in healthcare workers: an overview. | journal=Am. J. Med. | year=1997 | pages=9–15 | volume=102 | issue=5B | pmid=9845490

}}</ref>

|-
! style="text-align:left"| Receptive anal intercourse*
| 50<ref name=ESG>{{

cite journal | author=European Study Group on Heterosexual Transmission of HIV | title=Comparison of female to male and male to female transmission of HIV in 563 stable couples | journal=BMJ. | year=1992 | pages=809–813 | volume=304 | issue=6830 | pmid=1392708

}}</ref><ref name=Varghese>{{

cite journal | author=Varghese B, Maher JE, Peterman TA, Branson BM,Steketee RW | title=Reducing the risk of sexual HIV transmission: quantifying the per-act risk for HIV on the basis of choice of partner, sex act, and condom use | journal=Sex. Transm. Dis. | year=2002 | pages=38–43 | volume=29 | issue=1 | pmid=11773877

}}</ref>
|-
! style="text-align:left"| Insertive anal intercourse*
| 6.5<ref name=ESG /><ref name=Varghese />
|-
! style="text-align:left"| Receptive penile-vaginal intercourse*
| 10<ref name=ESG /><ref name=Varghese /><ref name=Leynaert>{{

cite journal | author=Leynaert B, Downs AM, de Vincenzi I | title=Heterosexual transmission of human immunodeficiency virus: variability of infectivity throughout the course of infection. European Study Group on Heterosexual Transmission of HIV | journal=Am. J. Epidemiol. | year=1998 | pages=88–96 | volume=148 | issue=1 | pmid=9663408

}}</ref>
|-
! style="text-align:left"| Insertive penile-vaginal intercourse*
| 5<ref name=ESG /><ref name=Varghese />
|-
! style="text-align:left"| Receptive oral intercourse*§
| 1<ref name=Varghese />
|-
! style="text-align:left"| Insertive oral intercourse*
| 0.5<ref name=Varghese />§
|- bgcolor="#efefef"
! colspan=5 style="border-right:0px;";| * assuming no condom use § source refers to oral intercourse performed on a man
|}
The three main transmission routes of HIV are sexual contact, exposure to infected body fluids or tissues, and from mother to [[fetus]] or child during [[perinatal]] period. It is possible to find HIV in the [[saliva]], [[tears]], and [[urine]] of infected individuals, but there are no recorded cases of infection by these secretions, and the risk of infection is negligible.<ref>{{

cite web
| url=http://www.avert.org/aids.htm
| publisher = avert.org
| title=Facts about AIDS & HIV
| accessdate = 2007-11-30

}}</ref>

===Sexual contact===

The majority of HIV infections are acquired through [[Bareback (sex)|unprotected sex]]ual relations between partners, one of whom has HIV. The primary mode of HIV infection worldwide is through sexual contact between members of the opposite sex.<ref>{{

cite journal | author=Johnson AM, Laga M
| title=Heterosexual transmission of HIV | journal=AIDS | year=1988 | pages=S49-S56| volume=2 | issue=suppl. 1
| pmid=3130121

}}</ref><ref>{{

cite journal | author=N'Galy B, Ryder RW
| title=Epidemiology of HIV infection in Africa | journal=Journal of Acquired Immune Deficiency Syndromes | year=1988 | pages=551-558 | volume=1 | issue=6
| pmid=3225742

}}</ref><ref>{{

cite journal | author=Deschamps MM, Pape JW, Hafner A, Johnson WD Jr.
| title=Heterosexual transmission of HIV in Haiti | journal=Annals of Internal Medicine | year=1996 | pages=324–330 | volume=125 | issue=4
| pmid=8678397

}}</ref>
Sexual transmission occurs with the contact between sexual secretions of one partner with the rectal, genital or oral [[mucous membrane]]s of another. Unprotected receptive sexual acts are riskier than unprotected insertive sexual acts, with the risk for transmitting HIV from an infected partner to an uninfected partner through unprotected anal intercourse greater than the risk for transmission through vaginal intercourse or oral sex. Oral sex is not without its risks as HIV is transmissible through both insertive and receptive oral sex.<ref name=Rothenberg>{{

cite journal | author=Rothenberg RB, Scarlett M, del Rio C, Reznik D, O'Daniels C
| title=Oral transmission of HIV | journal=AIDS | year=1998 | pages=2095–2105 | volume=12 | issue=16
| pmid=9833850

}}</ref> The risk of HIV transmission from exposure to [[saliva]] is considerably smaller than the risk from exposure to [[semen]]; contrary to popular belief, one would have to swallow liters of saliva from a carrier to run a significant risk of becoming infected.<ref name=Vincenzi>{{

cite journal | author=Mastro TD, de Vincenzi I
| title=Probabilities of sexual HIV-1 transmission | journal=AIDS | year=1996 | volume=10 | pages=S75–S82 | issue=Suppl A | pmid=8883613

}}</ref>

Approximately 30% of women in ten countries representing "diverse cultural, geographical and urban/rural settings" report that their first sexual experience was forced or coerced, making sexual violence a key driver of the HIV/AIDS [[pandemic]].<ref name=vaw>{{

cite web
| publisher=[[World Health Organization]] | year=2006
| url=http://www.who.int/gender/violence/who_multicountry_study/en/index.html
| title=WHO Multi-country Study on Women's Health and Domestic Violence against Women
| accessdate = 2006-12-14

}}</ref> Sexual assault greatly increases the risk of HIV transmission as protection is rarely employed and physical trauma to the vaginal cavity frequently occurs which facilitates the transmission of HIV.<ref>{{cite journal
|author=Koenig MA, Zablotska I, Lutalo T, Nalugoda F, Wagman J, Gray R
|title=Coerced first intercourse and reproductive health among adolescent women in Rakai, Uganda
|journal=Int Fam Plan Perspect
|volume=30
|issue=4
|pages=156–63
|year=2004
|pmid=15590381
|doi=10.1363/ifpp.30.156.04
}}</ref>

[[Sexually transmitted infection]]s (STI) increase the risk of HIV transmission and infection because they cause the disruption of the normal [[epithelial]] barrier by genital [[ulcer]]ation and/or microulceration; and by accumulation of pools of HIV-susceptible or HIV-infected cells ([[lymphocyte]]s and [[macrophage]]s) in semen and vaginal secretions. Epidemiological studies from sub-Saharan Africa, Europe and North America have suggested that there is approximately a four times greater risk of becoming infected with HIV in the presence of a genital ulcer such as those caused by [[syphilis]] and/or [[chancroid]]. There is also a significant though lesser increased risk in the presence of STIs such as [[gonorrhea]], [[Chlamydia infection|Chlamydial infection]] and [[trichomoniasis]] which cause local accumulations of lymphocytes and macrophages.<ref name=Laga>{{

cite journal
| author=Laga M, Nzila N, Goeman J
| title=The interrelationship of sexually transmitted diseases and HIV infection: implications for the control of both epidemics in Africa
| journal=AIDS | year=1991 | pages=S55–S63 | volume=5 | issue=Suppl 1
| pmid=1669925

}}</ref>

Transmission of HIV depends on the infectiousness of the index case and the susceptibility of the uninfected partner. Infectivity seems to vary during the course of illness and is not constant between individuals. An undetectable plasma [[viral load]] does not necessarily indicate a low viral load in the seminal liquid or genital secretions. Each 10-fold increment of blood plasma HIV RNA is associated with an 81% increased rate of HIV transmission.<ref name=Laga /><ref name=Tovanabutra>{{

cite journal
| author=Tovanabutra S, Robison V, Wongtrakul J, et al
| title=Male viral load and heterosexual transmission of HIV-1 subtype E in northern Thailand
| journal=J. Acquir. Immune. Defic. Syndr. | year=2002 | pages=275–283 | volume=29 | issue=3
| pmid=11873077

}}</ref> Women are more susceptible to HIV-1 infection due to hormonal changes, vaginal microbial ecology and physiology, and a higher prevalence of sexually transmitted diseases.<ref name=Sagar>{{

cite journal
| author=Sagar M, Lavreys L, Baeten JM, et al
| title=Identification of modifiable factors that affect the genetic diversity of the transmitted HIV-1 population
| journal=AIDS | year=2004 | pages=615–619 | volume=18 | issue=4
| pmid=15090766

}}</ref><ref name=Lavreys>{{

cite journal
| author= Lavreys L, Baeten JM, Martin HL Jr, et al | title=Hormonal contraception and risk of HIV-1 acquisition: results of a 10-year prospective study
| journal=AIDS | year=2004 | pages=695–697 | volume=18 | issue=4
| pmid=15090778

}}</ref> People who are infected with HIV can still be infected by other, more [[virulent]] strains.

During a sexual act, only male or female condoms can reduce the chances of infection with HIV and other STDs and the chances of becoming [[pregnant]]. The best evidence to date indicates that typical condom use reduces the risk of [[heterosexual]] HIV transmission by approximately 80% over the long-term, though the benefit is likely to be higher if condoms are used correctly on every occasion.<ref name=Cayley>{{

cite journal
| author=Cayley WE Jr.
| title=Effectiveness of condoms in reducing heterosexual transmission of HIV
| journal=Am. Fam. Physician | year=2004 | pages=1268–1269 | volume=70 | issue=7
| pmid=15508535

}}</ref> The effective use of condoms and screening of blood transfusion in North America, Western and Central Europe is credited with contributing to the low rates of AIDS in these regions. Promoting condom use, however, has often proved controversial and difficult. Many religious groups, most noticeably the Roman Catholic Church, have opposed the use of condoms on religious grounds, and have sometimes seen condom promotion as an affront to the promotion of marriage, monogamy and sexual morality. Defenders of the Catholic Church's role in AIDS and general STD prevention state that, while they may be against the use of contraception, they are strong advocates of abstinence outside marriage.<ref name=catechism>{{

cite book
| author = Catholic Church
| year = 1997
| title = Catechism of the Catholic Church : Second Edition
| chapter = Offenses against chastity
| chapterurl = http://www.scborromeo.org/ccc/p3s2c2a6.htm#II
| pages = 2353
| publisher = Amministrazione Del Patrimonio Della Sede Apostolica
| location = Vatican
| accessdate = 2006-06-14

}}</ref> This attitude is also found among some health care providers and policy makers in sub-Saharan African nations, where HIV and AIDS prevalence is extremely high.<ref name=HRW>{{

cite book
| author = Human Rights Watch
| year = 2005
| title = The Less They Know, the Better
| chapter = Restrictions on Condoms
| chapterurl = http://hrw.org/reports/2005/uganda0305/7.htm#_Toc98378385
| publisher = Human Rights Watch
| location = New York NY

}}</ref> They also believe that the distribution and promotion of condoms is tantamount to promoting sex amongst the youth and sending the wrong message to uninfected individuals. However, no evidence has been produced that promotion of condom use increases sexual promiscuity,<ref name=noauthors>{{

cite journal
| author=No authors listed
| title=Study shows condom use does not promote promiscuity
| journal=AIDS Policy Law | year=1997 | pages=6–7 | volume=12| issue=12
| pmid=11364411

}}</ref> and abstinence-only programs have been unsuccessful in the United States both in changing sexual behavior and in reducing HIV transmission.<ref name=HRW2>{{

cite web
| publisher=Human Rights Watch | date=2002-09-02
| url=http://www.hrw.org/reports/2002/usa0902/USA0902-04.htm
| title=Ignorance only: HIV/AIDS, Human rights and federally funded abstinence-only programs in the United States. Texas: A case study
| accessdate = 2006-03-28

}}</ref> Evaluations of several abstinence-only programs in the US showed a negative impact on the willingness of youths to use contraceptives, due to the emphasis on contraceptives' failure rates.<ref name=AbstinenceEvals>{{

cite web
| author=Hauser, Debra | publisher=Advocates for Youth | year=2004 | format=PDF
| url=http://www.advocatesforyouth.org/publications/stateevaluations.pdf
| title=Five Years of Abstinence-Only-Until-Marriage Education: Assessing the Impact
| accessdate = 2006-06-07

}}</ref>

The male latex condom, if used correctly without oil-based lubricants, is the single most effective available technology to reduce the sexual transmission of HIV and other sexually transmitted infections. Manufacturers recommend that oil-based lubricants such as petroleum jelly, butter, and lard not be used with latex condoms, because they dissolve the latex, making the condoms [[Porosity|porous]]. If necessary, manufacturers recommend using [[water]]-based lubricants. Oil-based lubricants can however be used with [[polyurethane]] condoms.<ref name=Durex>{{

cite web
| publisher=Durex | year=
| url=http://www.durex.com/cm/assets/SexEdDownloads/Module_5_condoms.doc
| title=Module 5/Guidelines for Educators
| format= Microsoft Word
| accessdate = 2006-04-17

}}</ref> Latex condoms degrade over time, making them porous, which is why condoms have expiration dates. In Europe and the United States, condoms have to conform to European (EC 600) or American (D3492) standards to be considered protective against HIV transmission.

The [[female condom]] is an alternative to the male condom and is made from [[polyurethane]], which allows it to be used in the presence of oil-based lubricants. They are larger than male condoms and have a stiffened ring-shaped opening, and are designed to be inserted into the vagina. The female condom contains an inner ring, which keeps the condom in place inside the vagina – inserting the female condom requires squeezing this ring. However, at present availability of female condoms is very low and the price remains prohibitive for many women. Preliminary studies suggest that, where female condoms are available, overall protected sexual acts increase relative to unprotected sexual acts, making them an important HIV prevention strategy.<ref name=PATH>{{

cite journal
| author=PATH
| title=The female condom: significant potential for STI and pregnancy prevention
| journal=Outlook | year=2006 | volume=22 | issue=2

}}</ref>

With consistent and correct use of condoms, there is a very low risk of HIV infection. Studies on couples where one partner is infected show that with consistent condom use, HIV infection rates for the uninfected partner are below 1% per year.<ref name=WHOCondoms>{{

cite web
| publisher=[[World Health Organization|WHO]]| year= August 2003
| url=http://www.wpro.who.int/media_centre/fact_sheets/fs_200308_Condoms.htm
| title=Condom Facts and Figures
| accessdate = 2006-01-17
}}</ref>

In December 2006, the last of three large, [[Randomized controlled trial|randomized trials]] confirmed that male [[circumcision]] lowers the risk of HIV infection among heterosexual African men by around 50%. It is expected that this intervention will be actively promoted in many of the countries worst affected by HIV, although doing so will involve confronting a number of practical, cultural and attitudinal issues. Some experts fear that a lower perception of vulnerability among circumcised men may result in more sexual risk-taking behavior, thus negating its preventive effects.<ref name=NIAIDCircumcision>{{

cite web
| publisher=[[National Institute of Allergy and Infectious Diseases|NIAID]]
| date=2006-12-13
| url=http://www3.niaid.nih.gov/news/newsreleases/2006/AMC12_06.htm
| title=Adult Male Circumcision Significantly Reduces Risk of Acquiring HIV: Trials Kenya and Uganda Stopped Early
| accessdate = 2006-12-15

}}</ref> Furthermore, South African medical experts are concerned that the repeated use of unsterilized blades in the ritual circumcision of adolescent boys may be spreading HIV.<ref name=Kaisercircum>{{

cite web
| publisher=Kaisernetwork.org | year=2005 | url=http://www.kaisernetwork.org/daily_reports/rep_index.cfm?DR_ID=31199 | title=Repeated Use of Unsterilized Blades in Ritual Circumcision Might Contribute to HIV Spread in S. Africa, Doctors Say | accessdate = 2006-03-28
}}</ref>

Prevention strategies are well-known in developed countries, however, recent epidemiological and behavioral studies in Europe and North America have suggested that a substantial minority of young people continue to engage in high-risk practices and that despite HIV/AIDS knowledge, young people underestimate their own risk of becoming infected with HIV.<ref name=Dias>{{

cite journal
| author=Dias SF, Matos MG, Goncalves, A. C.
| title=Preventing HIV transmission in adolescents: an analysis of the Portuguese data from the Health Behaviour School-aged Children study and focus groups
| journal=Eur. J. Public Health | year=2005 | pages=300–304 | volume=15 | issue=3
| pmid=15941747

}}</ref>

===Exposure to infected body fluids===
[[Image:AIDS Poster If You're Dabbling in Drugs 1989.jpg|thumb|250px|CDC poster from 1989 highlighting the threat of AIDS associated with drug use]]
This transmission route is particularly relevant to [[Intravenous drug use (recreational)|intravenous drug]] users, [[Haemophilia|hemophiliacs]] and recipients of [[blood transfusion]]s and blood products. Sharing and reusing [[syringe]]s contaminated with HIV-infected blood represents a major risk for infection with not only HIV, but also [[hepatitis B]] and [[hepatitis C]]. Needle sharing is the cause of one third of all new HIV-infections and 50% of hepatitis C infections in North America, China, and Eastern Europe. The risk of being infected with HIV from a single prick with a needle that has been used on an HIV-infected person is thought to be about 1 in 150 ([[AIDS#Transmission and prevention|see table above]]). [[Post-exposure prophylaxis]] with anti-HIV drugs can further reduce that small risk.<ref name=Fan>{{

cite book
| author =Fan H | year = 2005
| title =AIDS: science and society | chapterurl =
| editor = Fan, H., Conner, R. F. and Villarreal, L. P. eds
| edition = 4th | pages =
| publisher =Jones and Bartlett Publishers
| location = Boston, MA
| id = ISBN 0-7637-0086-X

}}</ref> Health care workers (nurses, laboratory workers, doctors etc) are also concerned, although more rarely. This route can affect people who give and receive tattoos and piercings. [[Universal precautions]] are frequently not followed in both sub-Saharan Africa and much of Asia because of both a shortage of supplies and inadequate training. The WHO estimates that approximately 2.5% of all HIV infections in sub-Saharan Africa are transmitted through unsafe healthcare injections.<ref name=WHOJapan>{{ cite web
| publisher=[[World Health Organization|WHO]]| date= 2003-03-17
| url=http://64.233.179.104/search?q=cache:adH68_6JGG8J:tokyo.usembassy.gov//e/p/tp-20030317a3.html+site:tokyo.usembassy.gov+HIV+healthcare+injection&hl=en&gl=us&ct=clnk&cd=1
| title=WHO, UNAIDS Reaffirm HIV as a Sexually Transmitted Disease
| accessdate = 2006-01-17

}}</ref> Because of this, the United Nations General Assembly, supported by universal medical opinion on the matter, has urged the nations of the world to implement universal precautions to prevent HIV transmission in health care settings.<ref name=PHR>{{

cite web
| publisher=Physicians for Human Rights | work=Partners in Health | date=2003-03-13
| url=http://www.phrusa.org/campaigns/aids/who_031303.html
| title=HIV Transmission in the Medical Setting: A White Paper by Physicians for Human Rights | accessdate = 2006-03-01

}}</ref>
Drug abuse has an additional effect of an increased tendency to engage in unprotected sexual intercourse.<ref> [http://www.drugtext.org/library/articles/peddr0016.htm Drugtext.org]</ref>

The risk of transmitting HIV to [[blood transfusion]] recipients is extremely low in developed countries where improved donor selection and HIV screening is performed. However, according to the [[World Health Organization|WHO]], the overwhelming majority of the world's population does not have access to safe blood and "between 5% and 10% of HIV infections worldwide are transmitted through the transfusion of infected blood and blood products".<ref name=WHO070401>{{

cite web
| publisher=[[World Health Organization|WHO]] | year= 2001
| url=http://www.who.int/inf-pr-2000/en/pr2000-25.html
| title=Blood safety....for too few
| accessdate = 2006-01-17

}}</ref>

Medical workers who follow universal precautions or body-substance isolation, such as wearing latex gloves when giving injections and washing the hands frequently, can help prevent infection by HIV.

All AIDS-prevention organizations advise drug-users not to share needles and other material required to prepare and take drugs (including syringes, cotton balls, the spoons, water for diluting the drug, straws, crack pipes, etc). It is important that people use new or properly sterilized needles for each injection. Information on cleaning needles using bleach is available from health care and addiction professionals and from needle exchanges. In some developed countries, clean needles are available free in some cities, at needle exchanges or [[safe injection site]]s. Additionally, many nations have decriminalized needle possession and made it possible to buy injection equipment from pharmacists without a prescription.

Transmission of HIV between intravenous drug users has clearly decreased, and HIV transmission by blood transfusion has become quite rare in developed countries.

===Mother-to-child transmission (MTCT)===
The transmission of the virus from the mother to the child can occur ''[[in utero]]'' during the last weeks of pregnancy and at childbirth. In the absence of treatment, the transmission rate between the mother to the child during pregnancy, labor and delivery is 25%. However, when the mother has access to antiretroviral therapy and gives birth by [[caesarean section]], the rate of transmission is just 1%.<ref name=Coovadia /> A number of factors influence the risk of infection, particularly the viral load of the mother at birth (the higher the viral load, the higher the risk). [[Breastfeeding]] increases the risk of transmission by 4.04%.<ref name=Coovadia2>{{

cite journal
| author=Coovadia HM, Bland RM| title=Preserving breastfeeding practice through the HIV pandemic
| journal=Trop. Med. Int. Health. | year=2007| pages=1116–1133 | volume=12 | issue=9
| pmid=17714431

}}</ref> This risk depends on clinical factors and may vary according to the pattern and duration of breast-feeding.<ref name=Coovadia2 />

Studies have shown that antiretroviral drugs, caesarean delivery and formula feeding reduce the chance of transmission of HIV from mother to child.<ref name=Sperling>{{

cite journal
| author=Sperling RS, Shapirom DE, Coombsm RW, et al | title=Maternal viral load, zidovudine treatment, and the risk of transmission of human immunodeficiency virus type 1 from mother to infant
| journal=N. Engl. J. Med. | year=1996 | pages=1621–1629 | volume=335 | issue=22
| pmid=8965861

}}</ref> Current recommendations state that when replacement feeding is acceptable, feasible, affordable, sustainable and safe, HIV-infected mothers should avoid breast-feeding their infant. However, if this is not the case, exclusive breast-feeding is recommended during the first months of life and discontinued as soon as possible.<ref>{{cite web |url=http://www.who.int/hiv/mediacentre/Infantfeedingconsensusstatement.pf.pdf |format=PDF |date=2006 |accessdate=2008-03-12 |title= Consensus statement |author= WHO HIV and Infant Feeding Technical Consultation
}}</ref> In 2005, around 700,000 children under 15 contracted HIV, mainly through MTCT, with 630,000 of these infections occurring in Africa.<ref name=avert>
{{ cite web
| author=Berry S
| publisher=avert.org
| date= 2006-06-08
| url=http://www.avert.org/children.htm
| title=Children, HIV and AIDS
| accessdate = 2006-06-15
}}</ref> Of the children currently living with HIV, almost 90% live in sub-Saharan Africa.<ref name=UNAIDS2007/>

In Africa, the number of MTCT and the prevalence of AIDS is beginning to reverse decades of steady progress in child survival.<ref name=UNMTCT>{{

cite web
| publisher=United Nations | year=2001
| url=http://www.un.org/ga/aids/ungassfactsheets/html/fsmotherchild_en.htm
| title=Fact Sheet: Mother-to-child transmission of HIV
| accessdate = 2006-03-10

}}</ref> Countries such as Uganda are attempting to curb the MTCT epidemic by offering VCT (voluntary counseling and testing), PMTCT (prevention of mother-to-child transmission) and ANC (ante-natal care) services, which include the distribution of antiretroviral therapy.

==Treatment==

:''See also [[HIV#Treatment|HIV Treatment]] and [[Antiretroviral drug]].
[[Image:Abacavir (Ziagen) 300mg.jpg|right|thumb|100px|''[[Abacavir]]'' – a nucleoside analog reverse transcriptase inhibitors (NARTIs or NRTIs)]]
[[Image:Abacavir_structure.svg|thumb|The chemical structure of Abacavir]]

There is currently no [[HIV vaccine|vaccine]] or cure for [[HIV]] or AIDS. The only known methods of prevention are based on avoiding exposure to the virus or, failing that, an antiretroviral treatment directly after a highly significant exposure, called [[post-exposure prophylaxis]] (PEP).<ref name=Fan/> PEP has a very demanding four week schedule of dosage. It also has very unpleasant side effects including [[diarrhea]], [[malaise]], [[nausea]] and [[Fatigue (physical)|fatigue]].<ref name=PEPpocketguide>{{

cite web
| publisher=Department of Health and Human Services
| date=February 2006
| url=http://hab.hrsa.gov/tools/HIVpocketguide/PktGPEP.htm
| title=A Pocket Guide to Adult HIV/AIDS Treatment February 2006 edition
| accessdate = 2006-09-01

}}</ref>

Current treatment for HIV infection consists of [[highly active antiretroviral therapy]], or HAART.<ref name=DhhsHivTreatment>{{

cite web
| publisher=Department of Health and Human Services
| date=February 2006
| url=http://hab.hrsa.gov/tools/HIVpocketguide/PktGARTtables.htm
| title=A Pocket Guide to Adult HIV/AIDS Treatment February 2006 edition
| accessdate = 2006-09-01

}}</ref> This has been highly beneficial to many HIV-infected individuals since its introduction in 1996 when the protease inhibitor-based HAART initially became available.<ref name=Palella/> Current optimal HAART options consist of combinations (or "cocktails") consisting of at least three drugs belonging to at least two types, or "classes," of [[antiretroviral]] agents. Typical regimens consist of two [[nucleoside analogue reverse transcriptase inhibitor]]s (NARTIs or NRTIs) plus either a [[protease inhibitor (pharmacology)|protease inhibitor]] or a [[non-nucleoside reverse transcriptase inhibitor]] (NNRTI). Because HIV disease progression in children is more rapid than in adults, and laboratory parameters are less predictive of risk for disease progression, particularly for young infants, treatment recommendations are more aggressive for children than for adults.<ref name=2005dhhsHivChildren>{{

cite web
| publisher=Department of Health and Human Services Working Group on Antiretroviral Therapy and Medical Management of HIV-Infected Children
| date=2005-11-03
| url=http://www.aidsinfo.nih.gov/ContentFiles/PediatricGuidelines_PDA.pdf
| title=Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection
| format= PDF
| accessdate = 2006-01-17

}}</ref> In developed countries where HAART is available, doctors assess the [[viral load]], rapidity in CD4 decline, and patient readiness while deciding when to recommend initiating treatment.<ref name=2005DhhsHivTreatment>{{

cite web
| publisher=Department of Health and Human Services Panel on Clinical Practices for Treatment of HIV Infection
| date=2005-10-06
| url=http://aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf
| title=Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents
| format= PDF
| accessdate = 2006-01-17

}}</ref>

HAART allows the stabilization of the patient’s symptoms and viremia, but it neither cures the patient of HIV, nor alleviates the symptoms, and high levels of HIV-1, often HAART resistant, return once treatment is stopped.<ref name=martinez>{{

cite journal
| author=Martinez-Picado J, DePasquale MP, Kartsonis N, et al| title=Antiretroviral resistance during successful therapy of human immunodeficiency virus type 1 infection | journal=Proc. Natl. Acad. Sci. U. S. A. | year=2000 | pages=10948–10953 | volume=97 | issue=20 | pmid=11005867

}}</ref><ref name=Dybul>{{

cite journal
| author=Dybul M, Fauci AS, Bartlett JG, Kaplan JE, Pau AK; Panel on Clinical Practices for Treatment of HIV.
| title=Guidelines for using antiretroviral agents among HIV-infected adults and adolescents
| journal=Ann. Intern. Med. | year=2002 | pages=381–433 | volume=137 | issue=5 Pt 2
| pmid=12617573

}}</ref> Moreover, it would take more than the lifetime of an individual to be cleared of HIV infection using HAART.<ref name=blankson>{{

cite journal
| author=Blankson JN, Persaud D, Siliciano RF | title=The challenge of viral reservoirs in HIV-1 infection | journal=Annu. Rev. Med. | year=2002 | pages=557–593 | volume=53 | issue= | pmid=11818490

}}</ref> Despite this, many HIV-infected individuals have experienced remarkable improvements in their general health and quality of life, which has led to the plummeting of HIV-associated morbidity and mortality.<ref name=Pallelal>{{

cite journal
| author=Palella FJ, Delaney KM, Moorman AC, Loveless MO, Fuhrer J, Satten GA, Aschman DJ, Holmberg SD | title=Declining morbidity and mortality among patients with advanced human immunodeficiency virus infection | journal=N. Engl. J. Med. | year=1998 | pages=853–860 | volume=338 | issue=13 | pmid=9516219

}}</ref><ref name=Wood>{{

cite journal
| author=Wood E, Hogg RS, Yip B, Harrigan PR, O'Shaughnessy MV, Montaner JS
| title=Is there a baseline CD4 cell count that precludes a survival response to modern antiretroviral therapy?
| journal=AIDS | year=2003 | pages=711–720 | volume=17 | issue=5
| pmid=12646794

}}</ref><ref name=Chene>{{

cite journal
| author=Chene G, Sterne JA, May M, Costagliola D, Ledergerber B, Phillips AN, Dabis F, Lundgren J, D'Arminio Monforte A, de Wolf F, Hogg R, Reiss P, Justice A, Leport C, Staszewski S, Gill J, Fatkenheuer G, Egger ME and the Antiretroviral Therapy Cohort Collaboration
| title=Prognostic importance of initial response in HIV-1 infected patients starting potent antiretroviral therapy: analysis of prospective studies
| journal=Lancet | year=2003 | pages=679–686 | volume=362 | issue=9385
| pmid=12957089 | doi=10.1016/S0140-6736(03)14229-8

}}</ref> In the absence of HAART, progression from HIV infection to AIDS occurs at a median of between nine to ten years and the median survival time after developing AIDS is only 9.2 months.<ref name=Morgan2 /> HAART is thought to increase survival time by between 4 and 12 years.<ref name=JTKing>{{

cite journal
| author=King JT, Justice AC, Roberts MS, Chang CH, Fusco JS and the CHORUS Program Team
| title=Long-Term HIV/AIDS Survival Estimation in the Highly Active Antiretroviral Therapy Era
| journal=Medical Decision Making | year=2003 | pages=9–20 | volume=23 | issue=1
| pmid=12583451

}}</ref><ref name=Tassie>{{

cite journal
| author=Tassie JM, Grabar S, Lancar R, Deloumeaux J, Bentata M, Costagliola D and the Clinical Epidemiology Group from the French Hospital Database on HIV
| title=Time to AIDS from 1992 to 1999 in HIV-1-infected subjects with known date of infection
| journal=Journal of acquired immune deficiency syndromes | year=2002 | pages=81–7 | volume=30 | issue=1
| pmid=12048367

}}</ref> This average reflects the fact that for some patients – and in many clinical cohorts this may be more than fifty percent of patients – HAART achieves far less than optimal results. This is due to a variety of reasons such as medication intolerance/side effects, prior ineffective antiretroviral therapy and infection with a drug-resistant strain of HIV. However, non-adherence and non-persistence with antiretroviral therapy is the major reason most individuals fail to get any benefit from and develop resistance to HAART.<ref name=becker>{{

cite journal
| author=Becker SL, Dezii CM, Burtcel B, Kawabata H, Hodder S. | title=Young HIV-infected adults are at greater risk for medication nonadherence | journal=MedGenMed. | year=2002 | pages=21 | volume=4| issue=3 | pmid=12466764

}}</ref> The reasons for non-adherence and non-persistence with HAART are varied and overlapping. Major psychosocial issues, such as poor access to medical care, inadequate social supports, psychiatric disease and drug abuse contribute to non-adherence. The complexity of these HAART regimens, whether due to pill number, dosing frequency, meal restrictions or other issues, along with side effects that create intentional non-adherence, also has a weighty impact.<ref name=Nieuwkerk>{{

cite journal
| author=Nieuwkerk P, Sprangers M, Burger D, Hoetelmans RM, Hugen PW, Danner SA, van Der Ende ME, Schneider MM, Schrey G, Meenhorst PL, Sprenger HG, Kauffmann RH, Jambroes M, Chesney MA, de Wolf F, Lange JM and the ATHENA Project | title=Limited Patient Adherence to Highly Active Antiretroviral Therapy for HIV-1 Infection in an Observational Cohort Study | journal=Arch. Intern. Med. | year=2001 | pages=1962–1968 | volume=161 | issue=16 | pmid=11525698

}}</ref><ref name=Kleeberger>{{

cite journal
| author=Kleeberger C, Phair J, Strathdee S, Detels R, Kingsley L, Jacobson LP | title=Determinants of Heterogeneous Adherence to HIV-Antiretroviral Therapies in the Multicenter AIDS Cohort Study| journal=J. Acquir. Immune Defic. Syndr. | year=2001 | pages=82–92 | volume=26 | issue=1 | pmid=11176272

}}</ref><ref name=heath>{{

cite journal
| author=Heath KV, Singer J, O'Shaughnessy MV, Montaner JS, Hogg RS | title=Intentional Nonadherence Due to Adverse Symptoms Associated With Antiretroviral Therapy | journal=J. Acquir. Immune Defic. Syndr. | year=2002 | pages=211–217 | volume=31 | issue=2 | pmid=12394800

}}</ref> The side effects include [[lipodystrophy]], [[dyslipidaemia]], [[insulin resistance]], an increase in [[cardiovascular]] risks and [[birth defect]]s.<ref name=Montessori>{{

cite journal |
author=Montessori V, Press N, Harris M, Akagi L, Montaner JS |
title=Adverse effects of antiretroviral therapy for HIV infection. |
journal=CMAJ | year=2004 | pages=229–238 | volume=170 | issue=2 | pmid=14734438

}}</ref><ref name=Saitoh>{{

cite journal
| author=Saitoh A, Hull AD, Franklin P, Spector SA
| title=Myelomeningocele in an infant with intrauterine exposure to efavirenz
| journal=J. Perinatol. | year=2005 | pages=555–556 | volume=25 | issue=8
| pmid=16047034 | doi=10.1038/sj.jp.7211343

}}</ref>

Daily multivitamin and mineral supplements have been found to reduce HIV disease progression among men and women. This could become an important low-cost intervention provided during early HIV disease to prolong the time before antiretroviral therapy is required.<ref name=Fawzi>{{

cite journal
| author=Fawzi W, Msamanga G, Spiegelman D, Hunter DJ
| title=Studies of vitamins and minerals and HIV transmission and disease progression
| journal=J. Nutrition| year=2005 | pages=938–944 | volume=135 | issue=4
| pmid=15795466
}}
</ref> Some individual nutrients have also been tried.<ref name=Hurwitz>([[Selenium]]:) {{

cite journal
| author=Hurwitz BE, Klaus JR, Llabre MM, Gonzalez A, Lawrence PJ, Maher KJ, Greeson JM, Baum MK, Shor-Posner G, Skyler JS, Schneiderman N
| title=Suppression of human immunodeficiency virus type 1 viral load with selenium supplementation: a randomized controlled trial
| journal=Arch Intern Med.| year=2007 | pages=148–155 | volume=167 | issue=2
| pmid=17242315
}}</ref><ref name=Cathcart1>([[Vitamin C]]:) {{

cite journal
| author=Cathcart RR
| title=Vitamin C in the Treatment of Acquired Immune Deficiency Syndrome
| journal=Medical Hypotheses | year=1984 | volume=14 | issue=4 | pages=423-433
| pmid=6238227 | doi=10.1016/0306-9877(84)90149-X
| url=http://www.doctoryourself.com/aids_cathcart.html

}}</ref> Anti-retroviral drugs are expensive, and the majority of the world's infected individuals do not have access to medications and treatments for HIV and AIDS.<ref name=Ferrantelli>{{

cite journal
| author=Ferrantelli F, Cafaro A, Ensoli B | title=Nonstructural HIV proteins as targets for prophylactic or therapeutic vaccines | journal=Curr Opin Biotechnol. | year=2004 | pages=543–556 | volume=15 | issue=6
| pmid=15560981

}}</ref> It has been postulated that only a vaccine can halt the pandemic because a vaccine would possibly cost less, thus being affordable for developing countries, and would not require daily treatments.<ref name=Ferrantelli/> However, after over 20 years of research, HIV-1 remains a difficult target for a vaccine.<ref name=Ferrantelli/>

Research to improve current treatments includes decreasing side effects of current drugs, further simplifying drug regimens to improve adherence, and determining the best sequence of regimens to manage drug resistance. A number of studies have shown that measures to prevent opportunistic infections can be beneficial when treating patients with HIV infection or AIDS. [[Vaccination]] against [[hepatitis]] A and B is advised for patients who are not infected with these viruses and are at risk of becoming infected.<ref name=Laurence>{{

cite journal
| author=Laurence J
| title=Hepatitis A and B virus immunization in HIV-infected persons
| journal=AIDS Reader | year=2006 | pages=15–17 | volume=16 | issue=1
| pmid=16433468

}}</ref> Patients with substantial immunosuppression are also advised to receive prophylactic therapy for [[Pneumocystis jiroveci pneumonia]] (PCP), and many patients may benefit from prophylactic therapy for [[toxoplasmosis]] and [[Cryptococcus]] [[meningitis]] as well.<ref name=PEPpocketguide>{{

cite web
| publisher=Department of Health and Human Services
| date = 2007-02-02
| url=http://www.guideline.gov/summary/summary.aspx?ss=14&doc_id=6223&string=infected+AND+patients
| title=Treating opportunistic infections among HIV-infected adults and adolescents. Recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association/Infectious Diseases Society of America.
| accessdate = 2007-02-05

}}</ref>

Various forms of [[alternative medicine]] have been used to treat symptoms or alter the course of the disease.<ref name=Saltmarsh>{{

cite journal
| author=Saltmarsh S
| title=Voodoo or valid? Alternative therapies benefit those living with HIV
| journal=Positively Aware | year=2005 | pages=46 | volume=3 | issue=16
| pmid=16479668 | url=http://www.tpan.com/publications/pa/may_jun_05/voodoo.shtml

}}
</ref> In the first decade of the [[epidemic]] when no useful conventional treatment was available, a large number of people with AIDS experimented with alternative therapies. The definition of "alternative therapies" in AIDS has changed since that time. Then, the phrase often referred to community-driven treatments, untested by government or pharmaceutical company research, that some hoped would directly suppress the virus or stimulate immunity against it. Examples of alternative medicine that people hoped would improve their symptoms or their quality of life include massage, stress management, herbal and flower remedies such as boxwood,<ref name=Pharo>{{

cite journal
| author=Pharo A, et al
| title=Evaluation of the safety and efficacy of SPV-30 (boxwood extract) in patients with HIV disease
| journal=Int Conf AIDS | year=1996 | issue=Jul 7–12 | pages=11:19 | id=abstract no. Mo. B.180
| url=http://www.aegis.org/conferences/iac/1996/MoB180.html

}}
</ref><ref name=Durant>{{

cite journal
| author=Durant J, et al
| title=Efficacy and safety of Buxussempervirens L. preparations (SPV-30) in HIV infected asymptomatic patients: a multi-centre, randomized, double-blind, placebo-controlled trial.
| journal=Phytomedicine | year = 1998 | issue=5 | pages=1–10

}}
</ref> and [[acupuncture]];<ref name=Saltmarsh /> when used with conventional treatment, many now refer to these as "complementary" approaches. Despite the widespread use of complementary and alternative medicine by people living with HIV/AIDS, the effectiveness of these therapies has not been established.<ref name=Mills>{{

cite journal
| author=Mills E, Wu P, Ernst E
| title=Complementary therapies for the treatment of HIV: in search of the evidence.
| journal=Int. J. STD AIDS.| year=2005 | pages=395–403 | volume=16 | issue=6
| pmid=15969772

}}</ref>

==Prognosis==

Without treatment, the net median survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype,<ref name=UNAIDS2007/> and the median survival rate after diagnosis of AIDS in resource-limited settings where treatment is not available ranges between 6 and 19 months, depending on the study.<ref>{{cite paper |title= Progression and mortality of untreated HIV-positive individuals living in resource-limited settings: update of literature review and evidence synthesis |author= Zwahlen M, Egger M |url=http://data.unaids.org/pub/Periodical/2006/zwahlen_unaids_hq_05_422204_2007_en.pdf |format=PDF |date=2006 |accessdate=2008-03-19 |version= UNAIDS Obligation HQ/05/422204}}</ref> In areas where it is widely available, the development of [[HAART]] as effective therapy for HIV infection and AIDS reduced the death rate from this disease by 80%, and raised the life expectancy for a newly-diagnosed HIV-infected person to about 20 years.<ref>{{cite journal |journal= Int J Dermatol |date=2007 |volume=46 |issue=12 |pages=1219–28 |title= Current status of HIV infection: a review for non-HIV-treating physicians |author= Knoll B, Lassmann B, Temesgen Z |pmid=18173512 |doi=10.1111/j.1365-4632.2007.03520.x |pmid=18173512}}</ref>

===Economic impact===
[[Image:Life expectancy in some Southern African countries 1958 to 2003.jpg|right|295px|thumb|Changes in life expectancy in some hard-hit African countries.
{{legend-line|red solid 2px|Botswana}}{{legend-line|darkgreen solid 2px|Zimbabwe}}{{legend-line|blue solid 2px|Kenya}}{{legend-line|black solid 2px|South Africa}}{{legend-line|grey solid 2px|Uganda}}]]

HIV and AIDS retard economic growth by destroying human capital.<ref name=Bell-et-al-2003/>
Without proper [[nutrition]], health care and medicine that is available in developed countries, large numbers of people are falling victim to AIDS. They will not only be unable to work, but will also require significant medical care. The forecast is that this will likely cause a collapse of economies and societies in the region. In some heavily infected areas, the epidemic has left behind many orphans cared for by elderly grandparents.<ref name=Greener>{{cite book
| author =Greener R
| year = 2002
| title = State of The Art: AIDS and Economics
| chapter = AIDS and macroeconomic impact
| editor = S, Forsyth (ed.)
| pages = 49–55
| publisher = IAEN
}}</ref>

The increased mortality in this region will result in a smaller skilled population and labor force.<ref name=Greener /> This smaller labor force will be predominantly young people, with reduced knowledge and work experience leading to reduced productivity. An increase in workers’ time off to look after sick family members or for sick leave will also lower productivity. Increased mortality will also weaken the mechanisms that generate human capital and investment in people, through loss of income and the death of parents.<ref name=Greener /> By killing off mainly young adults, AIDS seriously weakens the taxable population, reducing the resources available for public expenditures such as education and health services not related to AIDS resulting in increasing pressure for the state's finances and slower growth of the economy. This results in a slower growth of the tax base, an effect that will be reinforced if there are growing expenditures on treating the sick, training (to replace sick workers), sick pay and caring for AIDS orphans. This is especially true if the sharp increase in adult mortality shifts the responsibility and blame from the family to the government in caring for these orphans.<ref name=Greener />

On the level of the household, AIDS results in both the loss of income and increased spending on healthcare by the household. The income effects of this lead to spending reduction as well as a substitution effect away from education and towards healthcare and funeral spending. A study in Côte d'Ivoire showed that households with an HIV/AIDS patient spent twice as much on medical expenses as other households.<ref name=WBank>{{

cite journal |
author=Over M |
title=The macroeconomic impact of AIDS in Sub-Saharan Africa, Population and Human Resources Department |
journal=The World Bank | year=1992

}}</ref>

UNAIDS, WHO and the United Nations Development Programme have documented a correlation between the decreasing life expectancies and the lowering of gross national product in many African countries with prevalence rates of 10% or more. Indeed, since 1992 predictions that AIDS would slow economic growth in these countries have been published. The degree of impact depended on assumptions about the extent to which illness would be funded by savings and who would be infected.<ref name=WBank /> Conclusions reached from models of the growth trajectories of 30 sub-Saharan economies over the period 1990–2025 were that the economic growth rates of these countries would be between 0.56 and 1.47% lower. The impact on gross domestic product (GDP) per capita was less conclusive. However, in 2000, the rate of growth of Africa's per capita GDP was in fact reduced by 0.7% per year from 1990–1997 with a further 0.3% per year lower in countries also affected by [[malaria]].<ref name=Bonnel>{{

cite journal |
author=Bonnel R |
title=HIV/AIDS and Economic Growth: A Global Perspective |
journal=S. A. J. Economics | year=2000 | pages=820–855 | volume=68 | issue=5 |

}}</ref> The forecast now is that the growth of GDP for these countries will undergo a further reduction of between 0.5 and 2.6% per annum.<ref name=Greener /> However, these estimates may be an underestimate, as they do not look at the effects on output per capita.<ref name=Bell-et-al-2003>{{

cite paper
|author= Bell C, Devarajan S, Gersbach H |date=2003
|url=http://ssrn.com/abstract=636571
| title=The long-run economic costs of AIDS: theory and an application to South Africa
|accessdate= 2008-03-12
|version= World Bank Policy Research Working Paper No. 3152

}}</ref>

Many governments in sub-Saharan Africa denied that there was a problem for years, and are only now starting to work towards solutions. Underfunding is a problem in all areas of HIV prevention when compared to even conservative estimates of the problems.

Recent research by the Overseas Development Institute (ODI) has suggested that the private sector has begun to recognize the impact of HIV/AIDS on the bottom line, both directly and indirectly. It is estimated that a company can generate an average return of US$3 for every US$1 invested in employee health due to a reduced absenteeism, better productivity and reduction in employee turnover.<ref>{{cite journal
| author = Goetzel RZ, Ozminkowski RJ, Baase CM, Billotti GM
| title = Estimating the return-on-investment from changes in employee health risks on the Dow Chemical Company’s health care costs
| journal = Journal of Occupational and Environmental Medicine
| volume = 47
| year = 2005
| pages = 759-68
| pmid = 16093925}}</ref> Indirectly there are also important implications on the supply chain. Many multi-national corporations (MNCs) have therefore gotten involved in HIV/AIDS initiatives of three main types: a community-based partnerships, supply chain support, and sector-based initiatives.<ref name="odi">{{cite web |url=http://www.odi.org.uk/publications/briefing/bp_hiv_privatesector_nov07.pdf |format=PDF|title= AIDS and the private sector: The case of South Africa |accessyear=2007 |year=2007 |publisher=Overseas Development Institute}}</ref>

The launching of the world's first official HIV/AIDS Toolkit in Zimbabwe on October 3 2006 is a product of collaborative work between the International Federation of Red Cross and Red Crescent Societies, World Health Organization and the Southern Africa HIV/AIDS Information Dissemination Service. It is for the strengthening of people living with HIV/AIDS and nurses by minimal external support. The package, which is in form of eight modules focusing on basic facts about HIV and AIDS, was pre-tested in Zimbabwe in March 2006 to determine its adaptability. It disposes, among other things, categorized guidelines on clinical management, education and counseling of AIDS victims at community level.<ref name=xinhua>{{

cite web
| author=Mu Xuequan | publisher=xinhua | year= 2006
| url=http://news.xinhuanet.com/english/2006-10/04/content_5167991.htm
| title=Zimbabwe launches world's first AIDS training package
| accessdate = 2006-10-03

}}</ref>

The Copenhagen Consensus is a project that seeks to establish priorities for advancing global welfare using methodologies based on the theory of welfare economics. The participants are all economists, with the focus of the project being a rational prioritization based on economic analysis. The project is based on the contention that, in spite of the billions of dollars spent on global challenges by the United Nations, the governments of wealthy nations, foundations, charities, and non-governmental organizations, the money spent on problems such as malnutrition and climate change is not sufficient to meet many internationally-agreed targets. The highest priority was assigned to implementing new measures to prevent the spread of HIV and AIDS. The economists estimated that an investment of $27 billion could avert nearly 30 million new infections by 2010.<ref name=Kaiserfunds>{{

cite web
| publisher=kaisernetwork.org | year= 2002
| url=http://kaisernetwork.org/aids2002/syndication.asp?show=daily_report_1.html
| title=$27 Billion Boost for HIV Prevention Programs Could Avert Majority of Projected HIV Infections Worldwide
| accessdate = 2008-03-10

}}</ref>

===Stigma===
[[Image:Saigon AIDS Sign.jpg|thumb|250px|right|AIDS Awareness Sign. Ho Chi Minh City, Vietnam (August 2005).]]
AIDS stigma exists around the world in a variety of ways, including ostracism, rejection, discrimination and avoidance of HIV infected people; compulsory HIV testing without prior [[consent]] or protection of confidentiality; violence against HIV infected individuals or people who are perceived to be infected with HIV; and the [[quarantine]] of HIV infected individuals.<ref name=UNAIDS2006Ch4>{{

cite book
| publisher =[[Joint United Nations Programme on HIV/AIDS|UNAIDS]]
| year = 2006
| title = 2006 Report on the global AIDS epidemic
| chapter = The impact of AIDS on people and societies
| chapterurl = http://data.unaids.org/pub/GlobalReport/2006/2006_GR_CH04_en.pdf
| accessdate = 2006-06-14
| format= PDF

}}</ref> Stigma-related violence or the fear of violence prevents many people from seeking HIV testing, returning for their results, or securing treatment, possibly turning what could be a manageable chronic illness into a death sentence and perpetuating the spread of HIV.<ref name=Ogden>{{

cite web
| author =Ogden J, Nyblade L
| publisher = [[International Center for Research on Women]] | year = 2005 | title = Common at its core: HIV-related stigma across contexts | url = http://www.icrw.org/docs/2005_report_stigma_synthesis.pdf | format = PDF | accessdate = 2007-02-15

}}</ref>

AIDS stigma has been further divided into the following three categories:

# Instrumental AIDS stigma—a reflection of the fear and apprehension that are likely to be associated with any deadly and transmissible illness.<ref name=Herek1999>{{

cite journal
| author=Herek GM, Capitanio JP | journal=American Behavioral Scientist | year=1999
| url=http://psychology.ucdavis.edu/rainbow/html/abs99_sp.pdf
| format= PDF
| title=AIDS Stigma and sexual prejudice
| accessdate = 2006-03-27
| volume=42
| issue=7
| pages=1130-1147
| doi=10.1177/0002764299042007006

}}</ref>
# Symbolic AIDS stigma—the use of HIV/AIDS to express attitudes toward the social groups or lifestyles perceived to be associated with the disease.<ref name=Herek1999 />
# Courtesy AIDS stigma—stigmatization of people connected to the issue of HIV/AIDS or HIV- positive people.<ref name=Snyder>{{

cite journal |
author=Snyder M, Omoto AM, Crain AL |
title=Punished for their good deeds: stigmatization for AIDS volunteers |
journal=American Behavioral Scientist | year=1999 | pages=1175–1192 | volume=42 | issue=7 | doi=10.1177/0002764299042007009

}}</ref>

Often, AIDS stigma is expressed in conjunction with one or more other stigmas, particularly those associated with [[homosexuality]], bisexuality, promiscuity, and [[Intravenous drug use (recreational)|intravenous drug use]].

In many developed countries, there is an association between AIDS and homosexuality or bisexuality, and this association is correlated with higher levels of sexual prejudice such as anti-homosexual attitudes.<ref name=Herek2002>{{cite journal
|author=Herek GM, Capitanio JP, Widaman KF
|title=HIV-related stigma and knowledge in the United States: prevalence and trends, 1991-1999
|journal=Am J Public Health
|volume=92
|issue=3
|pages=371–7
|year=2002
|pmid=11867313
|doi=
|url=http://psychology.ucdavis.edu/rainbow/html/ajph2002.pdf
|accessdate=2008-03-10
}}</ref> There is also a perceived association between AIDS and all male-male sexual behavior, including sex between uninfected men.<ref name=Herek1999/>

== Prevention ==
The diverse transmission routes of HIV are well-known and established. Also well-known is how to prevent transmission of HIV. However, recent epidemiological and behavioral studies in Europe and North America have suggested that a substantial minority of young people continue to engage in high-risk practices and that despite HIV/AIDS knowledge, young people underestimate their own risk of becoming infected with HIV (Dias et al., 2005). However, transmission of HIV between intravenous drug users has clearly decreased and HIV transmission by blood transfusion has become almost obsolete in this population.

== Prevention of sexual transmission of HIV ==

=== Underlying science ===
* Unprotected receptive sexual acts are at more risk than unprotected insertive sexual acts, with the risk for transmitting HIV from an infected partner to an uninfected partner through unprotected insertive anal intercourse (UIAI) greater than the risk for transmission through receptive anal intercourse or oral sex. According to the French ministry for health, the probability of transmission per act varies from 0.03% to 0.07% for the case of receptive vaginal sex, from 0.02 to 0.05% in the case of insertive vaginal sex, from 0.01% to 0.185% in the case of insertive anal sex, and 0.5% to 3% in the case of receptive anal sex [1].

* Sexually-transmitted infections (STI) increase the risk of HIV transmission and infection because they cause the disruption of the normal epithelial barrier by genital ulceration and/or microulceration; and by accumulation of pools of HIV-susceptible or HIV-infected cells (lymphocytes and macrophages) in semen and vaginal secretions. Epidemiological studies from sub-Saharan Africa, Europe and North America have suggested that there is approximately, a four times greater risk of becoming HIV-infected in the presence of a genital ulcer such as caused by syphilis and/or chancroid; and a significant though lesser increased risk in the presence of STIs such as gonorrhoea, chlamydial infection and trichomoniasis which cause local accumulations of lymphocytes and macrophages (Laga et al., 1991).
* Transmission of HIV depends on the infectiousness of the index case and the susceptibility of the uninfected partner. Infectivity seems to vary during the course of illness and is not constant between individuals. An undetectable plasma viral load does not mean that you have a low viral load in the seminal liquid or genital secretions. Each 10 fold increment of seminal HIV RNA is associated with an 81% increased rate of HIV transmission (Tovanabutra et al., 2002).

* People who are infected with HIV can still be infected by other, more virulent strains.

* Oral sex is not without its risks as it has been established that HIV can be transmitted through both insertive and receptive oral sex (Rothenberg et al., 1998).

* Women are more susceptible to HIV-1 due to hormonal changes, vaginal microbial ecology and physiology, and a higher prevalence of sexually transmitted diseases (Sagar et al., 2004; Lavreys et al., 2004).

=== Prevention strategies ===

During a sexual act, only condoms, be they male or female, can reduce the chances of infection with HIV and other STIs and the chances of becoming pregnant. They must be used during all penetrative sexual intercourse with a partner who is HIV positive or whose status is unknown (Cayley, 2004). The effective use of condoms and screening of blood transfusion in North America, Western and Central Europe is credited with the low rates of AIDS in these regions. Adopting these effective prevention methods in other regions has proved controversial and difficult. Some claim this is in part because of the strong influence of the Roman Catholic Church, which opposes the use of condoms.

* The male latex condom is the single most efficient available technology to reduce the sexual transmission of HIV and other sexually transmitted infections. In order to be effective, they must be used correctly during each sexual act. Lubricants containing oil, such as petroleum jelly, or butter, must not be used as they weaken latex condoms and make them porous. If necessary, lubricants made from water are recommended. However, it is not recommended to use a lubricant for fellatio. Also, condoms have standards and expiration dates. It is essential to check the expiration date and if it conforms to European (EC 600) or American (D3492) standards before use.
* The female condom is an alternative to the male condom and is made from polyurethane, which allows it to be used in the presence of oil-based lubricants. They are larger than male condoms and have a stiffened ring-shaped opening, and are designed to be inserted into the vagina. The female condom also contains an inner ring which keeps the condom in place inside the vagina - inserting the female condom requires squeezing this ring.
With consistent and correct use of condoms, there is a very low risk of HIV infection. Studies on couples where one partner is infected show that with consistent condom use, HIV infection rates for the uninfected partner are below 1% per year

=== Government programs ===
The U.S. government and U.S. health organizations both endorse the ABC Approach to lower the risk of acquiring AIDS during sex:

* Abstinence or delay of sexual activity, especially for youth,
* Being faithful, especially for those in committed relationships,
* Condom use, for those who engage in risky behavior.

This approach has been very successful in Uganda, where HIV prevalence has decreased from 15% to 5%. However, the ABC approach is far from all that Uganda has done, as "Uganda has pioneered approaches towards reducing stigma, bringing discussion of sexual behavior out into the open, involving HIV-infected people in public education, persuading individuals and couples to be tested and counseled, improving the status of women, involving religious organizations, enlisting traditional healers, and much more." (Edward Green, Harvard medical anthropologist). Also, it must be noted that there is no conclusive proof that abstinence-only programs have been successful in any country in the world in reducing HIV transmission. This is why condom use is heavily co-promoted. There is also considerable overlap with the CNN Approach. This is:

* Condom use, for those who engage in risky behavior.
* Needles, use clean ones
* Negotiating skills; negotiating safer sex with a partner and empowering women to make smart choices

The ABC approach has been criticized, because a faithful partner of an unfaithful partner is at risk of AIDS [3]. Many think that the combination of the CNN approach with the ABC approach will be the optimum prevention platform.

=== Circumcision ===

Current research is clarifying the relationship between male circumcision and HIV in differing social and cultural contexts. UNAIDS believes that it is premature to recommend male circumcision services as part of HIV prevention programmes [4].

Moreover, South African medical experts are concerned that the repeated use of unsterilised blades in the ritual circumcision of adolescent boys may be spreading HIV.

== Prevention of blood or blood product route of HIV transmission ==

=== Underlying science ===

* Sharing and reusing syringes contaminated with HIV-infected blood represents a major risk for infection with not only HIV but also hepatitis B and C. In the United States a third of all new HIV infections can be traced to needle sharing and almost 50% of long-term addicts have hepatitis C.

* The risk of being infected with HIV from a single prick with a needle that has been used on an HIV infected person though is thought to be about 1 in 150 (see table above). Post-exposure prophylaxis with anti-HIV drugs can further reduce that small risk.

* Universal precautions are frequently not followed in both sub-Saharan Africa and much of Asia because of both a shortage of supplies and inadequate training. The WHO estimates that approximately 2.5% of all HIV infections in sub-Saharan Africa are transmitted through unsafe healthcare injections.Because of this, the United Nations General Assembly, supported by universal medical opinion on the matter, has urged the nations of the world to implement universal precautions to prevent HIV transmission in health care settings.

=== Prevention strategies ===

* In those countries where improved donor selection and antibody tests have been introduced, the risk of transmitting HIV infection to blood transfusion recipients has been effectively eliminated. According to the WHO, the overwhelming majority of the world's population does not have access to safe blood and "between 5% and 10% of HIV infections worldwide are transmitted through the transfusion of infected blood and blood products."

* Medical workers who follow universal precautions or body substance isolation such as wearing latex gloves when giving injections and washing the hands frequently can help prevent infection of HIV.

* All AIDS-prevention organizations advise drug-users not to share needles and other material required to prepare and take drugs (including syringes, cotton balls, the spoons, water for diluting the drug, straws, crack pipes etc). It is important that people use new or properly sterilized needles for each injection. Information on cleaning needles using bleach is available from health care and addiction professionals and from needle exchanges. In the United States and other western countries, clean needles are available free in some cities, at needle exchanges or safe injection sites.

== Mother to child transmission ==

=== Underlying science ===

* There is a 15–30% risk of transmission of HIV from mother to child during pregnancy, labour and delivery (Orendi et al., 1998). In developed countries the risk can of transmission of HIV from mother to child can be as low as 0-5%. A number of factors influence the risk of infection, particularly the viral load of the mother at birth (the higher the load, the higher the risk). Breastfeeding increases the risk of transmission by 10–15%. This risk depends on clinical factors and may vary according to the pattern and duration of breastfeeding.

=== Prevention strategies ===

* Studies have shown that antiretroviral drugs, cesarean delivery and formula feeding reduce the chance of transmission of HIV from mother to child (Sperling et al., 1996).

* When replacement feeding is acceptable, feasible, affordable, sustainable and safe, HIV-infected mothers are recommended to avoid breast feeding their infant. Otherwise, exclusive breastfeeding is recommended during the first months of life and should be discontinued as soon as possible.

===== References =====
http://en.wikipedia.org/wiki/Acquired_Immune_Deficiency_Syndrome#Prevention

==References==
{{reflist|3}}

==Further reading==
*{{cite web
|url=http://data.unaids.org/pub/EPISlides/2007/2007_epiupdate_en.pdf
|title=2007 AIDS epidemic update
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://data.unaids.org/pub/Report/2007/2006_unaids_annual_report_en.pdf
|title=UNAIDS Annual Report - Making the money work
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://data.unaids.org/pub/Report/2007/20070925_advocacy_grne2_en.pdf
|title= Financial Resources Required to Achieve, Universal Access to HIV Prevention, Treatment Care and Support
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://data.unaids.org/pub/Manual/2007/20070306_prevention_guidelines_towards_universal_access_en.pdf
|title= Practical Guidelines for Intensifying HIV Prevention
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://aidsinfo.nih.gov/contentfiles/AntiretroviralFormulations_FS_en.pdf
|title= Antiretroviral Formulations
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=pdf
|work=
}}
*{{cite web
|url=http://aidsinfo.nih.gov/contentfiles/ApprovedMedstoTreatHIV_FS_en.pdf
|title= Approved Medications to Treat HIV Infection
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=pdf
|work=
}}
*{{cite web
|url=http://aidsinfo.nih.gov/contentfiles/HIVLifeCycle_FS_en.pdf
|title= The HIV Life Cycle
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=pdf
|work=
}}

==External links==
* {{Dmoz|Health/Conditions_and_Diseases/Immune_Disorders/Immune_Deficiency/AIDS/|HIV/AIDS}}
* {{cite web
|url=http://aidsinfo.nih.gov/
|title=AIDSinfo - HIV/AIDS Treatment Information
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=
|work=
}}
* {{cite web
|url=http://www.unaids.org/en/
|title=UNAIDS: The Joint United Nations Programme on HIV/AIDS
|accessdate=2008-03-21
|publisher=UNAIDS
|format=
|work=
}}
{{AIDS}}
{{Viral diseases}}
{{STD/STI}}
{{SIB}}

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{{WikiDoc Help Menu}}
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HIV AIDS

2009-07-07T18:52:05Z

Michaelagibson:

{{Infobox_Disease |
Name = Acquired immunodeficiency syndrome (AIDS) |
Image = Red_Ribbon.svg |
Caption = The Red ribbon is a symbol for solidarity with HIV-positive people and those living with AIDS. |
Width = 200 |
DiseasesDB = 5938 |
ICD10 = {{ICD10|B|24||b|20}} |
ICD9 = {{ICD9|042}} |
ICDO = |
OMIM = |
MedlinePlus = 000594 |
eMedicineSubj = emerg |
eMedicineTopic = 253 |
MeshID = D000163 |
}}
{| style="float: right; clear:right; margin: 0 0 0.5em 1em; padding: 0.5em; background: #fffff4; border: 1px solid #ddb; width: 250px; font-size:90%;"
|-
|List of abbreviations used in this article 
'''AIDS''': Acquired immune deficiency syndrome 
'''HIV''': [[Human immunodeficiency virus]] 
'''CD4+''': [[T helper cells]] 
'''CCR5''': [[Chemokine (C-C motif) receptor 5]] 
'''CDC''': [[Centers for Disease Control and Prevention]] 
'''WHO''': [[World Health Organization]] 
'''PCP''': [[Pneumocystis pneumonia]] 
'''TB''': [[Tuberculosis]] 
'''MTCT''': Mother-to-child transmission 
'''HAART''': [[Highly active antiretroviral therapy]] 
'''STI/STD''': [[Sexually transmitted infection]]/disease
|}
{{SI}}
{{CMG}}

{{Editor Help}}

For AIDS Patient Information click [[|AIDS Patient Information|here]]

'''Acquired immune deficiency syndrome ''' or '''acquired immunodeficiency syndrome''' ('''AIDS''' or '''Aids''') is a [[syndrome|collection of symptoms and infections]] resulting from the specific damage to the [[immune system]] caused by the [[HIV|human immunodeficiency virus]] (HIV) in humans,<ref>{{cite web
|url=http://www.niaid.nih.gov/Publications/hivaids/hivaids.htm
|title=The Relationship Between the Human Immunodeficiency Virus and the Acquired Immunodeficiency Syndrome |publisher= NIAID
|accessdate=2008-03-10}}</ref> and similar viruses in other species ([[Simian immunodeficiency virus|SIV]], [[Feline immunodeficiency virus|FIV]], etc.). The late stage of the condition leaves individuals susceptible to [[opportunistic infection]]s and [[tumor]]s. Although treatments for AIDS and HIV exist to decelerate the [[virus]]'s progression, there is currently no known cure. HIV is [[Transmission (medicine)|transmitted]] through direct contact of a [[mucous membrane]] or the bloodstream with a [[bodily fluid]] containing HIV, such as [[blood]], [[semen]], [[vaginal fluid]], [[preseminal fluid]], and [[breast milk]].<ref name=CDCtransmission>{{

cite web
| author=[[Divisions of HIV/AIDS Prevention]]
| publisher=[[Centers for Disease Control & Prevention]] | year= 2003
| url=http://www.cdc.gov/HIV/pubs/facts/transmission.htm
| title=HIV and Its Transmission
| accessdate = 2006-05-23
}}</ref><ref name=sfaf>{{

cite web
| author=[[San Francisco AIDS Foundation]]
| publisher=
| year= [[2006-04-14]]
| url=http://www.sfaf.org/aids101/transmission.html
| title=How HIV is spread | accessdate = 2006-05-23

}}</ref> This transmission can come in the form of [[anal sex|anal]], [[vaginal sex|vaginal]] or [[oral sex|oral]] [[Sexual intercourse|sex]], [[blood transfusion]], contaminated [[hypodermic needle]]s, exchange between mother and baby during [[pregnancy]], [[childbirth]], or [[breastfeeding]], or other exposure to one of the above bodily fluids.

