Ebola classification: Difference between revisions

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{{Ebola}}
{{Ebola}}
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==Overview==
==Overview==
Ebola virus can be classified into 5 subtypes: ''Zaïre'', ''Sudan'', ''Reston'', ''Tai (Ivory Coast)'' and ''Bundibugyo'', according to the place of discovery.


==Subtypes==
==Classification==
<!-- The correct term is "ebolavirus" without any spaces -->
The table below summarizes the [[ebola virus]] [[strains]] identified until now:
Microbiologists have defined several subtypes of Ebola. The following list is not exclusive. A new strain of Ebola has been identified in Uganda during an outbreak. It does not match any of the four Ebola subtypes previously identified by scientists.<ref>{{cite news |first= |last= |authorlink= |coauthors= |title=New subtype of Ebola suspected in Uganda |url=http://www.usatoday.com/news/world/2007-11-30-uganda-ebola_N.htm |work=[[USA Today]] |publisher= |date=2007-11-30 |accessdate=2008-02-25 }}</ref>
{| style="border: 0px; font-size: 90%; margin: 0 18px;"
! style="width: 250px; background: #4479BA; text-align: center;"| {{fontcolor|#FFF|Ebola Virus Strain}}
! style="width: 250px; background: #4479BA; text-align: center;"| {{fontcolor|#FFF|Place of Discovery}}
! style="width: 250px; background: #4479BA; text-align: center;"| {{fontcolor|#FFF|Date Identified}}
|-
| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Sudan ebolavirus'''
| style="background: #DCDCDC; padding: 5px;"| Nzara and Maridi, Sudan
| style="background: #F5F5F5; padding: 5px;"| Between June and November 1976
|-
| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Zaire ebolavirus'''
| style="background: #DCDCDC; padding: 5px;"| Yambuku, Democratic Republic of the Congo
| style="background: #F5F5F5; padding: 5px;"| Between August and November 1976
|-
| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Reston ebolavirus'''
| style="background: #DCDCDC; padding: 5px;"| Reston, Virginia, US.
| style="background: #F5F5F5; padding: 5px;"| November 1989
|-
| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Ivory Coast ebolavirus'''
| style="background: #DCDCDC; padding: 5px;"| Tai Forest, Ivory Coast.
| style="background: #F5F5F5; padding: 5px;"| November 1994
|-
| style="background: #F5F5F5; padding: 5px; text-align: center;"| '''Bundibugyo ebolavirus'''
| style="background: #DCDCDC; padding: 5px;"| Bundibugyo District, Uganda
| style="background: #F5F5F5; padding: 5px;"|  November 2007
|}


=== ''Zaïre ebola virus'' ===
=====''Zaïre Ebolavirus''=====
[[Image:Ebola-zaire chart.jpg|thumb|300px|right|Known human cases and deaths during outbreaks of ''Zaïre Ebolavirus'' between 1976 and 2003]]
*Among the five [[strains]], ''Zaïre Ebolavirus'' carries the highest [[mortality rate]].
*A [[virus]] of the genus ''[[Ebolavirus]]'' is considered member of the [[species]] ''Zaire ebolavirus'' if:<ref name="KuhnBecker2010">{{cite journal|last1=Kuhn|first1=Jens H.|last2=Becker|first2=Stephan|last3=Ebihara|first3=Hideki|last4=Geisbert|first4=Thomas W.|last5=Johnson|first5=Karl M.|last6=Kawaoka|first6=Yoshihiro|last7=Lipkin|first7=W. Ian|last8=Negredo|first8=Ana I.|last9=Netesov|first9=Sergey V.|last10=Nichol|first10=Stuart T.|last11=Palacios|first11=Gustavo|last12=Peters|first12=Clarence J.|last13=Tenorio|first13=Antonio|last14=Volchkov|first14=Viktor E.|last15=Jahrling|first15=Peter B.|title=Proposal for a revised taxonomy of the family Filoviridae: classification, names of taxa and viruses, and virus abbreviations|journal=Archives of Virology|volume=155|issue=12|year=2010|pages=2083–2103|issn=0304-8608|doi=10.1007/s00705-010-0814-x}}</ref>
:*It is found in the Democratic Republic of the Congo, Gabon, or the Republic of the Congo.
:*It has a [[genome]] with two or three [[gene]] overlaps (''VP35''/''VP40'', ''GP''/''VP30'', ''VP24''/''L'').
:*It has a [[genomic sequence]] that differs from the [[virus]] type by less than 30%.


The ''Zaïre Ebola virus'' has the highest mortality rate, up to 90% in some epidemics, with an average of approximately 83% mortality over 27 years. The case-fatality rates were 88% in 1976, 100% in 1977, 59% in 1994, 81% in 1995, 73% in 1996, 80% in 2001-2002 and 90% in 2003. There have been more outbreaks of ''Zaïre Ebola virus'' than any other strain.
=====''Sudan Ebolavirus''=====
*A [[virus]] of the genus ''[[Ebolavirus]]'' is considered member of the [[species]] ''Sudan ebolavirus'' if:<ref name="KuhnBecker2010">{{cite journal|last1=Kuhn|first1=Jens H.|last2=Becker|first2=Stephan|last3=Ebihara|first3=Hideki|last4=Geisbert|first4=Thomas W.|last5=Johnson|first5=Karl M.|last6=Kawaoka|first6=Yoshihiro|last7=Lipkin|first7=W. Ian|last8=Negredo|first8=Ana I.|last9=Netesov|first9=Sergey V.|last10=Nichol|first10=Stuart T.|last11=Palacios|first11=Gustavo|last12=Peters|first12=Clarence J.|last13=Tenorio|first13=Antonio|last14=Volchkov|first14=Viktor E.|last15=Jahrling|first15=Peter B.|title=Proposal for a revised taxonomy of the family Filoviridae: classification, names of taxa and viruses, and virus abbreviations|journal=Archives of Virology|volume=155|issue=12|year=2010|pages=2083–2103|issn=0304-8608|doi=10.1007/s00705-010-0814-x}}</ref>
:*It is [[endemic]] in Sudan and/or Uganda.
:*It has a [[genome]] with three [[gene]] overlaps (''VP35''/''VP40'', ''GP''/''VP30'', ''VP24''/''L'').
:*It has a [[genomic]] sequence different from ''[[Ebola virus]]'' by ≥30%, but different from that of Sudan [[virus]] by <30%.


The first outbreak took place on [[August 26]] [[1976]] in [[Yambuku]], a town in the north of [[Zaire|Zaïre]]. The first recorded case was Mabalo Lokela, a 44-year-old schoolteacher returning from a trip around the north of the state. His high fever was diagnosed as possible [[malaria]] and he was subsequently given a [[quinine]] shot. Lokela returned to the hospital every day. A week later, his symptoms included uncontrolled [[vomiting]], bloody diarrhea, [[headache]], [[dizziness]], and trouble breathing. Later, he began bleeding from his nose, mouth, and anus. Lokela died on [[September 8]] [[1976]], roughly 14 days after the onset of symptoms.
=====''Reston Ebolavirus''=====
*A [[virus]] of the [[genus]] ''[[Ebolavirus]]'' is considered member of the [[species]] ''Reston ebolavirus'' if:<ref name="KuhnBecker2010">{{cite journal|last1=Kuhn|first1=Jens H.|last2=Becker|first2=Stephan|last3=Ebihara|first3=Hideki|last4=Geisbert|first4=Thomas W.|last5=Johnson|first5=Karl M.|last6=Kawaoka|first6=Yoshihiro|last7=Lipkin|first7=W. Ian|last8=Negredo|first8=Ana I.|last9=Netesov|first9=Sergey V.|last10=Nichol|first10=Stuart T.|last11=Palacios|first11=Gustavo|last12=Peters|first12=Clarence J.|last13=Tenorio|first13=Antonio|last14=Volchkov|first14=Viktor E.|last15=Jahrling|first15=Peter B.|title=Proposal for a revised taxonomy of the family Filoviridae: classification, names of taxa and viruses, and virus abbreviations|journal=Archives of Virology|volume=155|issue=12|year=2010|pages=2083–2103|issn=0304-8608|doi=10.1007/s00705-010-0814-x}}</ref>
:*If its [[genome]] diverges from that of the prototype ''Reston [[virus]]'', the ''Reston virus'' variant Pennsylvania, by ≤10% at the [[nucleotide]] level.