Most researchers believe that HIV originated in sub-Saharan Africa during the twentieth century.<ref name=Gao>

{{ cite journal
| author=Gao F, Bailes E, Robertson DL, et al
| title=Origin of HIV-1 in the Chimpanzee Pan troglodytes troglodytes
| journal=Nature
| year=1999
| pages=436–441
| volume=397
| issue=6718
| pmid=9989410 |doi=10.1038/17130

}}</ref> It is now a [[pandemic]]. In 2007, an estimated 33.2 million people lived with the disease worldwide, and it claimed the lives of an estimated 2.1 million people, including 330,000 children.<ref name=UNAIDS2007/> Over three-fourths of these deaths occurred in sub-Saharan Africa,<ref name=UNAIDS2007/> retarding economic growth and destroying human capital.<ref name=Bell-et-al-2003/> [[antiretroviral drug|Antiretroviral]] treatment reduces both the [[Mortality rate|mortality]] and the morbidity of HIV infection, but routine access to antiretroviral [[medication]] is not available in all countries.<ref name=Palella>{{

cite journal
| author=Palella FJ Jr, Delaney KM, Moorman AC, et al
| title=Declining morbidity and mortality among patients with advanced human immunodeficiency virus infection. HIV Outpatient Study Investigators
| journal=N. Engl. J. Med | year=1998 | pages=853–860 | volume=338 | issue=13
| pmid=9516219

}}</ref>

HIV/AIDS [[social stigma|stigma]] is more severe than that associated with some other life-threatening conditions and extends beyond the disease itself to providers and even volunteers involved with the care of people living with HIV.<ref name=Snyder>{{

cite journal |
author=Snyder M, Omoto AM, Crain AL |
title=Punished for their good deeds: stigmatization for AIDS volunteers |
journal=American Behavioral Scientist | year=1999 | pages=1175–1192 | volume=42 | issue=7 | doi=10.1177/0002764299042007009

}}</ref>

==History==
{{main|AIDS origin}}

AIDS was first reported June 5, 1981, when the U.S. Centers for Disease Control and Prevention recorded a cluster of [[Pneumocystis pneumonia (PCP)|''Pneumocystis carinii'' pneumonia]] (now still classified as PCP but known to be caused by [[Pneumocystis pneumonia (PCP)|''Pneumocystis jirovecii'']]) in five homosexual men in Los Angeles.<ref name=MMWR2>{{cite journal
|author=Gottlieb MS
|title=Pneumocystis pneumonia--Los Angeles. 1981
|journal=Am J Public Health
|volume=96
|issue=6
|pages=980–1; discussion 982–3
|year=2006
|pmid=16714472
|url=http://www.cdc.gov/mmwr/preview/mmwrhtml/june_5.htm
|doi=
}}</ref>

Three of the earliest known instances of HIV infection are:
#A plasma sample taken in 1959 from an adult male living in Kinshasa, today part of the Democratic Republic of the Congo.<ref name=Zhu>{{

cite journal
| author=Zhu T, Korber BT, Nahmias AJ, et al | title=An African HIV-1 Sequence from 1959 and Implications for the Origin of the Epidemic
| journal=Nature | year=1998 | pages=594–597 | volume=391 | issue=6667
| pmid=9468138 | doi=10.1038/35400

}}</ref>
#HIV found in tissue samples from "Robert R.", a 15 year old African-American teenager who died in St. Louis in 1969.<ref name=Kolata>

{{cite news
| author=Kolata G
| url=http://query.nytimes.com/gst/fullpage.html?res=9B0DEFD6173AF93BA15753C1A961948260&sec=&pagewanted=all
| title=Boy's 1969 death suggests AIDS invaded U.S. several times
| work=The New York Times
| date=1987-10-28
| accessdate = 2006-06-19
}}
</ref>
#HIV found in tissue samples from Arvid Noe, a Norwegian sailor who died around 1976.<ref name=HooperBMJ>{{

cite journal
| author=Hooper E
| title=Sailors and star-bursts, and the arrival of HIV
| url=http://bmj.bmjjournals.com/cgi/content/full/315/7123/1689
| journal=BMJ | year=1997 | pages=1689–1691 | volume=315 | issue=7123
| pmid=9448543

}}</ref>

Two species of HIV infect humans: [[HIV-1]] and [[HIV-2]]. HIV-1 is more virulent and more easily transmitted. HIV-1 is the source of the majority of HIV infections throughout the world, while HIV-2 is not as easily transmitted and is largely confined to West Africa.<ref name=Reeves>{{

cite journal
| author=Reeves JD, Doms RW
| title=Human Immunodeficiency Virus Type 2
| journal=J. Gen. Virol. | year=2002 | pages=1253–1265 | volume=83 | issue=Pt 6
| pmid=12029140

}}</ref> Both HIV-1 and HIV-2 are of [[primate]] origin. The origin of HIV-1 is the Central Common Chimpanzee (''Pan troglodytes troglodytes'') found in southern Cameroon.<ref name=Keele>{{

cite journal
| author=Keele BF, van Heuverswyn F, Li YY, et al | title=Chimpanzee Reservoirs of Pandemic and Nonpandemic HIV-1
| journal=Science | year=2006 |volume=313 |issue=5786 |pages=523–6
| url= http://www.sciencemag.org/cgi/content/abstract/1126531
| pmid=16728595 | doi=10.1126/science.1126531

}}</ref> It is established that HIV-2 originated from the Sooty Mangabey (''Cercocebus atys''), an Old World monkey of Guinea Bissau, Gabon, and Cameroon.

Most experts believe that HIV probably transferred to humans as a result of direct contact with primates, for instance during hunting or butchery.<ref name=CohenOrigns>{{

cite journal
| author=Cohen J
| title=Vaccine Theory of AIDS Origins Disputed at Royal Society
| journal=Science | year=2000 | pages=1850–1851 | volume= 289| issue=5486 |
pmid=11012346 | doi=10.1126/science.289.5486.1850

}}</ref>
A more controversial theory known as the [[OPV AIDS hypothesis]] suggests that the AIDS epidemic was inadvertently started in the late 1950s in the Belgian Congo by [[Hilary Koprowski]]'s research into a [[poliomyelitis]] [[vaccine]].<ref name=Curtis>{{

cite news |
author=Curtis T |
title=The origin of AIDS|
work=Rolling Stone | year=1992 | pages=54–59, 61, 106, 108 | issue=626 | url=http://www.uow.edu.au/arts/sts/bmartin/dissent/documents/AIDS/Curtis92.html|accessdate=2008-03-10

}}</ref><ref name=Hooper>{{

cite book
| author = Hooper E
| year = 1999
| title = The River : A Journey to the Source of HIV and AIDS
| edition = 1st
| pages = 1–1070
| publisher = Little Brown & Co
| location = Boston, MA
| id = ISBN 0-316-37261-7

}}</ref>
According to scientific consensus, this scenario is not supported by the available evidence.<ref name=refuted>{{

cite journal
| author = Worobey M, Santiago ML, Keele BF, et al |title = Origin of AIDS: contaminated polio vaccine theory refuted
|journal=Nature | year=2004 | pages=820 | volume=428| issue=6985 | pmid=15103367 | doi=10.1038/428820a}}</ref><ref name=Berry>{{

cite journal
| author = Berry N, Jenkins A, Martin J, et al |title = Mitochondrial DNA and retroviral RNA analyses of archival oral polio vaccine (OPV CHAT) materials: evidence of macaque nuclear sequences confirms substrate identity
|journal=Vaccine | year=2005 | pages=1639–1648 | volume=23 | pmid=15705467 | doi=10.1016/j.vaccine.2004.10.038}}</ref><ref name=VaccineQA>{{

cite web
| publisher=[[Centers for Disease Control and Prevention]]
| date= 2004-03-23
| url=http://www.cdc.gov/nip/vacsafe/concerns/aids/poliovac-hiv-aids-qa.htm
| title= Oral Polio Vaccine and HIV / AIDS: Questions and Answers | accessdate = 2006-11-20

}}</ref>

A recent study states that HIV probably moved from Africa to Haiti and then entered the United States around 1969.<ref>{{cite journal
|author=Gilbert MT, Rambaut A, Wlasiuk G, Spira TJ, Pitchenik AE, Worobey M
|title=The emergence of HIV/AIDS in the Americas and beyond
|journal=Proc. Natl. Acad. Sci. U.S.A.
|volume=104
|issue=47
|pages=18566–70
|year=2007
|pmid=17978186
|doi=10.1073/pnas.0705329104
}}
</ref>

==Epidemiology==

{{main|AIDS pandemic}}

[[Image:HIV Epidem.png|290px|thumb|left|Percentage of adult HIV prevalence per country at the end of 2005]]

The AIDS pandemic can also be seen as several epidemics of separate subtypes; the major factors in its spread are sexual transmission and vertical transmission from mother to child at birth and through breast milk.<ref name=Kallings/> Despite recent, improved access to antiretroviral treatment and care in many regions of the world, the AIDS pandemic claimed an estimated 2.1 million (range 1.9–2.4 million) lives in 2007 of which an estimated 330,000 were children under 15 years.<ref name=UNAIDS2007>{{
cite web
| author =[[Joint United Nations Programme on HIV/AIDS|UNAIDS]], [[World Health Organization|WHO]]
| date = December 2007
| title = 2007 AIDS epidemic update
| url= http://data.unaids.org/pub/EPISlides/2007/2007_epiupdate_en.pdf
| accessdate = 2008-03-12
| format= PDF
}}</ref>
Globally, an estimated 33.2 million people lived with HIV in 2007, including 2.5 million children. An estimated 2.5 million (range 1.8–4.1 million) people were newly infected in 2007, including 420,000 children.<ref name=UNAIDS2007/>

[[AIDS pandemic#Sub-Saharan Africa|Sub-Saharan Africa]] remains by far the worst affected region. In 2007 it contained an estimated 68% of all people living with AIDS and 76% of all AIDS deaths, with 1.7 million new infections bringing the number of people living with HIV to 22.5 million, and with 11.4 million AIDS orphans living in the region. Unlike other regions, most people living with HIV in sub-Saharan Africa in 2007 (61%) were women. Adult prevalence in 2007 was an estimated 5.0%, and AIDS continued to be the single largest cause of mortality in this region.<ref name=UNAIDS2007/> South Africa has the largest population of HIV patients in the world, followed by Nigeria and India.<ref>
{{cite news
| date = 2007-11-20
| title= U.N. agency to say it overstated extent of H.I.V. cases by millions
| url= http://query.nytimes.com/gst/fullpage.html?res=9C01EEDF103BF933A15752C1A9619C8B63
| work= New York Times | accessdate=2008-03-18
| author= McNeil DG Jr
}}</ref> [[AIDS pandemic#South and South-East Asia|South & South East Asia]] are second worst affected; in 2007 this region contained an estimated 18% of all people living with AIDS, and an estimated 300,000 deaths from AIDS.<ref name=UNAIDS2007/> India has an estimated 2.5 million infections and an estimated adult prevalence of 0.36%.<ref name=UNAIDS2007/> [[Life expectancy]] has fallen dramatically in the worst-affected countries; for example, in 2006 it was estimated that it had dropped from 65 to 35 years in Botswana.<ref name=Kallings>{{cite journal |journal= J Intern Med |date=2008 |volume=263 |issue=3 |pages=218–43 |title= The first postmodern pandemic: 25 years of HIV/AIDS |author= Kallings LO |doi=10.1111/j.1365-2796.2007.01910.x |pmid=18205765}}</ref>

==Demographics==
[http://www.unaids.org UNAIDS] and the [http://www.who.int/en/ WHO] estimate that AIDS has killed more than 25 million people since it was first recognized in 1981, making it one of the most destructive epidemics in recorded history.

Despite recent, improved access to antiretroviral treatment and care in many regions of the world, the AIDS epidemic claimed an estimated 3.1 million (between 2.8 and 3.6 million) lives in 2005 of which more than half a million (570,000) were children.
Globally, between 36.7 and 45.3 million people are currently living with HIV.

In 2005, between 4.3 and 6.6 million people were newly infected and between 2.8 and 3.6 million people with AIDS died, an increase from 2004 and the highest number since 1981(UNAIDS, 2005).

Sub-Saharan Africa remains by far the worst-affected region, with an estimated 23.8 to 28.9 million people currently living with HIV. More than 60% of all people living with HIV are in sub-Saharan Africa, as are more than three quarters (76%) of all women living with HIV. [15] South & South East Asia are second most affected with 15%. AIDS accounts for the deaths of 500,000 children.

The latest evaluation report of the World Bank's Operations Evaluation Department assesses the development effectiveness of the World Bank's country-level HIV/AIDS assistance defined as policy dialogue, analytic work, and lending with the explicit objective of reducing the scope or impact of the AIDS epidemic. This is the first comprehensive evaluation of the World Bank's HIV/AIDS support to countries, from the beginning of the epidemic through mid-2004. Because the Bank's assistance is for implementation of government programs by government, it provides important insights on how national AIDS programs can be made more effective.

==Pathophysiology==

The pathophysiology of AIDS is complex, as is the case with all [[syndrome]]s.<ref name="pmid8040596">{{cite journal
|author=Guss DA
|title=The acquired immune deficiency syndrome: an overview for the emergency physician, Part 1
|journal=J Emerg Med
|volume=12
|issue=3
|pages=375-84
|year=1994
|pmid=8040596
|doi=
}}</ref>

=== The major pulmonary illnesses ===

=== Pneumocystis jiroveci pneumonia ===
[[Image:Pneumocystis_jiroveci.jpg|thumb|left|Pneumocystis jiroveci is present in this lung impression smear, using Giemsa stain]]
Pneumocystis jiroveci pneumonia (originally known as Pneumocystis carinii pneumonia, often abbreviated PCP) is relatively rare in normal, immunocompetent people but common among HIV-infected individuals. Before the advent of effective treatment and diagnosis in Western countries it was a common immediate cause of death.
In developing countries, it is still one of the first indications of AIDS in untested individuals, although it does not generally occur unless the CD4 count is less than 200 per µl (Feldman, 2005).

==== Tuberculosis ====
[[Image:Tuberculosis_SEM.jpg|thumb|left|Scanning electron micrograph (SEM) of a number of Gram-positive Mycobacterium tuberculosis bacteria]]
Among infections associated with HIV, [[Tuberculosis]] (TB) is unique in that it may be transmitted to immunocompetent persons via the respiratory route, is easily treatable once identified, may occur in early-stage HIV disease, and is preventable with drug therapy. However, multi-drug resistance is a potentially serious problem. Even though its incidence has declined because of the use of directly observed therapy and other improved practices in Western countries, this is not the case in developing countries where HIV is most prevalent. In early-stage HIV infection (CD4 count >300 cells per µl), TB typically presents as a pulmonary disease.
In advanced HIV infection, TB may present atypically and extrapulmonary TB is common infecting bone marrow, bone, urinary and gastrointestinal tracts, liver, regional lymph nodes, and the central nervous system (Decker and Lazarus, 2000).

=== The major gastro-intestinal illnesses ===

==== Esophagitis ====

Esophagitis is an inflammation of the lining of the lower end of the esophagus (gullet or swallowing tube leading to the stomach). In HIV infected individuals, this could be due to fungus (candidiasis), virus (herpes simplex-1 or cytomegalovirus). In rare cases, it could be due to mycobacteria (Zaidi and Cervia, 2002).

==== Unexplained chronic diarrhea ====

In HIV infection, there are many possible causes of diarrhea, including common bacterial (Salmonella, Shigella, Listeria, Campylobacter, or Escherichia coli) and parasitic infections, and uncommon opportunistic infections such as cryptosporidiosis, microsporidiosis, Mycobacterium avium complex (MAC) and cytomegalovirus (CMV) colitis. Diarrhea may follow a course of antibiotics (common for Clostridium difficile). It may also be a side effect of several drugs used to treat HIV, or it may simply accompany HIV infection, particularly during primary HIV infection. In the later stages of HIV infection, diarrhea is thought to be a reflection of changes in the way the intestinal tract absorbs nutrients, and may be an important component of HIV-related wasting (Guerrant et al., 1990).

=== The major neurological illnesses ===

==== Toxoplasmosis ====
[[Image:Toxoplasmosi_AIDS.jpg|thumb|left|Toxoplasmosis of heart in AIDS]]
Toxoplasmosis is a disease caused by the single-celled parasite called Toxoplasma gondii. T. gondii usually infects the brain causing toxoplasma encephalitis. It can also infect and cause disease in the eyes and lungs (Luft and Chua, 2000).

==== Progressive multifocal leukoencephalopathy ====

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease, in which the myelin sheath covering the axons of nerve cells is gradually destroyed, impairing the transmission of nerve impulses. It is caused by a virus called JC virus which occurs in 70% of the population in latent form, causing disease only when the immune system has been severly weakened, as is the case for AIDS patients. It progresses rapidly, usually causing death within months of diagnosis (Sadler and Nelson, 1997).

==== HIV-associated dementia ====

HIV-1 associated dementia (HAD) is a metabolic encephalopathy induced by HIV infection and fueled by immune activation of brain macrophages and microglia (Gray et al., 2001). These cells are actively infected with HIV and secrete neurotoxins of both host and viral origin. Specific neurologic impairments are manifested by cognitive, behavioral, and motor abnormalities that occur after years of HIV infection and is associated with low CD4+ T cell levels and high plasma viral loads. Prevalence is between 15-30% in Western countries (Heaton et al., 1995; White et al., 1995) and has only been seen in 1-2% of India based infections (Satischandra et al., 2000; Wadia et al., 2001).

=== HIV-associated malignancies ===

Patients with HIV infection are susceptible to a number of malignancies (Yarchoan et al., 2005). The most common is Kaposi's sarcoma, and the appearance of this tumor in young gay men in New York in 1981 was one of the first signals of the AIDS epidemic. In addition, patients with HIV infection have a higher incidence of certain high grade B cell lymphomas, especially Burkitt-like and large cell lymphomas. These tumors, as well as aggressive cervical cancer in women, confer a diagnosis of AIDS in patients with HIV infection.

==Symptoms==

[[Image:Hiv-timecourse.png|450px|thumb|right|A generalized graph of the relationship between HIV copies (viral load) and CD4 counts over the average course of untreated HIV infection; any particular individual's disease course may vary considerably.
{{legend-line|blue solid 2px|CD4+ T Lymphocyte count (cells/mm³)}}
{{legend-line|red solid 2px|HIV RNA copies per mL of plasma}}
]]

The symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy [[immune system]]s. Most of these conditions are infections caused by [[bacteria]], [[virus]]es, [[fungus|fungi]] and [[parasite]]s that are normally controlled by the elements of the immune system that HIV damages. [[Opportunistic infection]]s are common in people with AIDS.<ref name=Holmes>{{

cite journal
| author=Holmes CB, Losina E, Walensky RP, Yazdanpanah Y, Freedberg KA
| title=Review of human immunodeficiency virus type 1-related opportunistic infections in sub-Saharan Africa
| journal=Clin. Infect. Dis. | year=2003 | pages=656–662 | volume=36 | issue=5
| pmid=12594648

}}</ref> HIV affects nearly every [[organ system]]. People with AIDS also have an increased risk of developing various cancers such as [[Kaposi's sarcoma]], [[cervical cancer]] and cancers of the immune system known as [[lymphoma]]s.

Additionally, people with AIDS often have systemic symptoms of infection like [[fever]]s, [[sweat]]s (particularly at night), swollen glands, chills, weakness, and [[weight loss]].<ref name=Guss>{{

cite journal
| author=Guss DA
| title=The acquired immune deficiency syndrome: an overview for the emergency physician, Part 1
| journal=J. Emerg. Med. | year=1994 | pages=375–384 | volume=12 | issue=3
| pmid=8040596

}}</ref><ref name=Guss2>{{

cite journal
| author=Guss DA
| title=The acquired immune deficiency syndrome: an overview for the emergency physician, Part 2
| journal=J. Emerg. Med. | year=1994 | pages=491–497 | volume=12 | issue=4
| pmid=7963396

}}</ref> After the diagnosis of AIDS is made, the current average survival time with antiretroviral therapy (as of 2005) is estimated to be more than 5 years,<ref name=Schneider>{{

cite journal
| author=Schneider MF, Gange SJ, Williams CM, Anastos K, Greenblatt RM, Kingsley L, Detels R, Munoz A
| title=Patterns of the hazard of death after AIDS through the evolution of antiretroviral therapy: 1984–2004
| journal=AIDS | year=2005 | pages=2009–2018 | volume=19 | issue=17
| pmid=16260908

}}</ref> but because new treatments continue to be developed and because HIV continues to [[Evolution|evolve]] resistance to treatments, estimates of survival time are likely to continue to change. Without antiretroviral therapy, death normally occurs within a year.<ref name=Morgan2 /> Most patients die from opportunistic infections or [[malignancies]] associated with the progressive failure of the immune system.<ref name=Lawn>{{

cite journal
| author=Lawn SD
| title=AIDS in Africa: the impact of coinfections on the pathogenesis of HIV-1 infection
| journal=J. Infect. Dis. | year=2004 | pages=1–12 | volume=48 | issue=1
| pmid=14667787

}}</ref>

The rate of clinical disease progression varies widely between individuals and has been shown to be affected by many factors such as host susceptibility and immune function<ref name=Clerici /><ref name=Morgan /><ref name=Tang /> health care and co-infections,<ref name=Morgan2 /><ref name=Lawn /> as well as factors relating to the viral strain.<ref name=Campbell /><ref name=Campbell2>{{

cite journal
| author=Campbell GR, Watkins JD, Esquieu D, Pasquier E, Loret EP, Spector SA
| title=The C terminus of HIV-1 Tat modulates the extent of CD178-mediated apoptosis of T cells
| journal=J. Biol. Chem. | year=2005 | pages=38376–39382 | volume=280 | issue=46
| pmid=16155003

}}</ref><ref name=Senkaali>{{

cite journal
| author=Senkaali D, Muwonge R, Morgan D, Yirrell D, Whitworth J, Kaleebu P
| title=The relationship between HIV type 1 disease progression and V3 serotype in a rural Ugandan cohort
| journal=AIDS Res. Hum. Retroviruses. | year=2005 | pages=932–937 | volume=20 | issue=9
| pmid=15585080

}}</ref> The specific opportunistic infections that AIDS patients develop depend in part on the prevalence of these infections in the geographic area in which the patient lives.

===Pulmonary infections===
[[Image:PCPxray.jpg|thumb|right|150px|X-ray of [[Pneumocystis pneumonia (PCP)|''Pneumocystis jirovecii'']] caused pneumonia. There is increased white (opacity) in the lower lungs on both sides, characteristic of ''Pneumocystis'' pneumonia]]
[[Pneumocystis pneumonia (PCP)|Pneumocystis pneumonia]] (originally known as ''Pneumocystis carinii'' pneumonia, and still abbreviated as PCP, which now stands for '''P'''neumo'''c'''ystis '''p'''neumonia) is relatively rare in healthy, [[immunocompetent]] people, but common among HIV-infected individuals. It is caused by [[Pneumocystis pneumonia (PCP)|''Pneumocystis jirovecii'']]. Before the advent of effective diagnosis, treatment and routine [[prophylaxis]] in Western countries, it was a common immediate cause of death. In developing countries, it is still one of the first indications of AIDS in untested individuals, although it does not generally occur unless the CD4 count is less than 200 per µL.<ref name=Feldman>{{

cite journal
| author=Feldman C | title=Pneumonia associated with HIV infection
| journal=Curr. Opin. Infect. Dis. | year=2005 | pages=165–170 | volume=18 | issue=2
| pmid=15735422

}}</ref>

[[Tuberculosis]] (TB) is unique among infections associated with HIV because it is transmissible to immunocompetent people via the respiratory route, is easily treatable once identified, may occur in early-stage HIV disease, and is preventable with drug therapy. However, [[multidrug resistance]] is a potentially serious problem. Even though its incidence has declined because of the use of directly observed therapy and other improved practices in Western countries, this is not the case in developing countries where HIV is most prevalent. In early-stage HIV infection (CD4 count >300 cells per µL), TB typically presents as a pulmonary disease. In advanced HIV infection, TB often presents atypically with extrapulmonary (systemic) disease a common feature. Symptoms are usually constitutional and are not localized to one particular site, often affecting [[bone marrow]], [[bone]], urinary and [[gastrointestinal tract]]s, [[liver]], regional [[lymph node]]s, and the [[central nervous system]].<ref name=Decker>{{

cite journal
| author=Decker CF, Lazarus A
| title=Tuberculosis and HIV infection. How to safely treat both disorders concurrently
| journal=Postgrad Med. | year=2000 | pages=57–60, 65–68 | volume=108 | issue=2
| pmid=10951746

}}</ref>

===Gastrointestinal infections===

[[Esophagitis]] is an inflammation of the lining of the lower end of the [[esophagus]] (gullet or swallowing tube leading to the [[stomach]]). In HIV infected individuals, this is normally due to fungal ([[candidiasis]]) or viral ([[Herpes simplex virus|herpes simplex-1]] or [[cytomegalovirus]]) infections. In rare cases, it could be due to [[mycobacteria]].<ref name=Zaidi>{{

cite journal
| author=Zaidi SA, Cervia JS
| title=Diagnosis and management of infectious esophagitis associated with human immunodeficiency virus infection
| journal=J. Int. Assoc. Physicians AIDS Care (Chic Ill) | year=2002 | pages=53–62 | volume=1 | issue=2
| pmid=12942677

}}</ref>

Unexplained chronic [[diarrhea]] in HIV infection is due to many possible causes, including common bacterial (''[[Salmonella]]'', ''[[Shigella]]'', ''[[Listeria]]'', ''[[Campylobacter]]'', or ''[[Escherichia coli]]'') and parasitic infections; and uncommon opportunistic infections such as [[cryptosporidiosis]], [[microsporidiosis]], ''[[Mycobacterium avium]]'' complex (MAC) and [[cytomegalovirus]] (CMV) [[colitis]]. In some cases, diarrhea may be a side effect of several drugs used to treat HIV, or it may simply accompany HIV infection, particularly during primary HIV infection. It may also be a side effect of [[antibiotic]]s used to treat bacterial causes of diarrhea (common for ''[[Clostridium difficile]]''). In the later stages of HIV infection, diarrhea is thought to be a reflection of changes in the way the [[intestinal tract]] absorbs nutrients, and may be an important component of HIV-related [[wasting]].<ref name=Guerrant>{{

cite journal
| author=Guerrant RL, Hughes JM, Lima NL, Crane J
| title=Diarrhea in developed and developing countries: magnitude, special settings, and etiologies
| journal=Rev. Infect. Dis. | year=1990 | pages=S41–S50 | volume=12 | issue=Suppl 1
| pmid=2406855

}}</ref>

===Neurological diseases===

[[Toxoplasmosis]] is a disease caused by the single-celled [[parasite]] called ''Toxoplasma gondii''; it usually infects the brain causing toxoplasma [[encephalitis]] but it can infect and cause disease in the [[eye]]s and lungs.<ref name=Luft>{{

cite journal
| author=Luft BJ, Chua A
| title=Central Nervous System Toxoplasmosis in HIV Pathogenesis, Diagnosis, and Therapy
| journal=Curr. Infect. Dis. Rep. | year=2000 | pages=358–362 | volume=2 | issue=4
| pmid=11095878

}}</ref>

[[Progressive multifocal leukoencephalopathy]] (PML) is a [[demyelinating disease]], in which the gradual destruction of the [[myelin]] sheath covering the [[axon]]s of nerve cells impairs the transmission of nerve impulses. It is caused by a virus called [[JC virus]] which occurs in 70% of the population in [[Virus latency|latent]] form, causing disease only when the immune system has been severely weakened, as is the case for AIDS patients. It progresses rapidly, usually causing death within months of diagnosis.<ref name=Sadler>{{

cite journal
| author=Sadler M, Nelson MR
| title=Progressive multifocal leukoencephalopathy in HIV
| journal=Int. J. STD AIDS | year=1997 | pages=351–357 | volume=8 | issue=6
| pmid=9179644

}}</ref>
[[AIDS dementia complex]] (ADC) is a metabolic [[encephalopathy]] induced by HIV infection and fueled by immune activation of HIV infected brain [[macrophage]]s and [[microglia]] which secrete [[neurotoxin]]s of both host and viral origin.<ref name=Gray>{{

cite journal
| author=Gray F, Adle-Biassette H, Chrétien F, Lorin de la Grandmaison G, Force G, Keohane C
| title=Neuropathology and neurodegeneration in human immunodeficiency virus infection. Pathogenesis of HIV-induced lesions of the brain, correlations with HIV-associated disorders and modifications according to treatments
| journal=Clin. Neuropathol. | year=2001 | pages=146–155 | volume=20 | issue=4
| pmid=11495003

}}</ref> Specific neurological impairments are manifested by cognitive, behavioral, and motor abnormalities that occur after years of HIV infection and is associated with low CD4+ T cell levels and high plasma viral loads. Prevalence is 10–20% in Western countries<ref name=Grant>{{

cite book
| author = Grant I, Sacktor H, McArthur J
| year = 2005
| title = The Neurology of AIDS
| chapter = HIV neurocognitive disorders
| chapterurl = http://www.hnrc.ucsd.edu/publications_pdf/2005grant1.pdf
| editor = H. E. Gendelman, I. Grant, I. Everall, S. A. Lipton, and S. Swindells. (ed.)
| edition = 2nd
| pages = 357–373
| publisher = Oxford University Press
| location = London, UK
| format= PDF
| id = ISBN 0-19-852610-5

}}</ref> but only 1–2% of HIV infections in India.<ref name=Satischandra>{{

cite journal
| author=Satishchandra P, Nalini A, Gourie-Devi M, et al | title=Profile of neurologic disorders associated with HIV/AIDS from Bangalore, South India (1989–1996)
| journal=Indian J. Med. Res. | year=2000 | pages=14–23 | volume=11 | issue=
| pmid=10793489

}}</ref><ref name=Wadia>{{

cite journal
| author=Wadia RS, Pujari SN, Kothari S, Udhar M, Kulkarni S, Bhagat S, Nanivadekar A
| title=Neurological manifestations of HIV disease
| journal=J. Assoc. Physicians India | year=2001 | pages=343–348 | volume=49 | issue=
| pmid=11291974

}}</ref> This difference is possibly due to the HIV subtype in India.

Cryptococcal meningitis is an infection of the [[meninges|meninx]] (the membrane covering the brain and [[spinal cord]]) by the fungus ''[[Cryptococcus]] neoformans''. It can cause fevers, [[headache]], [[Fatigue (medical)|fatigue]], [[nausea]], and [[vomiting]]. Patients may also develop [[seizure]]s and confusion; left untreated, it can be lethal.

===Tumors and malignancies===

[[Image:Kaposi's Sarcoma.jpg|thumb|right|150px|Kaposi's sarcoma]]

Patients with HIV infection have substantially increased incidence of several malignant [[cancer]]s. This is primarily due to co-infection with an [[oncogene|oncogenic]] [[DNA virus]], especially [[Epstein-Barr virus]] (EBV), Kaposi's sarcoma-associated herpesvirus ([[KSHV]]), and human [[papillomavirus]] (HPV).<ref name=Boshoff>{{

cite journal
| author=Boshoff C, Weiss R
| title=AIDS-related malignancies
| journal=Nat. Rev. Cancer | year=2002 | pages=373–382 | volume=2 | issue=5
| pmid=12044013

}}</ref><ref name=Yarchoan>{{

cite journal
| author=Yarchoan R, Tosatom G, Littlem RF
| title=Therapy insight: AIDS-related malignancies — the influence of antiviral therapy on pathogenesis and management
| journal=Nat. Clin. Pract. Oncol. | year=2005 | pages=406–415 | volume=2 | issue=8
| pmid=16130937

}}</ref>

Kaposi's sarcoma (KS) is the most common tumor in HIV-infected patients. The appearance of this tumor in young homosexual men in 1981 was one of the first signals of the AIDS epidemic. Caused by a [[Gammaherpesvirinae|gammaherpes]] virus called [[Kaposi's sarcoma-associated herpes virus]] (KSHV), it often appears as purplish [[Nodule (medicine)|nodules]] on the skin, but can affect other organs, especially the [[mouth]], gastrointestinal tract, and lungs.

High-grade [[B cell]] [[lymphoma]]s such as [[Burkitt's lymphoma]], Burkitt's-like lymphoma, diffuse large B-cell lymphoma (DLBCL), and [[primary central nervous system lymphoma]] present more often in HIV-infected patients. These particular cancers often foreshadow a poor prognosis. In some cases these lymphomas are AIDS-defining. [[Epstein-Barr virus]] (EBV) or KSHV cause many of these lymphomas.

[[Cervical cancer]] in HIV-infected women is considered AIDS-defining. It is caused by [[human papillomavirus]] (HPV).<ref>{{cite journal
|author=Palefsky J
|title=Human papillomavirus infection in HIV-infected persons
|journal=Top HIV Med
|volume=15
|issue=4
|pages=130–3
|year=2007
|pmid=17720998
|doi=
}}</ref>

In addition to the AIDS-defining tumors listed above, HIV-infected patients are at increased risk of certain other tumors, such as [[Hodgkin's disease]] and [[Anal cancer|anal]] and [[rectal carcinoma]]s. However, the incidence of many common tumors, such as [[breast cancer]] or [[colon cancer]], does not increase in HIV-infected patients. In areas where [[HAART]] is extensively used to treat AIDS, the incidence of many AIDS-related malignancies has decreased, but at the same time malignant cancers overall have become the most common cause of death of HIV-infected patients.<ref name=Bonnet>{{

cite journal
| author=Bonnet F, Lewden C, May T, et al | title=Malignancy-related causes of death in human immunodeficiency virus-infected patients in the era of highly active antiretroviral therapy
| journal=Cancer | year=2004 | pages=317–324 | volume=101 | issue=2
| pmid=15241829

}}</ref>

===Other opportunistic infections===

AIDS patients often develop opportunistic infections that present with non-specific symptoms, especially [[low-grade fever]]s and weight loss. These include infection with ''[[Mycobacterium avium]]-intracellulare'' and [[cytomegalovirus]] (CMV). CMV can cause colitis, as described above, and [[Cytomegalovirus retinitis|CMV retinitis]] can cause [[blindness]]. [[Penicilliosis]] due to ''[[Penicillium marneffei]]'' is now the third most common opportunistic infection (after extrapulmonary tuberculosis and [[cryptococcosis]]) in HIV-positive individuals within the endemic area of Southeast Asia.<ref name=Skoulidis>{{

cite journal
| author=Skoulidis F, Morgan MS, MacLeod KM
| title=Penicillium marneffei: a pathogen on our doorstep?
| journal=J. R. Soc. Med.| year=2004 | pages=394–396 | volume=97 | issue=2
| pmid=15286196

}}</ref>

==Cause==
{{details|HIV}}
[[Image:HIV-budding.jpg|right|thumbnail|300px|[[Scanning electron microscope|Scanning electron micrograph]] of HIV-1 budding from cultured [[lymphocyte]].]]

AIDS is the most severe acceleration of [[infection]] with HIV. HIV is a [[retrovirus]] that primarily infects vital organs of the human [[immune system]] such as [[T helper cell|CD4+ T cells]] (a subset of [[T cell]]s), [[macrophage]]s and [[dendritic cell]]s. It directly and indirectly destroys CD4+ T cells.<ref name=Alimonti>{{

cite journal
| author=Alimonti JB, Ball TB, Fowke KR
| title=Mechanisms of CD4+ T lymphocyte cell death in human immunodeficiency virus infection and AIDS.
| journal=J. Gen. Virol. | year=2003 | pages=1649–1661 | volume=84 | issue=7 | pmid=12810858 | doi=10.1099/vir.0.19110-0

}}</ref> CD4+ T cells are required for the proper functioning of the immune system. When HIV kills CD4+ T cells so that there are fewer than 200 CD4+ T cells per [[microliter]] (µL) of [[blood]], [[cellular immunity]] is lost. In some countries, such as the United States, this leads to a diagnosis of AIDS. In other jurisdictions, such as in Canada, AIDS is only diagnosed when a person infected with HIV is diagnosed with one or more of several AIDS-related opportunistic infections or cancers.<ref>[http://www.phac-aspc.gc.ca/publicat/haest-tesvs/a_e.html#AIDS_DIAGNOSIS Public Health Agency of Canada] (Note that this source is mistaken in its assertion that the U.S. definition of AIDS requires a CD4 count of <200.)</ref><ref>McGovern, Theresa and Smith, Raymond (1998). [http://www.thebody.com/content/art14002.html AIDS, Case Definition of.] TheBody.com. Retrieved on 2008-03-10.</ref><ref>[http://www.aegis.com/topics/definition.html AEGIS]</ref> [[Acute (medicine)|Acute]] HIV infection progresses over time to clinical latent HIV infection and then to early [[symptomatic]] HIV infection and later to AIDS, which is identified either on the basis of the amount of CD4+ T cells in the blood, and/or the presence of certain infections, as noted above.

In the absence of [[Antiretroviral drug|antiretroviral therapy]], the median [[HIV Disease Progression Rates|time of progression from HIV infection to AIDS]] is nine to ten years, and the median survival time after developing AIDS is only 9.2 months.<ref name=Morgan2>{{

cite journal
| author=Morgan D, Mahe C, Mayanja B, Okongo JM, Lubega R, Whitworth JA
| title=HIV-1 infection in rural Africa: is there a difference in median time to AIDS and survival compared with that in industrialized countries?
| journal=AIDS | year=2002 | pages=597–632 | volume=16 | issue=4 | pmid=11873003

}}</ref> However, the rate of clinical disease progression varies widely between individuals, from two weeks up to 20 years. Many factors affect the rate of progression. These include factors that influence the body's ability to defend against HIV such as the infected person's general immune function.<ref name=Clerici>{{

cite journal
| author=Clerici M, Balotta C, Meroni L, et al | title=Type 1 cytokine production and low prevalence of viral isolation correlate with long-term non progression in HIV infection
| journal=AIDS Res. Hum. Retroviruses. | year=1996 | pages=1053–1061 | volume=12 | issue=11
| pmid=8827221

}}</ref><ref name=Morgan>{{

cite journal
| author=Morgan D, Mahe C, Mayanja B, Whitworth JA
| title=Progression to symptomatic disease in people infected with HIV-1 in rural Uganda: prospective cohort study
| journal=BMJ | year=2002 | pages=193–196 | volume=324 | issue=7331
| pmid=11809639 | doi=10.1136/bmj.324.7331.193

}}</ref> Older people have weaker immune systems, and therefore have a greater risk of rapid disease progression than younger people. Poor access to [[health care]] and the existence of coexisting infections such as [[tuberculosis]] also may predispose people to faster disease progression.<ref name=Morgan2 /><ref name=Gendelman>{{

cite journal
| author=Gendelman HE, Phelps W, Feigenbaum L, et al | title=Transactivation of the human immunodeficiency virus long terminal repeat sequences by DNA viruses
| journal=Proc. Natl. Acad. Sci. U. S. A. | year=1986 | pages=9759–9763 | volume=83 | issue=24
| pmid=2432602

}}</ref><ref name=Bentwich>{{

cite journal
| author=Bentwich Z, Kalinkovich, A, Weisman Z
| title=Immune activation is a dominant factor in the pathogenesis of African AIDS.
| journal=Immunol. Today | year=1995 | pages=187–191 | volume=16 | issue=4
| pmid=7734046

}}</ref> The infected person's [[genetics|genetic inheritance]] plays an important role and some people are resistant to certain strains of HIV. An example of this is people with the [[homozygous]] [[CCR5-Δ32]] variation are resistant to infection with certain [[strain (biology)|strains]] of HIV.<ref name=Tang>{{

cite journal
| author=Tang J, Kaslow RA
| title=The impact of host genetics on HIV infection and disease progression in the era of highly active antiretroviral therapy
| journal=AIDS | year=2003 | pages=S51–S60 | volume=17 | issue=Suppl 4
| pmid=15080180

}}</ref> HIV is genetically variable and exists as different strains, which cause different rates of clinical disease progression.<ref name=Quinones>{{

cite journal
| author=Quiñones-Mateu ME, Mas A, Lain de Lera T, Soriano V, Alcami J, Lederman MM, Domingo E
| title=LTR and tat variability of HIV-1 isolates from patients with divergent rates of disease progression
| journal=Virus Research | year=1998 | pages=11–20 | volume=57 | issue=1
| pmid=9833881

}}</ref><ref name=Campbell>{{

cite journal
| author=Campbell GR, Pasquier E, Watkins J, et al | title=The glutamine-rich region of the HIV-1 Tat protein is involved in T-cell apoptosis
| journal=J. Biol. Chem. | year=2004 | pages=48197–48204 | volume=279 | issue=46
| pmid=15331610 | doi=10.1074/jbc.M406195200

}}</ref><ref name=Kaleebu>{{

cite journal
| author=Kaleebu P, French N, Mahe C, et al | title=Effect of human immunodeficiency virus (HIV) type 1 envelope subtypes A and D on disease progression in a large cohort of HIV-1-positive persons in Uganda | journal=J. Infect. Dis. | year=2002 | pages=1244–1250 | volume=185 | issue=9
| pmid=12001041

}}</ref> The use of highly active antiretroviral therapy prolongs both the median time of progression to AIDS and the median survival time.

===Alternative hypotheses===
{{main|AIDS reappraisal}}

A small minority of scientists and activists question the connection between HIV and AIDS,<ref name=Duesberg>{{cite journal
| author=Duesberg PH
| title=HIV is not the cause of AIDS
| journal=Science | year=1988 | pages=514, 517 | volume=241 | issue=4865
| pmid=3399880 | doi=10.1126/science.3399880
}}</ref> the existence of HIV itself,<ref name=Papadopulos>{{
cite journal
| author=Papadopulos-Eleopulos E, Turner VF, Papadimitriou J, et al
| title=A critique of the Montagnier evidence for the HIV/AIDS hypothesis
| journal=Med Hypotheses | year=2004 | pages=597–601 | volume=63 | issue=4
| pmid=15325002 | doi=10.1016/j.mehy.2004.03.025
}}</ref> or the validity of current testing and treatment methods. Though these claims have been examined and widely rejected by the scientific community,<ref name=consensus>For evidence of the [[scientific consensus]] that HIV is the cause of AIDS, see (for example):
*{{cite journal |title=The Durban Declaration |journal=Nature |volume=406 |issue=6791 |pages=15–6 |year=2000 |pmid=10894520 |doi=10.1038/35017662}} – full text [http://www.nature.com/nature/journal/v406/n6791/full/406015a0.html here].
*{{cite journal
| author=Cohen J
| title=The Controversy over HIV and AIDS
| journal=Science | year=1994 | pages=1642–1649 | volume=266 | issue=5191
| url=http://www.sciencemag.org/feature/data/cohen/266-5191-1642a.pdf|format=PDF}}
*{{cite web
| publisher=[[National Institute of Allergy and Infectious Diseases]] | year=
| url=http://www3.niaid.nih.gov/news/focuson/hiv/resources/
| title=Focus on the HIV-AIDS Connection: Resource links
| accessdate = 2006-09-07
}}
*{{cite journal |author=O'Brien SJ, Goedert JJ |title=HIV causes AIDS: Koch's postulates fulfilled |journal=Curr. Opin. Immunol. |volume=8 |issue=5 |pages=613-8 |year=1996 |pmid=8902385 |doi=}}
*{{cite journal |author=Galéa P, Chermann JC |title=HIV as the cause of AIDS and associated diseases |journal=Genetica |volume=104 |issue=2 |pages=133–42 |year=1998 |pmid=10220906 |doi=}}</ref> they continue to be promulgated through the Internet<ref>{{cite journal |author=Smith TC, Novella SP |title=HIV denial in the Internet era |journal=PLoS Med. |volume=4 |issue=8 |pages=e256 |year=2007 |pmid=17713982 |doi=10.1371/journal.pmed.0040256}}</ref> and have had a significant political impact, particularly in South Africa, where until late 2006 the Thabo Mbeki government did not accept that AIDS was caused by HIV, lead to an ineffective response to that country's AIDS epidemic.<ref>{{cite journal |author=Watson J |title=Scientists, activists sue South Africa's AIDS 'denialists' |journal=Nat. Med. |volume=12 |issue=1 |pages=6 |year=2006 |pmid=16397537 |doi=10.1038/nm0106-6a}}</ref><ref>{{cite journal |author=Baleta A |title=S Africa's AIDS activists accuse government of murder |journal=Lancet |volume=361 |issue=9363 |pages=1105 |year=2003 |pmid=12672319 |doi=10.1016/S0140-6736(03)12909-1}}</ref><ref>{{cite journal |author=Cohen J |title=South Africa's new enemy |journal=Science |volume=288 |issue=5474 |pages=2168-70 |year=2000 |pmid=10896606 |doi=10.1126/science.288.5474.2168}}</ref><ref>Andrew Meldrum. [http://www.guardian.co.uk/world/2006/oct/27/aids.southafrica South African government ends Aids denial], guardian.co.uk, 27 October 2006</ref>

===Misconceptions===
{{main|HIV and AIDS misconceptions}}
A number of misconceptions have arisen surrounding HIV/AIDS. Three of the most common are that AIDS can spread through casual contact, that sexual intercourse with a virgin will cure AIDS, and that HIV can infect only homosexual men and drug users. Other misconceptions are that any act of anal intercourse between gay men can lead to AIDS infection, and that open discussion of homosexuality and HIV in schools will lead to increased rates of homosexuality and AIDS.<ref>{{cite book
|author=Blechner MJ
|title=Hope and mortality: psychodynamic approaches to AIDS and HIV
|publisher=Analytic Press
|location=Hillsdale, NJ
|year=1997
|isbn=0-88163-223-6
}}</ref>

==Diagnosis==
[[Image:TEM HIV.jpg|thumb|200px|Thin-section transmission electron micrograph (TEM) depicting the ultrastructural details of two ”human immunodeficiency virus” (HIV) virions]]
[[Image:Kaposi's_sarcoma.jpg|thumb|Kaposi's sarcoma lesion commonly found in patients with stage IV AIDS]]
Since June 5, 1981, many definitions have been developed for [[epidemiology|epidemiological]] surveillance such as the Bangui definition and the 1994 expanded World Health Organization AIDS case definition. However, clinical staging of patients was not an intended use for these systems as they are neither sensitive, nor specific. In developing countries, the [[World Health Organization]] staging system for HIV infection and disease, using clinical and laboratory data, is used and in developed countries, the [[Centers for Disease Control and Prevention|Centers for Disease Control]] (CDC) Classification System is used.

===WHO disease staging system for HIV infection and disease===
{{main|WHO Disease Staging System for HIV Infection and Disease}}

In 1990, the [[World Health Organization]] (WHO) grouped these infections and conditions together by introducing a staging system for patients infected with HIV-1.<ref name=WHO>{{

cite journal
| author=World Health Organization
| title=Interim proposal for a WHO staging system for HIV infection and disease
| journal=WHO Wkly Epidem. Rec. | year=1990 | pages=221–228 | volume=65 | issue=29
| pmid=1974812

}}</ref> An update took place in September 2005. Most of these conditions are [[opportunistic infection]]s that are easily treatable in healthy people.
* Stage I: HIV infection is [[asymptomatic]] and not categorized as AIDS
* Stage II: includes minor [[Mucous membrane|mucocutaneous]] manifestations and recurrent [[upper respiratory tract]] infections
* Stage III: includes unexplained [[Chronic (medical)|chronic]] [[diarrhea]] for longer than a month, severe bacterial infections and [[pulmonary]] tuberculosis
* Stage IV: includes [[toxoplasmosis]] of the [[brain]], [[candidiasis]] of the [[esophagus]], [[Vertebrate trachea|trachea]], [[bronchi]] or [[lung]]s and [[Kaposi's sarcoma]]; these diseases are indicators of AIDS.

===CDC classification system for HIV infection===

{{main|CDC Classification System for HIV Infection}}

In the beginning, the [[Centers for Disease Control and Prevention]] (CDC) did not have an official name for the disease, often referring to it by way of the diseases that were associated with it, for example, [[lymphadenopathy]], the disease after which the discoverers of HIV originally named the virus.<ref name=MMWR1982a>{{

cite journal
| author=Centers for Disease Control (CDC)
| title=Persistent, generalized lymphadenopathy among homosexual males.
| journal=MMWR Morb Mortal Wkly Rep. | year=1982 | pages=249–251 | volume=31| issue=19
| pmid=6808340

}}</ref><ref name=Barre>{{cite journal | author=Barré-Sinoussi F, Chermann JC, Rey F, et al | title=Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS) | journal=Science | year=1983 | pages=868–871 | volume=220 | issue=4599 | pmid=6189183 | doi=10.1126/science.6189183 | format=
}}</ref> They also used ''Kaposi's Sarcoma and Opportunistic Infections'', the name by which a task force had been set up in 1981.<ref name=MMWR1982b>{{

cite journal
| author=Centers for Disease Control (CDC)
| title=Opportunistic infections and Kaposi's sarcoma among Haitians in the United States
| journal=MMWR Morb Mortal Wkly Rep. | year=1982 | pages=353–354; 360–361 | volume=31 | issue=26
| pmid=6811853

}}</ref> In the general press, the term ''GRID'', which stood for [[Gay-related immune deficiency]], had been coined.<ref name=Altman>{{

cite news
| author=Altman LK
| title=New homosexual disorder worries officials
| work=The New York Times | date=1982-05-11

}}</ref> However, after determining that AIDS was not isolated to the homosexual community,<ref name=MMWR1982b/> the term GRID became misleading and ''AIDS'' was introduced at a meeting in July 1982.<ref name=Kher>{{

cite news
| author=Kher U
| title=A Name for the Plague
| work=Time | date=1982-07-27 | url=http://www.time.com/time/80days/820727.html |accessdate=2008-03-10

}}</ref> By September 1982 the CDC started using the name AIDS, and properly defined the illness.<ref name=MMWR1982c>{{

cite journal
| author=Centers for Disease Control (CDC)
| title=Update on acquired immune deficiency syndrome (AIDS)—United States.
| journal=MMWR Morb Mortal Wkly Rep. | year=1982 | pages=507–508; 513–514 | volume=31 | issue=37
| pmid=6815471

}}</ref> In 1993, the CDC expanded their definition of AIDS to include all HIV positive people with a CD4+ T cell count below 200 per µL of blood or 14% of all [[lymphocyte]]s.<ref name=MMWR>{{

cite web | publisher=[[Centers for Disease Control and Prevention|CDC]] | publisher=CDC | year=1992
| url=http://www.cdc.gov/mmwr/preview/mmwrhtml/00018871.htm
| title=1993 Revised Classification System for HIV Infection and Expanded Surveillance Case Definition for AIDS Among Adolescents and Adults
| accessdate = 2006-02-09

}}</ref> The majority of new AIDS cases in developed countries use either this definition or the pre-1993 CDC definition. The AIDS diagnosis still stands even if, after treatment, the CD4+ T cell count rises to above 200 per µL of blood or other AIDS-defining illnesses are cured.

===HIV test===
{{main|HIV test}}

Many people are unaware that they are infected with HIV.<ref name=Kumaranayake>

{{cite journal
| author=Kumaranayake L, Watts C | title=
Resource allocation and priority setting of HIV/AIDS interventions: addressing the generalized epidemic in sub-Saharan Africa | journal=J. Int. Dev. | year=2001 | pages=451–466 | volume=13 | issue=4 | id={{DOI|10.1002/jid.798}}

}}</ref> Less than 1% of the sexually active urban population in Africa has been tested, and this proportion is even lower in rural populations. Furthermore, only 0.5% of pregnant women attending urban health facilities are counseled, tested or receive their test results. Again, this proportion is even lower in rural health facilities.<ref name=Kumaranayake>

{{cite journal
| author=Kumaranayake L, Watts C | title=
Resource allocation and priority setting of HIV/AIDS interventions: addressing the generalized epidemic in sub-Saharan Africa | journal=J. Int. Dev. | year=2001 | pages=451–466 | volume=13 | issue=4 | id={{DOI|10.1002/jid.798}}

}}</ref> Therefore, donor blood and blood products used in medicine and medical research are screened for HIV.

HIV tests are usually performed on venous blood. Many laboratories use ''fourth generation'' screening tests which detect anti-HIV antibody (IgG and IgM) and the HIV p24 antigen. The detection of HIV antibody or antigen in a patient previously known to be negative is evidence of HIV infection. Individuals whose first specimen indicates evidence of HIV infection will have a repeat test on a second blood sample to confirm the results. The window period (the time between initial infection and the development of detectable antibodies against the infection) can vary since it can take 3–6 months to [[seroconversion|seroconvert]] and to test positive. Detection of the virus using polymerase chain reaction ([[PCR]]) during the window period is possible, and evidence suggests that an infection may often be detected earlier than when using a fourth generation EIA screening test. Positive results obtained by PCR are confirmed by antibody tests.<ref name="pmid16706742">{{cite journal
|author=Weber B
|title=Screening of HIV infection: role of molecular and immunological assays
|journal=Expert Rev. Mol. Diagn.
|volume=6
|issue=3
|pages=399-411
|year=2006
|pmid=16706742
|doi=10.1586/14737159.6.3.399
|url=http://dx.doi.org/10.1586/14737159.6.3.399
}}</ref>
Routinely used HIV tests for infection in [[neonates]], born to HIV-positive mothers, have no value because of the presence of maternal antibody to HIV in the child's blood. HIV infection can only be diagnosed by PCR, testing for HIV pro-viral DNA in the children's [[lymphocyte]]s.<ref name="pmid11791341">{{cite journal
|author=Tóth FD, Bácsi A, Beck Z, Szabó J
|title=Vertical transmission of human immunodeficiency virus
|journal=Acta Microbiol Immunol Hung
|volume=48
|issue=3-4
|pages=413-27
|year=2001
|pmid=11791341
}}</ref>

==Transmission and prevention==

{| class="prettytable" style="float:right; font-size:85%; margin-left:15px;"
|- bgcolor="#efefef"
|+ Estimated per act risk for acquisition of HIV by exposure route<ref name=MMWR3>{{

cite journal | author=Smith DK, Grohskopf LA, Black RJ, et al | title=Antiretroviral Postexposure Prophylaxis After Sexual, Injection-Drug Use, or Other Nonoccupational Exposure to HIV in the United States | journal=MMWR | year=2005 | pages=1–20 | volume=54 | issue=RR02 | url=http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5402a1.htm#tab1

}}</ref>
|- bgcolor="#efefef"
! style="width: 100px" abbr="Route" | Exposure Route
! style="width: 130px" abbr="Infections" | Estimated infections per 10,000 exposures to an infected source
|-
! style="text-align:left"| Blood Transfusion
| 9,000<ref name=Donegan>{{

cite journal | author=Donegan E, Stuart M, Niland JC, et al | title=Infection with human immunodeficiency virus type 1 (HIV-1) among recipients of antibody-positive blood donations | journal=Ann. Intern. Med. | year=1990 | pages=733–739 | volume=113 | issue=10
| pmid=2240875

}}</ref>
|-
! style="text-align:left"| Childbirth
| 2,500<ref name=Coovadia>{{

cite journal | author=Coovadia H | title=Antiretroviral agents—how best to protect infants from HIV and save their mothers from AIDS | journal=N. Engl. J. Med. | year=2004 | pages=289–292 | volume=351 | issue=3 | pmid=15247337

}}</ref>
|-
! style="text-align:left"| Needle-sharing injection drug use
| 67<ref name=Kaplan>{{

cite journal | author=Kaplan EH, Heimer R | title=HIV incidence among New Haven needle exchange participants: updated estimates from syringe tracking and testing data | journal=J. Acquir. Immune Defic. Syndr. Hum. Retrovirol. | year=1995 | pages=175–176 | volume=10 | issue=2
| pmid=7552482

}}</ref>
|-
! style="text-align:left"| Percutaneous needle stick
| 30<ref name=Bell>{{

cite journal | author=Bell DM | title=Occupational risk of human immunodeficiency virus infection in healthcare workers: an overview. | journal=Am. J. Med. | year=1997 | pages=9–15 | volume=102 | issue=5B | pmid=9845490

}}</ref>

|-
! style="text-align:left"| Receptive anal intercourse*
| 50<ref name=ESG>{{

cite journal | author=European Study Group on Heterosexual Transmission of HIV | title=Comparison of female to male and male to female transmission of HIV in 563 stable couples | journal=BMJ. | year=1992 | pages=809–813 | volume=304 | issue=6830 | pmid=1392708

}}</ref><ref name=Varghese>{{

cite journal | author=Varghese B, Maher JE, Peterman TA, Branson BM,Steketee RW | title=Reducing the risk of sexual HIV transmission: quantifying the per-act risk for HIV on the basis of choice of partner, sex act, and condom use | journal=Sex. Transm. Dis. | year=2002 | pages=38–43 | volume=29 | issue=1 | pmid=11773877

}}</ref>
|-
! style="text-align:left"| Insertive anal intercourse*
| 6.5<ref name=ESG /><ref name=Varghese />
|-
! style="text-align:left"| Receptive penile-vaginal intercourse*
| 10<ref name=ESG /><ref name=Varghese /><ref name=Leynaert>{{

cite journal | author=Leynaert B, Downs AM, de Vincenzi I | title=Heterosexual transmission of human immunodeficiency virus: variability of infectivity throughout the course of infection. European Study Group on Heterosexual Transmission of HIV | journal=Am. J. Epidemiol. | year=1998 | pages=88–96 | volume=148 | issue=1 | pmid=9663408

}}</ref>
|-
! style="text-align:left"| Insertive penile-vaginal intercourse*
| 5<ref name=ESG /><ref name=Varghese />
|-
! style="text-align:left"| Receptive oral intercourse*§
| 1<ref name=Varghese />
|-
! style="text-align:left"| Insertive oral intercourse*
| 0.5<ref name=Varghese />§
|- bgcolor="#efefef"
! colspan=5 style="border-right:0px;";| * assuming no condom use § source refers to oral intercourse performed on a man
|}
The three main transmission routes of HIV are sexual contact, exposure to infected body fluids or tissues, and from mother to [[fetus]] or child during [[perinatal]] period. It is possible to find HIV in the [[saliva]], [[tears]], and [[urine]] of infected individuals, but there are no recorded cases of infection by these secretions, and the risk of infection is negligible.<ref>{{

cite web
| url=http://www.avert.org/aids.htm
| publisher = avert.org
| title=Facts about AIDS & HIV
| accessdate = 2007-11-30

}}</ref>

===Sexual contact===

The majority of HIV infections are acquired through [[Bareback (sex)|unprotected sex]]ual relations between partners, one of whom has HIV. The primary mode of HIV infection worldwide is through sexual contact between members of the opposite sex.<ref>{{

cite journal | author=Johnson AM, Laga M
| title=Heterosexual transmission of HIV | journal=AIDS | year=1988 | pages=S49-S56| volume=2 | issue=suppl. 1
| pmid=3130121

}}</ref><ref>{{

cite journal | author=N'Galy B, Ryder RW
| title=Epidemiology of HIV infection in Africa | journal=Journal of Acquired Immune Deficiency Syndromes | year=1988 | pages=551-558 | volume=1 | issue=6
| pmid=3225742

}}</ref><ref>{{

cite journal | author=Deschamps MM, Pape JW, Hafner A, Johnson WD Jr.
| title=Heterosexual transmission of HIV in Haiti | journal=Annals of Internal Medicine | year=1996 | pages=324–330 | volume=125 | issue=4
| pmid=8678397

}}</ref>
Sexual transmission occurs with the contact between sexual secretions of one partner with the rectal, genital or oral [[mucous membrane]]s of another. Unprotected receptive sexual acts are riskier than unprotected insertive sexual acts, with the risk for transmitting HIV from an infected partner to an uninfected partner through unprotected anal intercourse greater than the risk for transmission through vaginal intercourse or oral sex. Oral sex is not without its risks as HIV is transmissible through both insertive and receptive oral sex.<ref name=Rothenberg>{{

cite journal | author=Rothenberg RB, Scarlett M, del Rio C, Reznik D, O'Daniels C
| title=Oral transmission of HIV | journal=AIDS | year=1998 | pages=2095–2105 | volume=12 | issue=16
| pmid=9833850

}}</ref> The risk of HIV transmission from exposure to [[saliva]] is considerably smaller than the risk from exposure to [[semen]]; contrary to popular belief, one would have to swallow liters of saliva from a carrier to run a significant risk of becoming infected.<ref name=Vincenzi>{{

cite journal | author=Mastro TD, de Vincenzi I
| title=Probabilities of sexual HIV-1 transmission | journal=AIDS | year=1996 | volume=10 | pages=S75–S82 | issue=Suppl A | pmid=8883613

}}</ref>

Approximately 30% of women in ten countries representing "diverse cultural, geographical and urban/rural settings" report that their first sexual experience was forced or coerced, making sexual violence a key driver of the HIV/AIDS [[pandemic]].<ref name=vaw>{{

cite web
| publisher=[[World Health Organization]] | year=2006
| url=http://www.who.int/gender/violence/who_multicountry_study/en/index.html
| title=WHO Multi-country Study on Women's Health and Domestic Violence against Women
| accessdate = 2006-12-14

}}</ref> Sexual assault greatly increases the risk of HIV transmission as protection is rarely employed and physical trauma to the vaginal cavity frequently occurs which facilitates the transmission of HIV.<ref>{{cite journal
|author=Koenig MA, Zablotska I, Lutalo T, Nalugoda F, Wagman J, Gray R
|title=Coerced first intercourse and reproductive health among adolescent women in Rakai, Uganda
|journal=Int Fam Plan Perspect
|volume=30
|issue=4
|pages=156–63
|year=2004
|pmid=15590381
|doi=10.1363/ifpp.30.156.04
}}</ref>

[[Sexually transmitted infection]]s (STI) increase the risk of HIV transmission and infection because they cause the disruption of the normal [[epithelial]] barrier by genital [[ulcer]]ation and/or microulceration; and by accumulation of pools of HIV-susceptible or HIV-infected cells ([[lymphocyte]]s and [[macrophage]]s) in semen and vaginal secretions. Epidemiological studies from sub-Saharan Africa, Europe and North America have suggested that there is approximately a four times greater risk of becoming infected with HIV in the presence of a genital ulcer such as those caused by [[syphilis]] and/or [[chancroid]]. There is also a significant though lesser increased risk in the presence of STIs such as [[gonorrhea]], [[Chlamydia infection|Chlamydial infection]] and [[trichomoniasis]] which cause local accumulations of lymphocytes and macrophages.<ref name=Laga>{{

cite journal
| author=Laga M, Nzila N, Goeman J
| title=The interrelationship of sexually transmitted diseases and HIV infection: implications for the control of both epidemics in Africa
| journal=AIDS | year=1991 | pages=S55–S63 | volume=5 | issue=Suppl 1
| pmid=1669925

}}</ref>

Transmission of HIV depends on the infectiousness of the index case and the susceptibility of the uninfected partner. Infectivity seems to vary during the course of illness and is not constant between individuals. An undetectable plasma [[viral load]] does not necessarily indicate a low viral load in the seminal liquid or genital secretions. Each 10-fold increment of blood plasma HIV RNA is associated with an 81% increased rate of HIV transmission.<ref name=Laga /><ref name=Tovanabutra>{{

cite journal
| author=Tovanabutra S, Robison V, Wongtrakul J, et al
| title=Male viral load and heterosexual transmission of HIV-1 subtype E in northern Thailand
| journal=J. Acquir. Immune. Defic. Syndr. | year=2002 | pages=275–283 | volume=29 | issue=3
| pmid=11873077

}}</ref> Women are more susceptible to HIV-1 infection due to hormonal changes, vaginal microbial ecology and physiology, and a higher prevalence of sexually transmitted diseases.<ref name=Sagar>{{

cite journal
| author=Sagar M, Lavreys L, Baeten JM, et al
| title=Identification of modifiable factors that affect the genetic diversity of the transmitted HIV-1 population
| journal=AIDS | year=2004 | pages=615–619 | volume=18 | issue=4
| pmid=15090766

}}</ref><ref name=Lavreys>{{

cite journal
| author= Lavreys L, Baeten JM, Martin HL Jr, et al | title=Hormonal contraception and risk of HIV-1 acquisition: results of a 10-year prospective study
| journal=AIDS | year=2004 | pages=695–697 | volume=18 | issue=4
| pmid=15090778

}}</ref> People who are infected with HIV can still be infected by other, more [[virulent]] strains.

During a sexual act, only male or female condoms can reduce the chances of infection with HIV and other STDs and the chances of becoming [[pregnant]]. The best evidence to date indicates that typical condom use reduces the risk of [[heterosexual]] HIV transmission by approximately 80% over the long-term, though the benefit is likely to be higher if condoms are used correctly on every occasion.<ref name=Cayley>{{

cite journal
| author=Cayley WE Jr.
| title=Effectiveness of condoms in reducing heterosexual transmission of HIV
| journal=Am. Fam. Physician | year=2004 | pages=1268–1269 | volume=70 | issue=7
| pmid=15508535

}}</ref> The effective use of condoms and screening of blood transfusion in North America, Western and Central Europe is credited with contributing to the low rates of AIDS in these regions. Promoting condom use, however, has often proved controversial and difficult. Many religious groups, most noticeably the Roman Catholic Church, have opposed the use of condoms on religious grounds, and have sometimes seen condom promotion as an affront to the promotion of marriage, monogamy and sexual morality. Defenders of the Catholic Church's role in AIDS and general STD prevention state that, while they may be against the use of contraception, they are strong advocates of abstinence outside marriage.<ref name=catechism>{{

cite book
| author = Catholic Church
| year = 1997
| title = Catechism of the Catholic Church : Second Edition
| chapter = Offenses against chastity
| chapterurl = http://www.scborromeo.org/ccc/p3s2c2a6.htm#II
| pages = 2353
| publisher = Amministrazione Del Patrimonio Della Sede Apostolica
| location = Vatican
| accessdate = 2006-06-14

}}</ref> This attitude is also found among some health care providers and policy makers in sub-Saharan African nations, where HIV and AIDS prevalence is extremely high.<ref name=HRW>{{

cite book
| author = Human Rights Watch
| year = 2005
| title = The Less They Know, the Better
| chapter = Restrictions on Condoms
| chapterurl = http://hrw.org/reports/2005/uganda0305/7.htm#_Toc98378385
| publisher = Human Rights Watch
| location = New York NY

}}</ref> They also believe that the distribution and promotion of condoms is tantamount to promoting sex amongst the youth and sending the wrong message to uninfected individuals. However, no evidence has been produced that promotion of condom use increases sexual promiscuity,<ref name=noauthors>{{

cite journal
| author=No authors listed
| title=Study shows condom use does not promote promiscuity
| journal=AIDS Policy Law | year=1997 | pages=6–7 | volume=12| issue=12
| pmid=11364411

}}</ref> and abstinence-only programs have been unsuccessful in the United States both in changing sexual behavior and in reducing HIV transmission.<ref name=HRW2>{{

cite web
| publisher=Human Rights Watch | date=2002-09-02
| url=http://www.hrw.org/reports/2002/usa0902/USA0902-04.htm
| title=Ignorance only: HIV/AIDS, Human rights and federally funded abstinence-only programs in the United States. Texas: A case study
| accessdate = 2006-03-28

}}</ref> Evaluations of several abstinence-only programs in the US showed a negative impact on the willingness of youths to use contraceptives, due to the emphasis on contraceptives' failure rates.<ref name=AbstinenceEvals>{{

cite web
| author=Hauser, Debra | publisher=Advocates for Youth | year=2004 | format=PDF
| url=http://www.advocatesforyouth.org/publications/stateevaluations.pdf
| title=Five Years of Abstinence-Only-Until-Marriage Education: Assessing the Impact
| accessdate = 2006-06-07

}}</ref>

The male latex condom, if used correctly without oil-based lubricants, is the single most effective available technology to reduce the sexual transmission of HIV and other sexually transmitted infections. Manufacturers recommend that oil-based lubricants such as petroleum jelly, butter, and lard not be used with latex condoms, because they dissolve the latex, making the condoms [[Porosity|porous]]. If necessary, manufacturers recommend using [[water]]-based lubricants. Oil-based lubricants can however be used with [[polyurethane]] condoms.<ref name=Durex>{{

cite web
| publisher=Durex | year=
| url=http://www.durex.com/cm/assets/SexEdDownloads/Module_5_condoms.doc
| title=Module 5/Guidelines for Educators
| format= Microsoft Word
| accessdate = 2006-04-17

}}</ref> Latex condoms degrade over time, making them porous, which is why condoms have expiration dates. In Europe and the United States, condoms have to conform to European (EC 600) or American (D3492) standards to be considered protective against HIV transmission.

The [[female condom]] is an alternative to the male condom and is made from [[polyurethane]], which allows it to be used in the presence of oil-based lubricants. They are larger than male condoms and have a stiffened ring-shaped opening, and are designed to be inserted into the vagina. The female condom contains an inner ring, which keeps the condom in place inside the vagina – inserting the female condom requires squeezing this ring. However, at present availability of female condoms is very low and the price remains prohibitive for many women. Preliminary studies suggest that, where female condoms are available, overall protected sexual acts increase relative to unprotected sexual acts, making them an important HIV prevention strategy.<ref name=PATH>{{

cite journal
| author=PATH
| title=The female condom: significant potential for STI and pregnancy prevention
| journal=Outlook | year=2006 | volume=22 | issue=2

}}</ref>

With consistent and correct use of condoms, there is a very low risk of HIV infection. Studies on couples where one partner is infected show that with consistent condom use, HIV infection rates for the uninfected partner are below 1% per year.<ref name=WHOCondoms>{{

cite web
| publisher=[[World Health Organization|WHO]]| year= August 2003
| url=http://www.wpro.who.int/media_centre/fact_sheets/fs_200308_Condoms.htm
| title=Condom Facts and Figures
| accessdate = 2006-01-17
}}</ref>

In December 2006, the last of three large, [[Randomized controlled trial|randomized trials]] confirmed that male [[circumcision]] lowers the risk of HIV infection among heterosexual African men by around 50%. It is expected that this intervention will be actively promoted in many of the countries worst affected by HIV, although doing so will involve confronting a number of practical, cultural and attitudinal issues. Some experts fear that a lower perception of vulnerability among circumcised men may result in more sexual risk-taking behavior, thus negating its preventive effects.<ref name=NIAIDCircumcision>{{

cite web
| publisher=[[National Institute of Allergy and Infectious Diseases|NIAID]]
| date=2006-12-13
| url=http://www3.niaid.nih.gov/news/newsreleases/2006/AMC12_06.htm
| title=Adult Male Circumcision Significantly Reduces Risk of Acquiring HIV: Trials Kenya and Uganda Stopped Early
| accessdate = 2006-12-15

}}</ref> Furthermore, South African medical experts are concerned that the repeated use of unsterilized blades in the ritual circumcision of adolescent boys may be spreading HIV.<ref name=Kaisercircum>{{

cite web
| publisher=Kaisernetwork.org | year=2005 | url=http://www.kaisernetwork.org/daily_reports/rep_index.cfm?DR_ID=31199 | title=Repeated Use of Unsterilized Blades in Ritual Circumcision Might Contribute to HIV Spread in S. Africa, Doctors Say | accessdate = 2006-03-28
}}</ref>

Prevention strategies are well-known in developed countries, however, recent epidemiological and behavioral studies in Europe and North America have suggested that a substantial minority of young people continue to engage in high-risk practices and that despite HIV/AIDS knowledge, young people underestimate their own risk of becoming infected with HIV.<ref name=Dias>{{

cite journal
| author=Dias SF, Matos MG, Goncalves, A. C.
| title=Preventing HIV transmission in adolescents: an analysis of the Portuguese data from the Health Behaviour School-aged Children study and focus groups
| journal=Eur. J. Public Health | year=2005 | pages=300–304 | volume=15 | issue=3
| pmid=15941747

}}</ref>

===Exposure to infected body fluids===
[[Image:AIDS Poster If You're Dabbling in Drugs 1989.jpg|thumb|250px|CDC poster from 1989 highlighting the threat of AIDS associated with drug use]]
This transmission route is particularly relevant to [[Intravenous drug use (recreational)|intravenous drug]] users, [[Haemophilia|hemophiliacs]] and recipients of [[blood transfusion]]s and blood products. Sharing and reusing [[syringe]]s contaminated with HIV-infected blood represents a major risk for infection with not only HIV, but also [[hepatitis B]] and [[hepatitis C]]. Needle sharing is the cause of one third of all new HIV-infections and 50% of hepatitis C infections in North America, China, and Eastern Europe. The risk of being infected with HIV from a single prick with a needle that has been used on an HIV-infected person is thought to be about 1 in 150 ([[AIDS#Transmission and prevention|see table above]]). [[Post-exposure prophylaxis]] with anti-HIV drugs can further reduce that small risk.<ref name=Fan>{{

cite book
| author =Fan H | year = 2005
| title =AIDS: science and society | chapterurl =
| editor = Fan, H., Conner, R. F. and Villarreal, L. P. eds
| edition = 4th | pages =
| publisher =Jones and Bartlett Publishers
| location = Boston, MA
| id = ISBN 0-7637-0086-X

}}</ref> Health care workers (nurses, laboratory workers, doctors etc) are also concerned, although more rarely. This route can affect people who give and receive tattoos and piercings. [[Universal precautions]] are frequently not followed in both sub-Saharan Africa and much of Asia because of both a shortage of supplies and inadequate training. The WHO estimates that approximately 2.5% of all HIV infections in sub-Saharan Africa are transmitted through unsafe healthcare injections.<ref name=WHOJapan>{{ cite web
| publisher=[[World Health Organization|WHO]]| date= 2003-03-17
| url=http://64.233.179.104/search?q=cache:adH68_6JGG8J:tokyo.usembassy.gov//e/p/tp-20030317a3.html+site:tokyo.usembassy.gov+HIV+healthcare+injection&hl=en&gl=us&ct=clnk&cd=1
| title=WHO, UNAIDS Reaffirm HIV as a Sexually Transmitted Disease
| accessdate = 2006-01-17

}}</ref> Because of this, the United Nations General Assembly, supported by universal medical opinion on the matter, has urged the nations of the world to implement universal precautions to prevent HIV transmission in health care settings.<ref name=PHR>{{

cite web
| publisher=Physicians for Human Rights | work=Partners in Health | date=2003-03-13
| url=http://www.phrusa.org/campaigns/aids/who_031303.html
| title=HIV Transmission in the Medical Setting: A White Paper by Physicians for Human Rights | accessdate = 2006-03-01

}}</ref>
Drug abuse has an additional effect of an increased tendency to engage in unprotected sexual intercourse.<ref> [http://www.drugtext.org/library/articles/peddr0016.htm Drugtext.org]</ref>

The risk of transmitting HIV to [[blood transfusion]] recipients is extremely low in developed countries where improved donor selection and HIV screening is performed. However, according to the [[World Health Organization|WHO]], the overwhelming majority of the world's population does not have access to safe blood and "between 5% and 10% of HIV infections worldwide are transmitted through the transfusion of infected blood and blood products".<ref name=WHO070401>{{

cite web
| publisher=[[World Health Organization|WHO]] | year= 2001
| url=http://www.who.int/inf-pr-2000/en/pr2000-25.html
| title=Blood safety....for too few
| accessdate = 2006-01-17

}}</ref>

Medical workers who follow universal precautions or body-substance isolation, such as wearing latex gloves when giving injections and washing the hands frequently, can help prevent infection by HIV.

All AIDS-prevention organizations advise drug-users not to share needles and other material required to prepare and take drugs (including syringes, cotton balls, the spoons, water for diluting the drug, straws, crack pipes, etc). It is important that people use new or properly sterilized needles for each injection. Information on cleaning needles using bleach is available from health care and addiction professionals and from needle exchanges. In some developed countries, clean needles are available free in some cities, at needle exchanges or [[safe injection site]]s. Additionally, many nations have decriminalized needle possession and made it possible to buy injection equipment from pharmacists without a prescription.

Transmission of HIV between intravenous drug users has clearly decreased, and HIV transmission by blood transfusion has become quite rare in developed countries.

===Mother-to-child transmission (MTCT)===
The transmission of the virus from the mother to the child can occur ''[[in utero]]'' during the last weeks of pregnancy and at childbirth. In the absence of treatment, the transmission rate between the mother to the child during pregnancy, labor and delivery is 25%. However, when the mother has access to antiretroviral therapy and gives birth by [[caesarean section]], the rate of transmission is just 1%.<ref name=Coovadia /> A number of factors influence the risk of infection, particularly the viral load of the mother at birth (the higher the viral load, the higher the risk). [[Breastfeeding]] increases the risk of transmission by 4.04%.<ref name=Coovadia2>{{

cite journal
| author=Coovadia HM, Bland RM| title=Preserving breastfeeding practice through the HIV pandemic
| journal=Trop. Med. Int. Health. | year=2007| pages=1116–1133 | volume=12 | issue=9
| pmid=17714431

}}</ref> This risk depends on clinical factors and may vary according to the pattern and duration of breast-feeding.<ref name=Coovadia2 />

Studies have shown that antiretroviral drugs, caesarean delivery and formula feeding reduce the chance of transmission of HIV from mother to child.<ref name=Sperling>{{

cite journal
| author=Sperling RS, Shapirom DE, Coombsm RW, et al | title=Maternal viral load, zidovudine treatment, and the risk of transmission of human immunodeficiency virus type 1 from mother to infant
| journal=N. Engl. J. Med. | year=1996 | pages=1621–1629 | volume=335 | issue=22
| pmid=8965861

}}</ref> Current recommendations state that when replacement feeding is acceptable, feasible, affordable, sustainable and safe, HIV-infected mothers should avoid breast-feeding their infant. However, if this is not the case, exclusive breast-feeding is recommended during the first months of life and discontinued as soon as possible.<ref>{{cite web |url=http://www.who.int/hiv/mediacentre/Infantfeedingconsensusstatement.pf.pdf |format=PDF |date=2006 |accessdate=2008-03-12 |title= Consensus statement |author= WHO HIV and Infant Feeding Technical Consultation
}}</ref> In 2005, around 700,000 children under 15 contracted HIV, mainly through MTCT, with 630,000 of these infections occurring in Africa.<ref name=avert>
{{ cite web
| author=Berry S
| publisher=avert.org
| date= 2006-06-08
| url=http://www.avert.org/children.htm
| title=Children, HIV and AIDS
| accessdate = 2006-06-15
}}</ref> Of the children currently living with HIV, almost 90% live in sub-Saharan Africa.<ref name=UNAIDS2007/>

In Africa, the number of MTCT and the prevalence of AIDS is beginning to reverse decades of steady progress in child survival.<ref name=UNMTCT>{{

cite web
| publisher=United Nations | year=2001
| url=http://www.un.org/ga/aids/ungassfactsheets/html/fsmotherchild_en.htm
| title=Fact Sheet: Mother-to-child transmission of HIV
| accessdate = 2006-03-10

}}</ref> Countries such as Uganda are attempting to curb the MTCT epidemic by offering VCT (voluntary counseling and testing), PMTCT (prevention of mother-to-child transmission) and ANC (ante-natal care) services, which include the distribution of antiretroviral therapy.

==Treatment==

:''See also [[HIV#Treatment|HIV Treatment]] and [[Antiretroviral drug]].
[[Image:Abacavir (Ziagen) 300mg.jpg|right|thumb|100px|''[[Abacavir]]'' – a nucleoside analog reverse transcriptase inhibitors (NARTIs or NRTIs)]]
[[Image:Abacavir_structure.svg|thumb|The chemical structure of Abacavir]]

There is currently no [[HIV vaccine|vaccine]] or cure for [[HIV]] or AIDS. The only known methods of prevention are based on avoiding exposure to the virus or, failing that, an antiretroviral treatment directly after a highly significant exposure, called [[post-exposure prophylaxis]] (PEP).<ref name=Fan/> PEP has a very demanding four week schedule of dosage. It also has very unpleasant side effects including [[diarrhea]], [[malaise]], [[nausea]] and [[Fatigue (physical)|fatigue]].<ref name=PEPpocketguide>{{

cite web
| publisher=Department of Health and Human Services
| date=February 2006
| url=http://hab.hrsa.gov/tools/HIVpocketguide/PktGPEP.htm
| title=A Pocket Guide to Adult HIV/AIDS Treatment February 2006 edition
| accessdate = 2006-09-01

}}</ref>

Current treatment for HIV infection consists of [[highly active antiretroviral therapy]], or HAART.<ref name=DhhsHivTreatment>{{

cite web
| publisher=Department of Health and Human Services
| date=February 2006
| url=http://hab.hrsa.gov/tools/HIVpocketguide/PktGARTtables.htm
| title=A Pocket Guide to Adult HIV/AIDS Treatment February 2006 edition
| accessdate = 2006-09-01

}}</ref> This has been highly beneficial to many HIV-infected individuals since its introduction in 1996 when the protease inhibitor-based HAART initially became available.<ref name=Palella/> Current optimal HAART options consist of combinations (or "cocktails") consisting of at least three drugs belonging to at least two types, or "classes," of [[antiretroviral]] agents. Typical regimens consist of two [[nucleoside analogue reverse transcriptase inhibitor]]s (NARTIs or NRTIs) plus either a [[protease inhibitor (pharmacology)|protease inhibitor]] or a [[non-nucleoside reverse transcriptase inhibitor]] (NNRTI). Because HIV disease progression in children is more rapid than in adults, and laboratory parameters are less predictive of risk for disease progression, particularly for young infants, treatment recommendations are more aggressive for children than for adults.<ref name=2005dhhsHivChildren>{{

cite web
| publisher=Department of Health and Human Services Working Group on Antiretroviral Therapy and Medical Management of HIV-Infected Children
| date=2005-11-03
| url=http://www.aidsinfo.nih.gov/ContentFiles/PediatricGuidelines_PDA.pdf
| title=Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection
| format= PDF
| accessdate = 2006-01-17

}}</ref> In developed countries where HAART is available, doctors assess the [[viral load]], rapidity in CD4 decline, and patient readiness while deciding when to recommend initiating treatment.<ref name=2005DhhsHivTreatment>{{

cite web
| publisher=Department of Health and Human Services Panel on Clinical Practices for Treatment of HIV Infection
| date=2005-10-06
| url=http://aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf
| title=Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents
| format= PDF
| accessdate = 2006-01-17

}}</ref>

HAART allows the stabilization of the patient’s symptoms and viremia, but it neither cures the patient of HIV, nor alleviates the symptoms, and high levels of HIV-1, often HAART resistant, return once treatment is stopped.<ref name=martinez>{{

cite journal
| author=Martinez-Picado J, DePasquale MP, Kartsonis N, et al| title=Antiretroviral resistance during successful therapy of human immunodeficiency virus type 1 infection | journal=Proc. Natl. Acad. Sci. U. S. A. | year=2000 | pages=10948–10953 | volume=97 | issue=20 | pmid=11005867

}}</ref><ref name=Dybul>{{

cite journal
| author=Dybul M, Fauci AS, Bartlett JG, Kaplan JE, Pau AK; Panel on Clinical Practices for Treatment of HIV.
| title=Guidelines for using antiretroviral agents among HIV-infected adults and adolescents
| journal=Ann. Intern. Med. | year=2002 | pages=381–433 | volume=137 | issue=5 Pt 2
| pmid=12617573

}}</ref> Moreover, it would take more than the lifetime of an individual to be cleared of HIV infection using HAART.<ref name=blankson>{{

cite journal
| author=Blankson JN, Persaud D, Siliciano RF | title=The challenge of viral reservoirs in HIV-1 infection | journal=Annu. Rev. Med. | year=2002 | pages=557–593 | volume=53 | issue= | pmid=11818490

}}</ref> Despite this, many HIV-infected individuals have experienced remarkable improvements in their general health and quality of life, which has led to the plummeting of HIV-associated morbidity and mortality.<ref name=Pallelal>{{

cite journal
| author=Palella FJ, Delaney KM, Moorman AC, Loveless MO, Fuhrer J, Satten GA, Aschman DJ, Holmberg SD | title=Declining morbidity and mortality among patients with advanced human immunodeficiency virus infection | journal=N. Engl. J. Med. | year=1998 | pages=853–860 | volume=338 | issue=13 | pmid=9516219

}}</ref><ref name=Wood>{{

cite journal
| author=Wood E, Hogg RS, Yip B, Harrigan PR, O'Shaughnessy MV, Montaner JS
| title=Is there a baseline CD4 cell count that precludes a survival response to modern antiretroviral therapy?
| journal=AIDS | year=2003 | pages=711–720 | volume=17 | issue=5
| pmid=12646794

}}</ref><ref name=Chene>{{

cite journal
| author=Chene G, Sterne JA, May M, Costagliola D, Ledergerber B, Phillips AN, Dabis F, Lundgren J, D'Arminio Monforte A, de Wolf F, Hogg R, Reiss P, Justice A, Leport C, Staszewski S, Gill J, Fatkenheuer G, Egger ME and the Antiretroviral Therapy Cohort Collaboration
| title=Prognostic importance of initial response in HIV-1 infected patients starting potent antiretroviral therapy: analysis of prospective studies
| journal=Lancet | year=2003 | pages=679–686 | volume=362 | issue=9385
| pmid=12957089 | doi=10.1016/S0140-6736(03)14229-8

}}</ref> In the absence of HAART, progression from HIV infection to AIDS occurs at a median of between nine to ten years and the median survival time after developing AIDS is only 9.2 months.<ref name=Morgan2 /> HAART is thought to increase survival time by between 4 and 12 years.<ref name=JTKing>{{

cite journal
| author=King JT, Justice AC, Roberts MS, Chang CH, Fusco JS and the CHORUS Program Team
| title=Long-Term HIV/AIDS Survival Estimation in the Highly Active Antiretroviral Therapy Era
| journal=Medical Decision Making | year=2003 | pages=9–20 | volume=23 | issue=1
| pmid=12583451

}}</ref><ref name=Tassie>{{

cite journal
| author=Tassie JM, Grabar S, Lancar R, Deloumeaux J, Bentata M, Costagliola D and the Clinical Epidemiology Group from the French Hospital Database on HIV
| title=Time to AIDS from 1992 to 1999 in HIV-1-infected subjects with known date of infection
| journal=Journal of acquired immune deficiency syndromes | year=2002 | pages=81–7 | volume=30 | issue=1
| pmid=12048367

}}</ref> This average reflects the fact that for some patients – and in many clinical cohorts this may be more than fifty percent of patients – HAART achieves far less than optimal results. This is due to a variety of reasons such as medication intolerance/side effects, prior ineffective antiretroviral therapy and infection with a drug-resistant strain of HIV. However, non-adherence and non-persistence with antiretroviral therapy is the major reason most individuals fail to get any benefit from and develop resistance to HAART.<ref name=becker>{{

cite journal
| author=Becker SL, Dezii CM, Burtcel B, Kawabata H, Hodder S. | title=Young HIV-infected adults are at greater risk for medication nonadherence | journal=MedGenMed. | year=2002 | pages=21 | volume=4| issue=3 | pmid=12466764

}}</ref> The reasons for non-adherence and non-persistence with HAART are varied and overlapping. Major psychosocial issues, such as poor access to medical care, inadequate social supports, psychiatric disease and drug abuse contribute to non-adherence. The complexity of these HAART regimens, whether due to pill number, dosing frequency, meal restrictions or other issues, along with side effects that create intentional non-adherence, also has a weighty impact.<ref name=Nieuwkerk>{{

cite journal
| author=Nieuwkerk P, Sprangers M, Burger D, Hoetelmans RM, Hugen PW, Danner SA, van Der Ende ME, Schneider MM, Schrey G, Meenhorst PL, Sprenger HG, Kauffmann RH, Jambroes M, Chesney MA, de Wolf F, Lange JM and the ATHENA Project | title=Limited Patient Adherence to Highly Active Antiretroviral Therapy for HIV-1 Infection in an Observational Cohort Study | journal=Arch. Intern. Med. | year=2001 | pages=1962–1968 | volume=161 | issue=16 | pmid=11525698

}}</ref><ref name=Kleeberger>{{

cite journal
| author=Kleeberger C, Phair J, Strathdee S, Detels R, Kingsley L, Jacobson LP | title=Determinants of Heterogeneous Adherence to HIV-Antiretroviral Therapies in the Multicenter AIDS Cohort Study| journal=J. Acquir. Immune Defic. Syndr. | year=2001 | pages=82–92 | volume=26 | issue=1 | pmid=11176272

}}</ref><ref name=heath>{{

cite journal
| author=Heath KV, Singer J, O'Shaughnessy MV, Montaner JS, Hogg RS | title=Intentional Nonadherence Due to Adverse Symptoms Associated With Antiretroviral Therapy | journal=J. Acquir. Immune Defic. Syndr. | year=2002 | pages=211–217 | volume=31 | issue=2 | pmid=12394800

}}</ref> The side effects include [[lipodystrophy]], [[dyslipidaemia]], [[insulin resistance]], an increase in [[cardiovascular]] risks and [[birth defect]]s.<ref name=Montessori>{{

cite journal |
author=Montessori V, Press N, Harris M, Akagi L, Montaner JS |
title=Adverse effects of antiretroviral therapy for HIV infection. |
journal=CMAJ | year=2004 | pages=229–238 | volume=170 | issue=2 | pmid=14734438

}}</ref><ref name=Saitoh>{{

cite journal
| author=Saitoh A, Hull AD, Franklin P, Spector SA
| title=Myelomeningocele in an infant with intrauterine exposure to efavirenz
| journal=J. Perinatol. | year=2005 | pages=555–556 | volume=25 | issue=8
| pmid=16047034 | doi=10.1038/sj.jp.7211343

}}</ref>

Daily multivitamin and mineral supplements have been found to reduce HIV disease progression among men and women. This could become an important low-cost intervention provided during early HIV disease to prolong the time before antiretroviral therapy is required.<ref name=Fawzi>{{

cite journal
| author=Fawzi W, Msamanga G, Spiegelman D, Hunter DJ
| title=Studies of vitamins and minerals and HIV transmission and disease progression
| journal=J. Nutrition| year=2005 | pages=938–944 | volume=135 | issue=4
| pmid=15795466
}}
</ref> Some individual nutrients have also been tried.<ref name=Hurwitz>([[Selenium]]:) {{

cite journal
| author=Hurwitz BE, Klaus JR, Llabre MM, Gonzalez A, Lawrence PJ, Maher KJ, Greeson JM, Baum MK, Shor-Posner G, Skyler JS, Schneiderman N
| title=Suppression of human immunodeficiency virus type 1 viral load with selenium supplementation: a randomized controlled trial
| journal=Arch Intern Med.| year=2007 | pages=148–155 | volume=167 | issue=2
| pmid=17242315
}}</ref><ref name=Cathcart1>([[Vitamin C]]:) {{

cite journal
| author=Cathcart RR
| title=Vitamin C in the Treatment of Acquired Immune Deficiency Syndrome
| journal=Medical Hypotheses | year=1984 | volume=14 | issue=4 | pages=423-433
| pmid=6238227 | doi=10.1016/0306-9877(84)90149-X
| url=http://www.doctoryourself.com/aids_cathcart.html

}}</ref> Anti-retroviral drugs are expensive, and the majority of the world's infected individuals do not have access to medications and treatments for HIV and AIDS.<ref name=Ferrantelli>{{

cite journal
| author=Ferrantelli F, Cafaro A, Ensoli B | title=Nonstructural HIV proteins as targets for prophylactic or therapeutic vaccines | journal=Curr Opin Biotechnol. | year=2004 | pages=543–556 | volume=15 | issue=6
| pmid=15560981

}}</ref> It has been postulated that only a vaccine can halt the pandemic because a vaccine would possibly cost less, thus being affordable for developing countries, and would not require daily treatments.<ref name=Ferrantelli/> However, after over 20 years of research, HIV-1 remains a difficult target for a vaccine.<ref name=Ferrantelli/>

Research to improve current treatments includes decreasing side effects of current drugs, further simplifying drug regimens to improve adherence, and determining the best sequence of regimens to manage drug resistance. A number of studies have shown that measures to prevent opportunistic infections can be beneficial when treating patients with HIV infection or AIDS. [[Vaccination]] against [[hepatitis]] A and B is advised for patients who are not infected with these viruses and are at risk of becoming infected.<ref name=Laurence>{{

cite journal
| author=Laurence J
| title=Hepatitis A and B virus immunization in HIV-infected persons
| journal=AIDS Reader | year=2006 | pages=15–17 | volume=16 | issue=1
| pmid=16433468

}}</ref> Patients with substantial immunosuppression are also advised to receive prophylactic therapy for [[Pneumocystis jiroveci pneumonia]] (PCP), and many patients may benefit from prophylactic therapy for [[toxoplasmosis]] and [[Cryptococcus]] [[meningitis]] as well.<ref name=PEPpocketguide>{{

cite web
| publisher=Department of Health and Human Services
| date = 2007-02-02
| url=http://www.guideline.gov/summary/summary.aspx?ss=14&doc_id=6223&string=infected+AND+patients
| title=Treating opportunistic infections among HIV-infected adults and adolescents. Recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association/Infectious Diseases Society of America.
| accessdate = 2007-02-05

}}</ref>

Various forms of [[alternative medicine]] have been used to treat symptoms or alter the course of the disease.<ref name=Saltmarsh>{{

cite journal
| author=Saltmarsh S
| title=Voodoo or valid? Alternative therapies benefit those living with HIV
| journal=Positively Aware | year=2005 | pages=46 | volume=3 | issue=16
| pmid=16479668 | url=http://www.tpan.com/publications/pa/may_jun_05/voodoo.shtml

}}
</ref> In the first decade of the [[epidemic]] when no useful conventional treatment was available, a large number of people with AIDS experimented with alternative therapies. The definition of "alternative therapies" in AIDS has changed since that time. Then, the phrase often referred to community-driven treatments, untested by government or pharmaceutical company research, that some hoped would directly suppress the virus or stimulate immunity against it. Examples of alternative medicine that people hoped would improve their symptoms or their quality of life include massage, stress management, herbal and flower remedies such as boxwood,<ref name=Pharo>{{

cite journal
| author=Pharo A, et al
| title=Evaluation of the safety and efficacy of SPV-30 (boxwood extract) in patients with HIV disease
| journal=Int Conf AIDS | year=1996 | issue=Jul 7–12 | pages=11:19 | id=abstract no. Mo. B.180
| url=http://www.aegis.org/conferences/iac/1996/MoB180.html

}}
</ref><ref name=Durant>{{

cite journal
| author=Durant J, et al
| title=Efficacy and safety of Buxussempervirens L. preparations (SPV-30) in HIV infected asymptomatic patients: a multi-centre, randomized, double-blind, placebo-controlled trial.
| journal=Phytomedicine | year = 1998 | issue=5 | pages=1–10

}}
</ref> and [[acupuncture]];<ref name=Saltmarsh /> when used with conventional treatment, many now refer to these as "complementary" approaches. Despite the widespread use of complementary and alternative medicine by people living with HIV/AIDS, the effectiveness of these therapies has not been established.<ref name=Mills>{{

cite journal
| author=Mills E, Wu P, Ernst E
| title=Complementary therapies for the treatment of HIV: in search of the evidence.
| journal=Int. J. STD AIDS.| year=2005 | pages=395–403 | volume=16 | issue=6
| pmid=15969772

}}</ref>

==Prognosis==

Without treatment, the net median survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype,<ref name=UNAIDS2007/> and the median survival rate after diagnosis of AIDS in resource-limited settings where treatment is not available ranges between 6 and 19 months, depending on the study.<ref>{{cite paper |title= Progression and mortality of untreated HIV-positive individuals living in resource-limited settings: update of literature review and evidence synthesis |author= Zwahlen M, Egger M |url=http://data.unaids.org/pub/Periodical/2006/zwahlen_unaids_hq_05_422204_2007_en.pdf |format=PDF |date=2006 |accessdate=2008-03-19 |version= UNAIDS Obligation HQ/05/422204}}</ref> In areas where it is widely available, the development of [[HAART]] as effective therapy for HIV infection and AIDS reduced the death rate from this disease by 80%, and raised the life expectancy for a newly-diagnosed HIV-infected person to about 20 years.<ref>{{cite journal |journal= Int J Dermatol |date=2007 |volume=46 |issue=12 |pages=1219–28 |title= Current status of HIV infection: a review for non-HIV-treating physicians |author= Knoll B, Lassmann B, Temesgen Z |pmid=18173512 |doi=10.1111/j.1365-4632.2007.03520.x |pmid=18173512}}</ref>

===Economic impact===
[[Image:Life expectancy in some Southern African countries 1958 to 2003.jpg|right|295px|thumb|Changes in life expectancy in some hard-hit African countries.
{{legend-line|red solid 2px|Botswana}}{{legend-line|darkgreen solid 2px|Zimbabwe}}{{legend-line|blue solid 2px|Kenya}}{{legend-line|black solid 2px|South Africa}}{{legend-line|grey solid 2px|Uganda}}]]

HIV and AIDS retard economic growth by destroying human capital.<ref name=Bell-et-al-2003/>
Without proper [[nutrition]], health care and medicine that is available in developed countries, large numbers of people are falling victim to AIDS. They will not only be unable to work, but will also require significant medical care. The forecast is that this will likely cause a collapse of economies and societies in the region. In some heavily infected areas, the epidemic has left behind many orphans cared for by elderly grandparents.<ref name=Greener>{{cite book
| author =Greener R
| year = 2002
| title = State of The Art: AIDS and Economics
| chapter = AIDS and macroeconomic impact
| editor = S, Forsyth (ed.)
| pages = 49–55
| publisher = IAEN
}}</ref>

The increased mortality in this region will result in a smaller skilled population and labor force.<ref name=Greener /> This smaller labor force will be predominantly young people, with reduced knowledge and work experience leading to reduced productivity. An increase in workers’ time off to look after sick family members or for sick leave will also lower productivity. Increased mortality will also weaken the mechanisms that generate human capital and investment in people, through loss of income and the death of parents.<ref name=Greener /> By killing off mainly young adults, AIDS seriously weakens the taxable population, reducing the resources available for public expenditures such as education and health services not related to AIDS resulting in increasing pressure for the state's finances and slower growth of the economy. This results in a slower growth of the tax base, an effect that will be reinforced if there are growing expenditures on treating the sick, training (to replace sick workers), sick pay and caring for AIDS orphans. This is especially true if the sharp increase in adult mortality shifts the responsibility and blame from the family to the government in caring for these orphans.<ref name=Greener />

On the level of the household, AIDS results in both the loss of income and increased spending on healthcare by the household. The income effects of this lead to spending reduction as well as a substitution effect away from education and towards healthcare and funeral spending. A study in Côte d'Ivoire showed that households with an HIV/AIDS patient spent twice as much on medical expenses as other households.<ref name=WBank>{{

cite journal |
author=Over M |
title=The macroeconomic impact of AIDS in Sub-Saharan Africa, Population and Human Resources Department |
journal=The World Bank | year=1992

}}</ref>

UNAIDS, WHO and the United Nations Development Programme have documented a correlation between the decreasing life expectancies and the lowering of gross national product in many African countries with prevalence rates of 10% or more. Indeed, since 1992 predictions that AIDS would slow economic growth in these countries have been published. The degree of impact depended on assumptions about the extent to which illness would be funded by savings and who would be infected.<ref name=WBank /> Conclusions reached from models of the growth trajectories of 30 sub-Saharan economies over the period 1990–2025 were that the economic growth rates of these countries would be between 0.56 and 1.47% lower. The impact on gross domestic product (GDP) per capita was less conclusive. However, in 2000, the rate of growth of Africa's per capita GDP was in fact reduced by 0.7% per year from 1990–1997 with a further 0.3% per year lower in countries also affected by [[malaria]].<ref name=Bonnel>{{

cite journal |
author=Bonnel R |
title=HIV/AIDS and Economic Growth: A Global Perspective |
journal=S. A. J. Economics | year=2000 | pages=820–855 | volume=68 | issue=5 |

}}</ref> The forecast now is that the growth of GDP for these countries will undergo a further reduction of between 0.5 and 2.6% per annum.<ref name=Greener /> However, these estimates may be an underestimate, as they do not look at the effects on output per capita.<ref name=Bell-et-al-2003>{{

cite paper
|author= Bell C, Devarajan S, Gersbach H |date=2003
|url=http://ssrn.com/abstract=636571
| title=The long-run economic costs of AIDS: theory and an application to South Africa
|accessdate= 2008-03-12
|version= World Bank Policy Research Working Paper No. 3152

}}</ref>

Many governments in sub-Saharan Africa denied that there was a problem for years, and are only now starting to work towards solutions. Underfunding is a problem in all areas of HIV prevention when compared to even conservative estimates of the problems.

Recent research by the Overseas Development Institute (ODI) has suggested that the private sector has begun to recognize the impact of HIV/AIDS on the bottom line, both directly and indirectly. It is estimated that a company can generate an average return of US$3 for every US$1 invested in employee health due to a reduced absenteeism, better productivity and reduction in employee turnover.<ref>{{cite journal
| author = Goetzel RZ, Ozminkowski RJ, Baase CM, Billotti GM
| title = Estimating the return-on-investment from changes in employee health risks on the Dow Chemical Company’s health care costs
| journal = Journal of Occupational and Environmental Medicine
| volume = 47
| year = 2005
| pages = 759-68
| pmid = 16093925}}</ref> Indirectly there are also important implications on the supply chain. Many multi-national corporations (MNCs) have therefore gotten involved in HIV/AIDS initiatives of three main types: a community-based partnerships, supply chain support, and sector-based initiatives.<ref name="odi">{{cite web |url=http://www.odi.org.uk/publications/briefing/bp_hiv_privatesector_nov07.pdf |format=PDF|title= AIDS and the private sector: The case of South Africa |accessyear=2007 |year=2007 |publisher=Overseas Development Institute}}</ref>

The launching of the world's first official HIV/AIDS Toolkit in Zimbabwe on October 3 2006 is a product of collaborative work between the International Federation of Red Cross and Red Crescent Societies, World Health Organization and the Southern Africa HIV/AIDS Information Dissemination Service. It is for the strengthening of people living with HIV/AIDS and nurses by minimal external support. The package, which is in form of eight modules focusing on basic facts about HIV and AIDS, was pre-tested in Zimbabwe in March 2006 to determine its adaptability. It disposes, among other things, categorized guidelines on clinical management, education and counseling of AIDS victims at community level.<ref name=xinhua>{{

cite web
| author=Mu Xuequan | publisher=xinhua | year= 2006
| url=http://news.xinhuanet.com/english/2006-10/04/content_5167991.htm
| title=Zimbabwe launches world's first AIDS training package
| accessdate = 2006-10-03

}}</ref>

The Copenhagen Consensus is a project that seeks to establish priorities for advancing global welfare using methodologies based on the theory of welfare economics. The participants are all economists, with the focus of the project being a rational prioritization based on economic analysis. The project is based on the contention that, in spite of the billions of dollars spent on global challenges by the United Nations, the governments of wealthy nations, foundations, charities, and non-governmental organizations, the money spent on problems such as malnutrition and climate change is not sufficient to meet many internationally-agreed targets. The highest priority was assigned to implementing new measures to prevent the spread of HIV and AIDS. The economists estimated that an investment of $27 billion could avert nearly 30 million new infections by 2010.<ref name=Kaiserfunds>{{

cite web
| publisher=kaisernetwork.org | year= 2002
| url=http://kaisernetwork.org/aids2002/syndication.asp?show=daily_report_1.html
| title=$27 Billion Boost for HIV Prevention Programs Could Avert Majority of Projected HIV Infections Worldwide
| accessdate = 2008-03-10

}}</ref>

===Stigma===
[[Image:Saigon AIDS Sign.jpg|thumb|250px|right|AIDS Awareness Sign. Ho Chi Minh City, Vietnam (August 2005).]]
AIDS stigma exists around the world in a variety of ways, including ostracism, rejection, discrimination and avoidance of HIV infected people; compulsory HIV testing without prior [[consent]] or protection of confidentiality; violence against HIV infected individuals or people who are perceived to be infected with HIV; and the [[quarantine]] of HIV infected individuals.<ref name=UNAIDS2006Ch4>{{

cite book
| publisher =[[Joint United Nations Programme on HIV/AIDS|UNAIDS]]
| year = 2006
| title = 2006 Report on the global AIDS epidemic
| chapter = The impact of AIDS on people and societies
| chapterurl = http://data.unaids.org/pub/GlobalReport/2006/2006_GR_CH04_en.pdf
| accessdate = 2006-06-14
| format= PDF

}}</ref> Stigma-related violence or the fear of violence prevents many people from seeking HIV testing, returning for their results, or securing treatment, possibly turning what could be a manageable chronic illness into a death sentence and perpetuating the spread of HIV.<ref name=Ogden>{{

cite web
| author =Ogden J, Nyblade L
| publisher = [[International Center for Research on Women]] | year = 2005 | title = Common at its core: HIV-related stigma across contexts | url = http://www.icrw.org/docs/2005_report_stigma_synthesis.pdf | format = PDF | accessdate = 2007-02-15

}}</ref>

AIDS stigma has been further divided into the following three categories:

# Instrumental AIDS stigma—a reflection of the fear and apprehension that are likely to be associated with any deadly and transmissible illness.<ref name=Herek1999>{{

cite journal
| author=Herek GM, Capitanio JP | journal=American Behavioral Scientist | year=1999
| url=http://psychology.ucdavis.edu/rainbow/html/abs99_sp.pdf
| format= PDF
| title=AIDS Stigma and sexual prejudice
| accessdate = 2006-03-27
| volume=42
| issue=7
| pages=1130-1147
| doi=10.1177/0002764299042007006

}}</ref>
# Symbolic AIDS stigma—the use of HIV/AIDS to express attitudes toward the social groups or lifestyles perceived to be associated with the disease.<ref name=Herek1999 />
# Courtesy AIDS stigma—stigmatization of people connected to the issue of HIV/AIDS or HIV- positive people.<ref name=Snyder>{{

cite journal |
author=Snyder M, Omoto AM, Crain AL |
title=Punished for their good deeds: stigmatization for AIDS volunteers |
journal=American Behavioral Scientist | year=1999 | pages=1175–1192 | volume=42 | issue=7 | doi=10.1177/0002764299042007009

}}</ref>

Often, AIDS stigma is expressed in conjunction with one or more other stigmas, particularly those associated with [[homosexuality]], bisexuality, promiscuity, and [[Intravenous drug use (recreational)|intravenous drug use]].

In many developed countries, there is an association between AIDS and homosexuality or bisexuality, and this association is correlated with higher levels of sexual prejudice such as anti-homosexual attitudes.<ref name=Herek2002>{{cite journal
|author=Herek GM, Capitanio JP, Widaman KF
|title=HIV-related stigma and knowledge in the United States: prevalence and trends, 1991-1999
|journal=Am J Public Health
|volume=92
|issue=3
|pages=371–7
|year=2002
|pmid=11867313
|doi=
|url=http://psychology.ucdavis.edu/rainbow/html/ajph2002.pdf
|accessdate=2008-03-10
}}</ref> There is also a perceived association between AIDS and all male-male sexual behavior, including sex between uninfected men.<ref name=Herek1999/>

== Prevention ==
The diverse transmission routes of HIV are well-known and established. Also well-known is how to prevent transmission of HIV. However, recent epidemiological and behavioral studies in Europe and North America have suggested that a substantial minority of young people continue to engage in high-risk practices and that despite HIV/AIDS knowledge, young people underestimate their own risk of becoming infected with HIV (Dias et al., 2005). However, transmission of HIV between intravenous drug users has clearly decreased and HIV transmission by blood transfusion has become almost obsolete in this population.

== Prevention of sexual transmission of HIV ==

=== Underlying science ===
* Unprotected receptive sexual acts are at more risk than unprotected insertive sexual acts, with the risk for transmitting HIV from an infected partner to an uninfected partner through unprotected insertive anal intercourse (UIAI) greater than the risk for transmission through receptive anal intercourse or oral sex. According to the French ministry for health, the probability of transmission per act varies from 0.03% to 0.07% for the case of receptive vaginal sex, from 0.02 to 0.05% in the case of insertive vaginal sex, from 0.01% to 0.185% in the case of insertive anal sex, and 0.5% to 3% in the case of receptive anal sex [1].

* Sexually-transmitted infections (STI) increase the risk of HIV transmission and infection because they cause the disruption of the normal epithelial barrier by genital ulceration and/or microulceration; and by accumulation of pools of HIV-susceptible or HIV-infected cells (lymphocytes and macrophages) in semen and vaginal secretions. Epidemiological studies from sub-Saharan Africa, Europe and North America have suggested that there is approximately, a four times greater risk of becoming HIV-infected in the presence of a genital ulcer such as caused by syphilis and/or chancroid; and a significant though lesser increased risk in the presence of STIs such as gonorrhoea, chlamydial infection and trichomoniasis which cause local accumulations of lymphocytes and macrophages (Laga et al., 1991).
* Transmission of HIV depends on the infectiousness of the index case and the susceptibility of the uninfected partner. Infectivity seems to vary during the course of illness and is not constant between individuals. An undetectable plasma viral load does not mean that you have a low viral load in the seminal liquid or genital secretions. Each 10 fold increment of seminal HIV RNA is associated with an 81% increased rate of HIV transmission (Tovanabutra et al., 2002).

* People who are infected with HIV can still be infected by other, more virulent strains.

* Oral sex is not without its risks as it has been established that HIV can be transmitted through both insertive and receptive oral sex (Rothenberg et al., 1998).

* Women are more susceptible to HIV-1 due to hormonal changes, vaginal microbial ecology and physiology, and a higher prevalence of sexually transmitted diseases (Sagar et al., 2004; Lavreys et al., 2004).

=== Prevention strategies ===

During a sexual act, only condoms, be they male or female, can reduce the chances of infection with HIV and other STIs and the chances of becoming pregnant. They must be used during all penetrative sexual intercourse with a partner who is HIV positive or whose status is unknown (Cayley, 2004). The effective use of condoms and screening of blood transfusion in North America, Western and Central Europe is credited with the low rates of AIDS in these regions. Adopting these effective prevention methods in other regions has proved controversial and difficult. Some claim this is in part because of the strong influence of the Roman Catholic Church, which opposes the use of condoms.

* The male latex condom is the single most efficient available technology to reduce the sexual transmission of HIV and other sexually transmitted infections. In order to be effective, they must be used correctly during each sexual act. Lubricants containing oil, such as petroleum jelly, or butter, must not be used as they weaken latex condoms and make them porous. If necessary, lubricants made from water are recommended. However, it is not recommended to use a lubricant for fellatio. Also, condoms have standards and expiration dates. It is essential to check the expiration date and if it conforms to European (EC 600) or American (D3492) standards before use.
* The female condom is an alternative to the male condom and is made from polyurethane, which allows it to be used in the presence of oil-based lubricants. They are larger than male condoms and have a stiffened ring-shaped opening, and are designed to be inserted into the vagina. The female condom also contains an inner ring which keeps the condom in place inside the vagina - inserting the female condom requires squeezing this ring.
With consistent and correct use of condoms, there is a very low risk of HIV infection. Studies on couples where one partner is infected show that with consistent condom use, HIV infection rates for the uninfected partner are below 1% per year

=== Government programs ===
The U.S. government and U.S. health organizations both endorse the ABC Approach to lower the risk of acquiring AIDS during sex:

* Abstinence or delay of sexual activity, especially for youth,
* Being faithful, especially for those in committed relationships,
* Condom use, for those who engage in risky behavior.

This approach has been very successful in Uganda, where HIV prevalence has decreased from 15% to 5%. However, the ABC approach is far from all that Uganda has done, as "Uganda has pioneered approaches towards reducing stigma, bringing discussion of sexual behavior out into the open, involving HIV-infected people in public education, persuading individuals and couples to be tested and counseled, improving the status of women, involving religious organizations, enlisting traditional healers, and much more." (Edward Green, Harvard medical anthropologist). Also, it must be noted that there is no conclusive proof that abstinence-only programs have been successful in any country in the world in reducing HIV transmission. This is why condom use is heavily co-promoted. There is also considerable overlap with the CNN Approach. This is:

* Condom use, for those who engage in risky behavior.
* Needles, use clean ones
* Negotiating skills; negotiating safer sex with a partner and empowering women to make smart choices

The ABC approach has been criticized, because a faithful partner of an unfaithful partner is at risk of AIDS [3]. Many think that the combination of the CNN approach with the ABC approach will be the optimum prevention platform.

=== Circumcision ===

Current research is clarifying the relationship between male circumcision and HIV in differing social and cultural contexts. UNAIDS believes that it is premature to recommend male circumcision services as part of HIV prevention programmes [4].

Moreover, South African medical experts are concerned that the repeated use of unsterilised blades in the ritual circumcision of adolescent boys may be spreading HIV.

== Prevention of blood or blood product route of HIV transmission ==

=== Underlying science ===

* Sharing and reusing syringes contaminated with HIV-infected blood represents a major risk for infection with not only HIV but also hepatitis B and C. In the United States a third of all new HIV infections can be traced to needle sharing and almost 50% of long-term addicts have hepatitis C.

* The risk of being infected with HIV from a single prick with a needle that has been used on an HIV infected person though is thought to be about 1 in 150 (see table above). Post-exposure prophylaxis with anti-HIV drugs can further reduce that small risk.

* Universal precautions are frequently not followed in both sub-Saharan Africa and much of Asia because of both a shortage of supplies and inadequate training. The WHO estimates that approximately 2.5% of all HIV infections in sub-Saharan Africa are transmitted through unsafe healthcare injections.Because of this, the United Nations General Assembly, supported by universal medical opinion on the matter, has urged the nations of the world to implement universal precautions to prevent HIV transmission in health care settings.

=== Prevention strategies ===

* In those countries where improved donor selection and antibody tests have been introduced, the risk of transmitting HIV infection to blood transfusion recipients has been effectively eliminated. According to the WHO, the overwhelming majority of the world's population does not have access to safe blood and "between 5% and 10% of HIV infections worldwide are transmitted through the transfusion of infected blood and blood products."

* Medical workers who follow universal precautions or body substance isolation such as wearing latex gloves when giving injections and washing the hands frequently can help prevent infection of HIV.

* All AIDS-prevention organizations advise drug-users not to share needles and other material required to prepare and take drugs (including syringes, cotton balls, the spoons, water for diluting the drug, straws, crack pipes etc). It is important that people use new or properly sterilized needles for each injection. Information on cleaning needles using bleach is available from health care and addiction professionals and from needle exchanges. In the United States and other western countries, clean needles are available free in some cities, at needle exchanges or safe injection sites.

== Mother to child transmission ==

=== Underlying science ===

* There is a 15–30% risk of transmission of HIV from mother to child during pregnancy, labour and delivery (Orendi et al., 1998). In developed countries the risk can of transmission of HIV from mother to child can be as low as 0-5%. A number of factors influence the risk of infection, particularly the viral load of the mother at birth (the higher the load, the higher the risk). Breastfeeding increases the risk of transmission by 10–15%. This risk depends on clinical factors and may vary according to the pattern and duration of breastfeeding.

=== Prevention strategies ===

* Studies have shown that antiretroviral drugs, cesarean delivery and formula feeding reduce the chance of transmission of HIV from mother to child (Sperling et al., 1996).

* When replacement feeding is acceptable, feasible, affordable, sustainable and safe, HIV-infected mothers are recommended to avoid breast feeding their infant. Otherwise, exclusive breastfeeding is recommended during the first months of life and should be discontinued as soon as possible.

===== References =====
http://en.wikipedia.org/wiki/Acquired_Immune_Deficiency_Syndrome#Prevention

==References==
{{reflist|3}}

==Further reading==
*{{cite web
|url=http://data.unaids.org/pub/EPISlides/2007/2007_epiupdate_en.pdf
|title=2007 AIDS epidemic update
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://data.unaids.org/pub/Report/2007/2006_unaids_annual_report_en.pdf
|title=UNAIDS Annual Report - Making the money work
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://data.unaids.org/pub/Report/2007/20070925_advocacy_grne2_en.pdf
|title= Financial Resources Required to Achieve, Universal Access to HIV Prevention, Treatment Care and Support
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://data.unaids.org/pub/Manual/2007/20070306_prevention_guidelines_towards_universal_access_en.pdf
|title= Practical Guidelines for Intensifying HIV Prevention
|accessdate=2008-03-21
|publisher=UNAIDS
|format=pdf
|work=
}}
*{{cite web
|url=http://aidsinfo.nih.gov/contentfiles/AntiretroviralFormulations_FS_en.pdf
|title= Antiretroviral Formulations
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=pdf
|work=
}}
*{{cite web
|url=http://aidsinfo.nih.gov/contentfiles/ApprovedMedstoTreatHIV_FS_en.pdf
|title= Approved Medications to Treat HIV Infection
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=pdf
|work=
}}
*{{cite web
|url=http://aidsinfo.nih.gov/contentfiles/HIVLifeCycle_FS_en.pdf
|title= The HIV Life Cycle
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=pdf
|work=
}}

==External links==
* {{Dmoz|Health/Conditions_and_Diseases/Immune_Disorders/Immune_Deficiency/AIDS/|HIV/AIDS}}
* {{cite web
|url=http://aidsinfo.nih.gov/
|title=AIDSinfo - HIV/AIDS Treatment Information
|accessdate=2008-03-21
|publisher=US Department of Health and Human Services
|format=
|work=
}}
* {{cite web
|url=http://www.unaids.org/en/
|title=UNAIDS: The Joint United Nations Programme on HIV/AIDS
|accessdate=2008-03-21
|publisher=UNAIDS
|format=
|work=
}}
{{AIDS}}
{{Viral diseases}}
{{STD/STI}}
{{SIB}}

[[Category:HIV/AIDS]]
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[[Category:Virology]]
[[Category:AIDS origin hypotheses]]
[[Category:Medical disasters]]
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[[Category:Immunodeficiency]]
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{{Link FA|he}}
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Influenza (for patients)

2009-07-07T18:47:58Z

Michaelagibson: Influenza (for patients) moved to Influenza Patient Information

#REDIRECT [[Influenza Patient Information]]

Influenza

2009-07-07T18:44:39Z

Michaelagibson:

{{Infobox_Disease |
Name = Influenza |
Image = EM of influenza virus.jpg |
Caption = [[transmission electron microscopy|TEM]] of negatively stained influenza virons, magnified approximately 70,000 times |
Width = 226 |
DiseasesDB = 6791 |
ICD10 = {{ICD10|J|10||j|09}}, {{ICD10|J|11||j|09}} |
ICD9 = {{ICD9|487}} |
MedlinePlus = 000080 |
eMedicineSubj = med |
eMedicineTopic = 1170 |
eMedicine_mult = {{eMedicine2|ped|3006}} |
MeshID = D007251 |
}}
{{Flu}}
{{SI}}
{{CMG}}
__NOTOC__
{{Editor Help}}

'''For Patient information click [[Influenza Patient Information|here]]'''

==Overview==

'''Influenza''', commonly known as '''flu''', is an [[infectious disease]] of birds and [[mammal]]s caused by [[RNA virus]]es of the biological family [[Orthomyxoviridae]] (the influenza viruses). In humans, common symptoms of influenza infection are [[fever]], [[pharyngitis|sore throat]], [[myalgia|muscle pains]], severe [[headache]], [[cough]]ing, [[fatigue (medical)|weakness]] and [[malaise|general discomfort]].<ref name=Merck>{{cite web |author= Merck Manual Home Edition |title=Influenza: Viral Infections |url= http://www.merck.com/mmhe/sec17/ch198/ch198c.html?}}</ref> In more serious cases, influenza [[sequela|causes]] [[pneumonia]], which can be fatal, particularly in young children and the elderly. Sometimes confused with the [[common cold]], influenza is a much more severe disease and is caused by a different type of virus.<ref name=Eccles>{{cite journal | last = Eccles | first = R | title = Understanding the symptoms of the common cold and influenza | journal = Lancet Infect Dis | volume = 5 | issue = 11 | pages = 718–25 | year = 2005 | id = PMID 16253889}}</ref> Although [[nausea]] and [[vomiting]] can be produced, especially in children,<ref name=Merck/> these symptoms are more characteristic of the unrelated [[gastroenteritis]], which is sometimes called "stomach flu" or "24-hour flu."<ref> [http://coldflu.about.com/od/flumisconceptions/f/stomachflu.htm Seasonal Flu vs. Stomach Flu] by Kristina Duda, R.N.; accessed March 12, 2007 (Website: "About, Inc., A part of The New York Times Company")</ref>

Typically, influenza is transmitted from infected mammals through the air by coughs or sneezes, creating particulates/aerosols containing the virus, and from infected birds through their [[feces|droppings]]. Influenza can also be transmitted by [[saliva]], [[mucus|nasal secretions]], [[feces]] and [[blood]]. Infections also occur through contact with these body fluids or with contaminated surfaces.

Flu viruses can remain infectious for about one week at human body temperature, over 30 days at 0 °C (32 °F), and indefinitely at very low temperatures (such as lakes in northeast Siberia). Most influenza strains can be inactivated easily by [[disinfectant]]s and [[detergent]]s.<ref>{{cite journal | last = Suarez | first = D | coauthors = Spackman E, Senne D, Bulaga L, Welsch A, Froberg K | title = The effect of various disinfectants on detection of avian influenza virus by real time RT-PCR | journal = Avian Dis | volume = 47 | issue = 3 Suppl | pages = 1091–5 | year = 2003 | id = PMID 14575118}}</ref><ref>[http://www.cidrap.umn.edu/cidrap/content/influenza/avianflu/biofacts/avflu_human.html Avian Influenza (Bird Flu)]: Implications for Human Disease. Physical characteristics of influenza A viruses. UMN CIDRAP.</ref><ref name = "NHZ2006-11-30">[http://www.nzherald.co.nz/category/story.cfm?c_id=204&objectid=10413124 Flu viruses 'can live for decades' on ice], NZ Herald, November 30, 2006.</ref>

Flu spreads around the world in seasonal [[epidemic]]s, killing millions of people in [[pandemic]] years and hundreds of thousands in non-pandemic years. Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new [[strain (biology)|strain]] of the virus in humans. Often, these new strains result from the spread of an existing flu virus to humans from other animal [[species]].

Since it first killed humans in Asia in the 1990s, a deadly avian strain named [[H5N1]] has posed the greatest risk for a new [[influenza pandemic]]; fortunately, this virus has not [[mutation|mutated]] to a form that spreads easily between people.<ref>{{cite web | title=Avian influenza ("bird flu") fact sheet | url= http://www.who.int/mediacentre/factsheets/avian_influenza/en/ | date=February 2006 | publisher=WHO | accessdate=2006-10-20}}</ref>

[[Vaccination]]s against influenza are most commonly given to high-risk humans in industrialized countries<ref name=WHOvaccines>[http://www.who.int/wer/2005/wer8033.pdf WHO position paper: influenza vaccines] ''WHO weekly Epidemiological Record'' 19 August 2005, vol. 80, 33, pp. 277–288.</ref> and to farmed poultry.<ref>{{cite journal | last = Villegas | first = P | title = Viral diseases of the respiratory system | journal = Poult Sci | volume = 77 | issue = 8 | pages = 1143–5 | year = 1998 | id = PMID 9706079}}</ref> The most common human vaccine is the trivalent [[flu vaccine]] that contains purified and inactivated material from three viral strains. Typically this vaccine includes material from two [[influenzavirus A|influenza A virus]] subtypes and one [[Influenzavirus B|influenza B virus]] strain.<ref>{{cite journal | last = Horwood | first = F | coauthors = Macfarlane J | title = Pneumococcal and influenza vaccination: current situation and future prospects. | url= http://thorax.bmjjournals.com/cgi/reprint/57/suppl_2/ii24.pdf | journal = Thorax | volume = 57 Suppl 2 | issue = | pages = II24–II30 | year = | id = PMID 12364707}}</ref> A vaccine formulated for one year may be ineffective in the following year, since the influenza virus changes rapidly over time and different strains become dominant. [[Antiviral drug]]s can be used to treat influenza, with [[neuraminidase inhibitor]]s being particularly effective.

==Etymology==
The term influenza has its origins in 15th-century Italy, where the cause of the disease was ascribed to unfavourable astrological ''influences''. Evolution in medical thought led to its modification to ''influenza del freddo'', meaning "influence of the cold." The word "influenza" was first attested in English in 1743 when it was borrowed during an outbreak of the disease in Europe.<ref name=Harper>{{cite web | last = Harper | first = D | title=Influenza | url=http://www.etymonline.com/index.php?search=influenza&searchmode=none | publisher= Etymonlin}}</ref> Archaic terms for influenza include epidemic catarrh, grippe (from the French grippe, meaning flu; sometimes spelled "grip" or "gripe"), sweating sickness, and Spanish fever (particularly for the [[Spanish flu|1918 pandemic]] strain).<ref>{{cite web | last = Smith | first = P | title=Archaic Medical Terms | url= http://www.paul_smith.doctors.org.uk/ArchaicMedicalTerms.htm | accessdate = 2006-10-23}}</ref>

==History==
{{further|[[Influenza pandemic]], [[Spanish flu]]}}

[[Image:Influenza1.png|thumb|300px|left|Negatively stained flu viruses; these were the causative agents of [[Hong Kong Flu]]. (magnified approximately 70,000 times)]]

[[Image:W curve2.png|thumb|300px|left|The difference between the influenza mortality age-distributions of the 1918 epidemic and normal epidemics. Deaths per 100,000 persons in each age group, United States, for the interpandemic years 1911–1917 (dashed line) and the pandemic year 1918 (solid line).<ref name = "Taubenberger">{{cite journal | last = Taubenberger | first = J | coauthors = Morens D | title = 1918 Influenza: the mother of all pandemics. | url = http://www.cdc.gov/ncidod/EID/vol12no01/05-0979.htm | journal = Emerg Infect Dis | volume = 12 | issue = 1 | pages = 15–22 | year = 2006 | id = PMID 16494711}}</ref>]]

The symptoms of human influenza were clearly described by [[Hippocrates]] roughly 2400 years ago.<ref>{{cite journal | last =Martin | first = P | coauthors = Martin-Granel E | title=2,500-year evolution of the term epidemic | url= http://www.cdc.gov/ncidod/EID/vol12no06/05-1263.htm#cit | journal=Emerg Infect Dis | year=2006 | month = Jun | volume=12 | issue=6 | id = PMID 16707055}}</ref><ref>{{cite web | author=Hippocrates | coauthors = [[Francis Adams (translator)|Adams, Francis]] (transl.) | title=Of the Epidemics | url= http://classics.mit.edu/Hippocrates/epidemics.html | date= 400 BCE | accessdate=2006-10-18}}</ref> Since then, the virus has caused numerous pandemics. Historical data on influenza are difficult to interpret, because the symptoms can be similar to those of other diseases, such as [[diphtheria]], [[pneumonic plague]], [[typhoid fever]], [[dengue]], or [[typhus]]. The first convincing record of an influenza pandemic was of an outbreak in 1580, which began in Asia and spread to Europe via Africa. In Rome over 8,000 people were killed, and several Spanish cities were almost wiped out. Pandemics continued sporadically throughout the 17th and 18th centuries, with the pandemic of 1830–1833 being particularly widespread; it infected approximately a quarter of the people exposed.<ref name=Potter>{{cite journal | last =Potter | first = CW| title=A History of Influenza | url= http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2672.2001.01492.x | journal= J Appl Microbiol. | year=2006 | month=Oct | volume=91 | issue= 4 | pages = 572–579 | id = PMID 11576290}}</ref>

The most famous and lethal outbreak was the so-called [[Spanish flu]] pandemic ([[Influenzavirus A|type A influenza]], [[H1N1]] subtype), which lasted from 1918 to 1919. Older estimates say it killed 40–50 million people<ref name=Patterson1>{{cite journal | last =Patterson | first = KD | coauthors = Pyle GF | title=The geography and mortality of the 1918 influenza pandemic. | journal= Bull Hist Med. | year=1991 | month=Spring | volume=65 | issue=1 | pages = 4–21 | id = PMID 2021692}}</ref> while current estimates say 50 million to 100 million people worldwide were killed.<ref name=Knobler>{{cite book | editor=Knobler S, Mack A, Mahmoud A, Lemon S | title = The Threat of Pandemic Influenza: Are We Ready? Workshop Summary (2005) | chapter=1: The Story of Influenza | pages = 60–61 | chapterurl=http://darwin.nap.edu/books/0309095042/html/60.html | publisher=The National Academies Press | location=Washington, D.C.}}</ref> This pandemic has been described as "the greatest medical holocaust in history" and may have killed as many people as the [[Black Death]].<ref name=Potter/> This huge death toll was caused by an extremely high infection rate of up to 50% and the extreme severity of the symptoms, suspected to be caused by [[cytokine storm]]s.<ref name=Patterson1/> Indeed, symptoms in 1918 were so unusual that initially influenza was misdiagnosed as dengue, [[cholera]], or typhoid. One observer wrote, "One of the most striking of the complications was hemorrhage from mucous membranes, especially from the nose, stomach, and intestine. Bleeding from the ears and [[petechia|petechial hemorrhages]] in the skin also occurred."<ref name=Knobler/> The majority of deaths were from [[bacterial pneumonia]], a secondary infection caused by influenza, but the virus also killed people directly, causing massive [[bleeding|hemorrhages]] and [[edema]] in the lung.<ref name=Taubenberger>{{cite journal | last = Taubenberger | first = J | coauthors = Reid A, Janczewski T, Fanning T | title = Integrating historical, clinical and molecular genetic data in order to explain the origin and virulence of the 1918 Spanish influenza virus. | journal = Philos Trans R Soc Lond B Biol Sci | volume = 356 | issue = 1416 | pages = 1829–39 | year = 2001 | month=Dec 29 | id = PMID 11779381 | url= http://www.journals.royalsoc.ac.uk/(3sud2455cjw1ut55yowx1d45)/app/home/contribution.asp?referrer=parent&backto=issue,3,22;journal,61,225;linkingpublicationresults,1:102022,1}}</ref>

The Spanish flu pandemic was truly global, spreading even to the Arctic and remote Pacific islands. The unusually severe disease killed between 2 and 20% of those infected, as opposed to the more usual flu epidemic [[mortality rate]] of 0.1%.<ref name=Taubenberger/><ref name=Knobler/> Another unusual feature of this pandemic was that it mostly killed young adults, with 99% of pandemic influenza deaths occurring in people under 65, and more than half in young adults 20 to 40 years old.<ref>{{cite journal | last = Simonsen | first = L | coauthors = Clarke M, Schonberger L, Arden N, Cox N, Fukuda K | title = Pandemic versus epidemic influenza mortality: a pattern of changing age distribution. | journal = J Infect Dis | volume = 178 | issue = 1 | pages = 53–60 | year = 1998 | month=Jul | id = PMID 9652423}}</ref> This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70). The total mortality of the 1918–1919 pandemic is not known, but it is estimated that 2.5% to 5% of the world's population was killed. As many as 25 million may have been killed in the first 25 weeks; in contrast, [[AIDS|HIV/AIDS]] has killed 25 million in its first 25 years.<ref name=Knobler/>

Later flu pandemics were not so devastating. They included the 1957 [[Asian Flu]] (type A, [[H2N2]] strain) and the 1968 [[Hong Kong Flu]] (type A, [[H3N2]] strain), but even these smaller outbreaks killed millions of people. In later pandemics [[antibiotic]]s were available to control secondary infections and this may have helped reduce mortality compared to the Spanish Flu of 1918.<ref name= Taubenberger/>

{| class="wikitable" style="text-align:center"
|+ Known [[flu pandemic]]s<ref name=Hilleman>{{cite journal | last = Hilleman | first = M | title = Realities and enigmas of human viral influenza: pathogenesis, epidemiology and control. | journal = Vaccine | volume = 20 | issue = 25–26 | pages = 3068–87 | year = 2002 | month=Aug 19 | id = PMID 12163258}}</ref><ref name=Potter/>
! Name of pandemic !! Date !! Deaths !! Subtype involved !! [[Pandemic Severity Index]]
|-
! Asiatic (Russian) Flu
| 1889–1890 || 1 million || possibly [[H2N2]] || ?
|-
! [[Spanish flu|Spanish Flu]]
| 1918–1920 || 40 million || [[H1N1]] || 5
|-
! [[H2N2#Asian Flu|Asian Flu]]
| 1957–1958 || 1 to 1.5 million || [[H2N2]] || 2
|-
! [[H3N2#Hong Kong Flu|Hong Kong Flu]]
| 1968–1969 || 0.75 to 1 million || [[H3N2]] || 2
|-
|}

The [[etiology|etiological]] cause of influenza, the Orthomyxoviridae family of viruses, was first discovered in pigs by [[Richard Schope]] in 1931.<ref>{{cite journal | last =Shimizu | first = K | title= History of influenza epidemics and discovery of influenza virus | journal=Nippon Rinsho | year= 1997 | month=Oct | volume=55 | issue=10| pages=2505–201 | id = PMID 9360364}}</ref> This discovery was shortly followed by the isolation of the virus from humans by a group headed by [[Patrick Laidlaw]] at the [[Medical Research Council (UK)|Medical Research Council]] of the [[United Kingdom]] in 1933.<ref>{{cite journal | last =Smith | first = W | coauthors = Andrewes CH, Laidlaw PP | title=A virus obtained from influenza patients | journal=Lancet | year=1933 | volume=2 | pages = 66–68}}</ref> However, it was not until [[Wendell Stanley]] first crystallized [[tobacco mosaic virus]] in 1935 that the [[cell (biology)|non-cellular]] nature of viruses was appreciated.