Soon after, more patients arrived with varying but similar symptoms including fever, headache, muscle and joint aches, fatigue, nausea, and dizziness. These often progressed to bloody diarrhea, severe vomiting, and bleeding from the nose, mouth, and anus. The initial transmission was believed to be due to reuse of the needle for Lokela’s injection without sterilization. Subsequent transmission was also due to care of the sick patients without [[Universal precautions|barrier nursing]] and the traditional burial preparation method, which involved washing and [[gastrointestinal tract]] cleansing.
=====''Tai (Ivory Coast) Ebolavirus''=====
*A [[virus]] of the [[genus]] ''[[Ebolavirus]]'' is considered member of the [[species]] ''Tai Forest ebolavirus'' if:<ref name="KuhnBecker2010">{{cite journal|last1=Kuhn|first1=Jens H.|last2=Becker|first2=Stephan|last3=Ebihara|first3=Hideki|last4=Geisbert|first4=Thomas W.|last5=Johnson|first5=Karl M.|last6=Kawaoka|first6=Yoshihiro|last7=Lipkin|first7=W. Ian|last8=Negredo|first8=Ana I.|last9=Netesov|first9=Sergey V.|last10=Nichol|first10=Stuart T.|last11=Palacios|first11=Gustavo|last12=Peters|first12=Clarence J.|last13=Tenorio|first13=Antonio|last14=Volchkov|first14=Viktor E.|last15=Jahrling|first15=Peter B.|title=Proposal for a revised taxonomy of the family Filoviridae: classification, names of taxa and viruses, and virus abbreviations|journal=Archives of Virology|volume=155|issue=12|year=2010|pages=2083–2103|issn=0304-8608|doi=10.1007/s00705-010-0814-x}}</ref>
:*It is [[endemic]] in Côte d'Ivoire.
:*It has a [[genome]] with three [[gene]] overlaps (''VP35''/''VP40'', ''GP''/''VP30'', ''VP24''/''L'').
:*It has a [[genomic]] sequence different from ''[[Ebola virus]]'' by ≥30% but different from that of Tai Forest [[virus]] by <30%.


Two nuns working in Yambuku as nurses also died in the same outbreak.<ref>{{cite paper |last=Isaacson |first=Margaretha |author= |authorlink= |coauthors=''et al.'' |title=Two Belgian nurses died of Ebola |version= |publisher= |date= |url=http://www.itg.be/ebola/ebola-12.htm |format= |id= |accessdate= }}</ref>
=====''Bundibugyo Ebolavirus''=====
<!-- The correct term is "Ebola virus" with a space -->
*A [[virus]] of the [[genus]] ''[[Ebolavirus]]'' is considered member of the [[species]] ''Bundibugyo ebolavirus'' if:<ref name="KuhnBecker2010">{{cite journal|last1=Kuhn|first1=Jens H.|last2=Becker|first2=Stephan|last3=Ebihara|first3=Hideki|last4=Geisbert|first4=Thomas W.|last5=Johnson|first5=Karl M.|last6=Kawaoka|first6=Yoshihiro|last7=Lipkin|first7=W. Ian|last8=Negredo|first8=Ana I.|last9=Netesov|first9=Sergey V.|last10=Nichol|first10=Stuart T.|last11=Palacios|first11=Gustavo|last12=Peters|first12=Clarence J.|last13=Tenorio|first13=Antonio|last14=Volchkov|first14=Viktor E.|last15=Jahrling|first15=Peter B.|title=Proposal for a revised taxonomy of the family Filoviridae: classification, names of taxa and viruses, and virus abbreviations|journal=Archives of Virology|volume=155|issue=12|year=2010|pages=2083–2103|issn=0304-8608|doi=10.1007/s00705-010-0814-x}}</ref>
:*It is [[endemic]] in Uganda.
:*It has a [[genome]] with three [[gene]] overlaps (''VP35''/''VP40'', ''GP''/''VP30'', ''VP24''/''L'').
:*It has a [[genomic]] sequence different from ''[[Ebola virus]]'' by ≥30%, but different from that of Bundibugyo virus by <30%.


=== ''Sudan ebolavirus'' ===
==References==
[[Image:Ebola-sudan chart.jpg|thumb|300px|right|Known human cases and deaths during outbreaks of Sudan Ebolavirus between 1976 and 2003]]
{{Reflist|2}}
 
Sudan Ebolavirus was the second strand of Ebola reported in 1976. It apparently originated amongst cotton factory workers in Nzara, Sudan. The first case reported was a worker exposed to a potential natural reservoir at the cotton factory. Scientists tested all animals and insects in response to this, however none tested positive for the virus. The carrier is still unknown.
 
A second case involved a nightclub owner in Nzara, [[Sudan]]. The local hospital, Maridi, tested and attempted to treat the patient; however, nothing was successful, and he died. The hospital did not advocate safe and practical procedures in sterilizing and disinfecting the medical tools used on the nightclub owner, likely facilitating the spread of the virus in the hospital.
 