The first significant step towards preventing influenza was the development in 1944 of a killed-virus vaccine for influenza by [[Thomas Francis, Jr.]]. This built on work by [[Frank Macfarlane Burnet]], who showed that the virus lost virulence when it was cultured in fertilized hen's eggs.<ref name = "Nobel">[http://nobelprize.org/nobel_prizes/medicine/laureates/1960/burnet-bio.html Sir Frank Macfarlane Burnet: Biography] The Nobel Foundation. Accessed 22 Oct 06</ref> Application of this observation by Francis allowed his group of researchers at the [[University of Michigan]] to develop the first [[flu vaccine]], with support from the U.S. Army.<ref>{{cite journal | last = Kendall | first = H | title = Vaccine Innovation: Lessons from World War II | url= http://docstore.ingenta.com/cgi-bin/ds_deliver/1/u/d/ISIS/32620254.1/pal/jphp/2006/00000027/00000001/art00005/FB2494BF0313967611615398189A7A906334373166.pdf?link=http://www.ingentaconnect.com/error/delivery&format=pdf | journal = Journal of Public Health Policy | volume = 27 | issue = 1 | pages = 38–57 | year = 2006}}</ref> The Army was deeply involved in this research due to its experience of influenza in World War I, when thousands of troops were killed by the virus in a matter of months.<ref name= Knobler/>

Although there were scares in New Jersey in 1976 (with the [[Swine Flu]]), world wide in 1977 (with the [[Russian Flu]]), and in Hong Kong and other Asian countries in 1997 (with [[H5N1]] avian influenza), there have been no major pandemics since the 1968 Hong Kong Flu. Immunity to previous pandemic influenza strains and vaccination may have limited the spread of the virus and may have helped prevent further pandemics.<ref name=Hilleman/>

==Microbiology==

===Types of influenza virus===
[[Image:3D influenza virus.png|thumb|400px|left|Structure of the influenza [[wikt:virion|virion]]. The [[hemagglutinin]] (HA) and [[neuraminidase]] (NA) proteins are shown on the surface of the particle. The viral RNAs that make up the [[genome]] are shown as red coils inside the particle and bound to Ribonuclear Proteins (RNPs).]]
[[Image:Infnomenclature.svg|thumb|350px|right|Diagram of influenza virus [[International Committee on Taxonomy of Viruses|nomenclature]] (for a [[Fujian flu]] virus)]]

The influenza virus is an [[RNA virus]] of the family [[Orthomyxoviridae]], which comprises the influenzaviruses, [[Isavirus]], and [[Thogotovirus]].<ref name=Kawaoka>{{cite book | author = Kawaoka Y (editor). | title = Influenza Virology: Current Topics | publisher = Caister Academic Press | year = 2006 | url=http://www.horizonpress.com/flu | isbn = 978-1-904455-06-6}}</ref> There are three types of influenza virus: [[Influenzavirus A]], [[Influenzavirus B]], and [[Influenzavirus C]]. Influenza A and C infect multiple species, while influenza B almost exclusively infects humans.<ref name=hay>{{cite journal | last = Hay | first = A | coauthors = Gregory V, Douglas A, Lin Y | title = The evolution of human influenza viruses | journal = Philos Trans R Soc Lond B Biol Sci | volume = 356 | issue = 1416 | pages = 1861–70 | year = 2001 | month=Dec 29 | id = PMID 11779385}}</ref>
Wild aquatic birds are the natural hosts for a large variety of influenza A viruses. Occasionally viruses are transmitted to other species and may then cause devastating outbreaks in domestic poultry or give rise to human influenza [[pandemic]]s.<ref name=sobrino6>{{cite book |chapterurl=http://www.horizonpress.com/avir|author=Klenk et al|year=2008|chapter=Avian Influenza: Molecular Mechanisms of Pathogenesis and Host Range|title=Animal Viruses: Molecular Biology|publisher=Caister Academic Press|isbn = 978-1-904455-22-6}}</ref>
The type A viruses are the most virulent human pathogens among the three influenza types and cause the most severe disease. The Influenza A virus can be subdivided into different [[serovar|serotype]]s based on the [[antibody]] response to these viruses.<ref name=hay/> The serotypes that have been confirmed in humans, ordered by the number of known human pandemic deaths, are:

*[[H1N1]] caused "[[Spanish Flu]]."
*[[H2N2]] caused "Asian Flu."
*[[H3N2]] caused "Hong Kong Flu."
*[[H5N1]] is a [[pandemic]] threat in 2007–8 flu season.
*[[H7N7]] has unusual [[zoonotic]] potential.<ref>{{cite journal | last = Fouchier | first = R | coauthors = Schneeberger P, Rozendaal F, Broekman J, Kemink S, Munster V, Kuiken T, Rimmelzwaan G, Schutten M, Van Doornum G, Koch G, Bosman A, Koopmans M, Osterhaus A | title = Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. | url= http://www.pnas.org/cgi/content/full/101/5/1356 | journal = Proc Natl Acad Sci U S A | volume = 101 | issue = 5 | pages = 1356–61 | year = 2004 | id = PMID 14745020}}</ref>
*[[H1N2]] is endemic in humans and pigs.
*[[H9N2]], [[H7N2]], [[H7N3]], [[H10N7]].

Influenza B virus is almost exclusively a human pathogen and is less common than influenza A. The only other animal known to be susceptible to influenza B infection is the [[pinniped|seal]].<ref>{{cite journal | last = Osterhaus | first = A | coauthors = Rimmelzwaan G, Martina B, Bestebroer T, Fouchier R | title = Influenza B virus in seals. | journal = Science | volume = 288 | issue = 5468 | pages = 1051–3 | year = 2000 | id = PMID 10807575}}</ref> This type of influenza mutates at a rate 2–3 times lower than type A<ref>{{cite journal | last = Nobusawa | first = E | coauthors = Sato K | title = Comparison of the mutation rates of human influenza A and B viruses | journal = J Virol | volume = 80 | issue = 7 | pages = 3675–8 | year = 2006 | month=Apr | id = PMID 16537638}}</ref> and consequently is less genetically diverse, with only one influenza B serotype.<ref name=hay/> As a result of this lack of [[antigen]]ic diversity, a degree of [[immunity (medical)|immunity]] to influenza B is usually acquired at an early age. However, influenza B mutates enough that lasting immunity is not possible.<ref name=webster>{{cite journal | first = Webster | last = R | coauthors = Bean W, Gorman O, Chambers T, Kawaoka Y | title = Evolution and ecology of influenza A viruses. | url= http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=1579108 |journal = Microbiol Rev | volume = 56 | issue = 1 | pages = 152–79 | year = 1992 | id = PMID 1579108}}</ref> This reduced rate of antigenic change, combined with its limited host range (inhibiting cross species [[antigenic shift]]), ensures that pandemics of influenza B do not occur.<ref name=Zambon>{{cite journal | last = Zambon | first = M | title = Epidemiology and pathogenesis of influenza. | journal = J Antimicrob Chemother | volume = 44 Suppl B | issue = | pages = 3–9 | year = 1999 | month=Nov | id = PMID 10877456 | url=http://jac.oxfordjournals.org/cgi/reprint/44/suppl_2/3}}</ref>

The influenza C virus infects humans and pigs, and can cause severe illness and local epidemics.<ref name = "Matsuzaki">{{cite journal | last = Matsuzaki | first = Y | coauthors = Sugawara K, Mizuta K, Tsuchiya E, Muraki Y, Hongo S, Suzuki H, Nakamura K | title = Antigenic and genetic characterization of influenza C viruses which caused two outbreaks in Yamagata City, Japan, in 1996 and 1998 | url= http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=11825952 | journal = J Clin Microbiol | volume = 40 | issue = 2 | pages = 422–9 | year = 2002 | id = PMID 11825952}}</ref> However, influenza C is less common than the other types and usually seems to cause mild disease in children.<ref>{{cite journal | last = Matsuzaki | first = Y | coauthors = Katsushima N, Nagai Y, Shoji M, Itagaki T, Sakamoto M, Kitaoka S, Mizuta K, Nishimura H | title = Clinical features of influenza C virus infection in children. | journal = J Infect Dis | volume = 193 | issue = 9 | pages = 1229–35 | year = 2006 | month=May 1 | id = PMID 16586359}}</ref><ref name = "Katagiri">{{cite journal | last = Katagiri | first = S | coauthors = Ohizumi A, Homma M | title = An outbreak of type C influenza in a children's home. | journal = J Infect Dis | volume = 148 | issue = 1 | pages = 51–6 | year = 1983 | month=Jul | id = PMID 6309999}}</ref>

===Structure and properties===
The following applies for [[Influenzavirus A|Influenza A]] viruses, although other strains are very similar in structure:<ref>International Committee on Taxonomy of Viruses descriptions of: [http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/46000000.htm Orthomyxoviridae], [http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/46040000.htm Influenzavirus B] and [http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.046.0.02.htm Influenzavirus C]</ref>

The influenza A virus particle or ''virion'' is 80–120 nm in diameter and usually roughly spherical, although filamentous forms can occur.<ref>{{cite web |author= International Committee on Taxonomy of Viruses |title=The Universal Virus Database, version 4: Influenza A |url=http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.046.0.01.htm}}</ref> Unusually for a virus, the influenza A [[genome]] is not a single piece of [[nucleic acid]]; instead, it contains eight pieces of segmented [[negative-sense]] [[RNA]] (13.5 kilobases total), which encode 10 [[protein]]s (HA (hemagglutinin), NA (neuraminidase), NP (nucleoprotein), M1, M2, NS1, PA, PB1, PB1-F2, PB2).<ref name=Ghedin>{{cite journal | last = Ghedin | first = E | coauthors = Sengamalay N, Shumway M, Zaborsky J, Feldblyum T, Subbu V, Spiro D, Sitz J, Koo H, Bolotov P, Dernovoy D, Tatusova T, Bao Y, St George K, Taylor J, Lipman D, Fraser C, Taubenberger J, Salzberg S | title = Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution. | journal = Nature | volume = 437 | issue = 7062 | pages = 1162–6 | year = 2005 | month=Oct 20 | id = PMID 16208317}}</ref> The best-characterised of these viral proteins are [[hemagglutinin]] and [[neuraminidase]], two large [[glycoprotein]]s found on the outside of the viral particles. Neuraminidase is an [[enzyme]] involved in the release of progeny virus from infected cells, by cleaving sugars that bind the mature viral particles. By contrast, hemagglutinin is a [[lectin]] that mediates binding of the virus to target cells and entry of the viral genome into the target cell.<ref>{{cite journal | last = Suzuki | first = Y | title = Sialobiology of influenza: molecular mechanism of host range variation of influenza viruses. | url= http://www.jstage.jst.go.jp/article/bpb/28/3/399/_pdf | journal = Biol Pharm Bull | volume = 28 | issue = 3 | pages = 399–408 | year = 2005 | id = PMID 15744059}}</ref> The hemagglutinin (HA or H) and neuraminidase (NA or N) proteins are targets for [[antiviral drugs]].<ref>{{cite journal | last = Wilson | first = J | coauthors = von Itzstein M | title = Recent strategies in the search for new anti-influenza therapies | journal = Curr Drug Targets | volume = 4 | issue = 5 | pages = 389–408 | year = 2003 | month=Jul | id = PMID 12816348}}</ref> These proteins are also recognised by [[antibody|antibodies]], i.e. they are [[antigen]]s.<ref name=Hilleman/> The responses of antibodies to these proteins are used to classify the different [[serovar|serotype]]s of influenza A viruses, hence the ''H'' and ''N'' in ''H5N1''.

===Infection and replication===
[[Image:Virus Replication.svg|thumb|400px|left|Host cell invasion and replication by the influenza virus. The steps in this process are discussed in the text.]]

Influenza viruses bind through [[hemagglutinin]] onto [[sialic acid]] sugars on the surfaces of [[epithelium|epithelial cells]]; typically in the nose, throat and [[lung]]s of mammals and [[intestine]]s of birds (Stage 1 in infection figure).<ref name=Wagner>{{cite journal | last = Wagner | first = R | coauthors = Matrosovich M, Klenk H | title = Functional balance between haemagglutinin and neuraminidase in influenza virus infections. | journal = Rev Med Virol | volume = 12 | issue = 3 | pages = 159–66 | year = 2002 | month=May–Jun| id = PMID 11987141}}</ref> The cell imports the virus by [[endocytosis]]. In the acidic [[endosome]], part of the haemagglutinin protein fuses the viral envelope with the vacuole's membrane, releasing the viral RNA (vRNA) molecules, accessory proteins and [[RNA replicase|RNA-dependent RNA transcriptase]] into the [[cytoplasm]] (Stage 2).<ref>{{cite journal | last = Lakadamyali | first = M | coauthors = Rust M, Babcock H, Zhuang X | title = Visualizing infection of individual influenza viruses. | journal = Proc Natl Acad Sci U S A | volume = 100 | issue = 16 | pages = 9280–5 | year = 2003 | month=Aug 5 | id = PMID 12883000}}</ref> These proteins and vRNA form a complex that is transported into the [[cell nucleus]], where the RNA-dependent RNA transcriptase begins transcribing complementary positive-sense vRNA (Steps 3a and b).<ref>{{cite journal | last = Cros | first = J | coauthors = Palese P | title = Trafficking of viral genomic RNA into and out of the nucleus: influenza, Thogoto and Borna disease viruses. | journal = Virus Res | volume = 95 | issue = 1–2 | pages = 3–12 | year = 2003 | month=Sep | id = PMID 12921991}}</ref> The vRNA is either exported into the cytoplasm and translated (step 4), or remains in the nucleus. Newly-synthesised viral proteins are either secreted through the [[Golgi apparatus]] onto the cell surface (in the case of neuraminidase and hemagglutinin, step 5b) or transported back into the nucleus to bind vRNA and form new viral genome particles (step 5a). Other viral proteins have multiple actions in the host cell, including degrading cellular [[mRNA]] and using the released [[nucleotide]]s for vRNA synthesis and also inhibiting [[translation (biology)|translation]] of host-cell mRNAs.<ref>{{cite journal | last = Kash | first = J | coauthors = Goodman A, Korth M, Katze M | title = Hijacking of the host-cell response and translational control during influenza virus infection. | journal = Virus Res | volume = 119 | issue = 1 | pages = 111–20 | year = 2006 | month=Jul | id = PMID 16630668}}</ref>

Negative-sense vRNAs that form the [[genome]]s of future viruses, RNA-dependent RNA transcriptase, and other viral proteins are assembled into a virion. Hemagglutinin and neuraminidase molecules cluster into a bulge in the cell membrane. The vRNA and viral core proteins leave the nucleus and enter this membrane protrusion (step 6). The mature virus buds off from the cell in a sphere of host phospholipid membrane, acquiring hemagglutinin and neuraminidase with this membrane coat (step 7).<ref>{{cite journal | last = Nayak | first = D | coauthors = Hui E, Barman S | title = Assembly and budding of influenza virus. | journal = Virus Res | volume = 106 | issue = 2 | pages = 147–65 | year = 2004 | month =Dec | id = PMID 15567494}}</ref> As before, the viruses adhere to the cell through hemagglutinin; the mature viruses detach once their [[neuraminidase]] has cleaved sialic acid residues from the host cell.<ref name=Wagner/> After the release of new influenza virus, the host cell dies.

Because of the absence of RNA proofreading enzymes, the RNA-dependent RNA transcriptase makes a single nucleotide insertion error roughly every 10 thousand nucleotides, which is the approximate length of the influenza vRNA. Hence, nearly every newly-manufactured influenza virus is a mutant.<ref>{{cite journal | last = Drake | first = J | title = Rates of spontaneous mutation among RNA viruses. | journal = Proc Natl Acad Sci USA | volume = 90 | issue = 9 | pages = 4171–5 | year = 1993 | month=May 1 | id = PMID 8387212}}</ref> The separation of the genome into eight separate segments of vRNA allows mixing or ''reassortment'' of vRNAs if more than one viral line has infected a single cell. The resulting rapid change in viral genetics produces [[antigenic shift]]s and allow the virus to infect new host species and quickly overcome protective immunity.<ref name=Hilleman/> This is important in the emergence of pandemics, as discussed in [[#Epidemiology|Epidemiology]].

==Diagnosis==
[[Image:Aerosol from Sneeze.jpg |thumb |right|250px|Influenza spreads by [[aerosol]]s created by coughs or sneezes.]]
In humans, influenza's effects are much more severe than those of the [[common cold]], and last longer. Recovery takes about one to two weeks. Influenza, however, can be deadly, especially for the weak, old or chronically ill.<ref name=Hilleman/>

===Symptoms===
Symptoms of influenza can start quite suddenly one to two days after infection. Usually the first symptoms are chills or a chilly sensation but fever is also common early in the infection, with body temperatures as high as 39 °C (approximately 103 °F). Many people are so ill that they are confined to bed for several days, with aches and pains throughout their bodies, which are worst in their backs and legs.<ref name=Merck />

Common symptoms of the flu such as fever, headaches, and fatigue come from the huge amounts of proinflammatory [[cytokine]]s and [[chemokine]]s (such as [[interferon]] or [[Tumor necrosis factor-alpha|tumor necrosis factor]]) produced from influenza-infected cells.<ref name=Eccles/><ref>{{cite journal | author = Schmitz N, Kurrer M, Bachmann M, Kopf M | title = Interleukin-1 is responsible for acute lung immunopathology but increases survival of respiratory influenza virus infection. | journal = J Virol | volume = 79 | issue = 10 | pages = 6441–8 | year = 2005 | id = PMID 15858027}}</ref> In contrast to the [[rhinovirus]] that causes the [[common cold]], influenza does cause tissue damage, so symptoms are not entirely due to the inflammatory response.<ref>{{cite journal | author = Winther B, Gwaltney J, Mygind N, Hendley J | title = Viral-induced rhinitis. | journal = Am J Rhinol | volume = 12 | issue = 1 | pages = 17–20 | year = | id = PMID 9513654}}</ref> Symptoms of influenza may include:

:* Body aches, especially joints and throat
:* [[Cough]]ing and [[sneeze|sneezing]]
:* Extreme coldness and [[fever]]
:* [[Fatigue (medical)|Fatigue]]
:* [[Headache]]
:* Irritated watering eyes
:* [[Nasal congestion]]
:* [[Nausea]] and [[vomiting]]
:* Reddened eyes, skin (especially face), mouth, throat and nose

It can be difficult to distinguish between the common cold and influenza in the early stages of these infections,<ref name=Eccles/> but usually the symptoms of the flu are more severe than their common-cold equivalents. Research on signs and symptoms of influenza found that the best findings for excluding the diagnosis of influenza were:<ref name="pmid15728170">{{cite journal | author = Call S, Vollenweider M, Hornung C, Simel D, McKinney W | title = Does this patient have influenza? | journal = JAMA | volume = 293 | issue = 8 | pages = 987-97 | year = 2005 | doi = 10.1001/jama.293.8.987 | id = PMID 15728170}}</ref>

{| class="wikitable" style="text-align:center"
|+ Highest [[sensitivity (tests)|sensitive]] individual findings for diagnosing influenza<ref name="pmid15728170"/>
! Finding: !! [[sensitivity (tests)|sensitivity]] !! [[specificity (tests)|specificity]]
|-
! Fever
| 86% || 25%
|-
! Cough
| 98% || 23%
|-
! Nasal congestion
| 70–90% || 20–40%
|-
|}
Notes to table:
* [[Sensitivity (tests)|Sensitivity]] is the proportion of people that tested positive of all the positive people tested.
* [[Specificity (tests)|Specificity]] is the proportion of people that tested negative of all the negative people tested.
* All three findings, especially fever, were less sensitive in patients over 60 years of age.

Since anti-viral drugs are effective in treating influenza if given early (see treatment section, below), it can be important to identify cases early. Of the symptoms listed above, the combinations of findings below can improve diagnostic accuracy.<ref name="pmid11088084">{{cite journal | author = Monto A, Gravenstein S, Elliott M, Colopy M, Schweinle J | title = Clinical signs and symptoms predicting influenza infection. | journal = Arch Intern Med | volume = 160 | issue = 21 | pages = 3243–7 | year = 2000 | url http://archinte.ama-assn.org/cgi/content/abstract/160/21/3243 | id = PMID 11088084}}</ref> Unfortunately, even combinations of findings are imperfect. However, [[Bayes Theorem]] can combine pretest probability with clinical findings to adequately diagnose or exclude influenza in some patients. The pretest probability has a strong seasonal variation; the current prevalence of influenza among patients in the United States receiving sentinel testing is available at the [[Centers for Disease Control and Prevention|CDC]].<ref>Centers for Disease Control and Prevention. [http://www.cdc.gov/flu/weekly/ Weekly Report: Influenza Summary Update.] Accessed January 1, 2007.</ref> Using the CDC data, the following table shows how the likelihood of influenza varies with prevalence:
:

<table border="1" cellpadding="5" class="wikitable">
<caption>Combinations of findings for diagnosing influenza<ref name="pmid15728170"/></caption>
<tr>
<th rowspan="2">Combinations of findings </th>
<th rowspan="2">Sensitivity</th>
<th rowspan="2">Specificity</th>
<th colspan="2">As reported in study<ref name="pmid15728170">.</ref> and projected during local outbreaks 
(prevalence= 66%)
</th>
<th colspan="2">Projected during influenza season 
(prevalence=25%)</th>
<th colspan="2">Projected in off-season 
(prevalence=2%) </th>
</tr>
<tr>
<th>PPV</th>
<th>NPV</th>
<th>PPV</th>
<th>NPV</th>
<th>PPV</th>
<th>NPV</th>
</tr>
<tr>
<td>Fever and cough</td>
<td align="center">64%</td>
<td align="center">67%</td>
<td align="center">79%</td>
<td align="center">49%</td>
<td align="center">39%</td>
<td align="center">15%</td>
<td align="center">4%</td>
<td align="center">1%</td>
</tr>
<tr>
<td>Fever and cough and sore throat</td>
<td align="center">56</td>
<td align="center">71</td>
<td align="center">79</td>
<td align="center">45</td>
<td align="center">39</td>
<td align="center">17</td>
<td align="center">4</td>
<td align="center">2</td>
</tr>
<tr>
<td>Fever and cough and nasal congestion</td>
<td align="center">59</td>
<td align="center">74</td>
<td align="center">81</td>
<td align="center">48</td>
<td align="center">43</td>
<td align="center">16</td>
<td align="center">4</td>
<td align="center">1</td>
</tr>
</table>

Two [[decision analysis]] studies<ref name="pmif12361816">{{cite journal | author = Smith K, Roberts M | title = Cost-effectiveness of newer treatment strategies for influenza. | journal = Am J Med | volume = 113 | issue = 4 | pages = 300-7 | year = 2002 | doi = 10.1016/S0002-9343(02)01222-6 | id = PMID 12361816}}</ref><ref name="pimd12965940">{{cite journal | author = Rothberg M, Bellantonio S, Rose D | title = Management of influenza in adults older than 65 years of age: cost-effectiveness of rapid testing and antiviral therapy. | journal = Ann Intern Med | volume = 139 | issue = 5 Pt 1 | pages = 321-9 | year = 2003 | url = http://www.annals.org/cgi/content/abstract/139/5_Part_1/321 | id = PMID 12965940}}</ref> suggest that ''during local outbreaks'' of influenza, the prevalence will be over 70%<ref name="pimd12965940"/> and thus patients with any of the above combinations of symptoms may be treated with neuramidase inhibitors without testing. Even in the absence of a local outbreak, treatment may be justified in the elderly during the influenza season as long as the prevalence is over 15%.<ref name="pimd12965940"/>

Most people who get influenza will recover in one to two weeks, but others will develop life-threatening complications (such as [[pneumonia]]). According to the [[World Health Organization]]: "Every winter, tens of millions of people get the flu. Most are home, sick and miserable, for about a week. Some—mostly the elderly—die. We know the world-wide death toll exceeds a few hundred thousand people a year, but even in developed countries the numbers are uncertain, because medical authorities don't usually verify who actually died of influenza and who died of a flu-like illness."<ref>Peter M. Sandman and Jody Lanard [http://www.paho.org/English/DD/PIN/Number22_article1a.htm "Bird Flu: Communicating the Risk"] 2005 ''Perspectives in Health Magazine'' Vol. 10 issue 2.</ref> Even healthy people can be affected, and serious problems from influenza can happen at any age. People over 50 years old, very young children and people of any age with chronic medical conditions, are more likely to get complications from influenza: such as pneumonia, [[bronchitis]], [[sinus]], and [[ear infection]]s.<ref name=CDCkeyfacts> [http://www.cdc.gov/flu/protect/keyfacts.htm Key Facts about Influenza (Flu) Vaccine] CDC publication. Published October 17, 2006. Accessed 18 Oct 2006.</ref>

The flu can worsen chronic health problems. People with emphysema, chronic bronchitis or asthma may experience shortness of breath while they have the flu, and influenza may cause worsening of [[coronary heart disease]] or [[congestive heart failure]].<ref>Angelo SJ, Marshall PS, Chrissoheris MP, Chaves AM. "Clinical characteristics associated with poor outcome in patients acutely infected with Influenza A." ''Conn Med.'' 2004 Apr;68(4):199–205. PMID 15095826</ref> [[Tobacco smoking|Smoking]] is another [[risk factor]] associated with more serious disease and increased mortality from influenza.<ref>{{cite journal | author = Murin S, Bilello K | title = Respiratory tract infections: another reason not to smoke. | journal = Cleve Clin J Med | volume = 72 | issue = 10 | pages = 916-20 | year = 2005 | id = PMID 16231688}}</ref>

===Laboratory tests===
The available laboratory tests for influenza continue to improve. The United States [[Centers for Disease Control and Prevention]] (CDC) maintains an up-to-date summary of available laboratory tests.<ref>Centers for Disease Control and Prevention. [http://www.cdc.gov/flu/professionals/labdiagnosis.htm Lab Diagnosis of Influenza.] Accessed on January 1, 2007</ref> According to the CDC, rapid diagnostic tests have a sensitivity of 70–75% and specificity of 90–95% when compared with viral culture. These tests may be especially useful during the influenza season (prevalence=25%) but in the absence of a local outbreak, or peri-influenza season (prevalence=10%<ref name="pimd12965940"/>).

==Epidemiology==

===Seasonal variations===
{{further|[[Flu season]]}}

[[Image:H5n1 spread with regression.png|thumb|right|300px|Cumulative Confirmed Human Cases of H5N1.<ref name=WHOH5N1data>[http://www.who.int/csr/disease/avian_influenza/country/en/ WHO Confirmed Human Cases of H5N1] Data published by WHO Epidemic and Pandemic Alert and Response (EPR). Accessed 24 Oct. 2006</ref> The regression curve for deaths is shown extended through the end of November 2006.]]

Influenza reaches peak prevalence in winter, and because the Northern and Southern Hemisphere have winter at different times of the year, there are actually two different flu seasons each year. This is why the [[World Health Organization]] (assisted by the [[National Influenza Centers]]) makes recommendations for two different vaccine formulations every year; one for the Northern, and one for the Southern Hemisphere.<ref name= WHOrecommendation>[http://www.who.int/csr/disease/influenza/2007northreport.pdf Recommended composition of influenza virus vaccines for use in the 2006–2007 influenza season] WHO report 2006-02-14. Accessed [[19 October]] [[2006]].</ref>

It remains unclear why outbreaks of the flu occur seasonally rather than uniformly throughout the year. One possible explanation is that, because people are indoors more often during the winter, they are in close contact more often, and this promotes transmission from person to person. Another is that cold temperatures lead to drier air, which may dehydrate mucus, preventing the body from effectively expelling virus particles. The virus may also survive longer on exposed surfaces (doorknobs, countertops, etc.) in colder temperatures. Increased travel and visitation due to the Northern Hemisphere winter holiday season may also play a role.<ref name = "NPR2003-12-17">[http://www.npr.org/templates/story/story.php?storyId=1551913 Weather and the Flu Season] NPR Day to Day, [[December 17]] [[2003]]. Accessed, [[19 October]] [[2006]]</ref> However, seasonal changes in infection rates are also seen in tropical regions and these peaks of infection are seen mainly during the rainy season.<ref>Shek LP, Lee BW. "Epidemiology and seasonality of respiratory tract virus infections in the tropics." ''Paediatr Respir Rev.'' 2003 Jun;4(2):105–11. PMID 12758047</ref> Seasonal changes in contact rates from school-terms, which are a major factor in other childhood diseases such as [[measles]] and [[pertussis]], may also play a role in flu. A combination of these small seasonal effects may be amplified by "dynamical resonance" with the endogenous disease cycles.<ref>Dushoff J, Plotkin JB, Levin SA, Earn DJ. "Dynamical resonance can account for seasonality of influenza epidemics." ''Proc Natl Acad Sci U S A.'' [[30 November]][[2004]];101(48):16915–6. PMID 15557003</ref> [[H5N1]] exhibits seasonality in both humans and birds.<ref name=WHOH5N1data/>

An alternative hypothesis to explain seasonality in influenza infections is an effect of [[vitamin D]] levels on immunity to the virus.<ref>{{cite journal | last = Cannell | first = J | coauthors = Vieth R, Umhau J, Holick M, Grant W, Madronich S, Garland C, Giovannucci E | title = Epidemic influenza and vitamin D | journal = Epidemiol Infect | volume = 134 | issue = 6 | pages = 1129–40 | year = 2006 | id = PMID 16959053}}</ref> This idea was first proposed by Robert Edgar Hope-Simpson in 1965.<ref>{{cite journal | last = HOPE-SIMPSON | first = R | title = The nature of herpes zoster: a long-term study and a new hypothesis | journal = Proc R Soc Med | volume = 58 | issue = | pages = 9–20 | year = | id = PMID 14267505}}</ref> He proposed that the cause of influenza epidemics during winter may be connected to seasonal fluctuations of vitamin D, which is produced in the skin under the influence of solar (or artificial) [[ultraviolet|UV radiation]]. This could explain why influenza occurs mostly in winter and during the tropical rainy season, when people stay indoors, away from the sun, and their vitamin D levels fall. Furthermore, some studies have suggested that administering [[cod liver oil]], which contains large amounts of vitamin D, can reduce the incidence of respiratory tract infections.<ref name = "Linday2004">{{cite journal | last = Linday | first = L | coauthors = Shindledecker R, Tapia-Mendoza J, Dolitsky J | title = Effect of daily cod liver oil and a multivitamin-mineral supplement with selenium on upper respiratory tract pediatric visits by young, inner-city, Latino children: randomized pediatric sites | journal = Ann Otol Rhinol Laryngol | volume = 113 | issue = 11 | pages = 891–901 | year = 2004 | id = PMID 15562899}}</ref>

===Epidemic and pandemic spread===
{{further|[[Flu pandemic]]}}

[[Image:Antigenic drift versus shift.png|thumb|right|400px|[[Antigenic drift]] creates influenza viruses with slightly-modified antigens, while [[antigenic shift]] generates viruses with entirely novel antigens.]]

[[Image:Influenza geneticshift.jpg|thumb|right|300px|How antigenic shift, or reassortment, can result in novel and highly pathogenic strains of human influenza]]

As influenza is caused by a variety of species and strains of [[virus]]es, in any given year some strains can die out while others create [[epidemic]]s while yet another strain can cause a [[pandemic]]. Typically, in a year's normal two [[flu season]]s (one per hemisphere) there are between three and five million cases of severe illness and up to 500,000 deaths worldwide, which by some definitions is a yearly influenza epidemic.<ref>[http://www.who.int/mediacentre/factsheets/fs211/en/ Influenza] WHO Fact sheet N°211 revised March 2003. Accessed [[22 October]] [[2006]]</ref> Although the incidence of influenza can vary widely between years, approximately 36,000 deaths and more than 200,000 hospitalizations are directly associated with influenza every year in America.<ref>{{cite journal | last = Thompson | first = W | coauthors = Shay D, Weintraub E, Brammer L, Cox N, Anderson L, Fukuda K | title = Mortality associated with influenza and respiratory syncytial virus in the United States | url=http://jama.ama-assn.org/cgi/content/full/289/2/179 | journal = JAMA | volume = 289 | issue = 2 | pages = 179–86 | year = 2003 | id = PMID 12517228}}</ref><ref>{{cite journal | last = Thompson | first = W | coauthors = Shay D, Weintraub E, Brammer L, Bridges C, Cox N, Fukuda K | title = Influenza-associated hospitalizations in the United States | url= http://jama.ama-assn.org/cgi/content/full/292/11/1333 | journal = JAMA | volume = 292 | issue = 11 | pages = 1333–40 | year = 2004 | id = PMID 15367555}}</ref><ref>[http://www.niaid.nih.gov/factsheets/flu.htm Flu factsheet] National Institute of Allergy and Infectious Diseases Accessed 22 Dec 2006</ref> Every ten to twenty years a pandemic occurs, which infects a large proportion of the world's population, and can kill tens of millions of people (see history section).

New influenza viruses are constantly being produced by [[mutation]] or by [[reassortment]].<ref name= hay/> Mutations can cause small changes in the hemagglutinin and neuraminidase [[antigen]]s on the surface of the virus. This is called [[antigenic drift]], which creates an increasing variety of strains over time until one of the variants eventually achieves higher [[fitness (biology)|fitness]], becomes dominant, and rapidly sweeps through the human population – often causing an epidemic.<ref>{{cite journal | author = | title = Long intervals of stasis punctuated by bursts of positive selection in the seasonal evolution of influenza A virus | journal = Biol Direct | volume = 1 | issue = 1 | pages = 34 | year = 2006 | id = PMID 17067369}}</ref> In contrast, when influenza viruses re-assort, they may acquire new antigens — for example by reassortment between avian strains and human strains; this is called antigenic shift. If a human influenza virus is produced with entirely novel antigens, everybody will be susceptible and the novel influenza will spread uncontrollably, causing a pandemic.<ref>{{cite journal | last = Parrish | first = C | coauthors = Kawaoka Y | title = The origins of new pandemic viruses: the acquisition of new host ranges by canine parvovirus and influenza A viruses | journal = Annual Rev Microbiol | volume = 59 | issue = | pages = 553–86 | year = | id = PMID 16153179}}</ref> In contrast to this model of pandemics based on antigenic drift and shift, an alternative approach has been proposed where the periodic pandemics are produced by interactions of a fixed set of viral strains with a human population with a constantly-changing set of immunities to different viral strains.<ref>{{cite journal |author=Recker M, Pybus OG, Nee S, Gupta S |title=The generation of influenza outbreaks by a network of host immune responses against a limited set of antigenic types |url=http://www.pnas.org/cgi/content/full/104/18/7711 |journal=Proc Natl Acad Sci U S A. |volume=104 |issue=18 |pages=7711–7716 |year=2007 |pmid=17460037}}</ref>

==Prevention==
===Vaccination and infection control===
{{further|[[Flu vaccine]]}}
[[Image:Vaccination.jpg|thumb|240px|left|U.S. Navy personnel receiving influenza vaccination]]

Vaccination against influenza with a [[flu vaccine]] is strongly recommended for high-risk groups, such as children and the elderly.

Flu vaccines can be produced in several ways; the most common method is to grow the virus in fertilised hen eggs. After purification, the virus is inactivated (for example, by treatment with detergent) to produce an inactivated-virus vaccine. Alternatively, the virus can be grown in eggs until it loses [[virulence]] and the avirulent virus given as a live vaccine.<ref name=Hilleman/> The effectiveness of these flu vaccines is variable. Due to the high mutation rate of the virus, a particular flu vaccine usually confers protection for no more than a few years. Every year, the [[World Health Organization]] predicts which strains of the virus are most likely to be circulating in the next year, allowing [[pharmaceutical company|pharmaceutical companies]] to develop vaccines that will provide the best immunity against these strains.<ref name= WHOrecommendation/> Vaccines have also been developed to protect poultry from [[avian influenza]]. These vaccines can be effective against multiple strains and are used either as part of a preventative strategy, or combined with culling in attempts to eradicate outbreaks.<ref>{{cite journal | last = Capua | first = I | coauthors = Alexander D | title = The challenge of avian influenza to the veterinary community. | url= http://taylorandfrancis.metapress.com/media/gmuaahtvwk6vweuhugdh/contributions/t/2/n/2/t2n2431j4u176p7g.pdf | journal = Avian Pathol | volume = 35 | issue = 3 | pages = 189–205 | year = 2006 | id = PMID 16753610}}</ref>

It is possible to get vaccinated and still get influenza. The vaccine is reformulated each season for a few specific flu strains, but cannot possibly include all the strains actively infecting people in the world for that season. It takes about six months for the manufacturers to formulate and produce the millions of doses required to deal with the seasonal epidemics; occasionally, a new or overlooked strain becomes prominent during that time and infects people although they have been vaccinated (as by the [[Fujian flu|H3N2 Fujian flu]] in the 2003–2004 flu season).<ref>{{cite journal | last = Holmes | first = E | coauthors = Ghedin E, Miller N, Taylor J, Bao Y, St George K, Grenfell B, Salzberg S, Fraser C, Lipman D, Taubenberger J | title = Whole-genome analysis of human influenza A virus reveals multiple persistent lineages and reassortment among recent H3N2 viruses | journal = PLoS Biol | volume = 3 | issue = 9 | pages = e300 | year = 2005 | id = PMID 16026181}}</ref> It is also possible to get infected just before vaccination and get sick with the very strain that the vaccine is supposed to prevent, as the vaccine takes about two weeks to become effective.<ref name=CDCkeyfacts/>

The 2006–2007 season is the first in which the CDC has recommended that children younger than 59 months receive the annual flu vaccine.<ref name=cdcreport> [http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5510a1.htm Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP)] CDC report (MMWR 2006 Jul 28;55(RR10):1–42) accessed 19 Oct 2006.</ref> Vaccines can cause the [[immune system]] to react as if the body were actually being infected, and general infection symptoms (many cold and flu symptoms are just general infection symptoms) can appear, though these symptoms are usually not as severe or long-lasting as influenza. The most dangerous side-effect is a severe [[allergy|allergic reaction]] to either the virus material itself, or residues from the hen eggs used to grow the influenza; however, these reactions are extremely rare.<ref>[http://www.cdc.gov/flu/about/qa/flushot.htm Questions & Answers: Flu Shot] CDC publication updated Jul 24, 2006. Accessed 19 Oct 06.</ref>

[[Influenza pandemic#Personal health and hygiene|Good personal health and hygiene habits]] are reasonably effective in avoiding and minimizing influenza. People who contract influenza are most infective between the second and third days after infection and infectivity lasts for around 10 days.<ref name=Carrat>{{cite journal |author=Carrat F, Luong J, Lao H, Sallé A, Lajaunie C, Wackernagel H |title=A 'small-world-like' model for comparing interventions aimed at preventing and controlling influenza pandemics |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=17059593 |journal=BMC Med |volume=4 |issue= |pages=26 |year= |pmid=17059593}}</ref> Children are notably more infectious than adults, and shed virus from just before they develop symptoms until 2 weeks after infection.<ref name=Carrat/><ref>{{cite journal |author=Mitamura K, Sugaya N |title=[Diagnosis and Treatment of influenza—clinical investigation on viral shedding in children with influenza] |journal=Uirusu |volume=56 |issue=1 |pages=109-16 |year=2006 |pmid=17038819}}</ref>

Since influenza spreads through [[particulate|aerosols]] and contact with contaminated surfaces, it is important to persuade people to cover their mouths while sneezing and to wash their hands regularly.<ref name=cdcreport/> Surface sanitizing is recommended in areas where influenza may be present on surfaces.<ref>{{cite journal |author=Hota B |title=Contamination, disinfection, and cross-colonization: are hospital surfaces reservoirs for nosocomial infection? |journal=Clin Infect Dis |volume=39 |issue=8 |pages=1182–9 |year=2004 |id=PMID 15486843}}</ref> [[Alcohol]] is an effective sanitizer against influenza viruses, while [[quaternary ammonium]] compounds can be used with alcohol, to increase the duration of the sanitizing action.<ref name=McDonnell>{{cite journal |author=McDonnell G, Russell A |title=Antiseptics and disinfectants: activity, action, and resistance |url=http://cmr.asm.org/cgi/content/full/12/1/147?view=long&pmid=9880479 |journal=Clin Microbiol Rev |volume=12 |issue=1 |pages=147-79 |year=1999 |id=PMID 9880479}}</ref> In hospitals, [[quaternary ammonium]] compounds and halogen-releasing agents such as [[sodium hypochlorite]] are commonly used to sanitize rooms or equipment that have been occupied by patients with influenza symptoms.<ref name=McDonnell/> During past pandemics, closing schools, churches and theaters slowed the spread of the virus but did not have a large effect on the overall death rate.<ref>{{cite journal |author=Hatchett RJ, Mecher CE, Lipsitch M |title=Public health interventions and epidemic intensity during the 1918 influenza pandemic |url=http://www.pnas.org/cgi/content/full/104/18/7582 |journal=Proc Natl Acad Sci U S A. |volume=104 |issue=18 |pages=7582–7587 |year=2007 |pmid=17416679}}</ref><ref>{{cite journal |author=Bootsma MC, Ferguson NM |title=The effect of public health measures on the 1918 influenza pandemic in U.S. cities |url=http://www.pnas.org/cgi/content/full/104/18/7588 |journal=Proc Natl Acad Sci U S A. |volume=104 |issue=18 |pages=7588–7593 |year=2007 |pmid=17416677}}</ref>

==Treatment==
{{further|[[Influenza treatment]]}}

People with the flu are advised to get plenty of rest, drink a lot of liquids, avoid using [[alcoholic beverage|alcohol]] and [[tobacco smoking|tobacco]] and, if necessary, take medications such as [[paracetamol]] (acetaminophen) to relieve the fever and muscle aches associated with the flu. Children and teenagers with flu symptoms (particularly fever) should avoid taking [[aspirin]] during an influenza infection (especially [[Influenzavirus B|influenza type B]]) because doing so can lead to [[Reye's syndrome]], a rare but potentially fatal disease of the [[liver]].<ref>{{cite journal | last = Glasgow | first = J | coauthors = Middleton B | title = Reye syndrome — insights on causation and prognosis | url=http://adc.bmjjournals.com/cgi/content/full/85/5/351 | journal = Arch Dis Child | volume = 85 | issue = 5 | pages = 351–3 | year = 2001 | id = PMID 11668090}}</ref> Since influenza is caused by a virus, [[antibiotic]]s have no effect on the infection; unless prescribed for [[secondary infection]]s such as [[bacterial pneumonia]], they may lead to resistant bacteria. Antiviral medication is sometimes effective, but viruses can develop resistance to the standard antiviral drugs.

The two classes of anti-virals are neuraminidase inhibitors and M2 inhibitors ([[adamantane]] derivatives). Neuraminidase inhibitors are currently preferred for flu virus infections. The CDC recommended against using M2 inhibitors during the 2005–06 influenza season.<ref>Centers for Disease Control and Prevention. [http://www.cdc.gov/flu/han011406.htm CDC Recommends against the Use of Amantadine and Rimantadine for the Treatment or Prophylaxis of Influenza in the United States during the 2005–06 Influenza Season.] [[January 14]], [[2006]]. Retrieved on [[2007-01-01]]</ref>

===Neuraminidase inhibitors===
Antiviral drugs such as [[oseltamivir]] (trade name Tamiflu) and [[zanamivir]] (trade name Relenza) are [[neuraminidase inhibitor]]s that are designed to halt the spread of the virus in the body.<ref name= Neuraminidase_inhibitors>{{cite journal | last = Moscona | first = A | title = Neuraminidase inhibitors for influenza | url=http://content.nejm.org/cgi/content/full/353/13/1363 | journal = N Engl J Med | volume = 353 | issue = 13 | pages = 1363–73 | year = 2005 | id = PMID 16192481}}</ref> These drugs are often effective against both influenza A and B.<ref name=Stephenson/> The [[Cochrane Collaboration]] reviewed these drugs and concluded that they reduce symptoms and complications.<ref name="pmid16855962">{{cite journal | last = Jefferson | first = T | coauthors = Demicheli V, Di Pietrantonj C, Jones M, Rivetti D | title = Neuraminidase inhibitors for preventing and treating influenza in healthy adults | journal = Cochrane Database Syst Rev | volume = 3 | issue = | pages = CD001265 | year = | doi = 10.1002/14651858.CD001265.pub2 | id = PMID 16855962}}</ref> Different strains of influenza virus have differing degrees of resistance against these antivirals and it is impossible to predict what degree of resistance a future pandemic strain might have.<ref> {{cite journal | last = Webster | first = Robert G. | title = H5N1 Influenza — Continuing Evolution and Spread | url=http://content.nejm.org/cgi/content/full/355/21/2174 | journal = N Engl J Med | volume = 355 | issue = 21 | pages = 2174–77 | year = 2006 | id = PMID 16192481}}</ref>

===M2 inhibitors (adamantanes) ===
The [[antiviral drug]]s [[amantadine]] and [[rimantadine]] are designed to block a viral [[ion channel]] and prevent the virus from infecting cells. These drugs are sometimes effective against influenza A if given early in the infection, but are always ineffective against influenza B.<ref name= Stephenson>{{cite journal | last = Stephenson | first = I | coauthors = Nicholson K | title = Chemotherapeutic control of influenza | url=http://jac.oxfordjournals.org/cgi/content/full/44/1/6 | journal = J Antimicrob Chemother | volume = 44 | issue = 1 | pages = 6–10 | year = 1999 | id = PMID 10459804}}</ref> Measured resistance to amantadine and rimantadine in American isolates of [[H3N2]] has increased to 91% in 2005.<ref>{{cite journal | author = | title = High levels of adamantane resistance among influenza A (H3N2) viruses and interim guidelines for use of antiviral agents — United States, 2005–06 influenza season | url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5502a7.htm | journal = MMWR Morb Mortal Wkly Rep | volume = 55 | issue = 2 | pages = 44–6 | year = 2006 | id = PMID 16424859}}</ref>

==Research==
{{further|[[Influenza research]]}}
[[Image:Influenza research.jpg|thumb|220px|right|CDC scientist working on influenza under high bio-safety conditions]]

Research on influenza includes studies on [[molecular virology]], how the virus produces disease ([[pathogenesis]]), host [[immune response]]s, [[genomics|viral genomics]], and how the virus spreads ([[epidemiology]]). These studies help in developing influenza countermeasures; for example, a better understanding of the body's immune response helps [[vaccine]] development, and a detailed picture of how influenza invades cells aids the development of antiviral drugs. One important basic research program is the [[Influenza Genome Sequencing Project]], which is creating a library of influenza sequences; this library should help clarify which factors make one strain more lethal than another, which genes most affect [[immunogenicity]], and how the virus [[evolution|evolves]] over time.<ref> [http://msc.tigr.org/infl_a_virus/index.shtml Influenza A Virus Genome Project] at The Institute of Genomic Research. Accessed 19 Oct 06</ref>

Research into new vaccines is particularly important: as current vaccines are slow and expensive to produce and must be reformulated every year. The sequencing of the influenza genome and [[recombinant DNA]] technology may accelerate the generation of new vaccine strains by allowing scientists to substitute new antigens into a previously-developed vaccine strain.<ref>{{cite journal | author = Subbarao K, Katz J | title = Influenza vaccines generated by reverse genetics. | journal = Curr Top Microbiol Immunol | volume = 283 | issue = | pages = 313-42 | year = | id = PMID 15298174}}</ref> New technologies are also being developed to grow virus in [[cell culture]]; which promises higher yields, less cost, better quality and surge capacity.<ref>{{cite journal | author = Bardiya N, Bae J | title = Influenza vaccines: recent advances in production technologies. | url=http://www.springerlink.com/content/jdt26gc39v4bwk9q/ | journal = Appl Microbiol Biotechnol | volume = 67 | issue = 3 | pages = 299–305 | year = 2005 | id = PMID 15660212}}</ref> The U.S. government has purchased from [[Sanofi Pasteur]] and [[Chiron Corporation]] several million doses of vaccine meant to be used in case of an [[influenza pandemic]] of [[H5N1]] avian influenza and is conducting clinical trials with these vaccines.<ref> [http://www.nytimes.com/2006/03/30/health/30vaccine.html?_r=1&oref=slogin New York Times article ""Doubt Cast on Stockpile of a Vaccine for Bird Flu""] by Denise Grady. Published: March 30, 2006. Accessed 19 Oct 06</ref> The UK government is also stockpiling millions of antiviral drugs(tamiflu, oseltamivir, zanimivir) to give to its citizens in the event of an outbreak, the UK [[Health Protection Agency]] has also gathered a limited amount of HPAI H5N1 vaccines for experimental purposes.

==Infection in other animals==
{{H5N1}}{{further|[[Influenzavirus A]], [[H5N1]] and [[Transmission and infection of H5N1]]}}
Influenza infects many animal species and transfer of viral strains between species can occur. Birds are thought to be the main [[host (biology)|animal reservoir]]s of influenza viruses.<ref>{{cite journal | author = Gorman O, Bean W, Kawaoka Y, Webster R | title = Evolution of the nucleoprotein gene of influenza A virus. | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=2319644 | journal = J Virol | volume = 64 | issue = 4 | pages = 1487–97 | year = 1990 | id = PMID 2319644}}</ref> Sixteen forms of [[hemagglutinin]] and 9 forms of [[neuraminidase]] have been identified. All known subtypes (HxNy) are found in birds but many subtypes are endemic in humans, dogs, horses, and pigs; populations of camels, ferrets, cats, seals, mink, and whales also show evidence of prior infection or exposure to influenza.<ref name=webster/> Variants of flu virus are sometimes named according to the species the strain is endemic in or adapted to. The main variants named using this convention are: Bird flu, [[Human flu|Human Flu]], Swine Flu, Horse Flu and Dog Flu. (Cat flu generally refers to Feline viral rhinotracheitis or Feline calicivirus and not infection from an influenza virus.) In pigs, horses and dogs, influenza symptoms are similar to humans, with cough, fever and loss of appetite.<ref name=webster/> The frequency of animal diseases are not as well-studied as human infection, but an outbreak of influenza in harbour seals caused approximately 500 seal deaths off the New England coast in 1979–1980.<ref>{{cite journal | author = Hinshaw V, Bean W, Webster R, Rehg J, Fiorelli P, Early G, Geraci J, St Aubin D | title = Are seals frequently infected with avian influenza viruses? | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=6471169 | journal = J Virol | volume = 51 | issue = 3 | pages = 863-5 | year = 1984 | id = PMID 6471169}}</ref> On the other hand, outbreaks in pigs are common and do not cause severe mortality.<ref name=webster/>

Flu symptoms in birds are variable and can be unspecific.<ref>{{cite journal | author = Elbers A, Koch G, Bouma A | title = Performance of clinical signs in poultry for the detection of outbreaks during the avian influenza A (H7N7) epidemic in The Netherlands in 2003. | journal = Avian Pathol | volume = 34 | issue = 3 | pages = 181-7 | year = 2005 | id = PMID 16191700}}</ref> The symptoms following infection with low-pathogenicity avian influenza may be as mild as ruffled feathers, a small reduction in egg production, or weight loss combined with minor respiratory disease.<ref>Capua I, Mutinelli F. "Low pathogenicity (LPAI) and highly pathogenic (HPAI) avian inﬂuenza in turkeys and chicken." In: Capua I, Mutinelli F. (eds.), A Colour Atlas and Text on Avian Inﬂuenza, Papi Editore, Bologna, 2001, pp. 13–20</ref> Since these mild symptoms can make diagnosis in the field difficult, tracking the spread of avian influenza requires laboratory testing of samples from infected birds. Some strains such as Asian [[H9N2]] are highly virulent to poultry, and may cause more extreme symptoms and significant mortality.<ref>{{cite journal | author = Bano S, Naeem K, Malik S | title = Evaluation of pathogenic potential of avian influenza virus serotype H9N2 in chickens. | journal = Avian Dis | volume = 47 | issue = 3 Suppl | pages = 817-22 | year = 2003 | id = PMID 14575070}}</ref> In its most highly pathogenic form, influenza in chickens and turkeys produces a sudden appearance of severe symptoms and almost 100% mortality within two days.<ref>{{cite journal | author = Swayne D, Suarez D | title = Highly pathogenic avian influenza. | journal = Rev Sci Tech | volume = 19 | issue = 2 | pages = 463-82 | year = 2000 | id = PMID 10935274}}</ref> As the virus spreads rapidly in the crowded conditions seen in the intensive farming of chickens and turkeys, these outbreaks can cause large economic losses to poultry farmers.

An avian-adapted, highly pathogenic strain of H5N1 (called HPAI A(H5N1), for "highly pathogenic avian influenza virus of type A of subtype H5N1") causes [[transmission and infection of H5N1|H5N1 flu]], commonly known as "avian influenza" or simply "bird flu", and is [[endemic (epidemiology)|endemic]] in many bird populations, especially in Southeast Asia. This Asian lineage strain of HPAI A(H5N1) is [[global spread of H5N1|spreading globally]]. It is [[epizootic]] (an epidemic in non-humans) and panzootic (a disease affecting animals of many species, especially over a wide area) killing tens of millions of birds and spurring the culling of hundreds of millions of other birds in an attempt to control its spread. Most references in the media to "bird flu" and most references to H5N1 are about this specific strain.<ref>{{cite journal | author = Li K, Guan Y, Wang J, Smith G, Xu K, Duan L, Rahardjo A, Puthavathana P, Buranathai C, Nguyen T, Estoepangestie A, Chaisingh A, Auewarakul P, Long H, Hanh N, Webby R, Poon L, Chen H, Shortridge K, Yuen K, Webster R, Peiris J | title = Genesis of a highly pathogenic and potentially pandemic H5N1 influenza virus in eastern Asia. | journal = Nature | volume = 430 | issue = 6996 | pages = 209-13 | year = 2004 | id = PMID 15241415}}</ref><ref>Li KS, Guan Y, Wang J, Smith GJ, Xu KM, Duan L, Rahardjo AP, Puthavathana P, Buranathai C, Nguyen TD, Estoepangestie AT, Chaisingh A, Auewarakul P, Long HT, Hanh NT, Webby RJ, Poon LL, Chen H, Shortridge KF, Yuen KY, Webster RG, Peiris JS. [http://darwin.nap.edu/books/0309095042/html/116.html "The Threat of Pandemic Influenza: Are We Ready?" Workshop Summary] The National Academies Press (2005) "Today's Pandemic Threat: Genesis of a Highly Pathogenic and Potentially Pandemic H5N1 Influenza Virus in Eastern Asia", pages 116–130</ref>

At present, HPAI A(H5N1) is an avian disease and there is no evidence suggesting efficient human-to-human transmission of HPAI A(H5N1). In almost all cases, those infected have had extensive physical contact with infected birds.<ref>{{cite journal | author = Liu J | title = Avian influenza—a pandemic waiting to happen? | url=http://jmii.org/content/pdf/v39n1p4.pdf | journal = J Microbiol Immunol Infect | volume = 39 | issue = 1 | pages = 4–10 | year = 2006 | id = PMID 16440117}}</ref> In the future, H5N1 may mutate or reassort into a strain capable of efficient human-to-human transmission. Due to its high lethality and [[virulence]], its [[endemic (epidemiology)|endemic]] presence, and its large and increasing biological host reservoir, the H5N1 virus is the world's pandemic threat in the 2006–7 flu season, and billions of dollars are being raised and spent researching H5N1 and preparing for a potential [[influenza pandemic]].<ref name=Rosenthal> Rosenthal, E. and Bradsher, K. [http://www.nytimes.com/2006/03/16/business/16bird.html?_r=1&oref=slogin Is Business Ready for a Flu Pandemic?] The New York Times 16-03-2006 Accessed 17-04-2006</ref>

==Economic impact==
{{further|[[Social impact of H5N1]]}}
Influenza produces [[variable cost|direct cost]]s due to lost [[productivity]] and associated medical treatment, as well as [[indirect costs]] of preventative measures. In the United States, influenza is responsible for a total cost of over $10 billion per year, while it has been estimated that a future pandemic could cause hundreds of billions of dollars in direct and indirect costs.<ref>[http://www.whitehouse.gov/homeland/pandemic-influenza.html Statement from President George W. Bush on Influenza] Accessed 26 Oct 2006</ref> However, the economic impact of past pandemics have not been intensively studied, and some authors have suggested that the [[Spanish flu|Spanish influenza]] actually had a positive long-term effect on per-capita income growth, despite a large reduction in the working population and severe short-term depressive effects.<ref>Brainerd, E. and M. Siegler (2003), “The Economic Effects of the 1918 Influenza Epidemic”, ''CEPR Discussion Paper'', no. 3791.</ref> Other studies have attempted to predict the costs of a pandemic as serious as the 1918 Spanish flu on the U.S. economy, where 30% of all workers became ill, and 2.5% were killed. A 30% sickness rate and a three-week length of illness would decrease [[gross domestic product]] by 5%. Additional costs would come from medical treatment of 18 million to 45 million people, and total economic costs would be approximately $700 billion.<ref>{{cite journal | author = Poland G | title = Vaccines against avian influenza—a race against time. | url=http://content.nejm.org/cgi/content/full/354/13/1411 | journal = N Engl J Med | volume = 354 | issue = 13 | pages = 1411–3 | year = 2006 | id = PMID 16571885}}</ref>

Preventative costs are also high. Governments worldwide have spent billions of U.S. dollars preparing and planning for a potential H5N1 avian influenza pandemic, with costs associated with purchasing drugs and vaccines as well as developing disaster drills and strategies for improved border controls.<ref name=Rosenthal/> On November 1 2005, President George W. Bush unveiled the National Strategy to Safeguard Against the Danger of Pandemic Influenza<ref>[http://www.whitehouse.gov/homeland/pandemic-influenza.html National Strategy for Pandemic Influenza] Whitehouse.gov Accessed 26 Oct 2006.</ref> backed by a request to Congress for $7.1 billion to begin implementing the plan.<ref>[http://usinfo.state.gov/gi/Archive/2005/Nov/01-432345.html Bush Outlines $7 Billion Pandemic Flu Preparedness Plan] State.gov. Accessed 26 Oct 2006</ref> Internationally, on January 18 2006 donor nations pledged US$2 billion to combat bird flu at the two-day International Pledging Conference on Avian and Human Influenza held in China.<ref>[http://www.ens-newswire.com/ens/jan2006/2006-01-18-02.asp Donor Nations Pledge $1.85 Billion to Combat Bird Flu] Newswire Accessed 26 Oct 2006.</ref>

Up to 2006, over ten billion dollars have been spent and over two hundred million birds have been killed to try to contain H5N1 avian influenza.<ref>[http://www.usaid.gov/about_usaid/acvfa/intro_ai.pdf Avian Influenza and its Global Implications] US AID. Accessed 26 Oct 2006.</ref> However, as these efforts have been largely ineffective at controlling the spread of the virus, other approaches are being tried: for example, the Vietnamese government in 2005 adopted a combination of mass poultry vaccination, disinfecting, culling, information campaigns and bans on live poultry in cities.<ref> [http://today.reuters.co.uk/news/newsArticle.aspx?type=worldNews&storyID=2006-04-28T080147Z_01_HAN5054_RTRUKOC_0_UK-BIRDFLU-VIETNAM.xml Reuters Vietnam to unveil advanced plan to fight bird flu] published on April 28, 2006. Accessed 26 Oct 2006</ref> As a result of such measures, the cost of poultry farming has increased, while the cost to consumers has gone down due to demand for poultry falling below supply. This has resulted in devastating losses for many farmers. Poor poultry farmers cannot afford mandated measures which keep their bird livestock from contact with wild birds (and other measures), thus risking losing their livelihood altogether. Multinational poultry farming is increasingly becoming unprofitable as H5N1 avian influenza becomes endemic in wild birds worldwide.<ref>[http://www.irinnews.org/report.asp?ReportID=52471 Poultry sector suffers despite absence of bird flu] UN Office for the Coordination of Humanitarian Affairs. Accessed 26 Oct 2006</ref> Financial ruin for poor poultry farmers, which can be as severe as threatening starvation, has caused some to commit [[suicide]] and many others to stop cooperating with efforts to deal with this virus – further increasing the human toll, the spread of the disease, and the chances of a pandemic mutation.<ref>[http://www.expressindia.com/fullstory.php?newsid=65957 Nine poultry farmers commit suicide in flu-hit India] Reuters. Published on April 12, 2006. Accessed 26 Oct 2006.</ref><ref>[http://www.nytimes.com/2006/04/14/world/africa/14egypt.html?_r=1&oref=slogin In the Nile Delta, Bird Flu Preys on Ignorance and Poverty] The New York Times. Published on April 13, 2006. Accessed 26 Oct 2006.</ref>

==See also==


*[[Virus]]
*[[List of viruses]]
*[[List of epidemics]]

;Information concerning flu research can be found at:
<div style="-moz-column-count:2; column-count:2;">
*[[Influenza research]]
*[[H5N1 clinical trials]]
*[[Center for Biologics Evaluation and Research]]
*[[H5N1 genetic structure]]
*[[ICEID]]
*[[Influenza Genome Sequencing Project]]
*[[Cytokine storm]]
*[[International Partnership on Avian and Pandemic Influenza]]
*[[National Influenza Centers]]
*[[Pandemic Preparedness and Response Act]]
</div>

==References and notes==
{{reflist|2}}

==Further reading==
{{Col-begin}}
{{Col-1-of-2}}
'''General'''
* [http://content.nejm.org/cgi/content/full/353/13/1374 NEJM's Avian Influenza]
* Bernd Sebastian Kamps, Christian Hoffmann and Wolfgang Preiser (Eds.) [http://www.InfluenzaReport.com Influenza Report 2006] Flying publisher 2006.
*Arnold J. Levine 'Viruses' Scientific American Library, WH Freeman, 1992 ISBN 0-7167-5031-7
* Samuel Baron ''et al.'' '[http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed Medical Microbiology]' Fourth Edition, The University of Texas Medical Branch at Galveston 1996 ISBN 0-9631172-1-1.
*Cox NJ, Subbarao K. 'Influenza.' ''Lancet.'' 1999 Oct 9;354(9186):1277–82. PMID 10520648

'''History'''
*Edwin D. Kilbourne [http://www.cdc.gov/ncidod/EID/vol12no01/05-1254.htm Influenza Pandemics of the 20th Century] ''Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*Richard Collier 'The Plague of the Spanish Lady' Macmillan publishers (London) 1974 ISBN 0-7490-0246-8
*John M. Barry 'The Great Influenza: the Epic Story of the Deadliest Plague in History' Penguin 2004 ISBN 0-670-89473-7

'''Microbiology'''
*Webster RG, Bean WJ, Gorman OT, Chambers TM, Kawaoka Y. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=1579108 "Evolution and ecology of influenza A viruses."] ''Microbiol Rev.'' 1992 Mar;56(1):152–79. PMID 1579108
*Scholtissek C. 'Molecular epidemiology of influenza.' Arch Virol Suppl. 1997;13:99–103. PMID 9413530

{{Col-2-of-2}}
'''Pathogenesis'''
*Adolfo García-Sastre [http://www.cdc.gov/ncidod/EID/vol12no01/05-1186.htm Antiviral Response in Pandemic Influenza Viruses] 'Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*Zambon MC. 'The pathogenesis of influenza in humans.' Rev Med Virol. 2001 Jul–Aug;11(4):227–41. PMID 11479929

'''Epidemiology'''
*Walter R. Dowdle [http://www.cdc.gov/ncidod/EID/vol12no01/05-1013.htm Influenza Pandemic Periodicity, Virus Recycling, and the Art of Risk Assessment] 'Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*Horimoto T, Kawaoka Y. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=11148006 Pandemic threat posed by avian influenza A viruses.] ''Clin Microbiol Rev.'' 2001 Jan;14(1):129–49. PMID 11148006
*[http://www.who.int/wer/wer8126.pdf Epidemiology of WHO-confirmed human cases of avian influenza A(H5N1) infection]

'''Treatment and prevention'''
*CDC 2005. Centers for Disease Control. [http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5408a1.htm Prevention and Control of Influenza Recommendations] of the Advisory Committee on Immunization Practices (ACIP). MMWR 2005; 54 (RR08): 1–40.
*Arnold S. Monto [http://www.cdc.gov/ncidod/EID/vol12no01/05-1068.htm Vaccines and Antiviral Drugs in Pandemic Preparedness] ''Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006

'''Research'''
*Peter Palese [http://www.cdc.gov/ncidod/EID/vol12no01/05-1043.htm Making Better Influenza Virus Vaccines?] ''Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*[http://www.who.int/csr/disease/avian_influenza/guidelines/recommendationvaccine.pdf WHO (PDF} contains latest Evolutionary "Tree of Life" for H5N1] article ''Antigenic and genetic characteristics of H5N1 viruses and candidate H5N1 vaccine viruses developed for potential use as pre-pandemic vaccines'' published August 18, 2006
*[http://www.who.int/csr/resources/publications/influenza/WHO_CDS_EPR_GIP_2006_3C.pdf WHO's assessment of Flu Research] as of November 2006.
{{Col-end}}

==External links==
*[http://www.cdc.gov/flu/ Info on influenza] at [[Centers for Disease Control and Prevention|CDC]]
*[http://www.who.int/mediacentre/factsheets/fs211/en/index.html Fact Sheet] Overview of influenza at [[World Health Organization]]
*[http://www.nhsdirect.nhs.uk/en.aspx?articleId=163&sectionId=1725 Health encyclopedia entry] at [[NHS Direct]]
*[http://www.biohealthbase.org/ BioHealthBase Bioinformatics Resource Center] Database of influenza sequences and related information.
*[http://www.medicinenet.com/influenza/article.htm Overview of influenza] at [[MedicineNet]]
*[http://digital.library.unt.edu/govdocs/crs/search.tkl?q=influenza&search_crit=subject&search=Search&date1=Anytime&date2=Anytime&type=form Congressional Research Service (CRS) Reports regarding Influenza] Law related government reports at [[University of North Texas]]
*[http://www.fluwikie.com/index.php?n=Geographic.Geographic Influenza Surveillance and Contingency Plans] (by Country/Region)
*[http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/46000000.htm Orthomyxoviridae] The Universal Virus Database of the [[International Committee on Taxonomy of Viruses]]
*[http://www.ncbi.nlm.nih.gov/genomes/FLU/flubiology.html Influenza Virus Resource] from the [[National Center for Biotechnology Information|NCBI]]
*[http://www.influenzaworld.com/portal/eipf/pb/t/iwc/home InfluenzaWorld] Resource for all influenza-related information.

{{Influenza}}
{{Respiratory pathology}}
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[[th:ไข้หวัดใหญ่]]
[[vi:Bệnh cúm]]
[[wa:Virûsse del gripe]]
[[yi:פלו]]
[[zh:流行性感冒]]
[[zh-min-nan:Liû-hêng-sèng kám-mō͘]]
[[pl:Grypa]]
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[[Category:Influenza| ]]
[[Category:Infectious disease]]

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Influenza

2009-07-07T18:41:17Z

Michaelagibson:

{{Infobox_Disease |
Name = Influenza |
Image = EM of influenza virus.jpg |
Caption = [[transmission electron microscopy|TEM]] of negatively stained influenza virons, magnified approximately 70,000 times |
Width = 226 |
DiseasesDB = 6791 |
ICD10 = {{ICD10|J|10||j|09}}, {{ICD10|J|11||j|09}} |
ICD9 = {{ICD9|487}} |
MedlinePlus = 000080 |
eMedicineSubj = med |
eMedicineTopic = 1170 |
eMedicine_mult = {{eMedicine2|ped|3006}} |
MeshID = D007251 |
}}
{{Flu}}
{{SI}}
{{CMG}}
__NOTOC__
{{Editor Help}}

For Patient information click [[Influenza Patient Information|here]]

==Overview==

'''Influenza''', commonly known as '''flu''', is an [[infectious disease]] of birds and [[mammal]]s caused by [[RNA virus]]es of the biological family [[Orthomyxoviridae]] (the influenza viruses). In humans, common symptoms of influenza infection are [[fever]], [[pharyngitis|sore throat]], [[myalgia|muscle pains]], severe [[headache]], [[cough]]ing, [[fatigue (medical)|weakness]] and [[malaise|general discomfort]].<ref name=Merck>{{cite web |author= Merck Manual Home Edition |title=Influenza: Viral Infections |url= http://www.merck.com/mmhe/sec17/ch198/ch198c.html?}}</ref> In more serious cases, influenza [[sequela|causes]] [[pneumonia]], which can be fatal, particularly in young children and the elderly. Sometimes confused with the [[common cold]], influenza is a much more severe disease and is caused by a different type of virus.<ref name=Eccles>{{cite journal | last = Eccles | first = R | title = Understanding the symptoms of the common cold and influenza | journal = Lancet Infect Dis | volume = 5 | issue = 11 | pages = 718–25 | year = 2005 | id = PMID 16253889}}</ref> Although [[nausea]] and [[vomiting]] can be produced, especially in children,<ref name=Merck/> these symptoms are more characteristic of the unrelated [[gastroenteritis]], which is sometimes called "stomach flu" or "24-hour flu."<ref> [http://coldflu.about.com/od/flumisconceptions/f/stomachflu.htm Seasonal Flu vs. Stomach Flu] by Kristina Duda, R.N.; accessed March 12, 2007 (Website: "About, Inc., A part of The New York Times Company")</ref>

Typically, influenza is transmitted from infected mammals through the air by coughs or sneezes, creating particulates/aerosols containing the virus, and from infected birds through their [[feces|droppings]]. Influenza can also be transmitted by [[saliva]], [[mucus|nasal secretions]], [[feces]] and [[blood]]. Infections also occur through contact with these body fluids or with contaminated surfaces.

Flu viruses can remain infectious for about one week at human body temperature, over 30 days at 0 °C (32 °F), and indefinitely at very low temperatures (such as lakes in northeast Siberia). Most influenza strains can be inactivated easily by [[disinfectant]]s and [[detergent]]s.<ref>{{cite journal | last = Suarez | first = D | coauthors = Spackman E, Senne D, Bulaga L, Welsch A, Froberg K | title = The effect of various disinfectants on detection of avian influenza virus by real time RT-PCR | journal = Avian Dis | volume = 47 | issue = 3 Suppl | pages = 1091–5 | year = 2003 | id = PMID 14575118}}</ref><ref>[http://www.cidrap.umn.edu/cidrap/content/influenza/avianflu/biofacts/avflu_human.html Avian Influenza (Bird Flu)]: Implications for Human Disease. Physical characteristics of influenza A viruses. UMN CIDRAP.</ref><ref name = "NHZ2006-11-30">[http://www.nzherald.co.nz/category/story.cfm?c_id=204&objectid=10413124 Flu viruses 'can live for decades' on ice], NZ Herald, November 30, 2006.</ref>

Flu spreads around the world in seasonal [[epidemic]]s, killing millions of people in [[pandemic]] years and hundreds of thousands in non-pandemic years. Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new [[strain (biology)|strain]] of the virus in humans. Often, these new strains result from the spread of an existing flu virus to humans from other animal [[species]].

Since it first killed humans in Asia in the 1990s, a deadly avian strain named [[H5N1]] has posed the greatest risk for a new [[influenza pandemic]]; fortunately, this virus has not [[mutation|mutated]] to a form that spreads easily between people.<ref>{{cite web | title=Avian influenza ("bird flu") fact sheet | url= http://www.who.int/mediacentre/factsheets/avian_influenza/en/ | date=February 2006 | publisher=WHO | accessdate=2006-10-20}}</ref>

[[Vaccination]]s against influenza are most commonly given to high-risk humans in industrialized countries<ref name=WHOvaccines>[http://www.who.int/wer/2005/wer8033.pdf WHO position paper: influenza vaccines] ''WHO weekly Epidemiological Record'' 19 August 2005, vol. 80, 33, pp. 277–288.</ref> and to farmed poultry.<ref>{{cite journal | last = Villegas | first = P | title = Viral diseases of the respiratory system | journal = Poult Sci | volume = 77 | issue = 8 | pages = 1143–5 | year = 1998 | id = PMID 9706079}}</ref> The most common human vaccine is the trivalent [[flu vaccine]] that contains purified and inactivated material from three viral strains. Typically this vaccine includes material from two [[influenzavirus A|influenza A virus]] subtypes and one [[Influenzavirus B|influenza B virus]] strain.<ref>{{cite journal | last = Horwood | first = F | coauthors = Macfarlane J | title = Pneumococcal and influenza vaccination: current situation and future prospects. | url= http://thorax.bmjjournals.com/cgi/reprint/57/suppl_2/ii24.pdf | journal = Thorax | volume = 57 Suppl 2 | issue = | pages = II24–II30 | year = | id = PMID 12364707}}</ref> A vaccine formulated for one year may be ineffective in the following year, since the influenza virus changes rapidly over time and different strains become dominant. [[Antiviral drug]]s can be used to treat influenza, with [[neuraminidase inhibitor]]s being particularly effective.

==Etymology==
The term influenza has its origins in 15th-century Italy, where the cause of the disease was ascribed to unfavourable astrological ''influences''. Evolution in medical thought led to its modification to ''influenza del freddo'', meaning "influence of the cold." The word "influenza" was first attested in English in 1743 when it was borrowed during an outbreak of the disease in Europe.<ref name=Harper>{{cite web | last = Harper | first = D | title=Influenza | url=http://www.etymonline.com/index.php?search=influenza&searchmode=none | publisher= Etymonlin}}</ref> Archaic terms for influenza include epidemic catarrh, grippe (from the French grippe, meaning flu; sometimes spelled "grip" or "gripe"), sweating sickness, and Spanish fever (particularly for the [[Spanish flu|1918 pandemic]] strain).<ref>{{cite web | last = Smith | first = P | title=Archaic Medical Terms | url= http://www.paul_smith.doctors.org.uk/ArchaicMedicalTerms.htm | accessdate = 2006-10-23}}</ref>

==History==
{{further|[[Influenza pandemic]], [[Spanish flu]]}}

[[Image:Influenza1.png|thumb|300px|left|Negatively stained flu viruses; these were the causative agents of [[Hong Kong Flu]]. (magnified approximately 70,000 times)]]

[[Image:W curve2.png|thumb|300px|left|The difference between the influenza mortality age-distributions of the 1918 epidemic and normal epidemics. Deaths per 100,000 persons in each age group, United States, for the interpandemic years 1911–1917 (dashed line) and the pandemic year 1918 (solid line).<ref name = "Taubenberger">{{cite journal | last = Taubenberger | first = J | coauthors = Morens D | title = 1918 Influenza: the mother of all pandemics. | url = http://www.cdc.gov/ncidod/EID/vol12no01/05-0979.htm | journal = Emerg Infect Dis | volume = 12 | issue = 1 | pages = 15–22 | year = 2006 | id = PMID 16494711}}</ref>]]

The symptoms of human influenza were clearly described by [[Hippocrates]] roughly 2400 years ago.<ref>{{cite journal | last =Martin | first = P | coauthors = Martin-Granel E | title=2,500-year evolution of the term epidemic | url= http://www.cdc.gov/ncidod/EID/vol12no06/05-1263.htm#cit | journal=Emerg Infect Dis | year=2006 | month = Jun | volume=12 | issue=6 | id = PMID 16707055}}</ref><ref>{{cite web | author=Hippocrates | coauthors = [[Francis Adams (translator)|Adams, Francis]] (transl.) | title=Of the Epidemics | url= http://classics.mit.edu/Hippocrates/epidemics.html | date= 400 BCE | accessdate=2006-10-18}}</ref> Since then, the virus has caused numerous pandemics. Historical data on influenza are difficult to interpret, because the symptoms can be similar to those of other diseases, such as [[diphtheria]], [[pneumonic plague]], [[typhoid fever]], [[dengue]], or [[typhus]]. The first convincing record of an influenza pandemic was of an outbreak in 1580, which began in Asia and spread to Europe via Africa. In Rome over 8,000 people were killed, and several Spanish cities were almost wiped out. Pandemics continued sporadically throughout the 17th and 18th centuries, with the pandemic of 1830–1833 being particularly widespread; it infected approximately a quarter of the people exposed.<ref name=Potter>{{cite journal | last =Potter | first = CW| title=A History of Influenza | url= http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2672.2001.01492.x | journal= J Appl Microbiol. | year=2006 | month=Oct | volume=91 | issue= 4 | pages = 572–579 | id = PMID 11576290}}</ref>

The most famous and lethal outbreak was the so-called [[Spanish flu]] pandemic ([[Influenzavirus A|type A influenza]], [[H1N1]] subtype), which lasted from 1918 to 1919. Older estimates say it killed 40–50 million people<ref name=Patterson1>{{cite journal | last =Patterson | first = KD | coauthors = Pyle GF | title=The geography and mortality of the 1918 influenza pandemic. | journal= Bull Hist Med. | year=1991 | month=Spring | volume=65 | issue=1 | pages = 4–21 | id = PMID 2021692}}</ref> while current estimates say 50 million to 100 million people worldwide were killed.<ref name=Knobler>{{cite book | editor=Knobler S, Mack A, Mahmoud A, Lemon S | title = The Threat of Pandemic Influenza: Are We Ready? Workshop Summary (2005) | chapter=1: The Story of Influenza | pages = 60–61 | chapterurl=http://darwin.nap.edu/books/0309095042/html/60.html | publisher=The National Academies Press | location=Washington, D.C.}}</ref> This pandemic has been described as "the greatest medical holocaust in history" and may have killed as many people as the [[Black Death]].<ref name=Potter/> This huge death toll was caused by an extremely high infection rate of up to 50% and the extreme severity of the symptoms, suspected to be caused by [[cytokine storm]]s.<ref name=Patterson1/> Indeed, symptoms in 1918 were so unusual that initially influenza was misdiagnosed as dengue, [[cholera]], or typhoid. One observer wrote, "One of the most striking of the complications was hemorrhage from mucous membranes, especially from the nose, stomach, and intestine. Bleeding from the ears and [[petechia|petechial hemorrhages]] in the skin also occurred."<ref name=Knobler/> The majority of deaths were from [[bacterial pneumonia]], a secondary infection caused by influenza, but the virus also killed people directly, causing massive [[bleeding|hemorrhages]] and [[edema]] in the lung.<ref name=Taubenberger>{{cite journal | last = Taubenberger | first = J | coauthors = Reid A, Janczewski T, Fanning T | title = Integrating historical, clinical and molecular genetic data in order to explain the origin and virulence of the 1918 Spanish influenza virus. | journal = Philos Trans R Soc Lond B Biol Sci | volume = 356 | issue = 1416 | pages = 1829–39 | year = 2001 | month=Dec 29 | id = PMID 11779381 | url= http://www.journals.royalsoc.ac.uk/(3sud2455cjw1ut55yowx1d45)/app/home/contribution.asp?referrer=parent&backto=issue,3,22;journal,61,225;linkingpublicationresults,1:102022,1}}</ref>

The Spanish flu pandemic was truly global, spreading even to the Arctic and remote Pacific islands. The unusually severe disease killed between 2 and 20% of those infected, as opposed to the more usual flu epidemic [[mortality rate]] of 0.1%.<ref name=Taubenberger/><ref name=Knobler/> Another unusual feature of this pandemic was that it mostly killed young adults, with 99% of pandemic influenza deaths occurring in people under 65, and more than half in young adults 20 to 40 years old.<ref>{{cite journal | last = Simonsen | first = L | coauthors = Clarke M, Schonberger L, Arden N, Cox N, Fukuda K | title = Pandemic versus epidemic influenza mortality: a pattern of changing age distribution. | journal = J Infect Dis | volume = 178 | issue = 1 | pages = 53–60 | year = 1998 | month=Jul | id = PMID 9652423}}</ref> This is unusual since influenza is normally most deadly to the very young (under age 2) and the very old (over age 70). The total mortality of the 1918–1919 pandemic is not known, but it is estimated that 2.5% to 5% of the world's population was killed. As many as 25 million may have been killed in the first 25 weeks; in contrast, [[AIDS|HIV/AIDS]] has killed 25 million in its first 25 years.<ref name=Knobler/>

Later flu pandemics were not so devastating. They included the 1957 [[Asian Flu]] (type A, [[H2N2]] strain) and the 1968 [[Hong Kong Flu]] (type A, [[H3N2]] strain), but even these smaller outbreaks killed millions of people. In later pandemics [[antibiotic]]s were available to control secondary infections and this may have helped reduce mortality compared to the Spanish Flu of 1918.<ref name= Taubenberger/>

{| class="wikitable" style="text-align:center"
|+ Known [[flu pandemic]]s<ref name=Hilleman>{{cite journal | last = Hilleman | first = M | title = Realities and enigmas of human viral influenza: pathogenesis, epidemiology and control. | journal = Vaccine | volume = 20 | issue = 25–26 | pages = 3068–87 | year = 2002 | month=Aug 19 | id = PMID 12163258}}</ref><ref name=Potter/>
! Name of pandemic !! Date !! Deaths !! Subtype involved !! [[Pandemic Severity Index]]
|-
! Asiatic (Russian) Flu
| 1889–1890 || 1 million || possibly [[H2N2]] || ?
|-
! [[Spanish flu|Spanish Flu]]
| 1918–1920 || 40 million || [[H1N1]] || 5
|-
! [[H2N2#Asian Flu|Asian Flu]]
| 1957–1958 || 1 to 1.5 million || [[H2N2]] || 2
|-
! [[H3N2#Hong Kong Flu|Hong Kong Flu]]
| 1968–1969 || 0.75 to 1 million || [[H3N2]] || 2
|-
|}

The [[etiology|etiological]] cause of influenza, the Orthomyxoviridae family of viruses, was first discovered in pigs by [[Richard Schope]] in 1931.<ref>{{cite journal | last =Shimizu | first = K | title= History of influenza epidemics and discovery of influenza virus | journal=Nippon Rinsho | year= 1997 | month=Oct | volume=55 | issue=10| pages=2505–201 | id = PMID 9360364}}</ref> This discovery was shortly followed by the isolation of the virus from humans by a group headed by [[Patrick Laidlaw]] at the [[Medical Research Council (UK)|Medical Research Council]] of the [[United Kingdom]] in 1933.<ref>{{cite journal | last =Smith | first = W | coauthors = Andrewes CH, Laidlaw PP | title=A virus obtained from influenza patients | journal=Lancet | year=1933 | volume=2 | pages = 66–68}}</ref> However, it was not until [[Wendell Stanley]] first crystallized [[tobacco mosaic virus]] in 1935 that the [[cell (biology)|non-cellular]] nature of viruses was appreciated.

The first significant step towards preventing influenza was the development in 1944 of a killed-virus vaccine for influenza by [[Thomas Francis, Jr.]]. This built on work by [[Frank Macfarlane Burnet]], who showed that the virus lost virulence when it was cultured in fertilized hen's eggs.<ref name = "Nobel">[http://nobelprize.org/nobel_prizes/medicine/laureates/1960/burnet-bio.html Sir Frank Macfarlane Burnet: Biography] The Nobel Foundation. Accessed 22 Oct 06</ref> Application of this observation by Francis allowed his group of researchers at the [[University of Michigan]] to develop the first [[flu vaccine]], with support from the U.S. Army.<ref>{{cite journal | last = Kendall | first = H | title = Vaccine Innovation: Lessons from World War II | url= http://docstore.ingenta.com/cgi-bin/ds_deliver/1/u/d/ISIS/32620254.1/pal/jphp/2006/00000027/00000001/art00005/FB2494BF0313967611615398189A7A906334373166.pdf?link=http://www.ingentaconnect.com/error/delivery&format=pdf | journal = Journal of Public Health Policy | volume = 27 | issue = 1 | pages = 38–57 | year = 2006}}</ref> The Army was deeply involved in this research due to its experience of influenza in World War I, when thousands of troops were killed by the virus in a matter of months.<ref name= Knobler/>

Although there were scares in New Jersey in 1976 (with the [[Swine Flu]]), world wide in 1977 (with the [[Russian Flu]]), and in Hong Kong and other Asian countries in 1997 (with [[H5N1]] avian influenza), there have been no major pandemics since the 1968 Hong Kong Flu. Immunity to previous pandemic influenza strains and vaccination may have limited the spread of the virus and may have helped prevent further pandemics.<ref name=Hilleman/>

==Microbiology==

===Types of influenza virus===
[[Image:3D influenza virus.png|thumb|400px|left|Structure of the influenza [[wikt:virion|virion]]. The [[hemagglutinin]] (HA) and [[neuraminidase]] (NA) proteins are shown on the surface of the particle. The viral RNAs that make up the [[genome]] are shown as red coils inside the particle and bound to Ribonuclear Proteins (RNPs).]]
[[Image:Infnomenclature.svg|thumb|350px|right|Diagram of influenza virus [[International Committee on Taxonomy of Viruses|nomenclature]] (for a [[Fujian flu]] virus)]]

The influenza virus is an [[RNA virus]] of the family [[Orthomyxoviridae]], which comprises the influenzaviruses, [[Isavirus]], and [[Thogotovirus]].<ref name=Kawaoka>{{cite book | author = Kawaoka Y (editor). | title = Influenza Virology: Current Topics | publisher = Caister Academic Press | year = 2006 | url=http://www.horizonpress.com/flu | isbn = 978-1-904455-06-6}}</ref> There are three types of influenza virus: [[Influenzavirus A]], [[Influenzavirus B]], and [[Influenzavirus C]]. Influenza A and C infect multiple species, while influenza B almost exclusively infects humans.<ref name=hay>{{cite journal | last = Hay | first = A | coauthors = Gregory V, Douglas A, Lin Y | title = The evolution of human influenza viruses | journal = Philos Trans R Soc Lond B Biol Sci | volume = 356 | issue = 1416 | pages = 1861–70 | year = 2001 | month=Dec 29 | id = PMID 11779385}}</ref>
Wild aquatic birds are the natural hosts for a large variety of influenza A viruses. Occasionally viruses are transmitted to other species and may then cause devastating outbreaks in domestic poultry or give rise to human influenza [[pandemic]]s.<ref name=sobrino6>{{cite book |chapterurl=http://www.horizonpress.com/avir|author=Klenk et al|year=2008|chapter=Avian Influenza: Molecular Mechanisms of Pathogenesis and Host Range|title=Animal Viruses: Molecular Biology|publisher=Caister Academic Press|isbn = 978-1-904455-22-6}}</ref>
The type A viruses are the most virulent human pathogens among the three influenza types and cause the most severe disease. The Influenza A virus can be subdivided into different [[serovar|serotype]]s based on the [[antibody]] response to these viruses.<ref name=hay/> The serotypes that have been confirmed in humans, ordered by the number of known human pandemic deaths, are:

*[[H1N1]] caused "[[Spanish Flu]]."
*[[H2N2]] caused "Asian Flu."
*[[H3N2]] caused "Hong Kong Flu."
*[[H5N1]] is a [[pandemic]] threat in 2007–8 flu season.
*[[H7N7]] has unusual [[zoonotic]] potential.<ref>{{cite journal | last = Fouchier | first = R | coauthors = Schneeberger P, Rozendaal F, Broekman J, Kemink S, Munster V, Kuiken T, Rimmelzwaan G, Schutten M, Van Doornum G, Koch G, Bosman A, Koopmans M, Osterhaus A | title = Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. | url= http://www.pnas.org/cgi/content/full/101/5/1356 | journal = Proc Natl Acad Sci U S A | volume = 101 | issue = 5 | pages = 1356–61 | year = 2004 | id = PMID 14745020}}</ref>
*[[H1N2]] is endemic in humans and pigs.
*[[H9N2]], [[H7N2]], [[H7N3]], [[H10N7]].

Influenza B virus is almost exclusively a human pathogen and is less common than influenza A. The only other animal known to be susceptible to influenza B infection is the [[pinniped|seal]].<ref>{{cite journal | last = Osterhaus | first = A | coauthors = Rimmelzwaan G, Martina B, Bestebroer T, Fouchier R | title = Influenza B virus in seals. | journal = Science | volume = 288 | issue = 5468 | pages = 1051–3 | year = 2000 | id = PMID 10807575}}</ref> This type of influenza mutates at a rate 2–3 times lower than type A<ref>{{cite journal | last = Nobusawa | first = E | coauthors = Sato K | title = Comparison of the mutation rates of human influenza A and B viruses | journal = J Virol | volume = 80 | issue = 7 | pages = 3675–8 | year = 2006 | month=Apr | id = PMID 16537638}}</ref> and consequently is less genetically diverse, with only one influenza B serotype.<ref name=hay/> As a result of this lack of [[antigen]]ic diversity, a degree of [[immunity (medical)|immunity]] to influenza B is usually acquired at an early age. However, influenza B mutates enough that lasting immunity is not possible.<ref name=webster>{{cite journal | first = Webster | last = R | coauthors = Bean W, Gorman O, Chambers T, Kawaoka Y | title = Evolution and ecology of influenza A viruses. | url= http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=1579108 |journal = Microbiol Rev | volume = 56 | issue = 1 | pages = 152–79 | year = 1992 | id = PMID 1579108}}</ref> This reduced rate of antigenic change, combined with its limited host range (inhibiting cross species [[antigenic shift]]), ensures that pandemics of influenza B do not occur.<ref name=Zambon>{{cite journal | last = Zambon | first = M | title = Epidemiology and pathogenesis of influenza. | journal = J Antimicrob Chemother | volume = 44 Suppl B | issue = | pages = 3–9 | year = 1999 | month=Nov | id = PMID 10877456 | url=http://jac.oxfordjournals.org/cgi/reprint/44/suppl_2/3}}</ref>

The influenza C virus infects humans and pigs, and can cause severe illness and local epidemics.<ref name = "Matsuzaki">{{cite journal | last = Matsuzaki | first = Y | coauthors = Sugawara K, Mizuta K, Tsuchiya E, Muraki Y, Hongo S, Suzuki H, Nakamura K | title = Antigenic and genetic characterization of influenza C viruses which caused two outbreaks in Yamagata City, Japan, in 1996 and 1998 | url= http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=11825952 | journal = J Clin Microbiol | volume = 40 | issue = 2 | pages = 422–9 | year = 2002 | id = PMID 11825952}}</ref> However, influenza C is less common than the other types and usually seems to cause mild disease in children.<ref>{{cite journal | last = Matsuzaki | first = Y | coauthors = Katsushima N, Nagai Y, Shoji M, Itagaki T, Sakamoto M, Kitaoka S, Mizuta K, Nishimura H | title = Clinical features of influenza C virus infection in children. | journal = J Infect Dis | volume = 193 | issue = 9 | pages = 1229–35 | year = 2006 | month=May 1 | id = PMID 16586359}}</ref><ref name = "Katagiri">{{cite journal | last = Katagiri | first = S | coauthors = Ohizumi A, Homma M | title = An outbreak of type C influenza in a children's home. | journal = J Infect Dis | volume = 148 | issue = 1 | pages = 51–6 | year = 1983 | month=Jul | id = PMID 6309999}}</ref>

===Structure and properties===
The following applies for [[Influenzavirus A|Influenza A]] viruses, although other strains are very similar in structure:<ref>International Committee on Taxonomy of Viruses descriptions of: [http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/46000000.htm Orthomyxoviridae], [http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/46040000.htm Influenzavirus B] and [http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.046.0.02.htm Influenzavirus C]</ref>

The influenza A virus particle or ''virion'' is 80–120 nm in diameter and usually roughly spherical, although filamentous forms can occur.<ref>{{cite web |author= International Committee on Taxonomy of Viruses |title=The Universal Virus Database, version 4: Influenza A |url=http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.046.0.01.htm}}</ref> Unusually for a virus, the influenza A [[genome]] is not a single piece of [[nucleic acid]]; instead, it contains eight pieces of segmented [[negative-sense]] [[RNA]] (13.5 kilobases total), which encode 10 [[protein]]s (HA (hemagglutinin), NA (neuraminidase), NP (nucleoprotein), M1, M2, NS1, PA, PB1, PB1-F2, PB2).<ref name=Ghedin>{{cite journal | last = Ghedin | first = E | coauthors = Sengamalay N, Shumway M, Zaborsky J, Feldblyum T, Subbu V, Spiro D, Sitz J, Koo H, Bolotov P, Dernovoy D, Tatusova T, Bao Y, St George K, Taylor J, Lipman D, Fraser C, Taubenberger J, Salzberg S | title = Large-scale sequencing of human influenza reveals the dynamic nature of viral genome evolution. | journal = Nature | volume = 437 | issue = 7062 | pages = 1162–6 | year = 2005 | month=Oct 20 | id = PMID 16208317}}</ref> The best-characterised of these viral proteins are [[hemagglutinin]] and [[neuraminidase]], two large [[glycoprotein]]s found on the outside of the viral particles. Neuraminidase is an [[enzyme]] involved in the release of progeny virus from infected cells, by cleaving sugars that bind the mature viral particles. By contrast, hemagglutinin is a [[lectin]] that mediates binding of the virus to target cells and entry of the viral genome into the target cell.<ref>{{cite journal | last = Suzuki | first = Y | title = Sialobiology of influenza: molecular mechanism of host range variation of influenza viruses. | url= http://www.jstage.jst.go.jp/article/bpb/28/3/399/_pdf | journal = Biol Pharm Bull | volume = 28 | issue = 3 | pages = 399–408 | year = 2005 | id = PMID 15744059}}</ref> The hemagglutinin (HA or H) and neuraminidase (NA or N) proteins are targets for [[antiviral drugs]].<ref>{{cite journal | last = Wilson | first = J | coauthors = von Itzstein M | title = Recent strategies in the search for new anti-influenza therapies | journal = Curr Drug Targets | volume = 4 | issue = 5 | pages = 389–408 | year = 2003 | month=Jul | id = PMID 12816348}}</ref> These proteins are also recognised by [[antibody|antibodies]], i.e. they are [[antigen]]s.<ref name=Hilleman/> The responses of antibodies to these proteins are used to classify the different [[serovar|serotype]]s of influenza A viruses, hence the ''H'' and ''N'' in ''H5N1''.

===Infection and replication===
[[Image:Virus Replication.svg|thumb|400px|left|Host cell invasion and replication by the influenza virus. The steps in this process are discussed in the text.]]

Influenza viruses bind through [[hemagglutinin]] onto [[sialic acid]] sugars on the surfaces of [[epithelium|epithelial cells]]; typically in the nose, throat and [[lung]]s of mammals and [[intestine]]s of birds (Stage 1 in infection figure).<ref name=Wagner>{{cite journal | last = Wagner | first = R | coauthors = Matrosovich M, Klenk H | title = Functional balance between haemagglutinin and neuraminidase in influenza virus infections. | journal = Rev Med Virol | volume = 12 | issue = 3 | pages = 159–66 | year = 2002 | month=May–Jun| id = PMID 11987141}}</ref> The cell imports the virus by [[endocytosis]]. In the acidic [[endosome]], part of the haemagglutinin protein fuses the viral envelope with the vacuole's membrane, releasing the viral RNA (vRNA) molecules, accessory proteins and [[RNA replicase|RNA-dependent RNA transcriptase]] into the [[cytoplasm]] (Stage 2).<ref>{{cite journal | last = Lakadamyali | first = M | coauthors = Rust M, Babcock H, Zhuang X | title = Visualizing infection of individual influenza viruses. | journal = Proc Natl Acad Sci U S A | volume = 100 | issue = 16 | pages = 9280–5 | year = 2003 | month=Aug 5 | id = PMID 12883000}}</ref> These proteins and vRNA form a complex that is transported into the [[cell nucleus]], where the RNA-dependent RNA transcriptase begins transcribing complementary positive-sense vRNA (Steps 3a and b).<ref>{{cite journal | last = Cros | first = J | coauthors = Palese P | title = Trafficking of viral genomic RNA into and out of the nucleus: influenza, Thogoto and Borna disease viruses. | journal = Virus Res | volume = 95 | issue = 1–2 | pages = 3–12 | year = 2003 | month=Sep | id = PMID 12921991}}</ref> The vRNA is either exported into the cytoplasm and translated (step 4), or remains in the nucleus. Newly-synthesised viral proteins are either secreted through the [[Golgi apparatus]] onto the cell surface (in the case of neuraminidase and hemagglutinin, step 5b) or transported back into the nucleus to bind vRNA and form new viral genome particles (step 5a). Other viral proteins have multiple actions in the host cell, including degrading cellular [[mRNA]] and using the released [[nucleotide]]s for vRNA synthesis and also inhibiting [[translation (biology)|translation]] of host-cell mRNAs.<ref>{{cite journal | last = Kash | first = J | coauthors = Goodman A, Korth M, Katze M | title = Hijacking of the host-cell response and translational control during influenza virus infection. | journal = Virus Res | volume = 119 | issue = 1 | pages = 111–20 | year = 2006 | month=Jul | id = PMID 16630668}}</ref>

Negative-sense vRNAs that form the [[genome]]s of future viruses, RNA-dependent RNA transcriptase, and other viral proteins are assembled into a virion. Hemagglutinin and neuraminidase molecules cluster into a bulge in the cell membrane. The vRNA and viral core proteins leave the nucleus and enter this membrane protrusion (step 6). The mature virus buds off from the cell in a sphere of host phospholipid membrane, acquiring hemagglutinin and neuraminidase with this membrane coat (step 7).<ref>{{cite journal | last = Nayak | first = D | coauthors = Hui E, Barman S | title = Assembly and budding of influenza virus. | journal = Virus Res | volume = 106 | issue = 2 | pages = 147–65 | year = 2004 | month =Dec | id = PMID 15567494}}</ref> As before, the viruses adhere to the cell through hemagglutinin; the mature viruses detach once their [[neuraminidase]] has cleaved sialic acid residues from the host cell.<ref name=Wagner/> After the release of new influenza virus, the host cell dies.

Because of the absence of RNA proofreading enzymes, the RNA-dependent RNA transcriptase makes a single nucleotide insertion error roughly every 10 thousand nucleotides, which is the approximate length of the influenza vRNA. Hence, nearly every newly-manufactured influenza virus is a mutant.<ref>{{cite journal | last = Drake | first = J | title = Rates of spontaneous mutation among RNA viruses. | journal = Proc Natl Acad Sci USA | volume = 90 | issue = 9 | pages = 4171–5 | year = 1993 | month=May 1 | id = PMID 8387212}}</ref> The separation of the genome into eight separate segments of vRNA allows mixing or ''reassortment'' of vRNAs if more than one viral line has infected a single cell. The resulting rapid change in viral genetics produces [[antigenic shift]]s and allow the virus to infect new host species and quickly overcome protective immunity.<ref name=Hilleman/> This is important in the emergence of pandemics, as discussed in [[#Epidemiology|Epidemiology]].

==Diagnosis==
[[Image:Aerosol from Sneeze.jpg |thumb |right|250px|Influenza spreads by [[aerosol]]s created by coughs or sneezes.]]
In humans, influenza's effects are much more severe than those of the [[common cold]], and last longer. Recovery takes about one to two weeks. Influenza, however, can be deadly, especially for the weak, old or chronically ill.<ref name=Hilleman/>

===Symptoms===
Symptoms of influenza can start quite suddenly one to two days after infection. Usually the first symptoms are chills or a chilly sensation but fever is also common early in the infection, with body temperatures as high as 39 °C (approximately 103 °F). Many people are so ill that they are confined to bed for several days, with aches and pains throughout their bodies, which are worst in their backs and legs.<ref name=Merck />

Common symptoms of the flu such as fever, headaches, and fatigue come from the huge amounts of proinflammatory [[cytokine]]s and [[chemokine]]s (such as [[interferon]] or [[Tumor necrosis factor-alpha|tumor necrosis factor]]) produced from influenza-infected cells.<ref name=Eccles/><ref>{{cite journal | author = Schmitz N, Kurrer M, Bachmann M, Kopf M | title = Interleukin-1 is responsible for acute lung immunopathology but increases survival of respiratory influenza virus infection. | journal = J Virol | volume = 79 | issue = 10 | pages = 6441–8 | year = 2005 | id = PMID 15858027}}</ref> In contrast to the [[rhinovirus]] that causes the [[common cold]], influenza does cause tissue damage, so symptoms are not entirely due to the inflammatory response.<ref>{{cite journal | author = Winther B, Gwaltney J, Mygind N, Hendley J | title = Viral-induced rhinitis. | journal = Am J Rhinol | volume = 12 | issue = 1 | pages = 17–20 | year = | id = PMID 9513654}}</ref> Symptoms of influenza may include:

:* Body aches, especially joints and throat
:* [[Cough]]ing and [[sneeze|sneezing]]
:* Extreme coldness and [[fever]]
:* [[Fatigue (medical)|Fatigue]]
:* [[Headache]]
:* Irritated watering eyes
:* [[Nasal congestion]]
:* [[Nausea]] and [[vomiting]]
:* Reddened eyes, skin (especially face), mouth, throat and nose

It can be difficult to distinguish between the common cold and influenza in the early stages of these infections,<ref name=Eccles/> but usually the symptoms of the flu are more severe than their common-cold equivalents. Research on signs and symptoms of influenza found that the best findings for excluding the diagnosis of influenza were:<ref name="pmid15728170">{{cite journal | author = Call S, Vollenweider M, Hornung C, Simel D, McKinney W | title = Does this patient have influenza? | journal = JAMA | volume = 293 | issue = 8 | pages = 987-97 | year = 2005 | doi = 10.1001/jama.293.8.987 | id = PMID 15728170}}</ref>

{| class="wikitable" style="text-align:center"
|+ Highest [[sensitivity (tests)|sensitive]] individual findings for diagnosing influenza<ref name="pmid15728170"/>
! Finding: !! [[sensitivity (tests)|sensitivity]] !! [[specificity (tests)|specificity]]
|-
! Fever
| 86% || 25%
|-
! Cough
| 98% || 23%
|-
! Nasal congestion
| 70–90% || 20–40%
|-
|}
Notes to table:
* [[Sensitivity (tests)|Sensitivity]] is the proportion of people that tested positive of all the positive people tested.
* [[Specificity (tests)|Specificity]] is the proportion of people that tested negative of all the negative people tested.
* All three findings, especially fever, were less sensitive in patients over 60 years of age.

Since anti-viral drugs are effective in treating influenza if given early (see treatment section, below), it can be important to identify cases early. Of the symptoms listed above, the combinations of findings below can improve diagnostic accuracy.<ref name="pmid11088084">{{cite journal | author = Monto A, Gravenstein S, Elliott M, Colopy M, Schweinle J | title = Clinical signs and symptoms predicting influenza infection. | journal = Arch Intern Med | volume = 160 | issue = 21 | pages = 3243–7 | year = 2000 | url http://archinte.ama-assn.org/cgi/content/abstract/160/21/3243 | id = PMID 11088084}}</ref> Unfortunately, even combinations of findings are imperfect. However, [[Bayes Theorem]] can combine pretest probability with clinical findings to adequately diagnose or exclude influenza in some patients. The pretest probability has a strong seasonal variation; the current prevalence of influenza among patients in the United States receiving sentinel testing is available at the [[Centers for Disease Control and Prevention|CDC]].<ref>Centers for Disease Control and Prevention. [http://www.cdc.gov/flu/weekly/ Weekly Report: Influenza Summary Update.] Accessed January 1, 2007.</ref> Using the CDC data, the following table shows how the likelihood of influenza varies with prevalence:
:

<table border="1" cellpadding="5" class="wikitable">
<caption>Combinations of findings for diagnosing influenza<ref name="pmid15728170"/></caption>
<tr>
<th rowspan="2">Combinations of findings </th>
<th rowspan="2">Sensitivity</th>
<th rowspan="2">Specificity</th>
<th colspan="2">As reported in study<ref name="pmid15728170">.</ref> and projected during local outbreaks 
(prevalence= 66%)
</th>
<th colspan="2">Projected during influenza season 
(prevalence=25%)</th>
<th colspan="2">Projected in off-season 
(prevalence=2%) </th>
</tr>
<tr>
<th>PPV</th>
<th>NPV</th>
<th>PPV</th>
<th>NPV</th>
<th>PPV</th>
<th>NPV</th>
</tr>
<tr>
<td>Fever and cough</td>
<td align="center">64%</td>
<td align="center">67%</td>
<td align="center">79%</td>
<td align="center">49%</td>
<td align="center">39%</td>
<td align="center">15%</td>
<td align="center">4%</td>
<td align="center">1%</td>
</tr>
<tr>
<td>Fever and cough and sore throat</td>
<td align="center">56</td>
<td align="center">71</td>
<td align="center">79</td>
<td align="center">45</td>
<td align="center">39</td>
<td align="center">17</td>
<td align="center">4</td>
<td align="center">2</td>
</tr>
<tr>
<td>Fever and cough and nasal congestion</td>
<td align="center">59</td>
<td align="center">74</td>
<td align="center">81</td>
<td align="center">48</td>
<td align="center">43</td>
<td align="center">16</td>
<td align="center">4</td>
<td align="center">1</td>
</tr>
</table>

Two [[decision analysis]] studies<ref name="pmif12361816">{{cite journal | author = Smith K, Roberts M | title = Cost-effectiveness of newer treatment strategies for influenza. | journal = Am J Med | volume = 113 | issue = 4 | pages = 300-7 | year = 2002 | doi = 10.1016/S0002-9343(02)01222-6 | id = PMID 12361816}}</ref><ref name="pimd12965940">{{cite journal | author = Rothberg M, Bellantonio S, Rose D | title = Management of influenza in adults older than 65 years of age: cost-effectiveness of rapid testing and antiviral therapy. | journal = Ann Intern Med | volume = 139 | issue = 5 Pt 1 | pages = 321-9 | year = 2003 | url = http://www.annals.org/cgi/content/abstract/139/5_Part_1/321 | id = PMID 12965940}}</ref> suggest that ''during local outbreaks'' of influenza, the prevalence will be over 70%<ref name="pimd12965940"/> and thus patients with any of the above combinations of symptoms may be treated with neuramidase inhibitors without testing. Even in the absence of a local outbreak, treatment may be justified in the elderly during the influenza season as long as the prevalence is over 15%.<ref name="pimd12965940"/>

Most people who get influenza will recover in one to two weeks, but others will develop life-threatening complications (such as [[pneumonia]]). According to the [[World Health Organization]]: "Every winter, tens of millions of people get the flu. Most are home, sick and miserable, for about a week. Some—mostly the elderly—die. We know the world-wide death toll exceeds a few hundred thousand people a year, but even in developed countries the numbers are uncertain, because medical authorities don't usually verify who actually died of influenza and who died of a flu-like illness."<ref>Peter M. Sandman and Jody Lanard [http://www.paho.org/English/DD/PIN/Number22_article1a.htm "Bird Flu: Communicating the Risk"] 2005 ''Perspectives in Health Magazine'' Vol. 10 issue 2.</ref> Even healthy people can be affected, and serious problems from influenza can happen at any age. People over 50 years old, very young children and people of any age with chronic medical conditions, are more likely to get complications from influenza: such as pneumonia, [[bronchitis]], [[sinus]], and [[ear infection]]s.<ref name=CDCkeyfacts> [http://www.cdc.gov/flu/protect/keyfacts.htm Key Facts about Influenza (Flu) Vaccine] CDC publication. Published October 17, 2006. Accessed 18 Oct 2006.</ref>

The flu can worsen chronic health problems. People with emphysema, chronic bronchitis or asthma may experience shortness of breath while they have the flu, and influenza may cause worsening of [[coronary heart disease]] or [[congestive heart failure]].<ref>Angelo SJ, Marshall PS, Chrissoheris MP, Chaves AM. "Clinical characteristics associated with poor outcome in patients acutely infected with Influenza A." ''Conn Med.'' 2004 Apr;68(4):199–205. PMID 15095826</ref> [[Tobacco smoking|Smoking]] is another [[risk factor]] associated with more serious disease and increased mortality from influenza.<ref>{{cite journal | author = Murin S, Bilello K | title = Respiratory tract infections: another reason not to smoke. | journal = Cleve Clin J Med | volume = 72 | issue = 10 | pages = 916-20 | year = 2005 | id = PMID 16231688}}</ref>

===Laboratory tests===
The available laboratory tests for influenza continue to improve. The United States [[Centers for Disease Control and Prevention]] (CDC) maintains an up-to-date summary of available laboratory tests.<ref>Centers for Disease Control and Prevention. [http://www.cdc.gov/flu/professionals/labdiagnosis.htm Lab Diagnosis of Influenza.] Accessed on January 1, 2007</ref> According to the CDC, rapid diagnostic tests have a sensitivity of 70–75% and specificity of 90–95% when compared with viral culture. These tests may be especially useful during the influenza season (prevalence=25%) but in the absence of a local outbreak, or peri-influenza season (prevalence=10%<ref name="pimd12965940"/>).

==Epidemiology==

===Seasonal variations===
{{further|[[Flu season]]}}

[[Image:H5n1 spread with regression.png|thumb|right|300px|Cumulative Confirmed Human Cases of H5N1.<ref name=WHOH5N1data>[http://www.who.int/csr/disease/avian_influenza/country/en/ WHO Confirmed Human Cases of H5N1] Data published by WHO Epidemic and Pandemic Alert and Response (EPR). Accessed 24 Oct. 2006</ref> The regression curve for deaths is shown extended through the end of November 2006.]]

Influenza reaches peak prevalence in winter, and because the Northern and Southern Hemisphere have winter at different times of the year, there are actually two different flu seasons each year. This is why the [[World Health Organization]] (assisted by the [[National Influenza Centers]]) makes recommendations for two different vaccine formulations every year; one for the Northern, and one for the Southern Hemisphere.<ref name= WHOrecommendation>[http://www.who.int/csr/disease/influenza/2007northreport.pdf Recommended composition of influenza virus vaccines for use in the 2006–2007 influenza season] WHO report 2006-02-14. Accessed [[19 October]] [[2006]].</ref>

It remains unclear why outbreaks of the flu occur seasonally rather than uniformly throughout the year. One possible explanation is that, because people are indoors more often during the winter, they are in close contact more often, and this promotes transmission from person to person. Another is that cold temperatures lead to drier air, which may dehydrate mucus, preventing the body from effectively expelling virus particles. The virus may also survive longer on exposed surfaces (doorknobs, countertops, etc.) in colder temperatures. Increased travel and visitation due to the Northern Hemisphere winter holiday season may also play a role.<ref name = "NPR2003-12-17">[http://www.npr.org/templates/story/story.php?storyId=1551913 Weather and the Flu Season] NPR Day to Day, [[December 17]] [[2003]]. Accessed, [[19 October]] [[2006]]</ref> However, seasonal changes in infection rates are also seen in tropical regions and these peaks of infection are seen mainly during the rainy season.<ref>Shek LP, Lee BW. "Epidemiology and seasonality of respiratory tract virus infections in the tropics." ''Paediatr Respir Rev.'' 2003 Jun;4(2):105–11. PMID 12758047</ref> Seasonal changes in contact rates from school-terms, which are a major factor in other childhood diseases such as [[measles]] and [[pertussis]], may also play a role in flu. A combination of these small seasonal effects may be amplified by "dynamical resonance" with the endogenous disease cycles.<ref>Dushoff J, Plotkin JB, Levin SA, Earn DJ. "Dynamical resonance can account for seasonality of influenza epidemics." ''Proc Natl Acad Sci U S A.'' [[30 November]][[2004]];101(48):16915–6. PMID 15557003</ref> [[H5N1]] exhibits seasonality in both humans and birds.<ref name=WHOH5N1data/>

An alternative hypothesis to explain seasonality in influenza infections is an effect of [[vitamin D]] levels on immunity to the virus.<ref>{{cite journal | last = Cannell | first = J | coauthors = Vieth R, Umhau J, Holick M, Grant W, Madronich S, Garland C, Giovannucci E | title = Epidemic influenza and vitamin D | journal = Epidemiol Infect | volume = 134 | issue = 6 | pages = 1129–40 | year = 2006 | id = PMID 16959053}}</ref> This idea was first proposed by Robert Edgar Hope-Simpson in 1965.<ref>{{cite journal | last = HOPE-SIMPSON | first = R | title = The nature of herpes zoster: a long-term study and a new hypothesis | journal = Proc R Soc Med | volume = 58 | issue = | pages = 9–20 | year = | id = PMID 14267505}}</ref> He proposed that the cause of influenza epidemics during winter may be connected to seasonal fluctuations of vitamin D, which is produced in the skin under the influence of solar (or artificial) [[ultraviolet|UV radiation]]. This could explain why influenza occurs mostly in winter and during the tropical rainy season, when people stay indoors, away from the sun, and their vitamin D levels fall. Furthermore, some studies have suggested that administering [[cod liver oil]], which contains large amounts of vitamin D, can reduce the incidence of respiratory tract infections.<ref name = "Linday2004">{{cite journal | last = Linday | first = L | coauthors = Shindledecker R, Tapia-Mendoza J, Dolitsky J | title = Effect of daily cod liver oil and a multivitamin-mineral supplement with selenium on upper respiratory tract pediatric visits by young, inner-city, Latino children: randomized pediatric sites | journal = Ann Otol Rhinol Laryngol | volume = 113 | issue = 11 | pages = 891–901 | year = 2004 | id = PMID 15562899}}</ref>

===Epidemic and pandemic spread===
{{further|[[Flu pandemic]]}}

[[Image:Antigenic drift versus shift.png|thumb|right|400px|[[Antigenic drift]] creates influenza viruses with slightly-modified antigens, while [[antigenic shift]] generates viruses with entirely novel antigens.]]

[[Image:Influenza geneticshift.jpg|thumb|right|300px|How antigenic shift, or reassortment, can result in novel and highly pathogenic strains of human influenza]]

As influenza is caused by a variety of species and strains of [[virus]]es, in any given year some strains can die out while others create [[epidemic]]s while yet another strain can cause a [[pandemic]]. Typically, in a year's normal two [[flu season]]s (one per hemisphere) there are between three and five million cases of severe illness and up to 500,000 deaths worldwide, which by some definitions is a yearly influenza epidemic.<ref>[http://www.who.int/mediacentre/factsheets/fs211/en/ Influenza] WHO Fact sheet N°211 revised March 2003. Accessed [[22 October]] [[2006]]</ref> Although the incidence of influenza can vary widely between years, approximately 36,000 deaths and more than 200,000 hospitalizations are directly associated with influenza every year in America.<ref>{{cite journal | last = Thompson | first = W | coauthors = Shay D, Weintraub E, Brammer L, Cox N, Anderson L, Fukuda K | title = Mortality associated with influenza and respiratory syncytial virus in the United States | url=http://jama.ama-assn.org/cgi/content/full/289/2/179 | journal = JAMA | volume = 289 | issue = 2 | pages = 179–86 | year = 2003 | id = PMID 12517228}}</ref><ref>{{cite journal | last = Thompson | first = W | coauthors = Shay D, Weintraub E, Brammer L, Bridges C, Cox N, Fukuda K | title = Influenza-associated hospitalizations in the United States | url= http://jama.ama-assn.org/cgi/content/full/292/11/1333 | journal = JAMA | volume = 292 | issue = 11 | pages = 1333–40 | year = 2004 | id = PMID 15367555}}</ref><ref>[http://www.niaid.nih.gov/factsheets/flu.htm Flu factsheet] National Institute of Allergy and Infectious Diseases Accessed 22 Dec 2006</ref> Every ten to twenty years a pandemic occurs, which infects a large proportion of the world's population, and can kill tens of millions of people (see history section).

New influenza viruses are constantly being produced by [[mutation]] or by [[reassortment]].<ref name= hay/> Mutations can cause small changes in the hemagglutinin and neuraminidase [[antigen]]s on the surface of the virus. This is called [[antigenic drift]], which creates an increasing variety of strains over time until one of the variants eventually achieves higher [[fitness (biology)|fitness]], becomes dominant, and rapidly sweeps through the human population – often causing an epidemic.<ref>{{cite journal | author = | title = Long intervals of stasis punctuated by bursts of positive selection in the seasonal evolution of influenza A virus | journal = Biol Direct | volume = 1 | issue = 1 | pages = 34 | year = 2006 | id = PMID 17067369}}</ref> In contrast, when influenza viruses re-assort, they may acquire new antigens — for example by reassortment between avian strains and human strains; this is called antigenic shift. If a human influenza virus is produced with entirely novel antigens, everybody will be susceptible and the novel influenza will spread uncontrollably, causing a pandemic.<ref>{{cite journal | last = Parrish | first = C | coauthors = Kawaoka Y | title = The origins of new pandemic viruses: the acquisition of new host ranges by canine parvovirus and influenza A viruses | journal = Annual Rev Microbiol | volume = 59 | issue = | pages = 553–86 | year = | id = PMID 16153179}}</ref> In contrast to this model of pandemics based on antigenic drift and shift, an alternative approach has been proposed where the periodic pandemics are produced by interactions of a fixed set of viral strains with a human population with a constantly-changing set of immunities to different viral strains.<ref>{{cite journal |author=Recker M, Pybus OG, Nee S, Gupta S |title=The generation of influenza outbreaks by a network of host immune responses against a limited set of antigenic types |url=http://www.pnas.org/cgi/content/full/104/18/7711 |journal=Proc Natl Acad Sci U S A. |volume=104 |issue=18 |pages=7711–7716 |year=2007 |pmid=17460037}}</ref>

==Prevention==
===Vaccination and infection control===
{{further|[[Flu vaccine]]}}
[[Image:Vaccination.jpg|thumb|240px|left|U.S. Navy personnel receiving influenza vaccination]]

Vaccination against influenza with a [[flu vaccine]] is strongly recommended for high-risk groups, such as children and the elderly.

Flu vaccines can be produced in several ways; the most common method is to grow the virus in fertilised hen eggs. After purification, the virus is inactivated (for example, by treatment with detergent) to produce an inactivated-virus vaccine. Alternatively, the virus can be grown in eggs until it loses [[virulence]] and the avirulent virus given as a live vaccine.<ref name=Hilleman/> The effectiveness of these flu vaccines is variable. Due to the high mutation rate of the virus, a particular flu vaccine usually confers protection for no more than a few years. Every year, the [[World Health Organization]] predicts which strains of the virus are most likely to be circulating in the next year, allowing [[pharmaceutical company|pharmaceutical companies]] to develop vaccines that will provide the best immunity against these strains.<ref name= WHOrecommendation/> Vaccines have also been developed to protect poultry from [[avian influenza]]. These vaccines can be effective against multiple strains and are used either as part of a preventative strategy, or combined with culling in attempts to eradicate outbreaks.<ref>{{cite journal | last = Capua | first = I | coauthors = Alexander D | title = The challenge of avian influenza to the veterinary community. | url= http://taylorandfrancis.metapress.com/media/gmuaahtvwk6vweuhugdh/contributions/t/2/n/2/t2n2431j4u176p7g.pdf | journal = Avian Pathol | volume = 35 | issue = 3 | pages = 189–205 | year = 2006 | id = PMID 16753610}}</ref>

It is possible to get vaccinated and still get influenza. The vaccine is reformulated each season for a few specific flu strains, but cannot possibly include all the strains actively infecting people in the world for that season. It takes about six months for the manufacturers to formulate and produce the millions of doses required to deal with the seasonal epidemics; occasionally, a new or overlooked strain becomes prominent during that time and infects people although they have been vaccinated (as by the [[Fujian flu|H3N2 Fujian flu]] in the 2003–2004 flu season).<ref>{{cite journal | last = Holmes | first = E | coauthors = Ghedin E, Miller N, Taylor J, Bao Y, St George K, Grenfell B, Salzberg S, Fraser C, Lipman D, Taubenberger J | title = Whole-genome analysis of human influenza A virus reveals multiple persistent lineages and reassortment among recent H3N2 viruses | journal = PLoS Biol | volume = 3 | issue = 9 | pages = e300 | year = 2005 | id = PMID 16026181}}</ref> It is also possible to get infected just before vaccination and get sick with the very strain that the vaccine is supposed to prevent, as the vaccine takes about two weeks to become effective.<ref name=CDCkeyfacts/>

The 2006–2007 season is the first in which the CDC has recommended that children younger than 59 months receive the annual flu vaccine.<ref name=cdcreport> [http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5510a1.htm Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP)] CDC report (MMWR 2006 Jul 28;55(RR10):1–42) accessed 19 Oct 2006.</ref> Vaccines can cause the [[immune system]] to react as if the body were actually being infected, and general infection symptoms (many cold and flu symptoms are just general infection symptoms) can appear, though these symptoms are usually not as severe or long-lasting as influenza. The most dangerous side-effect is a severe [[allergy|allergic reaction]] to either the virus material itself, or residues from the hen eggs used to grow the influenza; however, these reactions are extremely rare.<ref>[http://www.cdc.gov/flu/about/qa/flushot.htm Questions & Answers: Flu Shot] CDC publication updated Jul 24, 2006. Accessed 19 Oct 06.</ref>

[[Influenza pandemic#Personal health and hygiene|Good personal health and hygiene habits]] are reasonably effective in avoiding and minimizing influenza. People who contract influenza are most infective between the second and third days after infection and infectivity lasts for around 10 days.<ref name=Carrat>{{cite journal |author=Carrat F, Luong J, Lao H, Sallé A, Lajaunie C, Wackernagel H |title=A 'small-world-like' model for comparing interventions aimed at preventing and controlling influenza pandemics |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=17059593 |journal=BMC Med |volume=4 |issue= |pages=26 |year= |pmid=17059593}}</ref> Children are notably more infectious than adults, and shed virus from just before they develop symptoms until 2 weeks after infection.<ref name=Carrat/><ref>{{cite journal |author=Mitamura K, Sugaya N |title=[Diagnosis and Treatment of influenza—clinical investigation on viral shedding in children with influenza] |journal=Uirusu |volume=56 |issue=1 |pages=109-16 |year=2006 |pmid=17038819}}</ref>

Since influenza spreads through [[particulate|aerosols]] and contact with contaminated surfaces, it is important to persuade people to cover their mouths while sneezing and to wash their hands regularly.<ref name=cdcreport/> Surface sanitizing is recommended in areas where influenza may be present on surfaces.<ref>{{cite journal |author=Hota B |title=Contamination, disinfection, and cross-colonization: are hospital surfaces reservoirs for nosocomial infection? |journal=Clin Infect Dis |volume=39 |issue=8 |pages=1182–9 |year=2004 |id=PMID 15486843}}</ref> [[Alcohol]] is an effective sanitizer against influenza viruses, while [[quaternary ammonium]] compounds can be used with alcohol, to increase the duration of the sanitizing action.<ref name=McDonnell>{{cite journal |author=McDonnell G, Russell A |title=Antiseptics and disinfectants: activity, action, and resistance |url=http://cmr.asm.org/cgi/content/full/12/1/147?view=long&pmid=9880479 |journal=Clin Microbiol Rev |volume=12 |issue=1 |pages=147-79 |year=1999 |id=PMID 9880479}}</ref> In hospitals, [[quaternary ammonium]] compounds and halogen-releasing agents such as [[sodium hypochlorite]] are commonly used to sanitize rooms or equipment that have been occupied by patients with influenza symptoms.<ref name=McDonnell/> During past pandemics, closing schools, churches and theaters slowed the spread of the virus but did not have a large effect on the overall death rate.<ref>{{cite journal |author=Hatchett RJ, Mecher CE, Lipsitch M |title=Public health interventions and epidemic intensity during the 1918 influenza pandemic |url=http://www.pnas.org/cgi/content/full/104/18/7582 |journal=Proc Natl Acad Sci U S A. |volume=104 |issue=18 |pages=7582–7587 |year=2007 |pmid=17416679}}</ref><ref>{{cite journal |author=Bootsma MC, Ferguson NM |title=The effect of public health measures on the 1918 influenza pandemic in U.S. cities |url=http://www.pnas.org/cgi/content/full/104/18/7588 |journal=Proc Natl Acad Sci U S A. |volume=104 |issue=18 |pages=7588–7593 |year=2007 |pmid=17416677}}</ref>

==Treatment==
{{further|[[Influenza treatment]]}}

People with the flu are advised to get plenty of rest, drink a lot of liquids, avoid using [[alcoholic beverage|alcohol]] and [[tobacco smoking|tobacco]] and, if necessary, take medications such as [[paracetamol]] (acetaminophen) to relieve the fever and muscle aches associated with the flu. Children and teenagers with flu symptoms (particularly fever) should avoid taking [[aspirin]] during an influenza infection (especially [[Influenzavirus B|influenza type B]]) because doing so can lead to [[Reye's syndrome]], a rare but potentially fatal disease of the [[liver]].<ref>{{cite journal | last = Glasgow | first = J | coauthors = Middleton B | title = Reye syndrome — insights on causation and prognosis | url=http://adc.bmjjournals.com/cgi/content/full/85/5/351 | journal = Arch Dis Child | volume = 85 | issue = 5 | pages = 351–3 | year = 2001 | id = PMID 11668090}}</ref> Since influenza is caused by a virus, [[antibiotic]]s have no effect on the infection; unless prescribed for [[secondary infection]]s such as [[bacterial pneumonia]], they may lead to resistant bacteria. Antiviral medication is sometimes effective, but viruses can develop resistance to the standard antiviral drugs.

The two classes of anti-virals are neuraminidase inhibitors and M2 inhibitors ([[adamantane]] derivatives). Neuraminidase inhibitors are currently preferred for flu virus infections. The CDC recommended against using M2 inhibitors during the 2005–06 influenza season.<ref>Centers for Disease Control and Prevention. [http://www.cdc.gov/flu/han011406.htm CDC Recommends against the Use of Amantadine and Rimantadine for the Treatment or Prophylaxis of Influenza in the United States during the 2005–06 Influenza Season.] [[January 14]], [[2006]]. Retrieved on [[2007-01-01]]</ref>

===Neuraminidase inhibitors===
Antiviral drugs such as [[oseltamivir]] (trade name Tamiflu) and [[zanamivir]] (trade name Relenza) are [[neuraminidase inhibitor]]s that are designed to halt the spread of the virus in the body.<ref name= Neuraminidase_inhibitors>{{cite journal | last = Moscona | first = A | title = Neuraminidase inhibitors for influenza | url=http://content.nejm.org/cgi/content/full/353/13/1363 | journal = N Engl J Med | volume = 353 | issue = 13 | pages = 1363–73 | year = 2005 | id = PMID 16192481}}</ref> These drugs are often effective against both influenza A and B.<ref name=Stephenson/> The [[Cochrane Collaboration]] reviewed these drugs and concluded that they reduce symptoms and complications.<ref name="pmid16855962">{{cite journal | last = Jefferson | first = T | coauthors = Demicheli V, Di Pietrantonj C, Jones M, Rivetti D | title = Neuraminidase inhibitors for preventing and treating influenza in healthy adults | journal = Cochrane Database Syst Rev | volume = 3 | issue = | pages = CD001265 | year = | doi = 10.1002/14651858.CD001265.pub2 | id = PMID 16855962}}</ref> Different strains of influenza virus have differing degrees of resistance against these antivirals and it is impossible to predict what degree of resistance a future pandemic strain might have.<ref> {{cite journal | last = Webster | first = Robert G. | title = H5N1 Influenza — Continuing Evolution and Spread | url=http://content.nejm.org/cgi/content/full/355/21/2174 | journal = N Engl J Med | volume = 355 | issue = 21 | pages = 2174–77 | year = 2006 | id = PMID 16192481}}</ref>

===M2 inhibitors (adamantanes) ===
The [[antiviral drug]]s [[amantadine]] and [[rimantadine]] are designed to block a viral [[ion channel]] and prevent the virus from infecting cells. These drugs are sometimes effective against influenza A if given early in the infection, but are always ineffective against influenza B.<ref name= Stephenson>{{cite journal | last = Stephenson | first = I | coauthors = Nicholson K | title = Chemotherapeutic control of influenza | url=http://jac.oxfordjournals.org/cgi/content/full/44/1/6 | journal = J Antimicrob Chemother | volume = 44 | issue = 1 | pages = 6–10 | year = 1999 | id = PMID 10459804}}</ref> Measured resistance to amantadine and rimantadine in American isolates of [[H3N2]] has increased to 91% in 2005.<ref>{{cite journal | author = | title = High levels of adamantane resistance among influenza A (H3N2) viruses and interim guidelines for use of antiviral agents — United States, 2005–06 influenza season | url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5502a7.htm | journal = MMWR Morb Mortal Wkly Rep | volume = 55 | issue = 2 | pages = 44–6 | year = 2006 | id = PMID 16424859}}</ref>

==Research==
{{further|[[Influenza research]]}}
[[Image:Influenza research.jpg|thumb|220px|right|CDC scientist working on influenza under high bio-safety conditions]]

Research on influenza includes studies on [[molecular virology]], how the virus produces disease ([[pathogenesis]]), host [[immune response]]s, [[genomics|viral genomics]], and how the virus spreads ([[epidemiology]]). These studies help in developing influenza countermeasures; for example, a better understanding of the body's immune response helps [[vaccine]] development, and a detailed picture of how influenza invades cells aids the development of antiviral drugs. One important basic research program is the [[Influenza Genome Sequencing Project]], which is creating a library of influenza sequences; this library should help clarify which factors make one strain more lethal than another, which genes most affect [[immunogenicity]], and how the virus [[evolution|evolves]] over time.<ref> [http://msc.tigr.org/infl_a_virus/index.shtml Influenza A Virus Genome Project] at The Institute of Genomic Research. Accessed 19 Oct 06</ref>

Research into new vaccines is particularly important: as current vaccines are slow and expensive to produce and must be reformulated every year. The sequencing of the influenza genome and [[recombinant DNA]] technology may accelerate the generation of new vaccine strains by allowing scientists to substitute new antigens into a previously-developed vaccine strain.<ref>{{cite journal | author = Subbarao K, Katz J | title = Influenza vaccines generated by reverse genetics. | journal = Curr Top Microbiol Immunol | volume = 283 | issue = | pages = 313-42 | year = | id = PMID 15298174}}</ref> New technologies are also being developed to grow virus in [[cell culture]]; which promises higher yields, less cost, better quality and surge capacity.<ref>{{cite journal | author = Bardiya N, Bae J | title = Influenza vaccines: recent advances in production technologies. | url=http://www.springerlink.com/content/jdt26gc39v4bwk9q/ | journal = Appl Microbiol Biotechnol | volume = 67 | issue = 3 | pages = 299–305 | year = 2005 | id = PMID 15660212}}</ref> The U.S. government has purchased from [[Sanofi Pasteur]] and [[Chiron Corporation]] several million doses of vaccine meant to be used in case of an [[influenza pandemic]] of [[H5N1]] avian influenza and is conducting clinical trials with these vaccines.<ref> [http://www.nytimes.com/2006/03/30/health/30vaccine.html?_r=1&oref=slogin New York Times article ""Doubt Cast on Stockpile of a Vaccine for Bird Flu""] by Denise Grady. Published: March 30, 2006. Accessed 19 Oct 06</ref> The UK government is also stockpiling millions of antiviral drugs(tamiflu, oseltamivir, zanimivir) to give to its citizens in the event of an outbreak, the UK [[Health Protection Agency]] has also gathered a limited amount of HPAI H5N1 vaccines for experimental purposes.

==Infection in other animals==
{{H5N1}}{{further|[[Influenzavirus A]], [[H5N1]] and [[Transmission and infection of H5N1]]}}
Influenza infects many animal species and transfer of viral strains between species can occur. Birds are thought to be the main [[host (biology)|animal reservoir]]s of influenza viruses.<ref>{{cite journal | author = Gorman O, Bean W, Kawaoka Y, Webster R | title = Evolution of the nucleoprotein gene of influenza A virus. | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=2319644 | journal = J Virol | volume = 64 | issue = 4 | pages = 1487–97 | year = 1990 | id = PMID 2319644}}</ref> Sixteen forms of [[hemagglutinin]] and 9 forms of [[neuraminidase]] have been identified. All known subtypes (HxNy) are found in birds but many subtypes are endemic in humans, dogs, horses, and pigs; populations of camels, ferrets, cats, seals, mink, and whales also show evidence of prior infection or exposure to influenza.<ref name=webster/> Variants of flu virus are sometimes named according to the species the strain is endemic in or adapted to. The main variants named using this convention are: Bird flu, [[Human flu|Human Flu]], Swine Flu, Horse Flu and Dog Flu. (Cat flu generally refers to Feline viral rhinotracheitis or Feline calicivirus and not infection from an influenza virus.) In pigs, horses and dogs, influenza symptoms are similar to humans, with cough, fever and loss of appetite.<ref name=webster/> The frequency of animal diseases are not as well-studied as human infection, but an outbreak of influenza in harbour seals caused approximately 500 seal deaths off the New England coast in 1979–1980.<ref>{{cite journal | author = Hinshaw V, Bean W, Webster R, Rehg J, Fiorelli P, Early G, Geraci J, St Aubin D | title = Are seals frequently infected with avian influenza viruses? | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=6471169 | journal = J Virol | volume = 51 | issue = 3 | pages = 863-5 | year = 1984 | id = PMID 6471169}}</ref> On the other hand, outbreaks in pigs are common and do not cause severe mortality.<ref name=webster/>

Flu symptoms in birds are variable and can be unspecific.<ref>{{cite journal | author = Elbers A, Koch G, Bouma A | title = Performance of clinical signs in poultry for the detection of outbreaks during the avian influenza A (H7N7) epidemic in The Netherlands in 2003. | journal = Avian Pathol | volume = 34 | issue = 3 | pages = 181-7 | year = 2005 | id = PMID 16191700}}</ref> The symptoms following infection with low-pathogenicity avian influenza may be as mild as ruffled feathers, a small reduction in egg production, or weight loss combined with minor respiratory disease.<ref>Capua I, Mutinelli F. "Low pathogenicity (LPAI) and highly pathogenic (HPAI) avian inﬂuenza in turkeys and chicken." In: Capua I, Mutinelli F. (eds.), A Colour Atlas and Text on Avian Inﬂuenza, Papi Editore, Bologna, 2001, pp. 13–20</ref> Since these mild symptoms can make diagnosis in the field difficult, tracking the spread of avian influenza requires laboratory testing of samples from infected birds. Some strains such as Asian [[H9N2]] are highly virulent to poultry, and may cause more extreme symptoms and significant mortality.<ref>{{cite journal | author = Bano S, Naeem K, Malik S | title = Evaluation of pathogenic potential of avian influenza virus serotype H9N2 in chickens. | journal = Avian Dis | volume = 47 | issue = 3 Suppl | pages = 817-22 | year = 2003 | id = PMID 14575070}}</ref> In its most highly pathogenic form, influenza in chickens and turkeys produces a sudden appearance of severe symptoms and almost 100% mortality within two days.<ref>{{cite journal | author = Swayne D, Suarez D | title = Highly pathogenic avian influenza. | journal = Rev Sci Tech | volume = 19 | issue = 2 | pages = 463-82 | year = 2000 | id = PMID 10935274}}</ref> As the virus spreads rapidly in the crowded conditions seen in the intensive farming of chickens and turkeys, these outbreaks can cause large economic losses to poultry farmers.

An avian-adapted, highly pathogenic strain of H5N1 (called HPAI A(H5N1), for "highly pathogenic avian influenza virus of type A of subtype H5N1") causes [[transmission and infection of H5N1|H5N1 flu]], commonly known as "avian influenza" or simply "bird flu", and is [[endemic (epidemiology)|endemic]] in many bird populations, especially in Southeast Asia. This Asian lineage strain of HPAI A(H5N1) is [[global spread of H5N1|spreading globally]]. It is [[epizootic]] (an epidemic in non-humans) and panzootic (a disease affecting animals of many species, especially over a wide area) killing tens of millions of birds and spurring the culling of hundreds of millions of other birds in an attempt to control its spread. Most references in the media to "bird flu" and most references to H5N1 are about this specific strain.<ref>{{cite journal | author = Li K, Guan Y, Wang J, Smith G, Xu K, Duan L, Rahardjo A, Puthavathana P, Buranathai C, Nguyen T, Estoepangestie A, Chaisingh A, Auewarakul P, Long H, Hanh N, Webby R, Poon L, Chen H, Shortridge K, Yuen K, Webster R, Peiris J | title = Genesis of a highly pathogenic and potentially pandemic H5N1 influenza virus in eastern Asia. | journal = Nature | volume = 430 | issue = 6996 | pages = 209-13 | year = 2004 | id = PMID 15241415}}</ref><ref>Li KS, Guan Y, Wang J, Smith GJ, Xu KM, Duan L, Rahardjo AP, Puthavathana P, Buranathai C, Nguyen TD, Estoepangestie AT, Chaisingh A, Auewarakul P, Long HT, Hanh NT, Webby RJ, Poon LL, Chen H, Shortridge KF, Yuen KY, Webster RG, Peiris JS. [http://darwin.nap.edu/books/0309095042/html/116.html "The Threat of Pandemic Influenza: Are We Ready?" Workshop Summary] The National Academies Press (2005) "Today's Pandemic Threat: Genesis of a Highly Pathogenic and Potentially Pandemic H5N1 Influenza Virus in Eastern Asia", pages 116–130</ref>

At present, HPAI A(H5N1) is an avian disease and there is no evidence suggesting efficient human-to-human transmission of HPAI A(H5N1). In almost all cases, those infected have had extensive physical contact with infected birds.<ref>{{cite journal | author = Liu J | title = Avian influenza—a pandemic waiting to happen? | url=http://jmii.org/content/pdf/v39n1p4.pdf | journal = J Microbiol Immunol Infect | volume = 39 | issue = 1 | pages = 4–10 | year = 2006 | id = PMID 16440117}}</ref> In the future, H5N1 may mutate or reassort into a strain capable of efficient human-to-human transmission. Due to its high lethality and [[virulence]], its [[endemic (epidemiology)|endemic]] presence, and its large and increasing biological host reservoir, the H5N1 virus is the world's pandemic threat in the 2006–7 flu season, and billions of dollars are being raised and spent researching H5N1 and preparing for a potential [[influenza pandemic]].<ref name=Rosenthal> Rosenthal, E. and Bradsher, K. [http://www.nytimes.com/2006/03/16/business/16bird.html?_r=1&oref=slogin Is Business Ready for a Flu Pandemic?] The New York Times 16-03-2006 Accessed 17-04-2006</ref>

==Economic impact==
{{further|[[Social impact of H5N1]]}}
Influenza produces [[variable cost|direct cost]]s due to lost [[productivity]] and associated medical treatment, as well as [[indirect costs]] of preventative measures. In the United States, influenza is responsible for a total cost of over $10 billion per year, while it has been estimated that a future pandemic could cause hundreds of billions of dollars in direct and indirect costs.<ref>[http://www.whitehouse.gov/homeland/pandemic-influenza.html Statement from President George W. Bush on Influenza] Accessed 26 Oct 2006</ref> However, the economic impact of past pandemics have not been intensively studied, and some authors have suggested that the [[Spanish flu|Spanish influenza]] actually had a positive long-term effect on per-capita income growth, despite a large reduction in the working population and severe short-term depressive effects.<ref>Brainerd, E. and M. Siegler (2003), “The Economic Effects of the 1918 Influenza Epidemic”, ''CEPR Discussion Paper'', no. 3791.</ref> Other studies have attempted to predict the costs of a pandemic as serious as the 1918 Spanish flu on the U.S. economy, where 30% of all workers became ill, and 2.5% were killed. A 30% sickness rate and a three-week length of illness would decrease [[gross domestic product]] by 5%. Additional costs would come from medical treatment of 18 million to 45 million people, and total economic costs would be approximately $700 billion.<ref>{{cite journal | author = Poland G | title = Vaccines against avian influenza—a race against time. | url=http://content.nejm.org/cgi/content/full/354/13/1411 | journal = N Engl J Med | volume = 354 | issue = 13 | pages = 1411–3 | year = 2006 | id = PMID 16571885}}</ref>

Preventative costs are also high. Governments worldwide have spent billions of U.S. dollars preparing and planning for a potential H5N1 avian influenza pandemic, with costs associated with purchasing drugs and vaccines as well as developing disaster drills and strategies for improved border controls.<ref name=Rosenthal/> On November 1 2005, President George W. Bush unveiled the National Strategy to Safeguard Against the Danger of Pandemic Influenza<ref>[http://www.whitehouse.gov/homeland/pandemic-influenza.html National Strategy for Pandemic Influenza] Whitehouse.gov Accessed 26 Oct 2006.</ref> backed by a request to Congress for $7.1 billion to begin implementing the plan.<ref>[http://usinfo.state.gov/gi/Archive/2005/Nov/01-432345.html Bush Outlines $7 Billion Pandemic Flu Preparedness Plan] State.gov. Accessed 26 Oct 2006</ref> Internationally, on January 18 2006 donor nations pledged US$2 billion to combat bird flu at the two-day International Pledging Conference on Avian and Human Influenza held in China.<ref>[http://www.ens-newswire.com/ens/jan2006/2006-01-18-02.asp Donor Nations Pledge $1.85 Billion to Combat Bird Flu] Newswire Accessed 26 Oct 2006.</ref>

Up to 2006, over ten billion dollars have been spent and over two hundred million birds have been killed to try to contain H5N1 avian influenza.<ref>[http://www.usaid.gov/about_usaid/acvfa/intro_ai.pdf Avian Influenza and its Global Implications] US AID. Accessed 26 Oct 2006.</ref> However, as these efforts have been largely ineffective at controlling the spread of the virus, other approaches are being tried: for example, the Vietnamese government in 2005 adopted a combination of mass poultry vaccination, disinfecting, culling, information campaigns and bans on live poultry in cities.<ref> [http://today.reuters.co.uk/news/newsArticle.aspx?type=worldNews&storyID=2006-04-28T080147Z_01_HAN5054_RTRUKOC_0_UK-BIRDFLU-VIETNAM.xml Reuters Vietnam to unveil advanced plan to fight bird flu] published on April 28, 2006. Accessed 26 Oct 2006</ref> As a result of such measures, the cost of poultry farming has increased, while the cost to consumers has gone down due to demand for poultry falling below supply. This has resulted in devastating losses for many farmers. Poor poultry farmers cannot afford mandated measures which keep their bird livestock from contact with wild birds (and other measures), thus risking losing their livelihood altogether. Multinational poultry farming is increasingly becoming unprofitable as H5N1 avian influenza becomes endemic in wild birds worldwide.<ref>[http://www.irinnews.org/report.asp?ReportID=52471 Poultry sector suffers despite absence of bird flu] UN Office for the Coordination of Humanitarian Affairs. Accessed 26 Oct 2006</ref> Financial ruin for poor poultry farmers, which can be as severe as threatening starvation, has caused some to commit [[suicide]] and many others to stop cooperating with efforts to deal with this virus – further increasing the human toll, the spread of the disease, and the chances of a pandemic mutation.<ref>[http://www.expressindia.com/fullstory.php?newsid=65957 Nine poultry farmers commit suicide in flu-hit India] Reuters. Published on April 12, 2006. Accessed 26 Oct 2006.</ref><ref>[http://www.nytimes.com/2006/04/14/world/africa/14egypt.html?_r=1&oref=slogin In the Nile Delta, Bird Flu Preys on Ignorance and Poverty] The New York Times. Published on April 13, 2006. Accessed 26 Oct 2006.</ref>

==See also==


*[[Virus]]
*[[List of viruses]]
*[[List of epidemics]]

;Information concerning flu research can be found at:
<div style="-moz-column-count:2; column-count:2;">
*[[Influenza research]]
*[[H5N1 clinical trials]]
*[[Center for Biologics Evaluation and Research]]
*[[H5N1 genetic structure]]
*[[ICEID]]
*[[Influenza Genome Sequencing Project]]
*[[Cytokine storm]]
*[[International Partnership on Avian and Pandemic Influenza]]
*[[National Influenza Centers]]
*[[Pandemic Preparedness and Response Act]]
</div>

==References and notes==
{{reflist|2}}

==Further reading==
{{Col-begin}}
{{Col-1-of-2}}
'''General'''
* [http://content.nejm.org/cgi/content/full/353/13/1374 NEJM's Avian Influenza]
* Bernd Sebastian Kamps, Christian Hoffmann and Wolfgang Preiser (Eds.) [http://www.InfluenzaReport.com Influenza Report 2006] Flying publisher 2006.
*Arnold J. Levine 'Viruses' Scientific American Library, WH Freeman, 1992 ISBN 0-7167-5031-7
* Samuel Baron ''et al.'' '[http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed Medical Microbiology]' Fourth Edition, The University of Texas Medical Branch at Galveston 1996 ISBN 0-9631172-1-1.
*Cox NJ, Subbarao K. 'Influenza.' ''Lancet.'' 1999 Oct 9;354(9186):1277–82. PMID 10520648

'''History'''
*Edwin D. Kilbourne [http://www.cdc.gov/ncidod/EID/vol12no01/05-1254.htm Influenza Pandemics of the 20th Century] ''Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*Richard Collier 'The Plague of the Spanish Lady' Macmillan publishers (London) 1974 ISBN 0-7490-0246-8
*John M. Barry 'The Great Influenza: the Epic Story of the Deadliest Plague in History' Penguin 2004 ISBN 0-670-89473-7

'''Microbiology'''
*Webster RG, Bean WJ, Gorman OT, Chambers TM, Kawaoka Y. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=1579108 "Evolution and ecology of influenza A viruses."] ''Microbiol Rev.'' 1992 Mar;56(1):152–79. PMID 1579108
*Scholtissek C. 'Molecular epidemiology of influenza.' Arch Virol Suppl. 1997;13:99–103. PMID 9413530

{{Col-2-of-2}}
'''Pathogenesis'''
*Adolfo García-Sastre [http://www.cdc.gov/ncidod/EID/vol12no01/05-1186.htm Antiviral Response in Pandemic Influenza Viruses] 'Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*Zambon MC. 'The pathogenesis of influenza in humans.' Rev Med Virol. 2001 Jul–Aug;11(4):227–41. PMID 11479929

'''Epidemiology'''
*Walter R. Dowdle [http://www.cdc.gov/ncidod/EID/vol12no01/05-1013.htm Influenza Pandemic Periodicity, Virus Recycling, and the Art of Risk Assessment] 'Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*Horimoto T, Kawaoka Y. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=11148006 Pandemic threat posed by avian influenza A viruses.] ''Clin Microbiol Rev.'' 2001 Jan;14(1):129–49. PMID 11148006
*[http://www.who.int/wer/wer8126.pdf Epidemiology of WHO-confirmed human cases of avian influenza A(H5N1) infection]

'''Treatment and prevention'''
*CDC 2005. Centers for Disease Control. [http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5408a1.htm Prevention and Control of Influenza Recommendations] of the Advisory Committee on Immunization Practices (ACIP). MMWR 2005; 54 (RR08): 1–40.
*Arnold S. Monto [http://www.cdc.gov/ncidod/EID/vol12no01/05-1068.htm Vaccines and Antiviral Drugs in Pandemic Preparedness] ''Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006

'''Research'''
*Peter Palese [http://www.cdc.gov/ncidod/EID/vol12no01/05-1043.htm Making Better Influenza Virus Vaccines?] ''Emerging Infectious Diseases'' Special Issue: Influenza Vol. 12, No. 1 January 2006
*[http://www.who.int/csr/disease/avian_influenza/guidelines/recommendationvaccine.pdf WHO (PDF} contains latest Evolutionary "Tree of Life" for H5N1] article ''Antigenic and genetic characteristics of H5N1 viruses and candidate H5N1 vaccine viruses developed for potential use as pre-pandemic vaccines'' published August 18, 2006
*[http://www.who.int/csr/resources/publications/influenza/WHO_CDS_EPR_GIP_2006_3C.pdf WHO's assessment of Flu Research] as of November 2006.
{{Col-end}}

==External links==
*[http://www.cdc.gov/flu/ Info on influenza] at [[Centers for Disease Control and Prevention|CDC]]
*[http://www.who.int/mediacentre/factsheets/fs211/en/index.html Fact Sheet] Overview of influenza at [[World Health Organization]]
*[http://www.nhsdirect.nhs.uk/en.aspx?articleId=163&sectionId=1725 Health encyclopedia entry] at [[NHS Direct]]
*[http://www.biohealthbase.org/ BioHealthBase Bioinformatics Resource Center] Database of influenza sequences and related information.
*[http://www.medicinenet.com/influenza/article.htm Overview of influenza] at [[MedicineNet]]
*[http://digital.library.unt.edu/govdocs/crs/search.tkl?q=influenza&search_crit=subject&search=Search&date1=Anytime&date2=Anytime&type=form Congressional Research Service (CRS) Reports regarding Influenza] Law related government reports at [[University of North Texas]]
*[http://www.fluwikie.com/index.php?n=Geographic.Geographic Influenza Surveillance and Contingency Plans] (by Country/Region)
*[http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/46000000.htm Orthomyxoviridae] The Universal Virus Database of the [[International Committee on Taxonomy of Viruses]]
*[http://www.ncbi.nlm.nih.gov/genomes/FLU/flubiology.html Influenza Virus Resource] from the [[National Center for Biotechnology Information|NCBI]]
*[http://www.influenzaworld.com/portal/eipf/pb/t/iwc/home InfluenzaWorld] Resource for all influenza-related information.

{{Influenza}}
{{Respiratory pathology}}
{{Viral diseases}}
{{Link FA|pt}}
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{| cellspacing="1" cellpadding="1" border="1"
| '''''Acronym'''''
| '''''Trial Name'''''
|-
| [[3CPO]]
| [[Effect Of Continuous Positive Airway Pressure And Noninvasive Positive Pressure Ventilation In Acute Cardiogenic Pulmonary Oedema]]
|-
| [[3T/2R]]
| [[Tailoring Treatment With Tirofiban in Patients Showing Resistance to Aspirin and/or Resistance to Clopidogrel]]
|-
| [[4D]]
| [[Deutsche Diabetes Dialysis Study]]
|-
| [[4E]]
| [[Efficacy And Safety Of Eplerenone, Enalapril, And Eplerenone/Enalapril Combination Therapy In Patients With Left Ventricular Hypertrophy]]
|-
| [[4S]]
| [[Scandinavian Simvastatin Survival Study]]
|-
| [[6C trial]]
| [[Cooperative Colorectal Cancer Combination Chemotherapy Clinical]]
|-
| [[A to Z, Phase A]]
| [[Aggrastat To Zocor]]
|-
| [[A to Z, Phase Z]]
| [[Evaluation Of Early Versus Delayed Initiation Of Simvastatin In Patients Who Receive Guideline Based Treatment For Acute Coronary Syndrome]]
|-
| [[A4 Study]]
| [[Catheter Ablation Versus Antiarrhythmic Drugs For Atrial Fibrillation]]
|-
| [[AAASPS]]
| [[African American Antiplatelet Stroke Prevention Study]]
|-
| [[AACHEN]]
| [[Angiotensin II Receptor Blocker Candesartan Cilexetil On Intimal Hyperplasia After Coronary Stent Implantation]]
|-
| [[AASK]]
| [[African American Study Of Kidney Disease And Hypertension]]
|-
| [[ABACAS]]
| [[Adjunctive Balloon Angioplasty Following Coronary Atherectomy Study]]
|-
| [[ABC study]]
| [[Association Of Black Cardiologists Study Of Hypertension]]
|-
| [[ABCD]]
| [[Alternans Before Cardioverter Defibrillator]]
|-
| [[AbESTT]]
| [[Abciximab Emergent Stroke Treatment Trial]]
|-
| [[ABOARD]]
| [[Immediate Versus Next Day Catheterization In Non-St Elevation Acute Coronary Syndrome]]
|-
| [[ABSORB: 6-month and 2-year results]]
| [[A Bioabsorbable Everolimus-Eluting Coronary Stent System For Patients With Single De-Novo Coronary Artery Lesions]]
|-
| [[ACADEMIC]]
| [[Azithromycin In Coronary Artery Disease: Elimination Of Myocardial Infection With Chlamydia]]
|-
| [[ACAS]]
| [[Asymptomatic Carotid Atherosclerosis Study]]
|-
| [[ACC AMI GAP]]
| [[American College Of Cardiology Acute Myocardial Infarction Guidelines Applied To Practice Study]]
|-
| [[ACCENT]]
| [[A Crohn's Disease Clinical Trial Evaluating Infliximab In A New Long-Term Treatment Regimen]]
|-
| [[ACCEPT]]
| [[The Accupril Canadian Clinical Evaluation And Patient Teaching Study]]
|-
| [[ACCESS]]
| [[Acute Candesartan Cilexetil Evaluation In Stroke Survivors]]
|-
| [[ACCLAIM]]
| [[Advanced Chronic Heart Failure Clinical Assessment Of Immune Modulation Therapy]]
|-
| [[ACCOMPLISH]]
| [[Avoiding Cardiovascular Events Through Combination Therapy In Patients Living With Systolic Hypertension]]
|-
| [[ACCORD]]
| [[Action To Control Cardiovascular Risk In Diabetes]]
|-
| [[ACCT]]
| [[Sex And Age Related Antihypertensive Effects Of Amlodipine]]
|-
| [[ACCURACY]]
| [[Assessment By Coronary Computed Tomographic Angiography Of Individuals Undergoing Invasive Coronary Angiography]]
|-
| [[ACE]]
| [[Abciximab-Carbostent Evaluation]]
|-
| [[ACE]]
| [[Anticoagulation For Cardioversion Using Enoxaparin]]
|-
| [[ACE (Carotid Endarterectomy)]]
| [[Asa And Carotid Endarterectomy Trial]]
|-
| [[ACES]]
| [[Azithromycin And Coronary Events Study In Patients With Stable Coronary Disease]]
|-
| [[ACES]]
| [[Clinical Experience Study]]
|-
| [[ACIP]]
| [[Asymptomatic Cardiac Ischemia Pilot Study]]
|-
| [[ACME]]
| [[Angioplasty Compared To Medicine]]
|-
| [[ACME-2]]
| [[Angioplasty Compared To Medicine - Two-Vessel Disease]]
|-
| [[A-COMET-I]]
| [[Azimilide—Cardioversion Maintenance Trial–I]]
|-
| [[A-COMET-II]]
| [[Azimilide—Cardioversion Maintenance Trial–II]]
|-
| [[ACORN]]
| [[Assessment Of A Cardiac Support Device (Csd) In Patients With Heart Failure]]
|-
| [[ACRE]]
| [[Appropriateness Of Coronary Revascularization]]
|-
| [[ACST]]
| [[Asymptomatic Carotid Surgery Trial]]
|-
| [[ACT]]
| [[Effects Of Physical Activity Counseling In Primary Care: The Activity Counseling Trial]]
|-
| [[ACT]]
| [[Angioplasty Compliance Trial]]
|-
| [[ACTION]]
| [[Coronary Disease Trial Investigating Outcome With Nifedipine Gits]]
|-
| [[ACTION]]
| [[Actinomycin Eluting Stent Improves Outcomes By Reducing Neointimal Hyperplasia]]
|-
| [[ACTIV in CHF]]
| [[Acute And Chronic Therapeutic Impact Of A Vasopressin 2 Antagonist (Tolvaptan) In Congestive Heart Failure]]
|-
| [[ACTIVATE]]
| [[Acat Inhibition On The Progression Of Coronary Atherosclerosis]]
|-
| [[ACTIVE A]]
| [[The Atrial Fibrillation Clopidogrel Trial With Irbesartan For Prevention Of Vascular Events]]
|-
| [[ACTIVE W]]
| [[Atrial Fibrillation Clopidogrel Trial With Irbesartan For Prevention Of Vascular Events]]
|-
| [[ACUITY]]
| [[Acute Catheterization And Urgent Intervention Triage Strategy Trial]]
|-
| [[ACUITY PCI: 30-day and 1-Year Results]]
| [[Acute Catheterization And Urgent Intervention Triage Strategy Trial - Pci Subgroup: 30-Day And 1-Year Results]]
|-
| [[ACUITY Timing Trial]]
| [[Acute Catheterization And Urgent Intervention Triage Strategy Timing Trial]]
|-
| [[ACUTE]]
| [[Assessment Of Cardioversion Using Transesophageal Echocardiography]]
|-
| [[ACUTE]]
| [[Analysis Of Coronary Ultrasound Thrombolysis Endpoints In Acute Myocardial Infarction]]
|-
| [[ACUTE II]]
| [[Assessment Of Cardioversion Using Transesophageal Echocardiography]]
|-
| [[ADAM]]
| [[Aneurysm Detection And Management Veterans Affairs Cooperative Study]]
|-
| [[ADAM]]
| [[Amsterdam Duration Of Antiretroviral Medication Study]]
|-
| [[ADAPT]]
| [[Alzheimer's Disease Anti-Inflammatory Prevention Trial]]
|-
| [[ADCS]]
| [[Alzheimer's Disease Cooperative Study]]
|-
| [[ADEMEX]]
| [[Adequacy Of Peritoneal Dialysis In Mexico]]
|-
| [[ADEPT]]
| [[Advanced Elements Of Pacing Trial]]
|-
| [[ADIOS]]
| [[Antiarrhythmic Drug Improve Outcome Study]]
|-
| [[ADMIRAL]]
| [[Platelet Glycoprotein IIb/IIia Inhibition With Coronary Stenting For Acute Myocardial Infarction]]
|-
| [[ADMIRAL]]
| [[Abciximab Before Direct Angioplasty And Stenting In Myocardial Infarction Regarding Acute And Long-Term Followup]]
|-
| [[ADMIT]]
| [[Arterial Disease Multiple Intervention Trial]]
|-
| [[ADONIS]]
| [[Aspirin Dose Optimized In Noncardioembolic Ischemic Stroke]]
|-
| [[ADOPT]]
| [[Atrial Dynamic Overdrive Pacing Trial]]
|-
| [[ADOPT]]
| [[A Diabetes Outcome Progression Trial]]
|-
| [[ADOPT-A]]
| [[Atrial Dynamic Overdrive Pacing Trial-A]]
|-
| [[ADVANCE]]
| [[A Randomized Comparison Of The Value Of Additional Stenting After Optimal Balloon Angioplasty For Long Coronary Lesions]]
|-
| [[ADVANCE]]
| [[Additive Value Of Tirofiban Administered With The High-Dose Bolus In The Prevention Of Ischemic Complications During High-Risk Coronary Angioplasty]]
|-
| [[ADVANCE]]
| [[Action In Diabetes And Vascular Disease: Preterax And Diamicron Modified Release Controlled Evaluation]]
|-
| [[ADVANCE]]
| [[A Dosing Evaluation Of A Vasopressin Antagonist In Chf Patients Undergoing Exercise]]
|-
| [[ADVENT]]
| [[Assessment Of Diabetes Control And Evaluation Of The Efficacy Of Niaspan Trial]]
|-
| [[AEGIS]]
| [[Alternative Graft Investigational Study]]
|-
| [[A-F]]
| [[Vascular Protection In High-Risk Non–St-Elevation Acute Coronary Syndromes: The Angioplasty Balloon-Associated Coronary Debris And The Ez Filterwire]]
|-
| [[AFASAK]]
| [[Atrial Fibrillation, Aspirin, Antikoagulation]]
|-
| [[AFASAK-2]]
| [[Second Copenhagen Atrial Fibrillation, Aspirin, And Anticoagulation Study]]
|-
| [[AFCAPS]]
| [[Air Force Coronary Atherosclerosis Prevention Study]]
|-
| [[AFCAPS/TEXCAPS]]
| [[Air Force Texas Coronary Atherosclerosis Prevention Study]]
|-
| [[AF-CHF]]
| [[Atrial Fibrillation And Congestive Heart Failure]]
|-
| [[AFFIRM]]
| [[Atrial Fibrillation Follow-Up Investigation Of Rhythm Management]]
|-
| [[AFIB]]
| [[Atrial Fibrillation Investigation With Bidisomide]]
|-
| [[AFREGS]]
| [[Armed Forces Regression Study]]
|-
| [[AGENT]]
| [[Angiogenic Gene Therapy]]
|-
| [[AGENT-2]]
| [[Angiogenic Gene Therapy Trial 2]]
|-
| [[AGENT-3]]
| [[A Multicenter, Prospective, Randomized Trial Of Intracoronary Administration Of Ad5Fgf-4 In Patients With No Revascularization Options]]
|-
| [[AGIS]]
| [[Advanced Glaucoma Intervention Study]]
|-
| [[A-HeFT]]
| [[African-American Heart Failure Trial]]
|-
| [[AiMI]]
| [[A Prospective, Randomized, Controlled Trial Of Thrombectomy With The Angiojet In Acute Myocardial Infarction]]
|-
| [[AIMS]]
| [[Apsac Intervention Mortality Study]]
|-
| [[AIR]]
| [[Aerosolized Iloprost Randomized Placebo-Controlled Study]]
|-
| [[Air PAMI]]
| [[The Air Primary Angioplasty In Myocardial Infarction Study]]
|-
| [[AIRCRAFT]]
| [[The Australian Intervention Randomized Control Of Rate In Atrial Fibrillation Trial]]
|-
| [[AIRE]]
| [[Acute Infarction Ramipril Efficacy Study]]
|-
| [[AIST-ASH]]
| [[Acute Ischemic Stroke Trial: Oral Aspirin Vs Intravenous Heparin On Stroke Progression]]
|-
| [[ALBION]]
| [[Assessment Of The Best Loading Dose Of Clopidogrel To Blunt Platelet Activation, Inflammation, And On-Going Necrosis]]
|-
| [[ALERT]]
| [[Assessment Of Lescol In Renal Transplantation]]
|-
| [[ALERT]]
| [[Adjunctive Lamictal In Epilepsy And Response To Treatment]]
|-
| [[ALIVE]]
| [[Azimilide Post-Infarct Survival Evaluation]]
|-
| [[ALIVE]]
| [[Adenosine Lidocaine Infarct Zone Viability Enhancement]]
|-
| [[ALIVE (amio vs. lidocaine]]
| [[Amiodarone As Compared With Lidocaine For Shock-Resistant Ventricular Fibrillation]]
|-
| [[ALKK]]
| [[Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte]]
|-
| [[ALLAY]]
| [[Aliskiren In Left Ventricular Hypertrophy]]
|-
| [[ALLHAT]]
| [[Antihypertensive And Lipid-Lowering Treatment To Prevent Heart Attack Trial]]
|-
| [[ALLIANCE]]
| [[Aggressive Lipid-Lowering Initiation Abates New Cardiac Events]]
|-
| [[ALOFT]]
| [[Aliskiren Observations Of Heart Failure Treatment]]
|-
| [[ALPHA]]
| [[T-Wave Alternans In Patients With Heart Failure]]
|-
| [[ALPHABET]]
| [[Effects Of Beraprost Sodium, An Oral Prostacyclin Analogue, In Patients With Pulmonary Arterial Hypertension: A Randomized, Double-Blind, Placebo-Controlled Trial]]
|-
| [[ALTS]]
| [[Ascus/Lsil Triage Study ]]
|-
| [[AMADEUS]]
| [[Comparison Of Idraparinux With Vitamin K Antagonists For Prevention Of Thromboembolism In Patients With Atrial Fibrillation]]
|-
| [[AMAZE]]
| [[A Multicenter Trial Using-Zestril Versus To Evaluate The Effects On Lowering Blood Pressure ]]
|-
| [[AMEthyst]]
| [[Assessment Of The Medtronic Ave Interceptor Saphenous Vein Graft Filter System]]
|-
| [[AMIGO]]
| [[Atherectomy And Multilink Stenting Improves Gain In Outcome Trial]]
|-
| [[AMIGO]]
| [[Ac2993: Diabetes Management For Improving Glucose Outcome]]
|-
| [[AMIHOT]]
| [[Acute Myocardial Infarction With Hyperoxemic Therapy]]
|-
| [[AMIHOT II]]
| [[Acute Myocardial Infarction With Hyperoxemic Therapy II]]
|-
| [[AMIOVIRT]]
| [[Amiodarone Versus Implantable Defibrillator In Patients With Nonischemic Cardiomyopathy And Asymptomatic Nonsustained Ventricular Tachycardia Study]]
|-
| [[AMISTAD I]]
| [[Acute Myocardial Infarction Study Of Adenosine Trial]]
|-
| [[AMISTAD II]]
| [[Acute Myocardial Infarction Study Of Adenosine II]]
|-
| [[AMRO]]
| [[Amsterdam-Rotterdam Trial]]
|-
| [[ANBP2]]
| [[Australian National Blood Pressure Study Group]]
|-
| [[ANDROMEDA]]
| [[Increased Mortality After Dronedarone Therapy For Severe Heart Failure]]
|-
| [[ANTHEM–TIMI-32]]
| [[Anticoagulation With Rnapc2 To Eliminate Mace/Timi 32]]
|-
| [[ANTIBIO]]
| [[Antibiotic Therapy After An Acute Myocardial Infarction]]
|-
| [[ANZ-Carvedilol]]
| [[Australia-New Zealand Heart Failure Research Collaborative Group Carvedilol Trial]]
|-
| [[APAF]]
| [[Ablation For Paroxysmal Atrial Fibrillation (Apaf) Trial]]
|-
| [[APASS]]
| [[Antiphospholipid Antibody Stroke Study]]
|-
| [[APC]]
| [[Adenoma Prevention With Celecoxib]]
|-
| [[APEX AMI]]
| [[Assessment Of Pexelizumab In Acute Myocardial Infarction]]
|-
| [[APLAUSE]]
| [[Anti-Platelet Treatment After Intravascular Ultrasound Guided Optimal Stent Expansion]]
|-
| [[APOCARD]]
| [[Imaging In Cardiac Transplant Patients]]
|-
| [[APPRAISE-1]]
| [[Safety Of The Factor Xa Inhibitor, Apixaban, In Combination With Antiplatelet Therapy After Acute Coronary Syndromes: A Dose-Guiding Trial]]
|-
| [[APPROACH]]
| [[Assessment On The Prevention Of Progression By Rosiglitazone On Atherosclerosis In Diabetes Patients With Cardiovascular History]]
|-
| [[APRES]]
| [[Angiotensin-Converting Enzyme Inhibition Post Revascularization Study]]
|-
| [[APRICOT]]
| [[Antithrombotics In The Prevention Of Reocclusion In Coronary Thrombolysis]]
|-
| [[APRICOT-2]]
| [[Antithrombotics In The Prevention Of Reocclusion In Coronary Thrombolysis-2]]
|-
| [[ARBITER 2]]
| [[Arterial Biology For The Investigation Of The Treatment Effects Of Reducing Cholesterol 2]]
|-
| [[ARCH]]
| [[Amiodarone Reduction In Coronary Heart Trial]]
|-
| [[ARCHeR]]
| [[For Revascularization Of Carotids In High-Risk Patients]]
|-
| [[AREDS]]
| [[Age-Related Eye Disease Study]]
|-
| [[ARG-911]]
| [[Argatroban-911]]
|-
| [[ARG-915]]
| [[Argatroban-915]]
|-
| [[ARGAMI-2]]
| [[Argatroban For Acute Myocardial Infarction]]
|-
| [[ARIC]]
| [[Atherosclerosis Risk In Communities]]
|-
| [[ARIES 1 and 2]]
| [[Ambrisentan In Pulmonary Arterial Hypertension Efficacy Study 1 And 2]]
|-
| [[ARISE]]
| [[Aggressive Reduction Of Inflammation Stops Events]]
|-
| [[ARMS]]
| [[Apsac Reocclusion Multicenter Study]]
|-
| [[ARMYDA]]
| [[Atorvastatin For Reduction Of Myocardial Damage During Angioplasty]]
|-
| [[ARMYDA-2]]
| [[Antiplatelet Therapy For Reduction Of Myocardial Damage During Angioplasty 2]]
|-
| [[ARMYDA-3]]
| [[Antiplatelet Therapy For Reduction Of Myocardial Damage During Angioplasty 3]]
|-
| [[ARMYDA-4]]
| [[Antiplatelet Therapy For Reduction Of Myocardial Damage During Angioplasty 4]]
|-
| [[ARMYDA-5]]
| [[Antiplatelet Therapy For Reduction Of Myocardial Damage During Angioplasty 5]]
|-
| [[ARMYDA-ACS]]
| [[Atorvastatin For Reduction Of Myocardial Damage During Angioplasty-Acute Coronary Syndromes]]
|-
| [[ARMYDA-RECAPTURE]]
| [[Atorvastatin For Reduction Of Myocardial Damage During Angioplasty-Recapture]]
|-
| [[ARMYDA-RELOAD]]
| [[Antiplatelet Therapy For Reduction Of Myocardial Damage During Angioplasty-Reload]]
|-
| [[ARPEGGIO]]
| [[Rimonabant Improves Glycemic Control In Insulin-Treated Type 2 Diabetes]]
|-
| [[ARREST]]
| [[Amiodarone For Resuscitation After Out-Of-Hospital Cardiac Arrest Due To Ventricular Fibrillation]]
|-
| [[ARREST]]
| [[Angiorad Radiation For Restenosis]]
|-
| [[ARTIST]]
| [[Angioplasty Versus Rotational Atherectomy For Treatment Of Diffuse In-Stent Restenosis Trial]]
|-
| [[ARTISTIC]]
| [[Angiorad Radiation Therapy For In-Stent Restenosis Intracoronary]]
|-
| [[ARTS]]
| [[Arterial Revascularization Therapies Study]]
|-
| [[ARTS I - Five year follow-up]]
| [[Five Year Clinical Follow-Up Of The Arterial Revascularisation Therapy Study]]
|-
| [[ARTS-II]]
| [[Arterial Revascularization Therapies Study Part II: Sirolimus-Eluting Stents For The Treatment Of Patients With Multivessel De Novo Coronary Artery Lesions]]
|-
| [[ASAP]]
| [[Effect Of Aggressive Versus Conventional Lipid Lowering On Atherosclerosis Progression In Familial Hypercholesterolemia]]
|-
| [[ASAP]]
| [[Azimilide Supraventricular Arrhythmia Program ]]
|-
| [[ASCENT]]
| [[Acs Stent Clinical Equivalence In De Novo Lesions Trial]]
|-
| [[ASCOT]]
| [[Anglo-Scandinavian Cardiac Outcome Trial]]
|-
| [[ASCOT - Blood Pressure Arm]]
| [[ Anglo-Scandinavian Cardiac Outcomes Trial: Blood Pressure-Lowering Arm]]
|-
| [[ASCOT - Lipid Arm]]
| [[ Anglo-Scandinavian Cardiac Outcomes Trial]]
|-
| [[ASFAST]]
| [[Atherosclerosis And Folic Acid Supplementation Trial]]
|-
| [[ASIS]]
| [[Angina And Silent Ischemia Study]]
|-
| [[ASPAC]]
| [[Asian-Pacific Collaboration On Chd Risk Factor Intervention]]
|-
| [[ASPECT]]
| [[Anticoagulants In Secondary Prevention Of Events In Coronary Thrombosis]]
|-
| [[ASPECT]]
| [[Asian Paclitaxel-Eluting Stent Clinical Trial]]
|-
| [[ASPECT-2]]
| [[Aspirin And Coumadin After Acute Coronary Syndromes (The Aspect-2) Study: A Randomised Controlled Trial.]]
|-
| [[ASPEN]]
| [[Atorvastatin Study For The Prevention Of Endpoints For Patients With Niddm]]
|-
| [[ASPIRE]]
| [[Arixtra Study In Percutaneous Coronary Intervention: A Randomized Evaluation]]
|-
| [[ASSENT 3]]
| [[The Assessment Of The Safety And Efficacy Of A New Thrombolytic Regimen (Assent)-3 Investigators. Efficacy And Safety Of Tenecteplase In Combination With Enoxaparin, Abciximab, Or Unfractionated Heparin: The Assent-3 Randomized Trial In Acute Mi]]
|-
| [[ASSENT 3 PLUS]]
| [[Assessment Of The Safety And Efficacy Of A New Thrombolytic Regimen-3]]
|-
| [[ASSENT-1]]
| [[Assessment Of The Safety and Efficacy Of A New Thrombolytic: Tnk-Tpa]]
|-
| [[ASSENT-2]]
| [[Assessment Of The Safety And Efficacy Of A New Thrombolytic: Tnk-Tpa-2]]
|-
| [[ASSENT-4 PCI]]
| [[Assessment Of The Safety And Efficacy Of A New Treatment Strategy For Acute Myocardial Infarction]]
|-
| [[ASSERT]]
| [[Aortic Stentless Versus Stented Valve Assessed By Echocardiography Randomized Trial]]
|-
| [[ASSET]]
| [[Anglo-Scandinavian Study Of Early Thrombolysis]]
|-
| [[ASSIST]]
| [[Assessment Of Implementation Strategies]]
|-
| [[ASSIST]]
| [[A Stop Smoking In Schools Trial]]
|-
| [[ASSURE]]
| [[Arrhythmia Single Shock Defibrillation Threshold Testing Versus Upper Limit Of Vulnerability: Risk Reduction Evaluation With Implantable Cardioverter Defibrillator Implantations]]
|-
| [[ASTAMI]]
| [[Astami]]
|-
| [[ASTEROID]]
| [[A Study To Evaluate The Effect Of Rosuvastatin On Intravascular Ultrasound-Derived Coronary Atheroma Burden]]
|-
| [[ASTIS]]
| [[Autologous Stem Cell Transplantation International Scleroderma Trial]]
|-
| [[ASTRAL]]
| [[Angioplasty And Stenting For Renal Artery Lesions]]
|-
| [[ASTRID]]
| [[Atrial Sensing Trial To Prevent Inappropriate Detections]]
|-
| [[ASTRONAUT]]
| [[Acid Suppression Trial: Ranitidine Zantac Versus Omeprazole]]
|-
| [[AT LAST]]
| [[Antiretroviral Trial Looking At Sex And Treatment]]
|-
| [[ATAC]]
| [[Arimidex (Anastrozole), Tamoxifen And Combination Therapy]]
|-
| [[ATBAT]]
| [[Anticoagulant Therapy With Bivalirudin To Assist In Pci 1St Inning Trial (Pci In Hit/Hitts)]]
|-
| [[ATBC]]
| [[Alpha-Tocopherol, Beta-Carotene Lung Cancer Prevention Study]]
|-
| [[ATHENA]]
| [[Effect Of Dronedarone On Cardiovascular Outcomes In High-Risk Patients With Atrial Fibrillation Or Atrial Flutter]]
|-
| [[ATHEROMA]]
| [[Atorvastatin Therapy: Effects Of Reduction Of Macrophage Activity]]
|-
| [[ATICH]]
| [[Antifibrinolytic Therapy In Acute Intracerebral Hemorrhage]]
|-
| [[ATLANTIC]]
| [[Angina Treatments - - Lasers And Normal Therapies In Comparison]]
|-
| [[ATLANTIS]]
| [[Alteplase Thrombolysis For Acute Noninterventional Therapy In Ischemic Stroke]]
|-
| [[ATLAS]]
| [[Assessment Of Treatment With Lisinopril And Survival]]
|-
| [[ATLAS]]
| [[Acolysis During Treatment Of Lesions Affecting Saphenous Vein Bypass Grafts Assessment Of Treatment With Lisinopril And Survival]]
|-
| [[ATLAS - SVG]]
| [[Acolysis During Treatment Of Lesions Affecting Saphenous Vein Bypass Grafts]]
|-
| [[ATLAST]]
| [[Antiplatelet Therapy Alone Versus Lovenox Plus Antiplatelet Therapy In Patients At Increased Risk Of Stent Thrombosis]]
|-
| [[ATLAS-TIMI 46]]
| [[Anti-Xa Therapy To Lower Cardiovascular Events In Addition To Aspirin With Or Without Thienopyridine In Subjects With Acute Coronary Syndromes–Thrombolysis In Myocardial Infarction 46]]
|-
| [[AtoZ]]
| [[Aggrastat To Zocor Study]]
|-
| [[ATRAMI]]
| [[Baroreflex Sensitivity And Heart-Rate Variability In Prediction Of Total Cardiac Mortality After Myocardial Infarction. Atrami (Autonomic Tone And Reflexes After Myocardial Infarction) Investigators.]]
|-
| [[ATRIA]]
| [[The Anticoagulation And Risk Factors In Atrial Fibrillation Study]]
|-
| [[ATRIA]]
| [[Anticoagulation And Risk Factors In Atrial Fibrillation ]]
|-
| [[Atrial Arrhythmia Conversion Trial]]
| [[Vernakalant Hydrochloride For Rapid Conversion Of Atrial Fibrillation]]
|-
| [[ATS]]
| [[Amblyopia Treatment Study]]
|-
| [[ATTACH]]
| [[Anti-Tnf Therapy Against Congestive Heart Failure Trial]]
|-
| [[ATTEST]]
| [[Atrial Therapy Efficacy And Safety Trial]]
|-
| [[ATTRACT]]
| [[Anti-Tnf Trial In Rheumatoid Arthritis With Ca2 Treatment ]]
|-
| [[AURORA]]
| [[A Study To Evaluate The Use Of Rosuvastatin In Subjects On Regular Hemodialysis: An Assessment Of Survival And Cardiovascular Events]]
|-
| [[AVASIS]]
| [[Aspirin Versus Anticoagulants In Symptomatic Intracranial Stenosis]]
|-
| [[AVERT]]
| [[Atorvastatin Versus Revascularization Treatments]]
|-
| [[AVERT]]
| [[Artificial Valve Endocarditis Reduction Trial]]
|-
| [[AVID]]
| [[Antiarrhythmics Versus Implantable Defibrillators]]
|-
| [[AVID]]
| [[Angiography Versus Intravascular Ultrasound-Directed Stent Placement]]
|-
| [[AVID Electrical Storm Substudy]]
| [[Electrical Storm Presages Nonsudden Death. The Antiarrhythmics Vs. Implantable Defibrillators (Avid) Trial]]
|-
| [[AVOID]]
| [[Aliskiren In The Evaluation Of Proteinuria In Diabetes]]
|-
| [[AWESOME]]
| [[Angina With Extremely Serious Operative Mortality Evaluation]]
|-
| [[AZACS]]
| [[Azithromycin In Acute Coronary Syndrome]]
|-
| [[BAATAF]]
| [[Boston Area Anticoagulation Trial For Atrial Fibrillation]]
|-
| [[BACH]]
| [[Bach]]
|-
| [[BARI]]
| [[Bypass Angioplasty Revascularization Investigation]]
|-
| [[BARI 2D]]
| [[Bypass Angioplasty Revascularization Investigation In Type 2 Diabetics]]
|-
| [[BARS]]
| [[Beaumont Alcohol Restenosis Study]]
|-
| [[BASC]]
| [[Blood Pressure In Acute Stroke Collaboration]]
|-
| [[BASEL]]
| [[Brain Natriuretic Peptide For Acute Shortness Of Breath Evaluation: A Randomized Comparison]]
|-
| [[BASIS]]
| [[Basel Antiarrhythmic Study Of Infarct Survival]]
|-
| [[BASKET]]
| [[Basel Stent Cost-Effectiveness Trial]]
|-
| [[BASKET LATE]]
| [[Late Clinical Events Related To Late Stent Thrombosis After Stopping Clopidogrel]]
|-
| [[BAT]]
| [[Bivalirudin Angioplasty Study]]
|-
| [[BATMAN]]
| [[Biodivysio 'Bat'Imastat Sv Stent Versus Balloon Angioplasty For The Reduction Of Restenosis In Small Coronary Arteries ]]
|-
| [[BBC ONE]]
| [[British Bifurcation Coronary Study: Old, New, And Evolving Strategies]]
|-
| [[BBS—Cognitive Study]]
| [[Best Bypass Surgery—Cognitive Study]]
|-
| [[BCAPS]]
| [[Beta-Blocker Cholesterol-Lowering Asymptomatic Plaque Study]]
|-
| [[BCPT]]
| [[Breast Cancer Prevention Trial]]
|-
| [[BEACH]]
| [[Boston Scientific Epi: A Carotid Stenting Trial For High-Risk Surgical Patients]]
|-
| [[BEAT]]
| [[Bucindolol Evaluation In Acute Myocardial Infarction Trial ]]
|-
| [[BEAUTIFUL]]
| [[Morbidity-Mortality Evaluation Of The If Inhibitor Ivabradine In Patients With Coronary Disease And Left-Ventricular Dysfunction]]
|-
| [[BECAIT]]
| [[Bezafibrate Coronary Atherosclerosis Intervention Trial]]
|-
| [[BECAIT]]
| [[Bezafibrate Coronary Atherosclerosis Intervention Trial]]
|-
| [[BELLES]]
| [[Beyond Endorsed Lipid Lowering With Ebt Scanning]]
|-
| [[BENEDICT]]
| [[Bergamo Nephrologic Diabetes Complications Trial]]
|-
| [[BENEFiT]]
| [[Bosentan Effects In Inoperable Forms Of Chronic Thromboembolic Pulmonary Hypertension]]
|-
| [[BENEFIT]]
| [[Betaferon (Betaseron In U.S.) In Newly Emerging Ms For Initial Treatment Information]]
|-
| [[BENESTENT I]]
| [[Belgian-Netherlands Stent Study (I)]]
|-
| [[BENESTENT II]]
| [[Belgian-Netherlands Stent Study II (Pilot)]]
|-
| [[BERT]]
| [[Beta Energy Restenosis Trial - 1]]
|-
| [[BESMART]]
| [[Bestent In Small Arteries Trial]]
|-
| [[BESSAMI]]
| [[Berlin Stent Study In Acute Myocardial Infarction]]
|-
| [[BEST]]
| [[Beta Blocker Evaluation Of Survival Trial]]
|-
| [[BEST]]
| [[Balloon Equivalent To Stent Trial]]
|-
| [[BEST-ICD]]
| [[Beta-Blocker Evaluation Of Survival Trial Plus Icd]]
|-
| [[BETA WRIST]]
| [[Washington Radiation For In-Stent Restenosis Trial]]
|-
| [[BETACATH]]
| [[Clinical And Angiographic Outcomes After Use Of Sr-90 Beta Radiation For The Treatment Of De Novo And Restenotic Coronary Lesions]]
|-
| [[BETTER]]
| [[Beta Radiation Trial To Eliminate Restenosis]]
|-
| [[BHACAS]]
| [[Early And Midterm Outcome After Off-Pump And On-Pump Surgery In Beating Heart Against Cardioplegic Arrest Studies (Bhacas 1 And 2): A Pooled Analysis Of Two Randomised Controlled Trials.]]
|-
| [[BHAT]]
| [[Beta Blocker Heart Attack Trial]]
|-
| [[BiCard]]
| [[Biphasic Vs. Monophasic Shock Waveform For Conversion Of Atrial Fibrillation. The Results Of An International Randomized, Double-Blind Multicenter Trial]]
|-
| [[BICC]]
| [[Beta-Interferon In Chronic Viral Cardiomyopathy]]
|-
| [[BIP]]
| [[Bezafibrate Infarction Prevention Study]]
|-
| [[BIRD]]
| [[ Bolus Versus Infusion In Rescupase (Saruplase) Development]]
|-
| [[BLIND-DATE]]
| [[Blinded Withdrawal Of Deprenyl In The Datatop Extension Trial]]
|-
| [[BLOSS]]
| [[Beta Blocker Length Of Stay Study]]
|-
| [[BNP]]
| [[Breathing Not Properly]]
|-
| [[BOAT]]
| [[Balloon Angioplasty Versus Optimal Atherectomy Trial]]
|-
| [[Bogalusa]]
| [[Bogalusa Heart Study]]
|-
| [[BOOST]]
| [[Bone Marrow Transfer To Enhance St-Elevation Infarct Regeneration]]
|-
| [[BPAV]]
| [[Balloon Prophylaxis Of Aneurysmal Vasospasm]]
|-
| [[BRAINS]]
| [[Bayer Randomized Acute Ischemia Neuroprotectant Study]]
|-
| [[BRAVE]]
| [[Bavarian Reperfusion Alternatives Evaluation]]
|-
| [[BRAVE-2]]
| [[Beyond 12 Hours Reperfusion Alternative Evaluation Trial]]
|-
| [[BRAVE-3]]
| [[Value Of Abciximab In Patients With Ami Undergoing Pci After High Loading Dose Of Clopidogrel Pretreatment]]
|-
| [[BRAVO]]
| [[Blockade Of The Glycoprotein IIb/IIia Receptor To Avoid Vascular Occlusion]]
|-
| [[BRAVO]]
| [[Beta Radiation For Treatment Of Arteriovenous Graft Outflow Sponsor:]]
|-
| [[BREATHE-1]]
| [[Bosentan (Tracleer): Randomized Trial Of Endothelin Receptor Antagonist Therapy For Pulmonary Hypertension]]
|-
| [[BRIDGE]]
| [[Beta-Radiation Investigation With Direct Stenting And Galileo In Europe]]
|-
| [[BRIE]]
| [[Beta Radiation In Europe]]
|-
| [[BRIEF-PCI]]
| [[Brief Infusion Of Eptifibatide Following Percutaneous Coronary Intervention]]
|-
| [[BRILLIANT]]
| [[Batimastat (Bb-94) Antirestenosis Trial Utilizing The Biodivysio Local Drug Delivery Pc Stent ]]
|-
| [[BRITE]]
| [[Beta Radiation To Reduce In-Stent Restenosis ]]
|-
| [[BRITE II]]
| [[Beta Radiation To Reduce In-Stent Restenosis II]]
|-
| [[BRITE-SVG]]
| [[Beta Radiation To Reduce In-Stent Restenosis In Saphenous Vein Grafts]]
|-
| [[CABERNET]]
| [[A Prospective Registry Of Carotid Stenting With The Nexstent And Distal Protection With The Filterwire Ex In High Risk Patients]]
|-
| [[CABERNET]]
| [[Carotid Artery Revascularization Using The Boston Scientific Epi Filterwire Ex And The Endotex Nexstent]]
|-
| [[CABG PATCH]]
| [[The Coronary Artery Bypass Graft Patch Trial]]
|-
| [[CABG Patch Cardioplegia Substudy]]
| [[Does Cardioplegia Type Affect Outcome And Survival In Patients With Advanced Left Ventricular Dysfunction? Results From The Cabg Patch Tria]]
|-
| [[CABRI]]
| [[Coronary Angioplasty Versus Bypass Revascularization Investigation]]
|-
| [[CACAF]]
| [[Catheter Ablation For The Cure Of Atrial Fibrillation Study]]
|-
| [[CACHET]]
| [[Comparison Of Abciximab Complications With Hirulog (Angiomax As Of 1999) Ischemic Events Trial]]
|-
| [[CACTUS]]
| [[Coronary Bifurcations: Application Of The Crushing Technique Using Sirolimus-Eluting Stents]]
|-
| [[CADILLAC]]
| [[Controlled Abciximab (Reopro) And Device Investigation To Lower Late Angioplasty Complications]]
|-
| [[CAESAR]]
| [[Canada, Australia, Europe, South Africa Aids Study ]]
|-
| [[CAFA]]
| [[Canadian Atrial Fibrillation Anticoagulation Study]]
|-
| [[CAFE]]
| [[Conduit Artery Function Evaluation]]
|-
| [[CALM]]
| [[Candesartan And Lisinopril Microalbuminuria Study]]
|-
| [[CALM-PD]]
| [[Comparison Of The Agonist Pramipexole Vs. Levodopa On Motor Complications In Parkinson Disease]]
|-
| [[CALYPSO]]
| [[Cylexin As An Adjunct To Lytic Therapy To Prevent Superoxide Reflow Injury]]
|-
| [[CAMELOT]]
| [[Comparison Of Amlodipine Versus Enalapril (Lipitor) To Limit Occurrences Of Thrombosis]]
|-
| [[CAMEO]]
| [[Cerebral Aneurysm Multicenter European]]
|-
| [[CAMIAT]]
| [[Canadian Amiodarone Myocardial Infarction Arrhythmia Trial (Pilot)]]
|-
| [[CANDLE]]
| [[Candesartan Versus Losartan Efficacy Comparison ]]
|-
| [[Cangrelor during PCI]]
| [[Cangrelor During Percutaneous Coronary Intervention]]
|-
| [[CANPAP]]
| [[Continuous Positive Airway Pressure For Heart Failure Patients With Central Sleep Apnea]]
|-
| [[CAPARES]]
| [[Coronary Angioplasty Amlodipine Restenosis Study]]
|-
| [[CAPE II]]
| [[Medical Treatment Of Myocardial Ischemia In Coronary Artery Disease: Effect Of Drug Regime And Irregular Dosing In The Cape II Trial]]
|-
| [[CAPITAL AMI]]
| [[Combined Angioplasty And Pharmacological Intervention Versus Thrombolytics Alone In Acute Myocardial Infarction]]
|-
| [[CAPPP]]
| [[Captopril Prevention Project]]
|-
| [[CAPRICORN]]
| [[Carvedilol Post Infarct Survival Control in Left Ventricular Dysfunction Study]]
|-
| [[CAPRIE]]
| [[Clopidogrel Versus Aspirin In Patients At Risk Of Ischemic Events ]]
|-
| [[CAPS]]
| [[The Cardiac Arrhythmic Pilot Study]]
|-
| [[CAPT]]
| [[Complications Of Amd (Age-Related Macular Degeneration) Prevention Trial]]
|-
| [[CAPTEN]]
| [[Captopril After Thrombolysis Trial ]]
|-
| [[CAPTIM]]
| [[Comparison Of Angioplasty And Prehospital Thrombolysis In Acute Myocardial Infarction]]
|-
| [[CAPTIN]]
| [[Captopril Plus Tissue Plasminogen Activator Following Acute Myocardial Infarction]]
|-
| [[CAPTIVATE]]
| [[Carotid Atherosclerosis Progression Trial Investigating Vascular Acat Inhibition Treatment Effects]]
|-
| [[CAPTIVE]]
| [[A Prospective, Randomized, Controlled Trial Of Distal Protection With The Third Generation Mednova Emboshield Compared To The Guardwire Or Filterwire]]
|-
| [[CAPTURE]]
| [[Chimeric 7E3 Antiplatelet Therapy In Unstable Angina Refractory To Standard Treatment]]
|-
| [[CAPTURE Registry]]
| [[Carotid Acculink/Accunet Post-Approval Trial To Uncover Unanticipated Or Rare Events Registry]]
|-
| [[CARAT]]
| [[Coronary Angioplasty And Rotational Atherectomy Trial]]
|-
| [[CARDIA]]
| [[Coronary Artery Risk Development In Young Adults]]
|-
| [[CARDia]]
| [[Coronary Artery Revascularization In Diabetes Trial]]
|-
| [[CARDINAL]]
| [[Complement And Reduction Of Infarct Size After Angioplasty Or Lytics]]
|-
| [[CARDS]]
| [[Collaborative Atorvastatin (Lipitor) And Diabetes Study]]
|-
| [[CARE]]
| [[Cardiac Angiography In Renally Impaired Patients]]
|-
| [[CARE]]
| [[Cholesterol And Recurrent Events]]
|-
| [[CARE]]
| [[Calcium Antagonist In Reperfusion Cholesterol And Recurrent Events Carvedilol Atherectomy Restenosis ]]
|-
| [[CARE-HD]]
| [[Coenzyme Q10 And Remacemide: Evaluation In Huntington Disease]]
|-
| [[CARE-HF]]
| [[Cardiac Resynchronization - Heart Failure European Complement To U.S./Canada Miracle Study]]
|-
| [[CARESS]]
| [[Clopidogrel And Aspirin For Reduction Of Emboli In Symptomatic Carotid Stenosis]]
|-
| [[CARESS-in-AMI: 30-Day and 1-Year Results]]
| [[Combined Abciximab Reteplase Stent Study In Acute Myocardial Infarction: 30-Day and 1-Year Results]]
|-
| [[CARET]]
| [[The Beta Carotene And Retinol Efficacy Trial]]
|-
| [[CARIBE]]
| [[Carvedilol Insuficiencia Cardiaca (Heart Failure) Beta-Receptor]]
|-
| [[CARISA]]
| [[Combination Assessment Of Ranolazine In Stable Angina ]]
|-
| [[CARMEN]]
| [[The Carvedilol And Ace-Inhibitor Remodeling Mild Heart Failure Evaluation Trial]]
|-
| [[CARMEN]]
| [[Carvedilol Ace Inhibitors Remodelling Mild Heart Failure Evaluation]]
|-
| [[CARP]]
| [[Coronary Artery Revascularization Prophylaxis]]
|-
| [[CARS]]
| [[Coumadin Aspirin Reinfarction Study]]
|-
| [[CART]]
| [[Canadian Antioxidant Restenosis Trial]]
|-
| [[CARVEDILOL]]
| [[The Effects Of Carvedilol On Morbidity And Mortality In Patients With Chronic Heart Failure]]
|-
| [[CASCADE]]
| [[Cardiac Arrest In Seattle: Conventional Versus Amiodarone Drug Evaluation Study]]
|-
| [[CASES]]
| [[Canadian Activase For Stroke Effectiveness Study]]
|-
| [[CASH]]
| [[Cardiac Arrest Study-Hamburg]]
|-
| [[CASIS]]
| [[Canadian Amlodipine/Atenolol In Silent Ischemia Study]]
|-
| [[CASS]]
| [[Coronary Artery Surgery Study]]
|-
| [[CAST]]
| [[Cardiac Arrhythmia Suppression Trial]]
|-
| [[CASTEMI]]
| [[Calderet In St Elevation Myocardial Infarction]]
|-
| [[CAST-II]]
| [[The Cardiac Arrhythmia Suppression Trial II]]
|-
| [[CASTLE]]
| [[Candesartan Amlodipine Study Of Tolerability And Efficacy]]
|-
| [[CAT]]
| [[Cardiomyopathy Trial]]
|-
| [[CAT]]
| [[Chinese Ace Inhibitor In Acute Myocardial Infarction Trial Cardiomyopathy Trial]]
|-
| [[CATAPULT]]
| [[Cisplatin And Tirapazamine In Subjects With Advanced Previously Untreated Non–Small Cell Lung Tumors]]
|-
| [[Cathedia Study]]
| [[Femoral Vs. Jugular Venous Catheterization And Risk Of Nosocomial Events In Adults Requiring Acute Renal Replacement Therapy]]
|-
| [[CATIE]]
| [[Clinical Antipsychotic Trials Of Intervention Effectiveness]]
|-
| [[CATS]]
| [[Canadian American Ticlopidine Study]]
|-
| [[CATS]]
| [[Captopril And Thrombolysis Study]]
|-
| [[CAVATAS]]
| [[Endovascular Versus Surgical Treatment In Patients With Carotid Stenosis In The Carotid And Vertebral Artery Transluminal Angioplasty Study (Cavatas)]]
|-
| [[CAVEAT I]]
| [[Coronary Angioplasty Versus Excisional Atherectomy Trial I]]
|-
| [[CAVEAT II]]
| [[Coronary Angioplasty Versus Excisional Atherectomy Trial II]]
|-
| [[CBT-CD]]
| [[Cognitive Behavior Therapy For The Chronic Depressions]]
|-
| [[CCAT]]
| [[Canadian Coronary Atherectomy Trial]]
|-
| [[CCP]]
| [[The Cooperative Cardiovascular Project]]
|-
| [[CCS-1]]
| [[Chinese Cardiac Study]]
|-
| [[CDP]]
| [[Coronary Drug Project]]
|-
| [[CEDARS]]
| [[Comprehensive Evaluation Of Defibrillators And Resuscitative Shock]]
|-
| [[CELL]]
| [[Cost Effectiveness Of Lipid Lowering Study]]
|-
| [[CEOS]]
| [[Congenital Esotropia Observational Study]]
|-
| [[CHAMP]]
| [[Combination Hemotherapy And Mortality Prevention (Champ) Study]]
|-
| [[CHAMP]]
| [[Children's Hiv And Aids Model Program]]
|-
| [[CHAMPIONS]]
| [[Controlled High-Risk Subjects Avonex Ms Prevention In Ongoing Neurologic Surveillance]]
|-
| [[CHAMPS]]
| [[Controlled High-Risk Subjects Avonex Ms Prevention Study]]
|-
| [[CHAOS]]
| [[Cambridge Heart Antioxidant Study]]
|-
| [[CHARISMA]]
| [[Clopidogrel For High Atherothrombotic Risk, Ischemic Stabilization, Management, And Avoidance]]
|-
| [[CHARM]]
| [[Candesartan Cilexitil (Atacand) In Heart Failure Assessment Of Reduction Mortality And Morbidity]]
|-
| [[CHARM Added Trial]]
| [[Candesartan In Heart Failure—Added Trial]]
|-
| [[CHARM Alternative Trial]]
| [[Candesartan In Heart Failure—Alternative Trial]]
|-
| [[CHARM Overall Programme Results]]
| [[Candesartan In Heart Failure—Assessment Of Reduction In Mortality And Morbidity]]
|-
| [[CHARM Preserved Trial]]
| [[Candesartan In Heart Failure—Preserved Trial]]
|-
| [[CHEESE]]
| [[Comparative Trial Of Hiv-Infected Patients Evaluating Efficacy And Safety Of Saquinavir-Enhanced Oral Formulation And Indinavir Given As Part Of A Triple Drug Therapy ]]
|-
| [[CHF-STAT]]
| [[Congestive Heart Failure Survival Trial Of Antiarrhythmic Therapy]]
|-
| [[CHICAGO]]
| [[Carotid Intima-Media Thickness In Atherosclerosis Using Pioglitazone]]
|-
| [[CHRISTMAS]]
| [[Carvedilol Hibernating Reversible Ischaemia Trial]]
|-
| [[CHS]]
| [[Cardiovascular Health Study]]
-----
---- [[CHS]]
---- [[Charleston Heart Study]]
-----
---- [[CHS]]
---- [[Community Health Study]]
-----
---- [[CHS]]
---- [[Congenital Heart Surgeons Society Study]]
-----
---- [[CHS]]
---- [[Coronary Heart Study]]
|-
| [[CIAO]]
| [[Coronary Interventions Antiplatelet-Based Only]]
|-
| [[CIBIS]]
| [[Cardiac Insufficiency Bisoprolol Study]]
|-
| [[CIBIS II]]
| [[The Cardiac Insufficiency Bisoprolol Study II]]
|-
| [[CIBIS III]]
| [[The Cardiac Insufficiency Bisoprolol Study III]]
|-
| [[CIDS]]
| [[Canadian Implantable Defibrillator Study]]
|-
| [[CIGTS]]
| [[Collaborative Initial Glaucoma Treatment Study]]
|-
| [[CLARIDI]]
| [[Cholesterol Lowering And Arrhythmias Recurrences After Internal Defibrillator Implantation]]
|-
| [[CLARITY-TIMI 28]]
| [[Clopidogrel As Adjunctive Reperfusion Therapy]]
|-
| [[CLAS I AND II]]
| [[Cholesterol Lowering Atherosclerosis Study (I And II)]]
|-
| [[CLASS]]
| [[Celecoxib (Celebrex) Long-Term Arthritis Safety Study]]
|-
| [[CLASSICS]]
| [[Clopidogrel (Plavix) Aspirin Stent International Cooperative Study]]
|-
| [[CLASS-IHT]]
| [[Clomethiazole Acute Stroke Study In Ischemic, Hemorrhagic, And Tpa Treated Stroke]]
|-
| [[CLEAR PLATELETS]]
| [[Clopidogrel Loading With Eptifibatide To Arrest The Reactivity Of Platelets Study]]
|-
| [[CLEAR PLATELETS-2]]
| [[Clopidogrel With Eptifibatide To Arrest The Reactivity Of Platelets-2]]
|-
| [[CLEERE]]
| [[Collaborative Longitudinal Evaluation Of Ethnicity And Refractive Error]]
|-
| [[COACH]]
| [[Coordinating Study Evaluating Outcomes Of Advising And Counseling In Heart Failure]]
|-
| [[COAST]]
| [[Heparin-Coated Stents In Small Coronary Arteries]]
|-
| [[COBALT]]
| [[Continuous Infusion Versus Double-Bolus Administration Of Alteplase]]
|-
| [[COCAD]]
| [[Cognitive Outcomes In Coronary Artery Disease]]
|-
| [[COLA]]
| [[Carvedilol Open Label Assessment]]
|-
| [[COLUMBUS]]
| [[Low Molecular Weight Heparin In The Treatment Of Patients With Venous Thromboembolism]]
|-
| [[COMBINE]]
| [[Combining Medications And Behavorial Interventions ]]
|-
| [[COMET]]
| [[Carvedilol Or Metoprolol European Trial]]
|-
| [[COMMA]]
| [[Compliment Inhibition In Myocardial Infarction Treated With Percutaneous Transluminal Coronary Angioplasty (Evaluation Of Iv Dosing Regimens Of H5G1.1-Scfv) ]]
|-
| [[COMMIT/CCS-2 – Clopidogrel]]
| [[Randomized, Placebo-Controlled Trial Of Adding Clopidogrel To Aspirin In 46,000 Acute Myocardial Infarction Patients]]
|-
| [[COMMIT/CCS-2 – Metoprolol]]
| [[Randomized, Placebo-Controlled Trial Of Early Metoprolol In 46,000 Acute Myocardial Infarction Patients]]
|-
| [[COMPANION]]
| [[Comparison Of Medical Therapy, Pacing And Defibrillation In Chronic Heart Failure]]
|-
| [[Comparison of GR-II Stent and Palmaz-Schatz Stent for Elective Treatment of Coronary Stenosis]]
| [[Randomized Clinical Trial Investigators. Randomized Comparison Of Gr-II Stent And Palmaz-Schatz Stent For Elective Treatment Of Coronary Stenosis]]
|-
| [[Comparison of Ibuprofen and Indomethacin for Closure of Patent Ductus Arteriosus]]
| [[A Comparison Of Ibuprofen And Indomethacin For Closure Of Patent Ductus Arteriosus]]
|-
| [[COMPASS]]
| [[Comparison Trial Of Saruplase And Streptokinase]]
|-
| [[COMPASS-HF]]
| [[Chronicle Offers Management To Patients With Advanced Signs And Symptoms Of Heart Failure]]
|-
| [[COMPLY]]
| [[Compliment Inhibition In Myocardial Infarction Treated With Thrombolytics (Evaluation Of Iv Dosing Regimens Of H5G1.1-Scfv) Sponsors]]
|-
| [[COMS]]
| [[Collaborative Ocular Melanoma Study]]
|-
| [[CONSENSUS]]
| [[The Effects Of Enalapril On Mortality In Severe Congestive Heart Failure]]
|-
| [[CONSENSUS II]]
| [[The Effects Of The Early Administration Of Enalapril On Mortality In Patients With Acute Myocardial Infarction: Results Of The Cooperative New Scandin-2]]
|-
| [[CONVERTIBLE]]
| [[Conventional Stenting Versus Direct Stenting In (Un)Stable Angina Pectoris]]
|-
| [[CONVINCE]]
| [[Controlled Onset Verapamil Investigation Of Cardiovascular Endpoints Trial]]
|-
| [[COOL]]
| [[Cardiovascular Thrombolytic To Open Occluded Lines]]
|-
| [[COOL AID]]
| [[Cooling For Acute Ischemic Brain Damage]]
|-
| [[COOL MI]]
| [[Cooling As An Adjunctive Therapy To Percutaneous Intervention In Patients With Acute Myocardial Infarction]]
|-
| [[COOLRCN]]
| [[Cooling To Prevent Radiocontrast Nephropathy]]
|-
| [[COPERNICUS]]
| [[Effect Of Carvedilol On Survival In Severe Chronic Heart Failure]]
|-
| [[COPPA]]
| [[Clinical Outcomes From The Prevention Of Postoperative Arrhythmia]]
|-
| [[CORE]]
| [[International Variation In Invasive Procedures And Outcomes In Acute Myocardial Infarction]]
|-
| [[CORE]]
| [[Continuing Outcomes Relevant To Evista]]
|-
| [[CORONA]]
| [[Controlled Rosuvastatin Multinational Trial In Heart Failure]]
|-
| [[CORSICA]]
| [[Chronic Occlusion Revascularization With Stent Implantation Versus Coronary Angioplasty]]
|-
| [[COSS]]
| [[Carotid Occlusion Surgery Study]]
|-
| [[COURAGE]]
| [[Clinical Outcomes Utilizing Revascularization And Aggressive Drug Evaluation ]]
|-
| [[COURT]]
| [[Contrast Utilization In High Risk Patients Undergoing Ptca]]
|-
| [[C-PORT]]
| [[Atlantic Cardiovascular Patient Outcomes Research Team Trial]]
|-
| [[CPVA for Chronic Atrial Fibrillation]]
| [[Circumferential Pulmonary Vein Ablation For Chronic Atrial Fibrillation]]
|-
| [[CQI in CABG]]
| [[Continuous Quality Improvement In Coranary Artery Bypass Graft]]
|-
| [[CRASH]]
| [[Corticosteroid Randomization After Significant Head Injury]]
|-
| [[CREATE]]
| [[Canadian Cardiac Randomized Evaluation Of Antidepressant And Psychotherapy Efficacy]]
|-
| [[CREATE ELCA - Reviparin]]
| [[Low Molecular Weight Heparin (Reviparin) In Preventing Mortality, Reinfarction, And Strokes In Over 15,500 Patients With St Elevation Acute Myocardial Infarction]]
|-
| [[CREATE-ECLA - GIK]]
| [[Impact Of Glucose-Insulin-Potassium On Mortality And Morbidity In Over 20,000 Patients With Acute Myocardial Infarction: The Create-Ecla International Trial]]
|-
| [[CREDO]]
| [[Clopidogrel For Reduction Of Events During Observation]]
|-
| [[CREST]]
| [[Cilostazol For Restenosis]]
|-
| [[CREST]]
| [[Carotid Revascularization Endarterectomy Vs Stenting Trial]]
|-
| [[CRIS]]
| [[A Controlled Trial Of Verapamil In Patients After Acute Myocardial Infarction: Results Of The Calcium, Antagonist Reinfarction Italian Study]]
|-
| [[CRUISE]]
| [[Can Routine Ultrasound Influence Stent Expansion]]
|-
| [[C-SIRIUS]]
| [[Canadian Sirolimus-Eluting Stent In Coronary Lesions]]
|-
| [[CSSS]]
| [[China Salt Substitute Study]]
|-
| [[CTAF]]
| [[Canadian Trial Of Atrial Fibrillation]]
|-
| [[CTOPP]]
| [[Canadian Trial Of Physiologic Pacing]]
|-
| [[CUBA]]
| [[Cutting Balloon Versus Conventional Angioplasty Study]]
|-
| [[CURE]]
| [[The Clopidogrel In Unstable Angina To Prevent Recurrent Events Trial Investigators: Effects Of Clopidogrel In Addition To Aspirin In Patients With Acute Coronary Syndromes Without St-Segment Elevation]]
|-
| [[CURE]]
| [[Clopidogrel In Unstable Angina To Prevent Recurrent Ischemic Events]]
|-
| [[DAIS]]
| [[Diabetes Atherosclerosis Intervention Study]]
|-
| [[DAISY]]
| [[Diabetes Autoimmunity Study In The Young]]
|-
| [[DANAMI]]
| [[Danish Myocardial Infarction Trial]]
|-
| [[DANAMI-2]]
| [[Danish Trial In Acute Myocardial Infarction-2]]
|-
| [[DANTE]]
| [[Diabetes Abciximab Stent Evaluation]]
|-
| [[DAPPAF]]
| [[Dual Site Atrial Pacing To Prevent Atrial Fibrillation]]
|-
| [[DART]]
| [[Dilation Versus Ablation Revascularization Trial]]
|-
| [[DASH]]
| [[Dietary Approaches To Stop Hypertension]]
|-
| [[DATATOP]]
| [[Deprenyl And Tocopherol Antioxidative Therapy Of Parkinsonism]]
|-
| [[DAVID]]
| [[Dual-Chamber And Vvi Implantable Defibrillator]]
|-
| [[DAVID – (Picotamide vs. Aspirin)]]
| [[Drug Evaluation In Atherosclerotic Vascular Disease In Diabetics]]
|-
| [[DAVID II]]
| [[Dual Chamber And Vvi Implantable Defibrillator II]]
|-
| [[DAVIT II]]
| [[Danish Study Group On Verapamil In Mi]]
|-
| [[DCCT]]
| [[Diabetes Control And Complications Trial]]
|-
| [[DEAR-MI]]
| [[Dethrombosis To Enhance Acute Reperfusion In Myocardial Infarction]]
|-
| [[DEBATE]]
| [[Doppler Endpoints Balloon Angioplasty Trial Europe]]
|-
| [[DEBATE II]]
| [[Doppler Endpoints Balloon Angioplasty Trial Europe-2]]
|-
| [[DEBUT]]
| [[Defibrillator Versus Beta-Blockers For Unexplained Death In Thailand]]
|-
| [[DECLARE-DIABETES]]
| [[Drug-Eluting Stenting Followed By Cilostazol Treatment Reduces Late Restenosis In Patients With Diabetes Mellitus]]
|-
| [[DECOPI]]
| [[Randomized Trial Of Occluded Artery Angioplasty After Acute Myocardial Infarction]]
|-
| [[DECOPI]]
| [[La Desobstruction Coronaire En Post-Infarctus ]]
|-
| [[DECREASE III]]
| [[Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echo III]]
|-
| [[DECREASE-V]]
| [[Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echo-V]]
|-
| [[DEDICATION: Distal Protection Study]]
| [[Drug Elution And Distal Protection In St-Elevation Myocardial Infarction]]
|-
| [[DEDICATION: Stent Study]]
| [[Drug Elution And Distal Protection In Acute Myocardial Infarction]]
|-
| [[DEFER]]
| [[Deferral Versus Performance Of Ptca In Patients Without Documented Ischemia]]
|-
| [[DEFINITE]]
| [[Defibrillators In Nonischemic Cardiomyopathy Treatment Evaluation]]
|-
| [[DEFUSE]]
| [[Diffusion-Weighted Imaging Evaluation For Understanding Stroke Evaluation ]]
|-
| [[DELTA MI]]
| [[Direct Inhibition Of Δ-Protein Kinase C Enzyme To Limit Total Infarct Size In Acute Mi]]
|-
| [[DES-DIABETES]]
| [[A Randomized Comparison Of Sirolimus- Versus Paclitaxel-Eluting Stent Implantation In Patients With Diabetes Mellitus]]
|-
| [[DESTINI-CFR]]
| [[Doppler Endpoints Stenting International Investigation - Coronary Flow Reserve ]]
|-
| [[DETAIL]]
| [[Diabetics Exposed To Telmisartan And Enalapril]]
|-
| [[DIABETES]]
| [[A Prospective, Randomized, Controlled Trial Of The Polymer-Based, Sirolimus-Eluting Stent Versus A Bare Metal Stent In Patients With Diabetes Mellitus]]
|-
| [[DIACOR]]
| [[Diabetes And Combined Lipid Therapy Regimen]]
|-
| [[DIAD]]
| [[Detection Of Ischemia In Asymptomatic Diabetics]]
|-
| [[DIADS]]
| [[Depression In Alzheimer Disease Study]]
|-
| [[DIAGNOSIS]]
| [[Diffusion-Weighted Imaging Assessment Of The Genuine Need For Other Studies In Ischemic Stroke]]
|-
| [[DIAL]]
| [[Randomized Trial Of Telephone Intervention In Chronic Heart Failure]]
|-
| [[DIAMOND]]
| [[Danish Investigations Of Arrhythmia And Mortality On Dofetilide]]
|-
| [[DIAMOND]]
| [[Distensibility Improvement With Alt-711 Remodeling In Diastolic Heart Failure Sponsor]]
|-
| [[DIAMOND CHF]]
| [[Danish Investigators Of Arrhythmia And Mortality On Dofetilde Congestive Heart Failure ]]
|-
| [[DIDI]]
| [[Diltiazem In Dilated Cardiomyopathy]]
|-
| [[DIG]]
| [[Digoxin Investigation Group]]
|-
| [[DIG Enalapril]]
| [[Enalapril Versus Digoxin In Patients With Congestive Heart Failure: A Multicenter Study (Canadian Enalapril Versus Digoxin Study Group)]]
|-
| [[DIGAMI]]
| [[Diabetes Mellitus Insulin-Glucose Infusion In Acute Myocardial Infarction]]
|-
| [[DIMT]]
| [[Double-Blind Placebo-Controlled Study Of Ibopamine And Digoxin In Patients With Mild To Moderate Heart Failure: Results Of The Dutch Ibopamine Multic]]
|-
| [[DINAMIT]]
| [[Defibrillation In Acute Myocardial Infarction Trial]]
|-
| [[DIPOM]]
| [[Diabetic Postoperative Mortality And Morbidity Trial]]
|-
| [[DIRECT]]
| [[Direct Stenting Using The Sirolimus-Eluting Stent]]
|-
| [[DIRECT]]
| [[Direct Myocardial Revascularization In Regeneration Of Endocardial Channels Trial]]
|-
| [[DIRECT]]
| [[Diabetic Retinopathy Candesartan Trial Candesartan Cilexetil (Atacand)]]
|-
| [[DIRECTOR]]
| [[Direct Stenting Study With Orbus R Stent]]
|-
| [[DISC]]
| [[Disability In Strategies For Care]]
|-
| [[DISCO]]
| [[Direct Coronary Stenting Versus Stenting With Balloon Predilation: Immediate And Follow-Up Results]]
|-
| [[DISTINCT]]
| [[Biodivysio Stent In Controlled Trial]]
|-
| [[DMIST]]
| [[Digital Mammographic Imaging Screening Trial]]
|-
| [[DPP]]
| [[Diabetes Prevention Program Trial]]
|-
| [[DPT-1]]
| [[Diabetes Prevention Trial - Type 1 ]]
|-
| [[DREAM]]
| [[Diabetes Reduction Approaches With Ramipril And Rosiglitazone Medications]]
|-
| [[DREAM - Ramipril]]
| [[Diabetes Reduction Assessment With Ramipril And Rosiglitazone Medication]]
|-
| [[DREAM - Rosiglitazone]]
| [[Diabetes Reduction Assessment With Ramipril And Rosiglitazone Medication]]
|-
| [[DUCCS-1]]
| [[Duke University Clinical Cardiology Study - 1]]
|-
| [[DUCCS-2]]
| [[Duke University Clinical Cardiology Study - 2]]
|-
| [[DYSBOT]]
| [[Dysport And Botox Study ]]
|-
| [[EAFT]]
| [[European Atrial Fibrillation Trial]]
|-
| [[EAGAR]]
| [[Estrogen And Graft Atherosclerosis Research Trial]]
|-
| [[EARLY]]
| [[Eptifibatide For Acute Coronary Syndromes—Rapid Versus Late Administration For Therapeutic Yield]]
|-
| [[EARLY]]
| [[Endothelin Antagonist Trial In Mildly Symptomatic Pulmonary Arterial Hypertension Patient]]
|-
| [[EARLY ACS]]
| [[Early Glycoprotein IIb/IIia Inhibition In Non–St-Segment Elevation Acute Coronary Syndromes]]
|-
| [[EARS]]
| [[European Atherosclerosis Research Study]]
|-
| [[EARTH]]
| [[Endothelin Receptor Antagonist Trial In Heart Failure]]
|-
| [[EASE]]
| [[Ezetimibe Add-On To Statin Therapy For Effectiveness Trial]]
|-
| [[EAST]]
| [[Emory Angioplasty Vs Surgery Trial]]
|-
| [[EASTER]]
| [[Estrogen And Stents To Eliminate Restenosis]]
|-
| [[EASY]]
| [[Early Discharge After Transradial Stenting Of Coronary Arteries]]
|-
| [[EASYAS]]
| [[Eastbourne Syncope Assessment Study]]
|-
| [[ECASS III]]
| [[European Cooperative Acute Stroke Study III]]
|-
| [[ECCE]]
| [[Effects Of Captopril On Cardiopulmonary Exercise Parameters (Ecce)]]
|-
| [[ECCO 2000]]
| [[Effects Of Citicoline (Ceraxon) On Clinical Outcome - 2000 Mg ]]
|-
| [[ECHO in PPH]]
| [[Echocardiographic Predictors Of Adverse Outcomes In Primary Pulmonary Hypertension.]]
|-
| [[ECLA GIK]]
| [[Estudios Cardiologicos Latinoamerica Glucose-Insulin-Potassium Pilot Trial]]
|-
| [[ECLIPSE]]
| [[Ensure's Vascular Closure Device Speeds Hemostasis Trial]]
|-
| [[ECRIS]]
| [[Endocoronary-Rhenium-Irradiation-Study]]
|-
| [[ECSG-1]]
| [[European Cooperative Study Group For Recombinant Tissue-Type Plasminogen Activator]]
|-
| [[ECSG-6]]
| [[European Cooperative Study Group For Recombinant Tissue-Type Plasminogen Activator II]]
|-
| [[ECSS]]
| [[European Coronary Surgery Study Group]]
|-
| [[ECST]]
| [[European Carotid Surgery Trial]]
|-
| [[EDGECAP]]
| [[Evaluation Of Daptomycin (Cidecin) In Gram-Positive Entities In The Treatment Of Community-Acquired Pneumonia]]
|-
| [[EDGESST]]
| [[Evaluation Of Daptomycin (Cidecin) In Gram-Positive Entities In The Treatment Of Complicated Skin And Soft Tissue Infections]]
|-
| [[EDGE]]
| [[Evaluation Of Daptomycin (Cidecin) In Gram-Positive Entities]]
|-
| [[EDGEUTI]]
| [[Evaluation Of Daptomycin (Cidecin) In Gram-Positive Entities In The Treatment Of Complicated Urinary Tract Infection]]
|-
| [[ED-IMPACT]]
| [[Emergency Department Impedance Cardiography-Aided Assessment Changes Therapy Sponsor: Cardiodynamics International]]
|-
| [[EFICAT]]
| [[Ejection Fraction In Cardiac Transplant Patients]]
|-
| [[EGASIS]]
| [[Early Gaba-Ergic Activation Sin Troke]]
|-
| [[ELATE]]
| [[Extended Low-Intensity Anticoagulation For Thrombo-Embolism Investigators]]
|-
| [[ELECT]]
| [[Evaluating Enoxaparin (Lovenox) Clotting Times]]
|-
| [[ELITE]]
| [[Evaluation Of Losartan In The Elderly]]
|-
| [[ELITE-II]]
| [[Losartan Heart Failure Survival Study]]
|-
| [[ELLDOPA]]
| [[Earlier Versus Later Levodopa In Parkinson Disease]]
|-
| [[ELUTES]]
| [[European Evaluation Of Paclitaxel Eluting Stent]]
|-
| [[ELVD-CHF]]
| [[Exercise In Left Ventricular Dysfunction And Chronic Heart Failure Trial]]
|-
| [[EMERALD]]
| [[Enhanced Myocardial Efficacy And Removal By Aspiration Of Liberated Debris]]
|-
| [[EMERALD]]
| [[European And Australian Multicenter Evaluative Research On Atrial Fibrillation—Dofetilide]]
|-
| [[EMERAS]]
| [[Estudio Multicentrico Estreptoquinasa Republicas De America Del Sur]]
|-
| [[EMIAT]]
| [[European Myocardial Infarction Amiodarone Trial]]
|-
| [[EMIP]]
| [[Prehospital Thrombolytic Therapy In Patients With Suspected Acute Myocardial Infarction]]
|-
| [[EMIP-FR]]
| [[European Myocardial Infarction Project—Free Radicals]]
|-
| [[EMIT]]
| [[European Mivazerol Trial]]
|-
| [[EMPIRIC]]
| [[Comparison Of Empiric To Physician-Tailored Programming Of Implantable Cardioverter Defibrillators Trial]]
|-
| [[ENABLE]]
| [[Effects Of The Endothelin Receptor Antagonist Bosentan On The Morbidity And Mortality In Patients With Chronic Heart Failure]]
|-
| [[ENCOR]]
| [[Enrasentan Cooperative Randomized Evaluation]]
|-
| [[ENCORE I]]
| [[Evaluation Of Nifedipine And Cerivastatin On Recovery Of Coronary Endothelial Function]]
|-
| [[ENCORE II]]
| [[Long-Term Effect Of Nifedipine On Vasomotion And Vessel Morphology In Patients With Coronary Artery Disease: An Intravascular Ultrasound-Assisted Evaluation]]
|-
| [[ENDEAVOR II]]
| [[Randomized Comparison Of The Endeavor Abt-578 Drug Eluting Stent With A Bare Metal Stent For Coronary Revascularization]]
|-
| [[ENDEAVOR III]]
| [[Randomized Comparison Of Zotarolimus-Eluting And Sirolimus-Eluting Stents In Patients With Coronary Artery Disease-3]]
|-
| [[ENDEAVOR IV]]
| [[Randomized Comparison Of Zotarolimus-Eluting And Paclitaxel-Eluting Stents In Patients With Coronary Artery Disease-4]]
|-
| [[ENDEAVOR-1]]
| [[Multicenter Evaluation Of Abt-578 Elution From A Phosphorylcholine-Coated Stent]]
|-
| [[ENHANCE]]
| [[Simvastatin With Or Without Ezetimibe In Familial Hypercholesterolemia]]
|-
| [[ENRICHD]]
| [[Enhancing Recovery In Coronary Heart Disease]]
|-
| [[ENTIRE]]
| [[Enoxaparin And Tnk-Tpa With Or Without Gp IIb/IIia Inhibitor As Reperfusion Strategy In St Elevation Mi (TIMI-23) ]]
|-
| [[EPAMSA]]
| [[Estudio Piloto Argentino De Muerte Subita Y Amioda Rone (Argentine Pilot Study Of Sudden Death And Amiodarone)]]
|-
| [[EPAT]]
| [[Estrogen In The Prevention Of Atherosclerosis Trial]]
|-
| [[EPHESUS]]
| [[Eplerenone Post-Ami Heart Failure Efficacy And Survival Study]]
|-
| [[EPIC]]
| [[Evaluation Of C7E3 For The Prevention Of Ischemic Complications]]
|-
| [[EPILOG]]
| [[Evaluation Of Ptca To Improve Long-Term Outcome By C7E3 Gp IIb/IIia Receptor (Abciximab) Blockade]]
|-
| [[EPISTENT]]
| [[Evaluation Of Platelet IIb/IIia Inhibitor For Stenting Trial]]
|-
| [[EPOS]]
| [[Elective Pci In Outpatient Study]]
|-
| [[ERA]]
| [[Enoxaparin Restenosis (Era) Trial.]]
|-
| [[ERA]]
| [[Early Rheumatoid Arthritis (Ra) Enoxaparin Restenosis After Angioplasty StudyEstrogen Replacement And Atherosclerosis Study]]
|-
| [[ERA (HRT)]]
| [[Effect Of Estrogen Replacement On The Progression Of Coronary Artery Atherosclerosis]]
|-
| [[ERACI]]
| [[Estudio Randomizado Argentino De Angioplastia Vs. Cirugía (Argentine Randomized Trial Of Percutaneous Transluminal Coronary Angioplasty Versus Coronary Artery Bypass Surgery In Multivessel Disease)]]
|-
| [[ERACI II]]
| [[Argentine Randomized Study: Coronary Angioplasty With Stenting Vs. Coronary Artery Bypass Surgery In Patients With Multiple-Vessel Disease (Eraci II): 30-Day And One Year Follow-Up Results]]
|-
| [[ERASE]]
| [[Emergency Room Assessment Of Sestamibi For Evaluation Of Chest Pain]]
|-
| [[ERASE]]
| [[Effects Of Rhdl On Atherosclerosis–Safety And Efficacy]]
|-
| [[ERASER]]
| [[Evaluation Of Reopro And Stenting To Eliminate Restenosis]]
|-
| [[ERBAC]]
| [[Excimer Laser, Rotational Atherectomy, Balloon Angioplasty Complications Study]]
|-
| [[ERGO]]
| [[Etomoxir For The Recovery Of Glucose Oxidation]]
|-
| [[ERICA]]
| [[Efficacy Of Ranolazine In Chronic Angina]]
|-
| [[ERNA]]
| [[Early Return To Normal Activities At Two Weeks After Acute Myocardial Infarction: Preliminary Results Of A Randomized Study]]
|-
| [[ER-TIMI]]
| [[Early Retavase - Thrombolysis In Myocardial Infarction]]
|-
| [[ESCAMI]]
| [[Evaluation Of The Safety And Cardioprotective Effects Of Eniporide In Acute Myocardial Infarction]]
|-
| [[ESCAPE]]
| [[Evaluation Study Of Congestive Heart Failure And Pulmonary Artery Catheterization Effectiveness]]
|-
| [[ESCAPE]]
| [[Evaluation Study Of Congestive Heart Failure And Pulmonary Artery Catheterization Effectiveness]]
|-
| [[E-SIRIUS]]
| [[European Sirolimus-Eluting Stent In Coronary Lesions]]
|-
| [[ESPRIT]]
| [[Enhanced Suppression Of The Platelet IIb/IIia Receptor With Integrilin TherapyEuropean Study Of The Prevention Of Reocclusion After Initial ThrombolysisEvaluation Of Subcutaneous Proleukin In A Randomized International Trial]]
|-
| [[ESPRIT HRT]]
| [[Oestrogen In The Prevention Of Reinfarction Trial]]
|-
| [[ESPS2]]
| [[European Stroke Prevention Study 2]]
|-
| [[ESPS-2]]
| [[European Stroke Prevention Study 2]]
|-
| [[ESSENCE]]
| [[Efficacy And Safety Of Subcutaneous Enoxaparin In Unstable Angina And Non-Q-Wave Mi]]
|-
| [[ESSENCE]]
| [[Efficacy And Safety Of Subcutaneous Enoxaparin In Non–Q-Wave Coronary Events ]]
|-
| [[ESSENTIAL]]
| [[The Studies Of Oral Enoximone Therapy In Advanced Heart Failure]]
|-
| [[ESSENTIAL]]
| [[The Studies Of Oral Enoximone Therapy In Advanced Heart Failure]]
|-
| [[ESTAT]]
| [[European Stroke Treatment With Ancrod Trial]]
|-
| [[ESTEEM]]
| [[Efficacy And Safety Of The Oral Direct Thrombin Inhibitor Ximelagatran In Patients After Acute Myocardial Infarction]]
|-
| [[ESVEM]]
| [[Electrophysiologic Study Versus Electrocardiographic Monitoring Trial]]
|-
| [[ETHECC]]
| [[Evaluation Of Thymitaq In Hepatocellular Carcinoma]]
|-
| [[ETICA]]
| [[Exercise Training Intervention After Coronary Angioplasty: The Etica Trial]]
|-
| [[[ETROP]]
| [[Early Treatment Of Retinopathy Of Prematurity]]
|-
| [[EURIDIS and ADONIS]]
| [[Maintenance Of Sinus Rhythm With Dronedarone In Patients With Atrial Fibrillation Or Flutter]]
|-
| [[EUROACTION]]
| [[Nurse-Coordinated Multidisciplinary, Family-Based Cardiovascular Disease Prevention Programme]]
|-
| [[EUROCARE]]
| [[Carvedilol For Prevention Of Restenosis After Directional Coronary Atherectomy]]
|-
| [[EUROPA]]
| [[European Trial On Reduction Of Cardiac Events With Perindopril In Stable Coronary Artery Disease]]
|-
| [[EURO-SPAH]]
| [[European Sonotherapy Trial To Prevent Arterial Hyperplasia]]
|-
| [[Euro-SPAH]]
| [[European-Sonotherapy Prevention Of Arterial Hyperplasia]]
|-
| [[EUROSTAR]]
| [[European Cobalt Stent With Antiproliferative For Restenosis Trial]]
|-
| [[EUTOPIA]]
| [[European Trial On Olmesartan And Pravastatin In Inflammation And Atherosclerosis]]
|-
| [[EVA]]
| [[Common Carotid Intima-Media Thickness Predicts Occurrence Of Carotid Atherosclerotic Plaques: Longitudinal Results From The Aging Vascular Study]]
|-
| [[EVA-AMI]]
| [[Eptifibatide Versus Abciximab In Primary Pci For Acute St Elevation Myocardial Infarction]]
|-
| [[EVEREST]]
| [[Efficacy Of Vasopressin Antagonism In Heart Failure: Outcome Study With Tolvaptan]]
|-
| [[EVEREST I]]
| [[Endovascular Valve Edge-To-Edge Repair Study]]
|-
| [[EVET]]
| [[Enoxaparin Versus Tinzaparin In Non-St-Segment Elevation Acute Coronary Syndromes]]
|-
| [[EVIDENCE]]
| [[Evidence For Interferon Dose-Effect: European-North American Comparative Efficacy Study (Rebif V. Avonex In Relapsing-Remitting Multiple Sclerosis (Rrms))]]
|-
| [[EVIDENT]]
| [[Endo-Vascular Investigation Determining The Safety Of A New Tacrolimus Eluting Stent Graft]]
|-
| [[EVIDENT]]
| [[Endovascular Investigation Determining The Safety Of A New Tacrolimus-Eluting Stent Graft]]
|-
| [[EXCITE]]
| [[Evaluation Of Oral Xemilofiban In Controlling Thrombotic Events]]
|-
| [[EXCITE]]
| [[Evaluation Of Oral Xemilofiban In Controlling Thrombotic Events ]]
|-
| [[EXCITe]]
| [[Extremity Constraint-Induced Therapy]]
|-
| [[EXCLAIM]]
| [[Extended Clinical Prophylaxis In Acutely Ill Medical Patients (Lovenox (Enoxaparin) Postmarketing (Phase Iv) Trial) ]]
|-
| [[EXPEDITION]]
| [[Na+/H+ Exchange Inhibition To Prevent Coronary Events In Acute Cardiac Conditions]]
|-
| [[EXPIRA]]
| [[ Thrombectomy With Export Catheter In Infarct-Related Artery During Primary Percutaneous Coronary Intervention]]
|-
| [[ExTRACT]]
| [[Enoxaparin And Thrombolysis Reperfusion For Acute Myocardial Infarction Treatment]]
|-
| [[F.I.R.E.]]
| [[Efficacy Of Fx06 In The Prevention Of Myocardial Reperfusion Injury Trial]]
|-
| [[FAAT]]
| [[Fatty Acid Antiarrhythmia Trial]]
|-
| [[FACET]]
| [[Flosequinan - Ace Inhibition Trial]]
|-
| [[FACET]]
| [[Fosinopril Versus Amlodipine Cardiovascular Events Randomized Trial]]
|-
| [[FACIT]]
| [[Folate After Coronary Intervention Trial]]
|-
| [[FACT]]
| [[Effect Of Nadroparin, A Low-Molecular-Weight Heparin, On Clinical And Angiographic Restenosis After Coronary Balloon Angioplasty]]
|-
| [[FAME]]
| [[Fractional Flow Reserve Versus Angiography For Multivessel Evaluation]]
|-
| [[FAME]]
| [[Fluvastatin (Lescol) Assessment Of Morbi-Mortality In The Elderly]]
|-
| [[FAMIS]]
| [[Fosinopril In Acute Myocardial Infarction Study]]
|-
| [[FANTASTIC]]
| [[Randomized Multicenter Comparison Of Conventional Anticoagulation Versus Antiplatelet Therapy In Unplanned And Elective Coronary Stenting]]
|-
| [[FAST]]
| [[Femoral Artery Stenting Trial]]
|-
| [[FASTER]]
| [[Fibrinolytic And Aggrastat St Elevation Resolution First Abarelix Depot Study For Treating Endometriosis RapidlyFirst And Second Trimester Evaluation Of Risk]]
|-
| [[FAST-MAG]]
| [[Field Administration Of Stroke Therapy - Magnesium]]
|-
| [[FATS]]
| [[Familial Atherosclerosis Treatment Study]]
|-
| [[FEMINA]]
| [[Addition Of Felodipine To Metoprolol Vs. Replacement Of Metoprolol By Felodipine In Patients With Angina Pectoris Despite Adequate Beta-Blockade]]
|-
| [[FERRIC-HF]]
| [[Effect Of Intravenous Ferrous Sucrose On Exercise Capacity In Chronic Heart Failure]]
|-
| [[FEST]]
| [[Fosinopril Efficacy/Safety Trial]]
|-
| [[FIELD]]
| [[Fenofibrate Intervention And Event Lowering In Diabetes]]
|-
| [[FIELD]]
| [[Fenofibrate (Tricor) Intervention And Event Lowering In Diabetes]]
|-
| [[FINESSE]]
| [[Facilitated Intervention With Enhanced Reperfusion Speed To Stop Events]]
|-
| [[FIRE]]
| [[Filterwire Ex Randomized Evaluation]]
|-
| [[FIRST]]
| [[Flolan International Randomized Survival Trial (Phase IIi (Develop Economic Data))]]
|-
| [[FIRST]]
| [[Flolan (Dobutamine) International Randomized Survival Trial First Trimester Integrated Risk Screening For Trisomy]]
|-
| [[FLARE]]
| [[Fluvastatin Angioplasty Restenosis]]
|-
| [[FLARE]]
| [[Fluvastatin (Lescol) Angiographic Restenosis]]
|-
| [[FLORIDA]]
| [[Fluvastatin On Risk Diminishing After Acute Myocardial Infarction]]
|-
| [[FLUCAD]]
| [[Influenza Vaccination In Secondary Prevention From Coronary Ischemic Events In Coronary Artery Disease]]
|-
| [[FOOD]]
| [[Feed Or Ordinary Diet]]
|-
| [[FOSIT]]
| [[Fosamax International Trial]]
|-
| [[FRAXIS]]
| [[Fraxiparin Versus Unfractionated Heparin In The Treatment Of Unstable Angina]]
|-
| [[FRAXIS / FRAX.I.S.]]
| [[Fraxiparine In Ischemic Syndromes]]
|-
| [[FRESCO]]
| [[Investigators In The Florence Randomized Elective Stenting In Acute Coronary Occlusions]]
|-
| [[FRIC]]
| [[Fragmin In Unstable Coronary Artery Disease]]
|-
| [[FRIC]]
| [[Fragmin In Unstable Coronary Artery Disease]]
|-
| [[FRISC]]
| [[Fast Revascularization During Instability In Coronary Artery Disease]]
|-
| [[FRISC II]]
| [[Fragmin And Fast Revascularization During Instability In Coronary Artery Disease]]
|-
| [[FROST]]
| [[French Optimal Stenting Trial]]
|-
| [[FROSTY]]
| [[Freezor Trial Of Supraventricular Tachycardia]]
|-
| [[FTT]]
| [[Fibrinolytic Therapy Trialists' Collaborative Group]]
|-
| [[FUSION]]
| [[Fractional Flow Reserve And Ultrasound Indices For Objective Narrowing Assessment]]
|-
| [[FUSION I]]
| [[Follow-Up Serial Infusions Of Nesiritide Trial]]
|-
| [[FUTURE I]]
| [[First Use To Underscore Restenosis Reduction With Everolimus]]
|-
| [[FUTURE II]]
| [[Multicenter Evaluation Of The Biosbsorbable Polymer-Based Everolimus-Eluting Stent]]
|-
| [[GABI]]
| [[German Angioplasty Vs. Bypass Surgery Investigation]]
|-
| [[GABI-2]]
| [[German Angioplasty Bypass Investigation - 2]]
|-
| [[GAMI]]
| [[ Glucose Abnormalities In Patients With Myocardial Infarction: Prevalence, Diagnosis, And Prognostic Implications]]
|-
| [[GAMMA II]]
| [[Gamma II Localized Radiation Therapy To Inhibit Restenosis]]
|-
| [[GAMMA V]]
| [[Gamma V Localized Radiation Therapy To Inhibit Restenosis]]
|-
| [[Gamma-One]]
| [[Localized Intracoronary Gamma-Radiation Therapy To Inhibit The Recurrence Of Restenosis After Stenting]]
|-
| [[GART study]]
| [[Genotypic Antiretroviral Resistance Testing]]
|-
| [[GEMICA]]
| [[Morbidity And Mortality Following Early Administration Of Amiodarone In Myocardial Infarction]]
|-
| [[GEMINI]]
| [[Glycemic Effects In Diabetes Mellitus: Carvedilol - Metoprolol Comparison In Hypertensives Trial]]
|-
| [[GEMS]]
| [['Ginkgo Biloba 'Evaluation Memory Study]]
|-
| [[GENESIS]]
| [[A Randomized, Multicenter Study Of The Pimecrolimus-Eluting And Pimecrolimus/Paclitaxel-Eluting Coronary Stent System In Patients With De Novo Lesions Of The Native Coronary Arteries]]
|-
| [[GENEVA]]
| [[ Intracoronary Beta Irradiation To Reduce Restenosis After Balloon Angioplasty]]
|-
| [[GENIUS-STEMI]]
| [[A Randomized Comparison Of Genous Stent Versus Chromium-Cobalt Stent For Treatment Of St-Elevation Myocardial Infarction]]
|-
| [[GenSalt]]
| [[Genetic Epidemiology Network Of Salt Sensitivity]]
|-
| [[GESICA]]
| [[Randomized Trial Of Low-Dose Amiodarone In Severe Congestive Heart Failure]]
|-
| [[GIPS]]
| [[Randomized Trial Of Glucose-Insulin-Potassium Infusion On 30 Day Mortality In Patients With Acute Myocardial Infarction Treated With Primary Angioplasty]]
|-
| [[GIPS II]]
| [[ Glucose - Insulin - Potassium Study In Patients With St Elevation Myocardial Infarction Without Signs Of Heart Failure]]
|-
| [[GISEN]]
| [[Gruppo Italiano Di Studi Epidemiologici In Nefrologia]]
|-
| [[GISSI-1]]
| [[Gruppo Italiano Per Lo Studio Della Sopravvivenza Nell'Infarto Miocardico Acuto-1]]
|-
| [[GISSI-2]]
| [[Gruppo Italiano Per Lo Studio Della Sopravvivenza Nell'Infarto Miocardico Acuto-2]]
|-
| [[GISSI-3]]
| [[Effects Of Lisinopril And Transdermal Glycerol Trinitrate Singly And Together On 6-Week Mortality And Ventricular Function After Ami]]
|-
| [[GISSI-HF: n-3 PUFA]]
| [[Gruppo Italiano Per Lo Studio Della Sopravvivenza Nell’Infarto Miocardico–Heart Failure: N-3 Pufa]]
|-
| [[GISSI-HF: Rosuvastatin]]
| [[Gruppo Italiano Per Lo Studio Della Sopravvivenza Nell’Infarto Miocardico–Heart Failure: Rosuvastatin]]
|-
| [[GOSPEL]]
| [[Global Secondary Prevention Strategies To Limit Event Recurrence After Myocardial Infarction]]
|-
| [[G-PAD]]
| [[Granulocyte-Macrophage Colony Stimulating Factor In Patients With Intermittent Claudication]]
|-
| [[GRACIA I]]
| [[Randomized Trial Comparing Stenting Within 24 Hours Of Thrombolysis Versus Ischemia-Guided Approach To Thrombolysed Acute Myocardial Infarction With St Elevation]]
|-
| [[GRACIA II]]
| [[Primary Optimal Percutaneous Coronary Intervention Versus Facilitated Intervention In Stemi Patients]]
|-
| [[GRAPE]]
| [[Grampian Region Early Anistreplase Trial]]
|-
| [[GUARDIAN]]
| [[Inhibition Of The Sodium-Hydrogen Exchanger With Cariporide To Prevent Myocardial Infarction In High-Risk Ischemic Situations: Main Results Of The Guard During Ischemia Against Necrosis (Guardian) Trial]]
|-
| [[GUSTO]]
| [[Global Utilization Of Streptokinase And Tpa For Occluded Arteries ]]
|-
| [[GUSTO IIB]]
| [[Global Utilization Of Streptokinase And Tpa For Occluded Arteries IIb]]
|-
| [[GUSTO V]]
| [[The Gusto V Randomised Trial]]
|-
| [[GUSTO-3]]
| [[Global Utilization Of Streptokinase And Tpa For Occluded Arteries-III]]
|-
| [[GUSTO-SPEED]]
| [[Global Utilization Of Streptokinase And Tpa For Occluded Arteries–Strategies For Patency Enhancement In The Emergency Department]]
|-
| [[HAAMU-STENT]]
| [[Helsinki Area Acute Myocardial Infarction Treatment Re-Evaluation - Should The Patients Get A Drug-Eluting Or Normal Stent]]
|-
| [[HACA]]
| [[Mild Therapeuric Hypothermia To Improve The Neurologic Outcome After Cardiac Arrest]]
|-
| [[HAEST]]
| [[Heparin In Acute Embolic Stroke Trial]]
|-
| [[HALT-C]]
| [[Hepatitis C Antiviral Long-Term Treatment To Prevent Cirrhosis ]]
|-
| [[HALT-MI]]
| [[Hu23F2G Anti-Adhesion To Limit Cytotoxic Injury Following Ami]]
|-
| [[HANDLS]]
| [[Health Aging In Nationally Diverse Longitudinal Samples]]
|-
| [[HANE]]
| [[Randomized, Double-Blind Multicenter Comparison Of Hydrochlorothiazide, Atenolol, Nitrendipine, And Enalapril In Antihypertensive Treatment]]
|-
| [[HARDBALL]]
| [[Heart Allograft Rejection: Detection With Breath Alkanes In Low Level]]
|-
| [[HARDBALL]]
| [[Heart Allograft Rejection: Detection With Breath Alkanes In Low Levels]]
|-
| [[HARP]]
| [[Harvard Atherosclerosis Reversibility Project]]
|-
| [[HART]]
| [[Heparin-Aspirin Reperfusion Trial]]
|-
| [[HART II]]
| [[Randomized Comparison Of Enoxaparin, A Low-Molecular-Weight Heparin, With Unfractionated Heparin Adjunctive To Recombinant Tissue Plasminogen Activator Thrombolysis And Aspirin: Second Trial Of Heparin And Aspirin Reperfusion Therapy]]
|-
| [[HAT]]
| [[Home Automatic External Defibrillator Trial]]
|-
| [[HAT 1]]
| [[Heparin-Associated Thrombocytopenia 1]]
|-
| [[HAT 2]]
| [[Heparin-Associated Thrombocytopenia 2]]
|-
| [[HATS]]
| [[Hdl-Atherosclerosis Treatment Study]]
|-
| [[HDFP]]
| [[Hypertension Detection And Follow-Up Program]]
|-
| [[HDOM]]
| [[Heart Disease On The Mend]]
|-
| [[HeADDFIRST]]
| [[Hemicraniectomy And Durotomy For Deterioration From Infarction Relating Swelling Trial]]
|-
| [[HEART]]
| [[Healing And Early Afterload Reducing Therapy Trial]]
|-
| [[HEART]]
| [[Healing And Early Afterload Reducing Therapy]]
|-
| [[HEAT 2]]
| [[Hypertension Endothelin Antagonist Treatment]]
|-
| [[Heidelberg]]
| [[Heidelberg Trial]]
|-
| [[HELAS]]
| [[Antithrombotic Therapy In Heart Failure: A Randomized Comparison Of Warfarin Vs. Aspirin]]
|-
| [[HELAS]]
| [[Antithrombotic Therapy In Heart Failure: A Randomized Comparison Of Warfarin Vs. Aspirin]]
|-
| [[Helsinki Heart Study]]
| [[Helsinski Heart Study]]
|-
| [[Helsinki Heart Study]]
| [[Helsinski Heart Study]]
|-
| [[HEME]]
| [[Hemorrhage Early Mri Evaluation]]
|-
| [[HERO]]
| [[Hirulog Early Reperfusion/Occlusion Trial]]
|-
| [[HERO]]
| [[Hirulog Early Reperfusion/Occlusion Trial]]
|-
| [[HERO-2]]
| [[Hirulog And Early Reperfusion Or Occlusion Trial]]
|-
| [[HERS]]
| [[Heart And Estrogen/Progestin Replacement Study]]
|-
| [[HERS]]
| [[Heart And Estrogen/Progestin Replacement Study Hiv Epidemiology Research Study]]
|-
| [[HESTIA]]
| [[Home Evaluation Of Stroke Induced Aid]]
|-
| [[HF-ACTION]]
| [[Heart Failure–A Randomized Controlled Trial Investigating Outcomes Of Exercise Training]]
|-
| [[HF-ACTION Substudy]]
| [[Effect Of Exercise Training On Health-Related Quality Of Life In Patients With Chronic Heart Failure]]
|-
| [[HHH]]
| [[Home Or Hospital Heart Failure]]
|-
| [[HIJ-CREATE]]
| [[Heart Institute Of Japan Candesartan Randomized Trial For Evaluation In Coronary Artery Disease]]
|-
| [[HIPS]]
| [[Heparin Infusion Prior To Stenting ]]
|-
| [[HIT]]
| [[Hdl-Cholesterol Intervention Trial Hirudin For The Improvement Of Thrombolysis]]
|-
| [[HIT-I]]
| [[Hirudin For The Improvement Of Thrombolysis]]
|-
| [[HIT-III]]
| [[Hirudin For Improvement Of Thrombolysis]]
|-
| [[HOME]]
| [[Hyperinsulinemia: The Outcome Of Its Metabolic Effects]]
|-
| [[HOPE]]
| [[Heart Outcomes Prevention Evaluation ]]
|-
| [[HOPE]]
| [[The Heart Outcomes Prevention Evaluation Study]]
|-
| [[HOPE-2]]
| [[Heart Outcomes Prevention Evaluation]]
|-
| [[HOPE-TOO]]
| [[Heart Outcomes Prevention Evaluation - The Ongoing Outcomes ]]
|-
| [[HORIZON]]
| [[Health Outcomes And Reduced Incidence With Zoledronic Once Yearly]]
|-
| [[HORIZONS-AMI]]
| [[Harmonizing Outcomes With Revascularization And Stents In Acute Myocardial Infarction]]
|-
| [[HORIZONS-AMI Stent]]
| [[Harmonizing Outcomes With Revascularization And Stents In Acute Myocardial Infarction]]
|-
| [[HOS]]
| [[Hypertension-Obesity-Sibutramine]]
|-
| [[HOT]]
| [[Hypertension Optimal Treatment Study]]
|-
| [[HOT]]
| [[Hypertension Optimum Treatment]]
|-
| [[HPS]]
| [[Medical Research Council/British Heart Foundation Heart Protection Study]]
|-
| [[HPS]]
| [[Heart Protection Study]]
|-
| [[HRS]]
| [[Health And Retirement Study]]
|-
| [[Hy-C]]
| [[The Hydralazine Captopril Trial]]
|-
| [[HYVET]]
| [[Hypertension In The Very Elderly Trial]]
|-
| [[HYVET]]
| [[Hypertension In The Very Elderly Trial]]
|-
| [[IBIS-2]]
| [[Integrated Biomarker And Imaging Study-2]]
|-
| [[ICE-IT]]
| [[Intravascular Cooling Adjunctive To Primary Coronary Intervention]]
|-
| [[ICON]]
| [[Ionic Versus Nonionic Contrast To Obviate Worsening Nephropathy After Angioplasty In Chronic Renal Failure Patients]]
|-
| [[ICSS]]
| [[International Carotid Stenting Study (Cavatas-2)]]
|-
| [[ICTUS]]
| [[Invasive Versus Conservative Treatment In Unstable Coronary Syndromes]]
|-
| [[IDEAL]]
| [[Incremental Decrease In Clinical Endpoints Through Aggressive Lipid Lowering]]
|-
| [[IDEAL]]
| [[Incremental Decrease In Endpoints Through Aggressive Lipid Lowering Iressa Dose Evaluation In Advanced Lung Cancer]]
|-
| [[IDNT]]
| [[Irbesartan Diabetic Nephropathy Trial]]
|-
| [[IDNT]]
| [[Irbesartan In Diabetic Nephropathy Trial]]
|-
| [[IHAST]]
| [[Intraoperative Hypothermia For Aneurysm Surgery Trial]]
|-
| [[ILLUMINATE]]
| [[ Investigation Of Lipid Level Management To Understand Its Impact In Atherosclerotic Events]]
|-
| [[ILLUSTRATE]]
| [[Investigation Of Lipid Level Management Using Coronary Ultrasound To Assess Reduction Of Atherosclerosis By Cetp Inhibition And Hdl Elevation]]
|-
| [[IMAGES]]
| [[Intravenous Magnesium Efficacy In Stroke]]
|-
| [[IMAGINE]]
| [[Ischemia Management With Accupril Post-Bypass Graft Via Inhibition Of The Converting Enzyme]]
|-
| [[IMAGINE]]
| [[Ischemic Management With Accupril Post Bypass Graft Via Inhibition Of Converting Enzyme]]
|-
| [[IMPACT]]
| [[Integrilin To Manage Platelet Aggregation To Prevent Coronary Thrombosis International Mexiletine Or Placebo Antiarrhythmic Coronary TrialInternational Multiple Sclerosis Secondary Progressive Avonex Controlled Trial]]
|-
| [[IMPACT II]]
| [[Integrilin To Minimise Platelet Aggregation And Coronary Thrombus - II]]
|-
| [[IMPACT-HF]]
| [[Initiation Management Predischarge: Process For Assessment Of Carvedilol Therapy In Heart Failure]]
|-
| [[IMPRESS]]
| [[ Immunosuppressive Therapy For The Prevention Of Restenosis After Coronary Artery Stent Implantation]]
|-
| [[IMPRESS]]
| [[Inhibition Of Metalloprotease By Bms-186716 In A Randomized Exercise And Symptoms Study ]]
|-
| [[IMPROVE-CHF]]
| [[Improved Management Of Patients With Congestive Heart Failure]]
|-
| [[IMS]]
| [[Interventional Management Of Stroke Study]]
|-
| [[IN-CHF]]
| [[Italian Network - Congestive Heart Failure]]
|-
| [[INCOMIN]]
| [[Independent Comparison Of Interferon (Betaseron V. Avonex In Relapsing-Remitting Multiple Sclerosis (Rrms)]]
|-
| [[InDDEx]]
| [[Investigation Into Delay To Diagnosis Of Alzheimer Disease With Exelon]]
|-
| [[INHIBIT]]
| [[Intimal Hyperplasia Inhibition With Beta In-Stent Trial]]
|-
| [[INHIBIT]]
| [[Intimal Hyperplasia Inhibition With Beta In-Stent Trial]]
|-
| [[INJECT]]
| [[International Joint Efficacy Comparison Of Thrombolytics]]
|-
| [[INSIGHT]]
| [[International Nifedipine Gits Study: Intervention As A Goal In Hypertension Treatment]]
|-
| [[INSIGHT]]
| [[International Nifedipine Once-Daily Study – Intervention As A Goal In Hypertension Treatment]]
|-
| [[INSPIRE]]
| [[Adenosine Sestamibi Post-Infarction Evaluation (Inspire) Trial]]
|-
| [[INSYNC]]
| [[Multisite Pacing As A Supplemental Treatment Of Congestive Heart Failure: The Medtronic Inc. Insync Study]]
|-
| [[INTACT]]
| [[Iressa Non–Small Cell Lung Cancer Trial Assessing Combination Treatment]]
|-
| [[INTAMI]]
| [[Integrilin In Acute Myocardial Infarction]]
|-
| [[INTEGRITI]]
| [[Integrilin And Tenecteplase In Acute Myocardial Infarction]]
|-
| [[INTEGRITI]]
| [[Integrilin And Tenecteplase In Acute Myocardial Infarction ]]
|-
| [[INTERACT]]
| [[Integrilin And Enoxaparin Randomized Assessment Of Acute Coronary Syndrome Treatment]]
|-
| [[INTERCEPT]]
| [[Incomplete Infarction Trial Of European Research Collaborators Evaluating Prognosis Post-Thrombolysis (Diltiazem)]]
|-
| [[INTERHEART]]
| [[A Study Of Risk Factors For First Myocardial Infarction In 52 Countries And Over 27,000 Subjects]]
|-
| [[InTIME]]
| [[Intravenous Npa For Treatment Of Infarcting Myocardium Early ]]
|-
| [[InTime-2]]
| [[Intravenous Npa For Treatment Of Infarcting Myocardium Early]]
|-
| [[INTrEPID]]
| [[Investigation Of Non–Transplant-Eligible Patients Who Are Inotrope Dependent See ]]
|-
| [[INTRINSIC RV]]
| [[ Inhibition Of Unnecessary Rv Pacing With Av Search Hysteresis In Icds]]
|-
| [[INTRO-AMI]]
| [[Integrilin And Reduced Dose Of Thrombolytic In Acute Myocardial Infarction]]
|-
| [[INVEST]]
| [[International Verapamil-Trandolapril Study]]
|-
| [[IONA]]
| [[Effect Of Nicorandil On Coronary Events In Patients With Stable]]
|-
| [[IONA]]
| [[Impact Of Nicorandil In Angina]]
|-
| [[IONDT]]
| [[Ischemic Optic Neuropathy Decompression Trial]]
|-
| [[I-PRESERVE]]
| [[Rbesartan In Heart Failure With Preserved Ejection Fraction Study]]
|-
| [[IRAS]]
| [[Insulin Resistance Atherosclerosis Study]]
|-
| [[IRIS]]
| [[Isostent For Restenosis Intervention Study]]
|-
| [[IRIS]]
| [[Isostent For Restenosis Intervention Study]]
|-
| [[IRMA 2]]
| [[Irbesartan In Type 2 Diabetes With Microalbuminuria 2]]
|-
| [[IRMA 2]]
| [[Irbesartan (Avapro) Microalbuminuria Type 2]]
|-
| [[ISAAC]]
| [[International Study Of Asthma And Allergies In Childhood]]
|-
| [[ISAM]]
| [[Intravenous Streptokinase In Acute Myocardial Infarction]]
|-
| [[ISAR]]
| [[Intracoronary Stenting And Antithrombotic Regimen Trial]]
|-
| [[ISAR]]
| [[Individualizable Drug-Eluting Stent System To Abrogate Restenosis Project]]
|-
| [[ISAR]]
| [[Intracoronary Stenting And Antithrombotic Regimen]]
|-
| [[ISAR DIABETES]]
| [[Paclitaxel-Eluting Stent Versus Sirolimus-Eluting Stent For The Prevention Of Restenosis In Diabetic Patients With Coronary Artery Disease]]
|-
| [[ISAR REACT]]
| [[Intracoronary Stenting And Antithrombotic Regimen Rapid Early Action For Coronary Treatment]]
|-
| [[ISAR-CHOICE]]
| [[Intracoronary Stenting And Antithrombotic Regimen: Choose Between 3 High Oral Doses For Immediate Clopidogrel Effect]]
|-
| [[ISAR-COOL]]
| [[Intracoronary Stenting With Antithrombotic Regimen Cooling-Off]]
|-
| [[ISAR-DESIRE]]
| [[Drug-Eluting Stents For In-Stent Restenosis]]
|-
| [[ISAR-LEFT MAIN]]
| [[Intracoronary Stenting And Angiographic Results: Drug-Eluting Stents For Unprotected Coronary Left Main Lesions]]
|-
| [[ISAR-PEACE]]
| [[ Intracoronary Stenting And Angiographic Restenosis: Promote Endothelial Cells With Estradiol]]
|-
| [[ISAR-REACT 2]]
| [[Intracoronary Stenting And Antithrombotic Regimen: Rapid Early Action For Coronary Treatment]]
|-
| [[ISAR-REACT 3]]
| [[Bivalirudin Versus Unfractionated Heparin During Percutaneous Coronary Intervention]]
|-
| [[ISAR-SHOCK]]
| [[Impella Lp2.5 Vs. Iabp In Cardiogenic Shock]]
|-
| [[ISAR-STEREO]]
| [[Intracoronary Stenting And Angiographic Results: Strut Thickness Effect On Restenosis Outcomes (Isar-Stereo) Trial]]
|-
| [[ISAR-STEREO]]
| [[Intracoronary Stenting And Angiographic Results - Strut Thickness Effect On Restenosis Outcome]]
|-
| [[ISAR-STEREO - 2]]
| [[Intracoronary Stenting And Angiographic Results - Strut Thicness Effect On Restenosis Outcome Trial - 2]]
|-
| [[ISAR-SWEET]]
| [[Is Abciximab A Superior Way To Eliminate Elevated Thrombotic Risk In Diabetics]]
|-
| [[ISAR-TEST]]
| [[Randomized Trial Of The Yukon Nonpolymer-Based Rapamycin-Coated Stent And The Polymer-Based Paclitaxel-Eluting Stent In Patients With Coronary Artery Disease]]
|-
| [[ISAR-TEST-2]]
| [[Intracoronary Stenting And Angiographic Results–Test Efficacy Of 3 Limus-Eluting Stents]]
|-
| [[ISAR-TEST-3]]
| [[Intracoronary Stenting And Angiographic Restenosis Investigators – Test Efficacy Of Rapamycin-Eluting Stents With Different Polymer Coating Strategies]]
|-
| [[ISAT]]
| [[International Subarachnoid Aneurysm Trial]]
|-
| [[ISIS-1]]
| [[First International Study Of Infarct Survival]]
|-
| [[ISIS-2]]
| [[International Study Of Infarct Survival-2]]
|-
| [[ISIS-3]]
| [[ International Study Of Infarct Survival-3]]
|-
| [[ISIS-4]]
| [[Fourth International Study Of Infarct Survival]]
|-
| [[IST]]
| [[The International Stroke Trial]]
|-
| [[ISTICH]]
| [[International Surgical Trial In Intracerebral Hemorrhage]]
|-
| [[ITALICS]]
| [[Investigation By The Thoraxcenter On Antisense Dna Using Local Delivery And Ivus After Coronary Stenting]]
|-
| [[ITT]]
| [[Intraventricular Thrombolysis Trial]]
|-
| [[IVAT]]
| [[Intermediate Sized Vessel Atherectomy Trial]]
|-
| [[JAMIS]]
| [[Effects Of Aspirin And Trapidil On Cardiovascular Events After Acute Myocardial Infarction]]
|-
| [[JELIS]]
| [[Japan Epa Lipid Intervention Study]]
|-
| [[JPAD]]
| [[Japanese Primary Prevention Of Atherosclerosis With Aspirin For Diabetes]]
|-
| [[JSAP]]
| [[Japanese Stable Angina Pectoris Study]]
|-
| [[JUMBO-TIMI 26]]
| [[Joint Utilisation Of Medications To Block Platelets Optimally]]
|-
| [[JUPITER]]
| [[Justification For The Use Of Statins In Prevention: An Intervention Trial Evaluating Rosuvastatin]]
|-
| [[J-WIND]]
| [[Japan Working Groups Of Acute Myocardial Infarction For The Reduction Of Necrotic Damage By Atrial Natriuretic Peptide Or Nicorandil]]
|-
| [[KAT II]]
| [[Kuopio Angiogenesis Trial]]
|-
| [[LACI]]
| [[Laser Angioplasty For Critical Ischemia ]]
|-
| [[LADIP]]
| [[Loire-Ardèche-Drôme-Isère-Puy-De-Dôme]]
|-
| [[LAMP]]
| [[Locally Advanced Multimodality Protoco]]
|-
| [[LARS]]
| [[Laser Angioplasty In Restenosed Stents]]
|-
| [[LATE]]
| [[Late Assessment Of Thrombolytic Efficacy Study]]
|-
| [[LAVA]]
| [[Prospective, Randomized, Multicenter Comparison Of Laser-Facilitated Balloon Angioplasty Versus Stand-Alone Balloon Angioplasty In Patients With Obstructive Coronary Artery Disease]]
|-
| [[L-CAD]]
| [[Lipid-Coronary Artery Disease (Pravastatin)]]
|-
| [[LCAS]]
| [[The Lipoprotein And Coronary Atherosclerosis Study (Lcas): Lipid And Metabolic Factors Related To Atheroma And Clinical Events]]
|-
| [[LEADER]]
| [[ Lower Extremity Arterial Disease Event Reduction Trial]]
|-
| [[LEADERS]]
| [[Limus Eluted From A Durable Vs Erodable Stent Coating]]
|-
| [[LHT]]
| [[Lifestyle Heart Trial]]
|-
| [[LIDO]]
| [[Levosimendan Infusion Versus Dobutamine]]
|-
| [[LIFE]]
| [[Losartan Intervention For Endpoint Reduction In Hypertension (Life) Study]]
|-
| [[LIMB]]
| [[Limbs International Medical Buflomedil Trial]]
|-
| [[LIMIT AMI]]
| [[Limitation Of Myocardial Infarction Following Thrombolysis In Acute]]
|-
| [[LIMIT-2]]
| [[Second Leicester Magnesium Intervention Trial]]
|-
| [[LIPID]]
| [[Long-Term Intervention With Pravastatin In Ischemic Disease Trial]]
|-
| [[LIPS]]
| [[Lescol Intervention Prevention Study]]
|-
| [[LISA]]
| [[Lescol In Severe Atherosclerosis Trial]]
|-
| [[LOCAT]]
| [[Prevention Of The Angiographic Progression Of Coronary And Vein-Graft Atherosclerosis By Gemfibrozil After Coronary Bypass Surgery In Men With Low Levels Of Hdl Cholesterol]]
|-
| [[LONG DES II]]
| [[Randomized Comparison Of The Efficacy Of Sirolimus-Eluting Stent Versus Paclitaxel-Eluting Stent In The Treatment Of Long Native Coronary Lesions]]
|-
| [[LONG-DES]]
| [[Multicenter Prospective Nonrandomized Registry Study For Drug-Eluting Stents In Very Long Coronary Lesions (Cypher Vs Taxus)]]
|-
| [[LRC-CPPT]]
| [[Lipid Research Clinics Coronary Primary Prevention Trial]]
|-
| [[MACH-1]]
| [[Mortality Assessment In Congestive Heart Failure Trial]]
|-
| [[MADIT]]
| [[Multicenter Automatic Defibrillator Implantation Trial]]
|-
| [[MADIT-II]]
| [[Multicenter Automatic Defibrillator Implantation Trial II]]
|-
| [[MAGIC]]
| [[Magnesium In Coronaries]]
|-
| [[MAGIC]]
| [[Myoblast Autologous Grafting In Ischemic Cardiomyopathy]]
|-
| [[MAGIC – Presented at AHA 2006]]
| [[Myoblast Autologous Grafting In Ischemic Cardiomyopathy]]
|-
| [[Male Health]]
| [[ Male Health Professionals Study]]
|-
| [[MAPPET-3]]
| [[ Management Strategies And Prognosis Of Pulmonary Embolism-3 Trial]]
|-
| [[MARS]]
| [[The Monitored Atherosclerosis Regression Study]]
|-
| [[MASCOT]]
| [[Management Of Atrial Fibrillation Suppression In Af-Hf Comorbidity Therapy]]
|-
| [[MASS]]
| [[The Medicine, Angioplasty Or Surgery Study]]
|-
| [[MASS]]
| [[The Multicenter Aneurysm Screening Study (Mass) Into The Effect Of Abdominal Aortic Aneurysm Screening On Mortality In Men: A Randomized Controlled Trial]]
|-
| [[MASS-II]]
| [[Second Medicine, Angioplasty, Or Surgery Study]]
|-
| [[MAST-E]]
| [[Thrombolytic Therapy With Streptokinase In Acute Ischemic Stroke]]
|-
| [[MASTER]]
| [[Microvolt T Wave Alternans Testing For Risk Stratification Of Post-Myocardial Infarction Patients]]
|-
| [[MATCH]]
| [[Management Of Atherothrombosis With Clopidogrel In High-Risk Patients]]
|-
| [[MATE]]
| [[Medicine Versus Angiography In Thrombolytic Exclusion Trial]]
|-
| [[MATH]]
| [[Endocrine And Renal Effects Of Nifedipine Gastrointestinal Theraputic System In Patients With Essential Hypertension: Results Of A Multicenter Trial]]
|-
| [[Matisse]]
| [[Subcutaneous Fondaparinux Versus Intravenous Unfractionated Heparin In The Initial Treatment Of Pulmonary Embolism]]
|-
| [[MATTIS]]
| [[Randomized Evaluation Of Anticoagulation Versus Antiplatelet Therapy After Coronary Stent Implantation In High-Risk Patients: The Multicenter Aspirin And Ticlopidine Trial After Intracoronary Stenting]]
|-
| [[MAVErIC II]]
| [[30-Day Results From A Prospective Registry Of Carotid Stenting With The Exponent Stent And Distal Protection With The Guardwire In High Risk Patients]]
|-
| [[MaVS]]
| [[Metoprolol After Vascular Surgery]]
|-
| [[MDC]]
| [[Metoprolol In Dilated Cardiomyopathy Trial]]
|-
| [[MDPIT]]
| [[The Multicenter Diltiazem Post Infarction Trial]]
|-
| [[MDRD]]
| [[Modification Of Diet In Renal Disease Study]]
|-
| [[MEDAL Program]]
| [[Multinational Etoricoxib And Diclofenac Arthritis Long-Term Study Program]]
|-
| [[MEDENOX]]
| [[Prophylaxis In Medical Patients With Enoxaparin]]
|-
| [[MEGA]]
| [[Management Of Elevated Cholesterol In The Primary Prevention Group Of Adult Japanese]]
|-
| [[MEND-CABG II]]
| [[Mc-1 To Eliminate Necrosis And Damage In Coronary Artery Bypass Graft Surgery II — Presented At Scai-Acc I2 Summit/Acc 2008]]
|-
| [[MERIT-HF]]
| [[Metoprolol Cr/Xl Randomized Intervention Trial In Congestive Heart Failure]]
|-
| [[MERLIN]]
| [[Middlesbrough Early Revascularization To Limit Infarction]]
|-
| [[MERLIN-TIMI 36]]
| [[Metabolic Efficiency With Ranolazine For Less Ischemia In Nste-Acs]]
|-
| [[METAFER]]
| [[Use Of Metoprolol To Maintain Sinus Rhythm After Conversion From Persistent Atrial Fibrillation]]
|-
| [[METEOR]]
| [[Measuring Effects On Intima-Media Thickness: An Evaluation Of Rosuvastatin]]
|-
| [[MEXIS]]
| [[The Effects Of B-Receptor Antagonists In Patients With Clinical Evidence Of Heart Failure After Myocardial Infarction: Double Blind Comparison Of Meto]]
|-
| [[M-HART]]
| [[Montreal Heart Attack Readjustment Trial]]
|-
| [[MHFT]]
| [[Munich Mild Heart Failure Trial]]
|-
| [[MIAMI]]
| [[Metoprolol In Acute Myocardial Infarction]]
|-
| [[MICRO-HOPE]]
| [[Microalbuminuria, Cardiovascular, And Renal Outcomes - Heart Outcomes Prevention Evaluation]]
|-
| [[MILIS]]
| [[Multiple Center Investigation Of The Limit Of Infarction]]
|-
| [[MINT]]
| [[A Multicenter, Randomized Study Of Argatroban Versus Heparin As Adjunct To Tissue Plasminogen Activator (Tpa) In Acute Myocardial Infarction: Myocardial Infarction With Novastan And Tpa (Mint) Study]]
|-
| [[MIRACL]]
| [[Effects Of Atorvastatin On Early Recurrent Ischemic Events In Acute Coronary Syndromes. The Miracl Study: A Randomized Controlled Trial]]
|-
| [[MIRACLE ICD]]
| [[Multicenter Insync Implantable Cardioversion Defibrillation Randomized Clinical Evaluation]]
|-
| [[MIST]]
| [[Migraine Intervention With Starflex Technology]]
|-
| [[MITI I]]
| [[Myocardial Infarction Triage And Intervention Project--Phase I]]
|-
| [[MITI II]]
| [[Myocardial Infarction Triage And Intervention Project--Phase I]]
|-
| [[MITRA]]
| [[Maximal Individual Therapy In Acute Myocardial Infarction]]
|-
| [[MOMENTUM]]
| [[Multicenter Trial Of The Orqis Medical Cancion System For The Enhanced Treatment Of Heart Failure Unresponsive To Medical Therapy]]
|-
| [[MONICA]]
| [[Monitoring Trends And Determinants In Cardiovascular Disease]]
|-
| [[MOST]]
| [[Mode Selection Trial (Most) In Sinus Node Dysfunction]]
|-
| [[MOXCON]]
| [[Excess Mortality In Chf Patients Treated With Sr Moxonidine Leads To Study Termination: Results Of The Sr Moxonidine For Congestive Heart Failure Trial]]
|-
| [[M-PATHY]]
| [[Multicenter Pacing Therapy]]
|-
| [[MPIP]]
| [[Multicenter Post-Infarction Program]]
|-
| [[MR PCI]]
| [[Multicenter Registry Of High-Risk Percutaneous Coronary Intervention And Adequate Platelet Inhibition]]
|-
| [[MRFIT]]
| [[Multiple Risk Factor Intervention Trial]]
|-
| [[MUSIC]]
| [[Multicenter Ultrasound Guided Stent Implantation In The Coronaries]]
|-
| [[MUST-EECP]]
| [[Multicenter Enhanced External Counterpulsation]]
|-
| [[MUSTIC]]
| [[Multisite Stimulation In Cardiomyopathies Study]]
|-
| [[MUSTT]]
| [[Multicenter Unsustained Tachycardia Trial]]
|-
| [[MVP]]
| [[Multivitamins And Probucol Study]]
|-
| [[NAMIS]]
| [[Nifedipine Angina Myocardial Infarction Study]]
|-
| [[NAPA]]
| [[Nesiritide Administered Peri-Anesthesia In Patients Undergoing Cardiac Surgery]]
|-
| [[NAPLES II]]
| [[Novel Approaches For Preventing Or Limiting Events II]]
|-
| [[NASCET]]
| [[North American Symptomatic Carotid Endarterectomy Trial]]
|-
| [[NEPHRIC]]
| [[Nephrotoxicity In High-Risk Patients Study Of Isoosmolar And Low-Osmolar Non-Ionic Contrast Media Study]]
|-
| [[NETWORK]]
| [[Clinical Outcome With Enalapril In Symptomatic Chronic Heart Failure: A Dose Comparison]]
|-
| [[NHANES III]]
| [[Third National Health And Nutrition Examination Survey]]
|-
| [[NHLBI]]
| [[The National Heart, Lung And Blood Institute Type II Coronary Intervention Study]]
|-
| [[NHLBI Dynamic]]
| [[Nhlbi Dynamic Registry Of Percutaneous Interventions: A Comparison To The 1985-86 Registry]]
|-
| [[NICE]]
| [[Nitrates In Congestive Heart Failure (Nice) Study]]
|-
| [[NICE-SUGAR]]
| [[Normoglycemia In Intensive Care Evaluation–Survival Using Glucose Algorithm Regulation]]
|-
| [[NICOLE]]
| [[Nisoldipine For Coronary Artery Disease In Leuven]]
|-
| [[NICS-EH]]
| [[National Intervention Cooperative Study In Elderly Hypertensives]]
|-
| [[NO-PAIN]]
| [[Nitric Oxide In Peripheral Arterial Insufficiency]]
|-
| [[NORDIL]]
| [[Nordic Diltiazem Study]]
|-
| [[NORVIT]]
| [[Norwegian Vitamin Trial]]
|-
| [[Norwegian Nifedipine]]
| [[Norwegian Nifedipine Multi-Center Trial]]
|-
| [[NRMI-2]]
| [[National Registry Of Myocardial Infarction (Second Phase)]]
|-
| [[NUT-2]]
| [[Efficacy Assessment Of Meloxicam, A Preferential Cyclooxygenase-2 Inhibitor, In Acute Coronary Syndromes Without St-Segment Elevation. The Nonsteroidal Anti-Inflammatory Drugs In Unstable Angina Treatment-2 (Nut-2) Pilot Study]]
|-
| [[OARS]]
| [[Optimal Atherectomy Restenosis Study]]
|-
| [[OASIS-1]]
| [[Organization To Assess Strategies For Ischemic Syndromes]]
|-
| [[OASIS-2]]
| [[Effects Of Long-Term, Moderate-Intensity Oral Anticoagulation In Addition To Aspirin In Unstable Angina]]
|-
| [[OASIS-6]]
| [[Organization For The Assessment Of Strategies For Ischemic Syndromes 6]]
|-
| [[OASIS-6 – GIK]]
| [[Oasis-6 – Glucose-Insulin-Potassium]]
|-
| [[OAT]]
| [[Occluded Artery Trial]]
|-
| [[OCBAS]]
| [[Optimal Coronary Balloon Angioplasty With Provisional Stenting Vs. Stent Trial]]
|-
| [[OCLA]]
| [[Omeprazole Clopidogrel Aspirin]]
|-
| [[ODESSA]]
| [[Optical Coherence Tomography For Des Safety]]
|-
| [[ODIXa-DVT]]
| [[Oral Direct Factor Xa Inhibitor Bay 59-7939 In Patients With Acute Symptomatic Deep-Vein Thrombosis]]
|-
| [[ODIXa-HIP]]
| [[Oral, Direct Factor Xa Inhibitor, Bay 59-7939, Given Once Daily In Patients Undergoing Total Hip Replacement]]
|-
| [[OMEGA]]
| [[Randomized Trial Of Omega-3 Fatty Acids On Top Of Modern Therapy After Acute Myocardial Infarction]]
|-
| [[ONTARGET]]
| [[Ongoing Telmisartan Alone And In Combination With Ramipril Global Endpoint Trial]]
|-
| [[ON-TIME]]
| [[Ongoing Tirofiban In Myocardial Infarction Evaluation Trial]]
|-
| [[On-TIME 2]]
| [[Ongoing Tirofiban In Myocardial Infarction Evaluation 2 Trial]]
|-
| [[OPALS]]
| [[Ontario Prehospital Advanced Life Support]]
|-
| [[OPT-CHF]]
| [[Oxypurinol Compared With Placebo For Class III-Iv Nyha Congestive Heart Failure]]
|-
| [[OPTIC]]
| [[Optimal Pharmacological Therapy In Cardioverter Defibrillator Patients Trial]]
|-
| [[OPTIMAAL]]
| [[Effects Of Losartan And Captopril On Mortality And Morbidity In High-Risk Patients After Acute Myocardial Infarction]]
|-
| [[OPTIME-CHF]]
| [[Outcomes Of A Prospective Trial Of Intravenous Milrinone For Exacerbations Of Chronic Heart Failure]]
|-
| [[OPTIMIZE]]
| [[Effect Of Image Optimization With Contrast On The Diagnostic Accuracy Of Dobutamine Echocardiography In Coronary Artery Disease]]
|-
| [[OPUS]]
| [[Optimal Angioplasty Versus Primary Stenting]]
|-
| [[ORAR II]]
| [[Oral Treatment Of Restenosis]]
|-
| [[ORBIT]]
| [[Oral Glycoprotein IIb/IIia Receptor Blockade To Inhibit Thrombosis]]
|-
| [[OSIRIS]]
| [[Oral Sirolimus To Inhibit Recurrent In-Stent Stenosis]]
|-
| [[OVERTURE]]
| [[Omapatrilat Versus Enalapril Randomized Trial Of Utility In Reducing Events]]
|-
| [[PABA CHF]]
| [[Pulmonary Vein Antrum Isolation Vs. Av Node Ablation With Biventricular Pacing For Treatment Of Atrial Fibrillation In Patients With Congestive Heart Failure]]
|-
| [[PACCOCATH ISR]]
| [[Treatment Of In-Stent Restenosis By Paclitaxel Coated Ptca Balloons]]
|-
| [[PACE]]
| [[Prevention By Low Dose Aspirin Of Cardiovascular Disease In The Elderly]]
|-
| [[PACIFIC]]
| [[Percutaneous Transmyocardial Laser Revascularization For Severe Angina: The Pacific Randomized Trial]]
|-
| [[PACT]]
| [[Plasminogen Activator-Angioplasty Compatibility Trial]]
|-
| [[PACT (Pravastatin)]]
| [[Pravastatin In Acute Coronary Treatment]]
|-
| [[PAD]]
| [[Public Access Defibrillation Trial]]
|-
| [[PAMI]]
| [[The Primary Angioplasty In Myocardial Infarction Study]]
|-
| [[PAMI-stent]]
| [[The Primary Angioplasty In Myocardial Infarction Study]]
|-
| [[PAPABEAR]]
| [[Prophylactic Amiodarone For The Prevention Of Arrhythmias That Begin Early After Revascularization, Valvular Repair Or Replacement]]
|-
| [[PARAGON]]
| [[Delaying And Preventing Ischemic Events In Patient With Acute Coronary Syndromes Using The Platelet Gp IIb/IIia Inhibitor Lamifiban]]
|-
| [[PARAGON B]]
| [[Platelet IIb/IIia Antagonist For The Reduction Of Acute Coronary Syndrome Events In A Global Organization Network]]
|-
| [[PARIS]]
| [[Effect Of Ace Inhibitors On Angiographic Restenosis After Coronary Stenting (Paris): A Randomised, Double-Blind, Placebo-Controlled Trial]]
|-
| [[PASE]]
| [[Pacemaker Selection In The Elderly]]
|-
| [[PASE(QOL)]]
| [[Quality Of Life And Clinical Outcomes In Elderly Patients Treated With Ventricular Pacing As Compared With Dual-Chamber Pacing]]
|-
| [[PASSION]]
| [[Paclitaxel Eluting Stent Versus Conventional Stent In St-Segment Elevation Myocardial Infarction]]
|-
| [[PATAF]]
| [[Primary Prevention Of Arterial Thromboembolism In Non-Rheumatic Atrial Fibrillation In Primary Care: Randomised Controlled Trial Comparing Two Intensities Of Coumarin With Aspirin]]
|-
| [[PATCH]]
| [[Program To Assess Alternative Treatment Strategies To Achieve Cardiac Health]]
|-
| [[PATH-CHF]]
| [[The Pacing Therapies For Congestive Heart Failure (Path-Chf) Study]]
|-
| [[PAVE]]
| [[Biventricular Pacing After Ablate Compared With Right Ventricular Therapy]]
|-
| [[PCI CLARITY]]
| [[Clopidogrel As Adjunctive Reperfusion Therapy: Percutaneous Coronary Intervention Subgroup Study]]
|-
| [[PCI-CURE]]
| [[Effects Of Pretreatment With Clopidogrel And Aspirin Followed By Long-Term Therapy In Patients Undergoing Percutaneous Coronary Intervention: The Pci-Cure Study]]
|-
| [[PCI-ExTRACT-TIMI 25]]
| [[Percutaneous Coronary Intervention Among Patients Treated With Enoxaparin Versus Unfractionated Heparin Following Fibrinolytic Administration For St-Elevation Mi]]
|-
| [[PC-Trial]]
| [[Physical Counterpressure Manoeuvre Trial]]
|-
| [[PEACE]]
| [[Platelet Activity Extinction In Non–Q-Wave Myocardial Infarction With Aspirin, Clopidogrel, And Eptifibatide]]
|-
| [[PEACE]]
| [[Prevention Of Events With Angiotensin-Converting Enzyme Inhibition Trial]]
|-
| [[PEECH]]
| [[Prospective Evaluation Of Enhanced External Counterpulsation In Congestive Heart Failure]]
|-
| [[PENTUA]]
| [[Pentasaccharide In Unstable Angina]]
|-
| [[PEP]]
| [[Pulmonary Embolism Prevention Trial]]
|-
| [[PEPAF]]
| [[Experimental Program For Physical Activity Promotion]]
|-
| [[PEP-CHF]]
| [[Perindopril For Elderly People With Chronic Heart Failure]]
|-
| [[PEPI]]
| [[Postmenopausal Estrogen/Progestin Interventions]]
|-
| [[PERISCOPE]]
| [[Pioglitazone Effect On Regression Of Intravascular Sonographic Coronary Obstruction Prospective Evaluation]]
|-
| [[PERM]]
| [[Prospective Evaluation Of Reperfusion Markers]]
|-
| [[PERSUADE]]
| [[Perindopril Substudy In Coronary Artery Disease And Diabetes: The Diabetic Substudy Of Europa]]
|-
| [[Perth]]
| [[Perth Community Stroke Study]]
|-
| [[PERTINENT]]
| [[Perindopril, Thrombosis, Inflammation, Endothelial Dysfunction, And Neurohormonal Activation Trial, A Subanalysis Of Europa]]
|-
| [[PHS II]]
| [[Physicians' Health Study II]]
|-
| [[PIAF]]
| [[Rhythm Or Rate Control In Atrial Fibrillation-Pharmacological Intervention In Atrial Fibrillation (Piaf): A Randomised Trial]]
|-
| [[PICTURE]]
| [[Post-Intracoronary Treatment Ultrasound Result Evaluation]]
|-
| [[PIHRATE]]
| [[Polish-Italian-Hungarian Randomized Thrombectomy Trial]]
|-
| [[PIONEER]]
| [[Proactive, Prospective Pioglitazone Clinical Trial In Macrovascular Events]]
|-
| [[PIOPED]]
| [[Prospective Investigation Of Pulmonary Embolism Diagnosis Study]]
|-
| [[PLAC-II]]
| [[Pravastatin, Lipids, And Atherosclerosis In The Carotid Arteries II]]
|-
| [[PLASMA]]
| [[Phospholipase Levels And Serological Markers Of Atherosclerosis]]
|-
| [[POISE]]
| [[Perioperative Ischemic Evaluation]]
|-
| [[POSCH]]
| [[Program On The Surgical Control Of The Hyperlipidemias]]
|-
| [[POST]]
| [[Prevention Of Syncope Trial]]
|-
| [[Post CABG]]
| [[Post Coronary Artery Bypass Graft Trial]]
|-
| [[POZNAN]]
| [[Percutaneous Transvenous Transplantation Of Autologous Myoblasts In The Treatment Of Postinfarction Heart Failure]]
|-
| [[PPAR Study]]
| [[Peroxisome Proliferator–Activated Receptor Study]]
|-
| [[PPP]]
| [[Primary Prevention Project]]
|-
| [[PQRST]]
| [[Probucol Quantitative Regression Swedish Trial]]
|-
| [[PRACTICAL]]
| [[Comparison Of Enalapril Versus Captopril On Left Ventricular Function And Survival Three Months After Acute Myocardial Infarction]]
|-
| [[PRAGUE]]
| [[Primary Angioplasty In Patients Transferred From General Community Hospitals To Specialized Ptca Units With Or Without Emergency Thrombolysis]]
|-
| [[PRAGUE-8]]
| [[Primary Angioplasty In Patients Transferred From General Community Hospitals To Specialized Ptca Units With Or Without Emergency Thrombolysis-8]]
|-
| [[PRAISE]]
| [[Prospective Randomized Amlopidine Survival Evaluation]]
|-
| [[PRAISE-1]]
| [[Prospective Randomized Amlodipine Survival Evaluation-1]]
|-
| [[PRAISE-2]]
| [[Prospective Randomized Amlodipine Survival Evaluation-2]]
|-
| [[PREAMI]]
| [[Perindopril Remodeling In Elderly With Acute Myocardial Infarction]]
|-
| [[PRECISE]]
| [[Double-Blind, Placebo-Controlled Study Of The Effects Of Carvedilol In Patients With Moderate To Severe Heart Failure]]
|-
| [[PREDICT]]
| [[Effect Of Pravastatin On Angiographic Restenosis After Coronary Balloon Angioplasty]]
|-
| [[PREMIAR]]
| [[Protection From Distal Embolization In High-Risk Patients With Acute St-Segment Elevation Myocardial Infarction]]
|-
| [[PREMIER]]
| [[Effects Of Pg-116800, A Matrix Metalloproteinase Inhibitor, To Prevent Left Ventricular Remodeling After Acute Myocardial Infarction]]
|-
| [[PREPAIR]]
| [[Clopidogrel 600-Mg Double Loading Dose Achieves Stronger Platelet Inhibition Than Conventional Regimens]]
|-
| [[PREPARE — Presented at TCT 2008]]
| [[Proximal Embolic Protection In Acute Mi And Resolution Of St-Elevation]]
|-
| [[PREPIC]]
| [[A Clinical Trial Of Vena Caval Filters In The Prevention Of Pulmonary Embolism In Patients With Proximal Deep-Vein Thrombosis]]
|-
| [[Pre-RELAX-AHF]]
| [[Preliminary Study Of Relaxin In Acute Heart Failure]]
|-
| [[PRESENT]]
| [[Preliminary Safety Evaluation Of Nanoporous Tacrolimus Eluting Stents]]
|-
| [[PRESERVE]]
| [[Prospective Randomized Trial Of Enalapril To Reverse Ventricular Enlargement]]
|-
| [[PRESTO]]
| [[Results Of Prevention Of Restenosis With Tranilast And Its Outcomes (Presto) Trial.]]
|-
| [[PREVEND IT]]
| [[Prevention Of Renal And Vascular End-Stage Disease Intervention Trial]]
|-
| [[PREVENT]]
| [[Prospective Randomized Evaluation Of The Vascular Effects Of Norvasc Trial]]
|-
| [[PREVENT (Dalteparin)]]
| [[Prospective Evaluation Of Dalteparin Efficacy For Prevention Of Vte In Immobilized Patients Trial]]
|-
| [[PREVENT (Warfarin)]]
| [[Prevention Of Recurrent Venous Thromboembolism]]
|-
| [[PREVENT II]]
| [[The Program In Ex Vivo Vein Graft Engineering Via Transfection II Study: E2F Decoy In Cabg]]
|-
| [[PREVENT IV]]
| [[Project Of Ex-Vivo Vein Graft Engineering Via Transfection]]
|-
| [[PREVENT(Radiation)]]
| [[Proliferation Reduction With Vascular Energy Trial]]
|-
| [[PRIDE]]
| [[A Prospective, Randomized, Controlled Trial Of Distal Protection With The Kensey-Nash Triactiv System Compared To The Guardwire Or Filterwire]]
|-
| [[PRIMA — Presented at ACC.09/i2]]
| [[Can Pro-Brain Natriuretic Peptide Guided Therapy Of Heart Failure Improve Heart Failure Morbidity And Mortality?]]
|-
| [[PRIME-2]]
| [[Second Prospective Randomized Study Of Ibopamine On Mortality And Efficacy In Heart Failure]]
|-
| [[PRIMI]]
| [[Pro-Urokinase For Myocardial Infarction]]
|-
| [[PRIMO-CABG]]
| [[Pexelizumab For The Reduction Of Infarction And Mortality In Coronary Artery Bypass Graft Surgery Study]]
|-
| [[PRIMO-CABG II]]
| [[Pexelizumab For The Reduction Of Infarction And Mortality In Coronary Artery Bypass Graft II]]
|-
| [[PRINCE]]
| [[Effect Of Statin Therapy On C-Reactive Protein Levels: The Pravastatin Inflammation/Crp Evaluation (Prince): A Randomized Trial And Cohort Study]]
|-
| [[PRINCESS]]
| [[Prevention Of Ischaemic Events By Early Treatment Of Cerivastatin After Acute Myocardial Infarction]]
|-
| [[PRINCIPLE-TIMI 44]]
| [[The Prasugrel In Comparison To Clopidogrel For Inhibition Of Platelet Activation And Aggregation–Thrombolysis In Myocardial Infarction 44 Trial]]
|-
| [[PRISM]]
| [[Platelet-Receptor Inhibition For Ischemic Syndrome Management]]
|-
| [[PRISM-PLUS]]
| [[Platelet-Receptor Inhibition For Ischemic Syndrome Management In Patients Limited By Unstable Signs And Symptoms]]
|-
| [[PRISM-Troponin]]
| [[Troponin Levels Identify Cad Patients Likely To Benefit From Tirofiban: Results From The Prism-Troponin Study, A Substudy Of The Platelet Receptor Inhibition In Ischemic Syndrome Management Study]]
|-
| [[PRISON II]]
| [[Prospective Randomized Trial Of Sirolimus-Eluting And Bare Metal Stents In Patients With Chronic Total Occlusions]]
|-
| [[PROactive]]
| [[Prospective Pioglitazone Clinical Trial In Macrovascular Events]]
|-
| [[PROCAM]]
| [[Simple Scoring Scheme For Calculating The Risk Of Acute Coronary Events Based On The 10-Year Follow-Up Of The Prospective Cardiovascular Münster (Procam) Study]]
|-
| [[PRoFESS]]
| [[Prevention Regimen For Effectively Avoiding Second Strokes]]
|-
| [[PROFILE]]
| [[Prospective Randomized Flosequinan Longevity Evaluation]]
|-
| [[PROGRESS]]
| [[Perindopril Protection Against Recurrent Stroke Study]]
|-
| [[PROGRESS-1]]
| [[Coronary Stenting With Absorbable Metal Stents]]
|-
| [[PROMISE]]
| [[Protection Devices In Pci-Treatment Of Myocardial Infarction For Salvage Of Endangered Myocardium Study]]
|-
| [[PROMISE]]
| [[The Effects Of Oral Milrinone On Mortality In Severe Chronic Heart Failure]]
|-
| [[PROSPER]]
| [[Prospective Study Of Pravastatin In The Elderly At Risk]]
|-
| [[PROTECT - TIMI 30]]
| [[Randomized Trial To Evaluate The Relative Protection Against Post-Pci Microvascular Dysfunction And Post-Pca Ischemia Among Anti-Platelet And Anti-Thrombotic Agents]]
|-
| [[PROTECT AF]]
| [[Randomized Prospective Trial Of Percutaneous Left Atrial Appendage Closure Versus Warfarin For Stroke Prevention In Atrial Fibrillation]]
|-
| [[PROTECT-CAD]]
| [[Prospective Randomized Trial Of Direct Endomyocardial Implantation Of Bone Marrow Cells For Therapeutic Angiogenesis In Coronary Artery Diseases]]
|-
| [[PROVE IT/TIMI 22]]
| [[Pravastatin Or Atorvastatin Evaluation And Infection Therapy: Thrombolysis In Myocardial Infarction 22]]
|-
| [[PROVE IT-TIMI 22 (Gatifloxacin)]]
| [[Pravastatin Or Atorvastatin Evaluation And Infection Therapy]]
|-
| [[PROVED]]
| [[Randomized Study Assessing The Effect Of Digoxin Withdrawal In Patients With Mild To Moderate Chronic Congestive Heart Failure: Results Of The Proved]]
|-
| [[PROVIDENCE 1]]
| [[Prospective Evaluation Of Rifalazil Effect On Vascular Symptoms Of Intermittent Claudication And Other Endpoints In Chlamydia Seropositive Patients]]
|-
| [[PROXIMAL]]
| [[Proximal Protection During Saphenous Vein Graft Intervention]]
|-
| [[PURSUIT]]
| [[Platelet Glycoprotein IIb/IIia In Unstable Angina:Receptor Suppression Using Integrilin Therapy]]
|-
| [[QUASAR]]
| [[Quinapril Anti-Ischemia And Symptoms Of Angina Reduction]]
|-
| [[QUIET]]
| [[Quinapril Ischemic Event Trial]]
|-
| [[R3]]
| [[Reopro Readministration Registry]]
|-
| [[RAAMI]]
| [[Randomized Angiographic Trial Of Recombinant Tissue-Type Plasminogen Activator (Alteplase) In Myocardial Infarction]]
|-
| [[RABBIT II]]
| [[Randomized Angioplasty Beta Blocker Intracoronary Trial II]]
|-
| [[RACE]]
| [[Rate Control Versus Electrical Cardioversion For Persistent Atrial Fibrillation]]
|-
| [[RACS]]
| [[Randomized Argentine Clopidogrel Stent Trial]]
|-
| [[RACTS]]
| [[A Prospective, Randomized Multicenter Trial Of Cilostozal Vs Ticlopidine In Patients Undergoing Stent Implantation]]
|-
| [[RADIANCE]]
| [[Withdrawal Of Digoxin From Patients With Chronic Heart Failure Treated With Angiotensin-Converting Enzyme Inhibitors]]
|-
| [[RADIANCE 1]]
| [[Rating Atherosclerotic Disease Change By Imaging With A New Cetp Inhibitor]]
|-
| [[RADIANCE 2]]
| [[Rating Atherosclerotic Disease Change By Imaging With A New Cetp Inhibitor - 2]]
|-
| [[RALES]]
| [[Randomized Aldactone Evaluation Study]]
|-
| [[RaMI]]
| [[Prehospital Thrombolysis In Rural Emergency Room And Subsequent Transport To A Coronary Care Unit: Ravenna Myocardial Infarction (Rami) Trial]]
|-
| [[RAPID-1]]
| [[Recombinant Plasminogen Activator Angiographic Phase II International Dose-Finding Study]]
|-
| [[RAPID-2]]
| [[Reteplase Vs Alteplase Patency Investigation During Myocardial Infarction]]
|-
| [[RAPPORT]]
| [[Reopro And Primary Ptca Organization And Randomized Trial]]
|-
| [[RAPS]]
| [[Radial Artery Patency Study]]
|-
| [[RAPT]]
| [[Ridogrel Versus Aspirin Patency Trial]]
|-
| [[RAVE]]
| [[Regional Angiogenesis With Vascular Endothelial Growth Factor In Peripheral Arterial Disease]]
|-
| [[RAVEL]]
| [[A Randomized Comparison Of A Sirolimus-Eluting Stent With A Standard Stent For Coronary Revascularization]]
|-
| [[REACH]]
| [[Reinforcing Education About Cholesterol]]
|-
| [[REACH Registry]]
| [[Reduction Of Atherothrombosis For Continued Health Registry]]
|-
| [[REACT]]
| [[Rescue Angioplasty Versus Conservative Therapy Or Repeat Thrombolysis Trial]]
|-
| [[REACT]]
| [[Rapid Early Action For Coronary Treatment]]
|-
| [[REALITY]]
| [[Prospective Randomized Multi-Center Head-To-Head Comparison Of The Sirolimus-Eluting Stent (Cypher) And The Paclitaxel-Eluting Stent (Taxus]]
|-
| [[RECORD]]
| [[Rosiglitazone Evaluated For Cardiovascular Outcomes — An Interim Analysis]]
|-
| [[RECORD1]]
| [[Regulation Of Coagulation In Orthopedic Surgery To Prevent Deep Venous Thrombosis And Pulmonary Embolism 1]]
|-
| [[RECORD2]]
| [[Regulation Of Coagulation In Orthopedic Surgery To Prevent Deep Venous Thrombosis And Pulmonary Embolism 2]]
|-
| [[RECORD3]]
| [[Regulation Of Coagulation In Orthopedic Surgery To Prevent Deep Venous Thrombosis And Pulmonary Embolism 3]]
|-
| [[RECOVER]]
| [[Renal Toxicity Evaluation And Comparison Between Visipaque And Hexabrix In Patients With Renal Insufficiency Undergoing Coronary Angiography]]
|-
| [[RECOVERS]]
| [[Randomized Evaluation Of Polytetrafluoroethylene-Covered Stent In Saphenous Vein Grafts]]
|-
| [[REDHOT]]
| [[Rapid Emergency Department Heart Failure Outpatient Trial]]
|-
| [[RED-LIP]]
| [[Trial Of Pravastatin In Primary Isolated Hypercholesterolemia]]
|-
| [[REDUCE]]
| [[Low Molecular Weight Heparin (Reviparin) In Percutaneous Transluminal Coronary Angioplasty]]
|-
| [[REDUCE III]]
| [[A Prospective, Randomized Multicenter Trial Of Cutting Balloon Before Stenting In Patients Undergoing Pci]]
|-
| [[REFLECT]]
| [[Double-Blind, Placebo-Controlled Study Of The Efficacy Of Flosequinan In Patients With Chronic Heart Failure]]
|-
| [[REGENT]]
| [[Myocardial Regeneration By Intracoronary Infusion Of Selected Population Of Stem Cells In Acute Myocardial Infarction]]
|-
| [[REGICOR]]
| [[Improvement In Survival After Myocardial Infarction Between 1978-85 And 1986-88 In The Regicor Study]]
|-
| [[REGRESS]]
| [[Effects Of Lipid Lowering By Pravastatin On Progression And Regression Of Coronary Artery Disease In Symptomatic Men With Normal To Moderately Elevated Serum Cholesterol Levels. The Regression Growth Evaluation Statin Study (Regress)]]
|-
| [[RELAx-AMI]]
| [[Randomized Early Versus Late Abciximab In Acute Myocardial Infarction Treated With Primary Coronary Intervention]]
|-
| [[RELOAD]]
| [[Reload With Clopidogrel Before Coronary Angioplasty In Subjects Treated Long Term With Dual Antiplatelet Therapy]]
|-
| [[REMATCH]]
| [[Randomized Evaluation Of Mechanical Assistance For The Treatment Of Congestive Heart Failure]]
|-
| [[REMEDIA]]
| [[Randomized Evaluation Of The Effect Of Mechanical Reduction Of Distal Embolization By Thrombus-Aspiration In Primary And Rescue Angioplasty]]
|-
| [[REMEDIAL]]
| [[Renal Insufficiency Following Contrast Media Administration Trial]]
|-
| [[RENAAL]]
| [[Effects Of Losartan On Renal And Cardiovascular Outcomes In Patients With Type 2 Diabetes And Nephropathy]]
|-
| [[RENEWAL - RECOVER]]
| [[Research Into Etanercept Cytokine Antagonism In Ventricular Dysfunction]]
|-
| [[RENEWAL - RENAISSANCE]]
| [[Randomized Etanercept North American Strategy To Study Antagonism Of Cytokines]]
|-
| [[REPAIR-AMI]]
| [[Reinfusion Of Enriched Progenitor Cells And Infarct Remodeling In Acute Myocardial Infarction]]
|-
| [[REPLACE 2]]
| [[Randomized Evaluation Of Pci Linking Angiomax To Reduced Clinical Events]]
|-
| [[RESCUE]]
| [[Randomized Evaluation Of Salvage Angioplasty With Combined Utilization Of Endpoints]]
|-
| [[RESEARCH]]
| [[Rapamycin-Eluting Stent Evaluated At Rotterdam Cardiology Hospital Registry]]
|-
| [[RESIST]]
| [[Impact Of Intravascular Ultrasound Guidance In Stent Deployment On 6-Month Restenosis Rate: A Multicenter, Randomized Study Comparing Two Strategies--With And Without Intravascular Ultrasound Guidance]]
|-
| [[RESOLVD]]
| [[Randomized Evaluation Of Strategies For Left Ventricular Dysfunction Pilot]]
|-
| [[REST]]
| [[Restenosis Stent Trial]]
|-
| [[Restenosis Stent]]
| [[Coronary-Artery Stenting Compared With Balloon Angioplasty For Restenosis After Initial Balloon Angioplasty]]
|-
| [[RESTORE]]
| [[Randomized Efficacy Study Of Tirofiban For Outcome And Restenosis]]
|-
| [[RethinQ]]
| [[Resynchronization Therapy In Patients With Narrow Qrs]]
|-
| [[REVERSAL]]
| [[Reversing Atherosclerosis With Aggressive Lipid Lowering]]
|-
| [[REVERSE]]
| [[Resynchronization Reverses Remodeling In Systolic Left Ventricular Dysfunction]]
|-
| [[REVERT]]
| [[Reversal Of Ventricular Remodeling With Toprol-Xl]]
|-
| [[REVIVAL-3]]
| [[The Regeneration Of Vital Myocardium In St-Segment Elevation Myocardial Infarction By Erythropoietin]]
|-
| [[RHYTHM II ICD]]
| [[Resynchronization For The Hemodynamic Treatment For Heart Failure Management II Implantable Cardioverter Defibrillator]]
|-
| [[RIO-Europe]]
| [[A Randomized Double-Blind Study Of Weight Reducing Effect And Safety Of Rimonabant In Obese Patients With Or Without Comorbidities]]
|-
| [[RIO-Lipids]]
| [[Rimonabant In Obesity]]
|-
| [[RIO-NA]]
| [[Rimonabant On Weight Reduction And Weight Maintenance: Rio-North America]]
|-
| [[RIS]]
| [[Efficacy Of Multiple Risk Factor Intervention In Treated Hypertensive Men]]
|-
| [[RISC]]
| [[Research On Instability In Coronary Artery Disease]]
|-
| [[RITA]]
| [[Randomized Intervention Treatment Of Angina Trial]]
|-
| [[RITA II]]
| [[The Second Randomized Intervention Treatment Of Angina]]
|-
| [[RITA-3]]
| [[Randomized Trial Of A Conservative Treatment Strategy Versus An Interventional Treatment Strategy In Patients With Unstable Angina]]
|-
| [[RITZ 2]]
| [[Randomized Intravenous Tezosentan For The Treatment Of Acute Heart Failure]]
|-
| [[RITZ-4]]
| [[Randomized Intravenous Tezosentan Study]]
|-
| [[RIVIERA Registry]]
| [[Registry On Intra-Venous Anticoagulation In The Elective And Primary Real World Of Angioplasty]]
|-
| [[ROADMAP]]
| [[Randomized Olmesartan And Diabetes Microalbuminuria Prevention Trial]]
|-
| [[ROBUST]]
| [[Recanalization Of Chronically Occluded Aorto-Coronary Saphenous Vein Bypass Grafts With Long-Term, Low Dose Direct Infusion Of Urokinase Trial]]
|-
| [[ROMAS]]
| [[Romanian Multicenter Study - Accelerated Streptokinase In Acute Myocardial Infarction]]
|-
| [[ROSTER]]
| [[Randomized Trial Of Rotational Atherectomy Versus Balloon Angioplasty For Diffuse In-Stent Restenosis]]
|-
| [[ROXIS]]
| [[Roxithromycin In Non-Q Wave Coronary Syndromes]]
|-
| [[RSVP]]
| [[Radial Artery Versus Saphenous Vein Patency]]
|-
| [[RUSSLAN]]
| [[Safety And Efficacy Of A Novel Calcium Sensitizer, Levosimendan, In Patients With Left Ventricular Failure Due To An Acute Myocardial Infarction]]
|-
| [[RUTH]]
| [[Raloxifene Use For The Heart]]
|-
| [[SADHART]]
| [[Sertraline Treatment Of Major Depression In Patients With Acute Mi Or Unstable Angina]]
|-
| [[SAFE]]
| [[Safety After Fifty Evaluation]]
|-
| [[SAFER]]
| [[The Saphenous Vein Graft Angioplasty Free Of Emboli Randomized Trial]]
|-
| [[SAFE-T]]
| [[Sotalol Amiodarone Atrial Fibrillation Efficacy Trial]]
|-
| [[SAGE]]
| [[Study Assessing Goals In The Elderly]]
|-
| [[SALT]]
| [[Swedish Aspirin Low-Dose Trial]]
|-
| [[SALT 1 and 2]]
| [[Study Of Ascending Levels Of Tolvaptan In Hyponatremia]]
|-
| [[SALTIRE]]
| [[Scottish Aortic Stenosis And Lipid Lowering Trial]]
|-
| [[SANDS]]
| [[Stop Atherosclerosis In Native Diabetics Study]]
|-
| [[SAPAT]]
| [[Double-Blind Trial Of Aspirin In Primary Prevention Of Myocardial Infarction In Patients With Stable Chronic Angina Pectoris]]
|-
| [[SAPPHIRE]]
| [[Stenting And Angioplasty With Protection In Patients At High Risk For Endarterectomy]]
|-
| [[SARECCO]]
| [[Stent Or Angioplasty After Recanalization Of Chronic Coronary Occlusions Trial]]
|-
| [[SAVE]]
| [[Survival And Ventricular Enlargement Trial]]
|-
| [[SAVE PACe]]
| [[Search Av Extension And Managed Ventricular Pacing For Promoting Atrioventricular Conduction]]
|-
| [[SAVED]]
| [[Saphenous Vein De Novo]]
|-
| [[SCANDSTENT]]
| [[Stenting Of Coronary Arteries In Non Stress/Benestent Disease Trial]]
|-
| [[SCAT]]
| [[Long-Term Effects Of Cholesterol Lowering And Angiotension-Converting Enzyme Inhibition On Coronary Atherosclerosis. The Simvastatin/Enalapril Coronary Atherosclerosis Trial (Scat).]]
|-
| [[SCD-HeFT]]
| [[Sudden Cardiac Death In Heart Failure Trial]]
|-
| [[SCOR]]
| [[University Of California, San Francisco, Arteriosclerosis Specialized Center Of Research (Scor) Intervention Trial]]
|-
| [[SCORE]]
| [[Study To Compare Restenosis Rate Between Quest And Quadds-Qp2]]
|-
| [[SCRIP]]
| [[Study Of Cardiovascular Risk Intervention By Pharmacists]]
|-
| [[SCRIPPS]]
| [[Scripps Coronary Radiation To Inhibit Proliferation Post Stenting]]
|-
| [[SCRIPPS II]]
| [[Scripps Coronary Radiation To Inhibit Proliferation Post Stenting II]]
|-
| [[SCRIPPS III]]
| [[Scripps Coronary Radiation To Inhibit Proliferation Post Stenting III]]
|-
| [[SCRIPPS IV]]
| [[Scripps Coronary Radiation To Inhibit Proliferation Post Stenting Iv]]
|-
| [[SEARCH]]
| [[Study Of The Effectiveness Of Additional Reductions In Cholesterol And Homocysteine]]
|-
| [[SEAS]]
| [[Simvastatin And Ezetimibe In Aortic Stenosis]]
|-
| [[SECURE]]
| [[Study To Evaluate Carotid Ultrasound Changes In Patients Treated With Ramipril And Vitamin E]]
|-
| [[SEEDS]]
| [[Syncope Evaluation In The Emergency Department Study]]
|-
| [[SEISMIC]]
| [[Safety And Effects Of Implanted (Autologous) Skeletal Myoblasts (Myocell) Using An Injection Catheter]]
|-
| [[SENIOR PAMI]]
| [[Senior Primary Angioplasty In Myocardial Infarction Study]]
|-
| [[SENIORS]]
| [[Study Of Effects Of Nebivolol Intervention On Outcomes And Rehospitalisation In Seniors With Heart Failure]]
|-
| [[SESAIR]]
| [[Randomised Comparison Of Subcutaneous Heparin, Intravenous Heparin, And Aspirin In Unstable Angina]]
|-
| [[SESAMI]]
| [[Sirolimus-Eluting Stent Versus Bare-Metal Stent In Acute Myocardial Infarction]]
|-
| [[SES-SMART]]
| [[Sirolimus-Eluting Stent And A Standard Stent In The Prevention Of Restenosis In Small Coronary Arteries]]
|-
| [[SHARP]]
| [[The Subcutaneous Heparin And Angioplasty Restenosis Prevention (Sharp) Trial. Results Of A Multicentre Randomized Trial Investigating The Effects Of High Dose Unfractionated Heparin On Angiographic Restenosis And Clinical Outcome]]
|-
| [[SHEP]]
| [[Systolic Hypertension In Elderly Program]]
|-
| [[SHIELD]]
| [[Shock Inhibition Evaluation With Azimilide]]
|-
| [[SHOCK]]
| [[Should We Emergently Revascularize Occluded Coronaries For Cardiogenic Shock?]]
|-
| [[SIAM]]
| [[Comparison Of Invasive And Conservative Strategies After Treatment With Streptokinase In Acute Myocardial Infarction]]
|-
| [[SIAM III]]
| [[Southwest German Interventional Study In Acute Myocardial Infarction]]
|-
| [[SICCO]]
| [[Stenting In Chronic Coronary Occlusion]]
|-
| [[SIMPADICO]]
| [[Study Of Immune Modulation Therapy In Patients With Symptomatic Peripheral Arterial Disease]]
|-
| [[SIPS]]
| [[Ultrasound-Guided Stratification For Provisional Stenting With Focal Balloon Combination Catheter. Results From The Randomized Strategy For Intracoronary Ultrasound-Guided Ptca And Stenting (Sips) Trial]]
|-
| [[SIRIUS]]
| [[Sirolimus-Eluting Stent In Coronary Lesions]]
|-
| [[SIRIUS-2]]
| [[Safety And Efficacy Of An Intravenous Placebo-Controlled Randomized Infusion Of Ularitide]]
|-
| [[SIRTAX]]
| [[Sirolimus-Eluting Stent Compared With Paclitaxel-Eluting Stent For Coronary Revascularization]]
|-
| [[SISR]]
| [[Sirolimus-Eluting Stent Vs. Brachytherapy In Patients With Bare Metal In-Stent Restenosis]]
|-
| [[SLIP]]
| [[Lipid Profile During Antihypertensive Treatment]]
|-
| [[SMART]]
| [[Surgical Management Of Arterial Revascularization Therapies]]
|-
| [[SMART]]
| [[Sirolimus-Eluting Stents For The Treatment Of Obstructive Superficial Femoral Artery Disease]]
|-
| [[SMARTT]]
| [[A Randomized Trial Of The Effects Of Early Cardiac Serum Marker Availability On Reperfusion Therapy In Patients With Acute Myocardial Infarction. The Serial Markers, Acute Myocardial Infarction And Rapid Treatment Trial (Smartt)]]
|-
| [[SMASH-VT]]
| [[Substrate Mapping And Ablation In Sinus Rhythm To Halt Ventricular Tachycardia]]
|-
| [[SMILE]]
| [[The Effects Of The Angiotensin-Converting-Enzyme Inhibitor Zofenopril On Mortality And Morbidity After Anterior Myocardial Infarction]]
|-
| [[SMT]]
| [[Stockholm Metoprolol Trial]]
|-
| [[SOFA]]
| [[Study On Omega-3 Fatty Acids And Ventricular Arrhythmia]]
|-
| [[SOLVD-Treatment]]
| [[The Effects Of Enalapril On Survival In Patients With Reduced Left Ventricular Ejection Fractions And Congestive Heart Failure (Treatment Trial)]]
|-
| [[SORT OUT II]]
| [[Comparison Of Paclitaxel- And Sirolimus-Eluting Stents In Everyday Clinical Practice]]
|-
| [[SoS]]
| [[Coronary Artery Bypass Surgery Vs. Percutaneous Coronary Intervention With Stent Implantation In Patients With Multivessel Coronary Disease (The Stent Or Surgery Trial)]]
|-
| [[SPACE]]
| [[Secondary Prevention With Antioxidants Of Cardiovascular Disease In End-Stage Renal Disease (Space): Randomized Placebo-Controlled Trial]]
|-
| [[SPAF]]
| [[Stroke Prevention In Atrial Fibrillation Study]]
|-
| [[SPAN CHF]]
| [[Specialized Primary And Networked Care In Heart Failure]]
|-
| [[SPARCL]]
| [[Stroke Prevention By Aggressive Reduction In Cholesterol Levels]]
|-
| [[SPIC]]
| [[Long-Term Survival Effect Of Metoprolol In Dilated Cardiomyopathy]]
|-
| [[SPICE]]
| [[Study Of Patients Intolerant Of Converting Enzyme Inhibitors]]
|-
| [[SPICE – Presented at ACC 2007]]
| [[Survival And Prognosis: Investigation Of Crataegus Extract Ws 1442 In Chf]]
|-
| [[SPINAF]]
| [[Stroke Prevention In Nonrheumatic Atrial Fibrillation]]
|-
| [[SPIRIT]]
| [[A Randomized Trial Of Anticoagulants Versus Aspirin After Cerebral Ischemia Of Presumed Arterial Origin]]
|-
| [[SPORTIF II]]
| [[Stroke Prevention Using The Oral Direct Thrombin Inhibitor Ximelagatran In Patients With Nonvalvular Atrial Fibrillation]]
|-
| [[SPORTIF III]]
| [[Stroke Prevention Using The Oral Direct Thrombin Inhibitor Ximelagatran In Patients With Nonvalvular Atrial Fibrillation]]
|-
| [[SPORTIF V]]
| [[Stroke Prevention Using The Oral Direct Thrombin Inhibitor Ximelagatran In Patients With Nonvalvular Atrial Fibrillation]]
|-
| [[SPRINT]]
| [[Secondary Prevention Reinfarction Israeli Nifedipine Trial]]
|-
| [[SSSD]]
| [[Spanish Study On Sudden Death]]
|-
| [[STAF]]
| [[Strategies Of Treatment Of Atrial Fibrillation]]
|-
| [[STAI]]
| [[Antiplatelet Treatment With Ticlopidine In Unstable Angina (Studio Della Ticlopidine Nell'Angina Instabile)]]
|-
| [[STAMI]]
| [[Ticlopidine Versus Aspirin After Myocardial Infarction (Stami) Trial]]
|-
| [[STAMINA]]
| [[Effect Of Treatment For Chlamydia Pneumoniae And Helicobacter Pylori On Markers Of Inflammation And Cardiac Events In Patients With Acute Coronary Syndromes]]
|-
| [[STAMINA]]
| [[South Thames Trial Of Antibiotics In Myocardial Infarction And Unstable Angina Pectoris]]
|-
| [[STAR]]
| [[A Randomized Trial Of Recombinant Staphylokinase Versus Altepase For Coronary Artery Patency In Acute Myocardial Infarction]]
|-
| [[STARC]]
| [[Angioplasty/Atherectomy/Laser Therapy: Trapidil (Triazolopyrimidine), A Platelet-Derived Growth Factor Antagonist, Reduces Restenosis After Percutaneous Transluminal Coronary Angioplasty: Results Of The Randomized, Double-Blind Starc Study]]
|-
| [[STARS-Antithrombotic]]
| [[Stent Antithrombotic Regimen Study]]
|-
| [[STARS-Atherosclerosis]]
| [[St. Thomas Atherosclerosis Regression Study]]
|-
| [[START]]
| [[Sr90 Treatment Of Angiographic Restenosis]]
|-
| [[STAT]]
| [[Stenting Vs. Thrombolysis In Acute Myocardial Infarction Trial (Stat)]]
|-
| [[STEEPLE]]
| [[Safety And Efficacy Of Enoxaparin In Percutaneous Coronary Intervention Patients: An International Randomized Evaluation]]
|-
| [[STEMMI]]
| [[Stem Cells In Myocardial Infarction]]
|-
| [[STENT PAMI]]
| [[Stent Primary Angioplasty In Mi]]
|-
| [[STENTIM-2]]
| [[Immediate Coronary Angioplasty With Elective Wiktor Stent Implantation Compared With Conventional Balloon Angioplasty In Acute Myocardial Infarction]]
|-
| [[STEP]]
| [[Study Of The Therapeutic Effects Of Intercessory Prayer]]
|-
| [[STICH]]
| [[Surgical Treatments For Ischemic Heart Failure Hypothesis 2]]
|-
| [[STIMS]]
| [[Prevention Of Myocardial Infarction And Stroke In Patients With Intermittent Claudication]]
|-
| [[STING]]
| [[Stents In Grafts]]
|-
| [[STONE]]
| [[Shanghai Trial Of Nifedipine In The Elderly]]
|-
| [[STOP-AMI 1]]
| [[Stent Versus Thrombolysis For Occluded Coronary Arteries In Patients With Acute Myocardial Infarction 1]]
|-
| [[STOP-HTN]]
| [[Swedish Trial In Old Patients With Hypertension]]
|-
| [[STOP-NIDDM]]
| [[Study To Prevent Noninsulin Dependent Diabetes Mellitus Trial]]
|-
| [[STRATAS]]
| [[Study To Determine Rotablator And Transluminal Angioplasty Strategy]]
|-
| [[STRATEGY]]
| [[Single High-Dose Bolus Tirofiban And Sirolimus-Eluting Stent Vs. Abciximab And Bare-Metal Stent In Myocardial Infarction]]
|-
| [[STRATUS-US]]
| [[Smoking Cessation In Smokers Motivated To Quit]]
|-
| [[STRESS I]]
| [[Stent Restenosis Study I]]
|-
| [[SURVIVE]]
| [[Survival Of Patients With Acute Heart Failure In Need Of Intravenous Inotropic Support]]
|-
| [[SUTAMI]]
| [[Double-Blind Multicenter Comparison Of The Efficacy And Safety Of Saruplase And Urokinase In The Treatment Of Acute Myocardial Infarction: Report Of The Sutami Study Group]]
|-
| [[SWEDES]]
| [[Swedish Early Decision Trial]]
|-
| [[SWIFT]]
| [[Should We Intervene Following Thrombolysis?]]
|-
| [[SWISH]]
| [[Swedish Isradipine Study In Hypertension]]
|-
| [[SWISSI II]]
| [[Swiss Interventional Study On Silent Ischemia Type II]]
|-
| [[SWITCH]]
| [[Switching From Lovenox To Angiomax In Patients With Acute Coronary Syndromes Without St Elevation Undergoing Pci]]
|-
| [[SWORD]]
| [[Survival With Oral D-Sotalol Trial]]
|-
| [[SYMBIOT III]]
| [[A Prospective, Randomized Trial Of A Self-Expanding Ptfe Stent Graft During Svg Intervention - Late Results]]
|-
| [[SYMPHONY I]]
| [[Sibrafiban Versus Aspirin To Yield Maximum Protection From Ischemic Heart Events Post-Acute Coronary Syndromes]]
|-
| [[SYMPHONY II]]
| [[Randomized Trial Of Aspirin, Sibrafiban, Or Both For Secondary Prevention After Acute Coronary Syndromes]]
|-
| [[SYNERGY]]
| [[Superior Yield Of The New Strategy Of Enoxaparin, Revascularization, And Glycoprotein IIb/IIia Inhibitors]]
|-
| [[SYNERGY-PCI]]
| [[A Prospective, Randomized Trial Of Enoxaparin And Unfractionated Heparin In Patients With Acute Coronary Syndromes - Results In Patients Undergoing Percutaneous Coronary Intervention]]
|-
| [[SYNTAX]]
| [[Synergy Between Percutaneous Coronary Intervention With Taxus And Cardiac Surgery]]
|-
| [[Syst-China]]
| [[Systolic Hypertension In China Trial]]
|-
| [[Syst-Eur]]
| [[For The Syst-Eur Investigators. The Prevention Of Dementia With Antihypertensive Treatment. New Evidence From The Systolic Hypertension In Europe (Syst-Eur) Study]]
|-
| [[TACT]]
| [[Therapeutic Angiogenesis For Patients With Limb Ischaemia By Autologous Transplantation Of Bone-Marrow Cells:A Pilot Study And A Randomized Controlled Trial.]]
|-
| [[TACTICS-TIMI 18]]
| [[Treat Angina With Aggrastat And Determine Cost Of Therapy With An Invasive Or Conservative Strategy]]
|-
| [[TAIM]]
| [[Trial Of Antihypertensive Interventions And Management]]
|-
| [[TAIST]]
| [[Tinzaparin In Acute Ischaemic Stroke Trial]]
|-
| [[TALISMAN]]
| [[Therapeutic Angiogenesis With Intramuscular Nv1Fgf In Patients With Critical Limb Ischemia]]
|-
| [[TAMI-5]]
| [[Thrombolysis And Angioplasty In Myocardial Infarction - Phase V]]
|-
| [[TAPAS]]
| [[Thrombus Aspiration During Percutaneous Coronary Intervention In Acute Myocardial Infarction]]
|-
| [[TAPS]]
| [[The Rt-Pa-Apsac Patency Study]]
|-
| [[TARGET]]
| [[Comparison Of Two Platelet Glycoprotein IIb/IIia Inhibitors, Tirofiban And Abciximab, For The Prevention Of Ischemic Events With Percutaneous Coronary Revascularization]]
|-
| [[TAUSA]]
| [[Thrombolysis And Angioplasty In Unstable Angina]]
|-
| [[TAXi]]
| [[Paclitaxel And Sirolimus Stents In The Real World Of Interventional Cardiology]]
|-
| [[TAXUS III]]
| [[In-Stent Restenosis Treated With Stent-Based Delivery Of Paclitaxel Incorporated In A Slow-Release Polymer Formulation]]
|-
| [[TAXUS V ISR]]
| [[Paclitaxel-Eluting Stents Vs. Brachytherapy For In-Stent Restenosis]]
|-
| [[TEAHAT]]
| [[Very Early Thrombolytic Therapy In Suspected Acute Myocardial Infarction]]
|-
| [[TEAM-2]]
| [[ Multicenter Patency Trial Of Intravenous Antistreplase Compared With Streptokinase In Acute Myocardial Infarction]]
|-
| [[TEAM-3]]
| [[Third Thrombolysis Trial Of Anistreplase (Eminase) In Acute Myocardial Infarction]]
|-
| [[TEN-HMS]]
| [[Telemonitoring For Heart Failure: Patient Characteristics And First Results]]
|-
| [[TETAMI]]
| [[Treatment Of Enoxaparin And Tirofiban In Acute Myocardial Infarction]]
|-
| [[THESEE]]
| [[A Comparison Of Low-Molecular-Weight Heparin With Unfractionated Heparin For Acute Pulmonary Embolism]]
|-
| [[THINRS]]
| [[The Home Inr Study]]
|-
| [[THOP]]
| [[Treatment Of Hypertension Based On Home Or Office Blood Pressure]]
|-
| [[THRIVE]]
| [[Thrombin Inhibitor In Venous Thromboembolism]]
|-
| [[Thrombectomy in STEMI]]
| [[Thrombectomy In St Elevation Myocardial Infarction]]
|-
| [[THUNDER]]
| [[Taxan With Short Time For Contact For Reduction Of Restenosis In Distal Arteries]]
|-
| [[TIBBS]]
| [[Total Ischemic Burden Bisoprolol Study]]
|-
| [[TIBET]]
| [[Total Ischemic Burden European Trial]]
|-
| [[TIGER-PA]]
| [[Tirofiban Given In The Emergency Room Before Primary Angioplasty]]
|-
| [[TIM]]
| [[Triflusal In Myocardial Infarction]]
|-
| [[TIMACS]]
| [[Timing Of Intervention In Patients With Acute Coronary Syndromes]]
|-
| [[TIMBER]]
| [[Transthoracic Incremental Monophasic Versus Biphasic Defibrillation By Emergency Responders]]
|-
| [[TIME]]
| [[Trial Of Invasive Versus Medical Therapy In The Elderly]]
|-
| [[TIME-CHF]]
| [[Trial Of Intensified Vs Standard Medical Therapy In Elderly Patients With Congestive Heart Failure]]
|-
| [[TIMI 1]]
| [[Thrombolysis In Myocardial Infarction Trial, Phase I]]
|-
| [[TIMI 10B]]
| [[Tnk-Tissue Plasminogen Activator Compared With Front-Loaded Tissue Plasminogen Activator In Acute Myocardial Infarction]]
|-
| [[TIMI 11B]]
| [[Thrombolysis In Myocardial Ischemia Trial, Phase 11B]]
|-
| [[TIMI 16-OPUS]]
| [[Orbofiban In Patients With Unstable Coronary Syndromes, Thrombolysis In Myocardial Infarction]]
|-
| [[TIMIC]]
| [[Efficacy Of Immunosuppressive Therapy In Patients With Virus-Negative Inflammatory Cardiomyopathy]]
|-
| [[TITAN - TIMI 34]]
| [[Time To Integrilin Therapy In Acute Myocardial Infarction]]
|-
| [[TITAX AMI]]
| [[Titanium Nitride Oxide Coated Stents And Paclitaxel Eluting Stents For Acute Myocardial Infarction]]
|-
| [[TMLR]]
| [[Transmyocardial Laser Revascularization In Patients With Refractory Angina: A Randomised]]
|-
| [[TMR]]
| [[Revascularization With Co2 Laser In Patients With Refractory Angina Pectoris: Clinical Results From The Norwegian Randomized Trial]]
|-
| [[TNT]]
| [[Treating To New Targets Study]]
|-
| [[TOAT]]
| [[The Occluded Artery Trial]]
|-
| [[TOHP II]]
| [[Effects Of Weight Loss And Sodium Reduction Intervention On Blood Pressure And Hypertension Incidence In Overweight People With High-Normal Blood Pressure: The Trials Of Hypertension Prevention, Phase II]]
|-
| [[TOMHS]]
| [[Treatment Of Mild Hypertension Study]]
|-
| [[TOMIIS]]
| [[Total Occlusion Post-Myocardial Infarction Intervention Study]]
|-
| [[TONE]]
| [[Sodium Reduction And Weight Loss In The Treatment Of Hypertension In Older Persons: A Randomized Controlled Trial Of Nonpharmacologic Interventions In The Elderly]]
|-
| [[TOPAS]]
| [[A Comparison Of Recombinant Urokinase With Vascular Surgery As Initial Treatment For Acute Arterial Occlusion Of The Legs]]
|-
| [[TOSCA]]
| [[Total Occlusion Study Of Canada]]
|-
| [[TOTAL]]
| [[Total Occlusion Trial With Angioplasty By Using Laser Guidewire]]
|-
| [[TPT]]
| [[Thrombosis Prevention Trial]]
|-
| [[TRACE]]
| [[The Trandolapril Cardiac Evaluation Trace Study]]
|-
| [[TRAFFIC]]
| [[Therapeutic Angiogenesis With Recombinant Fibroblast Growth Factor-2 For Intermittent Claudication (The Traffic Study)]]
|-
| [[TRANSCEND]]
| [[Telmisartan Randomised Assessment Study In Ace Intolerant Subjects With Cardiovascular Disease]]
|-
| [[TRANSFER-AMI]]
| [[Trial Of Routine Angioplasty And Stenting After Fibrinolysis To Enhance Reperfusion In Acute Myocardial Infarction]]
|-
| [[TRAPIST]]
| [[Trapidil In Stent]]
|-
| [[TREND]]
| [[Trial On Reversing Endothelial Dysfunction]]
|-
| [[TRENDS]]
| [[Tetra Randomized European Direct Stenting Study]]
|-
| [[TRENT]]
| [[Trial Of Early Nifedipine Treatment In Acute Myocardial Infarction]]
|-
| [[TRIC]]
| [[Thrombolysis With Recombinant Human Tissue-Type Plasminogen Activator During Instability In Coronary Artery Disease: Effect On Myocardial Ischemia And Need For Coronary Revascularization]]
|-
| [[TRIP-HF]]
| [[Triple Resynchronization In Paced Heart Failure Patients]]
|-
| [[TRITON-TIMI 38]]
| [[Trial To Assess Improvement In Therapeutic Outcomes By Optimizing Platelet Inhibition With Prasugrel]]
|-
| [[TRIUMPH]]
| [[Tilarginine Acetate Injection In A Randomized International Study In Unstable Mi Patients With Cardiogenic Shock]]
|-
| [[TROICA]]
| [[Thrombolysis In Cardiac Arrest]]
|-
| [[TROPHY]]
| [[Trial Of Preventing Hypertension]]
|-
| [[TWA in CHF]]
| [[T Wave Alternans In Congestive Heart Failure]]
|-
| [[TYPHOON]]
| [[Trial To Assess The Use Of The Cypher Stent In Acute Myocardial Infarction Treated With Angioplasty]]
|-
| [[UKPACE]]
| [[United Kingdom Pacing And Cardiovascular Events]]
|-
| [[UKPDS]]
| [[United Kingdom Prospective Diabetes Study]]
|-
| [[UK-TIA]]
| [[The United Kingdom Transient Ischemic Attack Aspirin Trial: Final Results]]
|-
| [[UNASEM]]
| [[Thrombolysis In Patients With Unstable Angina Improves The Angiographic But Not The Clinical Outcome]]
|-
| [[UNLOAD]]
| [[Ultrafiltration Versus Intravenous Diuretics For Patients Hospitalized For Acute Decompensated Heart Failure]]
|-
| [[USIM]]
| [[Urochinasi Per Via Sistemica Nell'Infarto Miocardico]]
|-
| [[VA-CABG]]
| [[Veterans Affairs (Va) Coronary Artery Bypass Surgery Cooperative Study Group]]
|-
| [[VADT]]
| [[Veterans Affairs Diabetes Trial]]
|-
| [[VA-HIT]]
| [[Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial]]
|-
| [[Val-HeFT]]
| [[Valsartan Heart Failuretrial]]
|-
| [[VALIANT]]
| [[Valsartan In Acute Myocardial Infarction Trial Investigators]]
|-
| [[VALIDD]]
| [[Valsartan In Diastolic Dysfunction]]
|-
| [[VALUE]]
| [[Valsartan Antihypertensive Long-Term Use Evaluation]]
|-
| [[VANQWISH]]
| [[Veterans Affairs (Va) Non-Q-Wave Infarction Strategies In-Hospital]]
|-
| [[VASIS]]
| [[Vasovagal Syncope International Study]]
|-
| [[VASP-02]]
| [[Vasodilator-Stimulated Phosphoprotein-02]]
|-
| [[VEAPS]]
| [[Vitamin E Atherosclerosis Prevention Study]]
|-
| [[VEGAS I]]
| [[The Vein Graft Angiojet Study I Pilot Trial]]
|-
| [[VEGAS-2]]
| [[Vein Graft Angiojet Study 2]]
|-
| [[VENUS]]
| [[Very Early Nimodipine Use In Stroke]]
|-
| [[VERBS]]
| [[Ventricular Endocardial Right Bifocal Stimulation In The Treatment Of Severe Dilated Cardiomyopathy Heart Failure With Wide Qrs]]
|-
| [[VERDICT]]
| [[Verapamil Versus Digoxin And Acute Versus Routine Serial Cardioversion Trial]]
|-
| [[VERITAS]]
| [[Value Of Endothelin Receptor Inhibition With Tezosentan In Acute Heart Failure Studies]]
|-
| [[VEST]]
| [[Vesnarinone Survival Trial]]
|-
| [[VHAS]]
| [[Clinical Results Of The Verapamil In Hypertension And Atherosclerosis Study]]
|-
| [[VHEFT-I]]
| [[The Effects Of Vasodilator Therapy On Mortality In Chronic Congestive Heart Failure]]
|-
| [[VHEFT-II]]
| [[Efficacy And Outcome With Felodipine In Heart Failure]]
|-
| [[VIAMI]]
| [[Viability-Guided Angioplasty After Acute Myocardial Infarction]]
|-
| [[VICTOR]]
| [[Vioxx In Colorectal Cancer Therapy: Definition Of Optimal Regimen]]
|-
| [[VINTAGE-MI]]
| [[Vascular Interaction With Age In Myocardial Infarction]]
|-
| [[VITAL]]
| [[Vasoflux International Trial For Acute Myocardial Infarction Lysis]]
|-
| [[VIVA]]
| [[ Vascular Endothelial Growth Factor In Ischemia For Vascular Angiogenesis]]
|-
| [[VMAC]]
| [[Vasodilation In The Management Of Acute Congestive Heart Failure]]
|-
| [[VPS]]
| [[The North American Vasovagal Pacemaker Study]]
|-
| [[VPS II]]
| [[Vasovagal Pacemaker Study II]]
|-
| [[WAFACS]]
| [[Women's Antioxidant And Folic Acid Cardiovascular Study]]
|-
| [[WARIS-II]]
| [[Warfarin, Aspirin, Or Both After Myocardial Infarction]]
|-
| [[WARSS]]
| [[Warfarin–Aspirin Recurrent Stroke Stud]]
|-
| [[WATCH]]
| [[Warfarin And Antiplatelet Trial In Chronic Heart Failure]]
|-
| [[WAVE]]
| [[Warfarin Antiplatelet Vascular Evaluation]]
|-
| [[WAVE]]
| [[Women's Angiographic Vitamin And Estrogen Trial]]
|-
| [[WELL-HART]]
| [[Women’s Estrogen–Progestin Lipid-Lowering Hormone Atherosclerosis Regression Trial]]
|-
| [[WENBIT]]
| [[Western Norway B-Vitamin Intervention Trial]]
|-
| [[WEST]]
| [[Which Early St-Elevation Myocardial Infarction Therapy]]
|-
| [[WHI]]
| [[Women's Health Initiative]]
|-
| [[WINS]]
| [[Women's Initiative For Nonsmoking]]
|-
| [[WISE]]
| [[Women's Ischemia Syndrome Evaluation]]
|-
| [[WITTI Women]]
| [[Secondary Prevention Beyond Walls Intervention Trial In Women]]
|-
| [[WIZARD]]
| [[Weekly Intervention With Zithromax For Atherosclerosis And Its Related Disorders]]
|-
| [[WRIST]]
| [[Washington Radiation For In-Stent Restenosis Trial]]
|-
| [[ZEST-AMI]]
| [[Zotarolimus-Eluting Stent Vs. Sirolimus-Eluting Stent Vs. Paclitaxel-Eluting Stent For Acute Myocardial Infarction Patients]]
|}

{{WH}}
{{WS}}

DIG Enalapril

2009-07-02T21:07:01Z

Michaelagibson: ←Redirected page to Enalapril Versus Digoxin In Patients With Congestive Heart Failure: A Multicenter Study (Canadian Enalapril Versus Digoxin Study Group)

#redirect:[[Enalapril Versus Digoxin In Patients With Congestive Heart Failure: A Multicenter Study (Canadian Enalapril Versus Digoxin Study Group)]]

DIG

2009-07-02T21:04:01Z

Michaelagibson: ←Redirected page to Digoxin Investigation Group

#redirect:[[Digoxin Investigation Group]]

DIDI

2009-07-02T21:03:37Z

Michaelagibson: ←Redirected page to Diltiazem In Dilated Cardiomyopathy

#redirect:[[Diltiazem In Dilated Cardiomyopathy]]

DIAMOND CHF

2009-07-02T21:03:13Z

Michaelagibson: ←Redirected page to Danish Investigators Of Arrhythmia And Mortality On Dofetilde Congestive Heart Failure

#redirect:[[Danish Investigators Of Arrhythmia And Mortality On Dofetilde Congestive Heart Failure]]

DIAMOND

2009-07-02T21:02:45Z

Michaelagibson: New page: Which page would you like: ==DIAMOND Clinical Trials:== Danish Investigations Of Arrhythmia And Mortality On Dofetilide [[Distensibility Improvement With Alt-711 Remodeling In Diast...

Which page would you like:

==DIAMOND Clinical Trials:==

[[Danish Investigations Of Arrhythmia And Mortality On Dofetilide]]

[[Distensibility Improvement With Alt-711 Remodeling In Diastolic Heart Failure Sponsor]]

DIAL

2009-07-02T21:00:02Z

Michaelagibson: ←Redirected page to Randomized Trial Of Telephone Intervention In Chronic Heart Failure

#redirect:[[Randomized Trial Of Telephone Intervention In Chronic Heart Failure]]

DIAGNOSIS

2009-07-02T20:59:08Z

Michaelagibson: ←Redirected page to Diffusion-Weighted Imaging Assessment Of The Genuine Need For Other Studies In Ischemic Stroke

#redirect:[[Diffusion-Weighted Imaging Assessment Of The Genuine Need For Other Studies In Ischemic Stroke]]

DIADS

2009-07-02T16:31:20Z

Michaelagibson: ←Redirected page to Depression In Alzheimer Disease Study

#redirect:[[Depression In Alzheimer Disease Study]]

DIAD

2009-07-02T16:30:54Z

Michaelagibson: ←Redirected page to Detection Of Ischemia In Asymptomatic Diabetics

#redirect:[[Detection Of Ischemia In Asymptomatic Diabetics]]

DIACOR

2009-07-02T16:30:29Z

Michaelagibson: ←Redirected page to Diabetes And Combined Lipid Therapy Regimen

#redirect:[[Diabetes And Combined Lipid Therapy Regimen]]