The most recent outbreak of ''Sudan Ebolavirus'' occurred in [[May]] [[2004]]. As of [[May]] [[2004]], 20 cases of ''Sudan Ebolavirus'' were reported in [[Yambio|Yambio County]], [[Sudan]], with 5 deaths resulting. The [[Centers for Disease Control and Prevention]] confirmed the virus a few days later. The neighbouring countries of [[Uganda]] and the [[Democratic Republic of Congo]] have increased surveillance in bordering areas, and other similar measures have been taken to control the outbreak. The average fatality rates for ''Sudan Ebolavirus'' were 54% in 1976, 68% in 1979, and 53% in 2000/2001. The average case-fatality rate is 54%.
<!-- The correct term is "ebolavirus" without any spaces -->
 
===''Reston ebolavirus''===
{{main|Ebola Reston}}
First discovered in [[November]] [[1989]] in a group of 100 [[Crab-eating Macaque|Crab-eating macaques]] (''{{lang|la|Macaca fascicularis}}'') imported from the [[Philippines]] to [[Reston, Virginia|Reston]], [[Virginia]]. A parallel infected shipment was also sent to [[Philadelphia]]. This strain was highly lethal in monkeys, but did not cause any fatalities in humans. Six of the Reston primate handlers tested positive for the virus, two due to previous exposure. The bio-thriller ''[[The Hot Zone]]'' was based on this incident.


Further ''Reston Ebolavirus'' infected monkeys were shipped again to Reston, and [[Alice, Texas|Alice]], [[Texas]], in February of 1990. More ''Reston Ebolavirus'' infected monkeys were discovered in 1992 in [[Siena]], [[Italy]] and in Texas again in March 1996. A high rate of co-infection with [[Simian hemorrhagic fever virus|Simian hemorragic fever]] (SHF) was present in all infected monkeys. No human illness has resulted from these two outbreaks.


===''Tai (Ivory Coast) ebolavirus''===
{{WH}}
This subtype of Ebola was first discovered amongst [[chimpanzee]]s of the Tai Forest in [[Côte d'Ivoire|Côte d’Ivoire]], [[Africa]]. On [[November 1]] [[1994]], the corpses of two chimpanzees were found in the forest. [[Necropsy|Necropsies]] showed blood within the heart to be liquid and brown, no obvious marks seen on the organs, and one presented lungs filled with liquid blood. Studies of tissues taken from the chimps showed results similar to human cases during the 1976 Ebola outbreaks in Zaïre and Sudan. Later in 1994, more dead chimpanzees were discovered, with many testing positive to Ebola using molecular techniques. The source of contamination was believed to be the meat of infected [[Western Red Colobus]] monkeys, upon which the chimpanzees preyed.<ref>[http://virus.stanford.edu/filo/eboci.html Ebola Cote d'Ivoire Outbreaks<!-- Bot generated title -->]</ref>
{{WS}}


One of the scientists performing the necropsies on the infected chimpanzees contracted Ebola. She developed symptoms similar to [[dengue fever]] approximately a week after the necropsy and was transported to Switzerland for treatment. After two weeks she was discharged from hospital, and was fully recovered six weeks after the infection.
[[Category:Mononegavirales]]
 
[[Category:Viral diseases]]
===''Bundibugyo ebolavirus''===
[[Category:Biological weapons]]
On [[November 24]] [[2007]], the Uganda Ministry of Health confirmed an outbreak of Ebola in the [[Bundibugyo District]].  After confirmation of samples tested by the United States National Reference Laboratories and the [[Centers for Disease Control]], the World Health Organization has confirmed the presence of a new species of the Ebola virus. On [[February 20]] [[2008]], the Uganda Ministry officially announced the end of the epidemic in Bundibugyo with the last infected person discharged on [[January 8]] [[2008]].<ref>{{cite press release |title=End of Ebola outbreak in Uganda |publisher=[[World Health Organization]] |date=2008-02-20 |url=http://www.who.int/csr/don/2007_02_20b/en/index.html |format= |language= |accessdate= |quote= }}</ref> Ugandan officials confirmed a total of 149 cases of this new Ebola species, with 37 deaths attributed to the strain.<ref>{{cite news |first=Tim |last= Cocks|authorlink= |coauthors= |title=Uganda confirms 113 suspected Ebola cases |url=http://africa.reuters.com/top/news/usnBAN126612.html |work= |publisher=[[Reuters]] |date=2007-12-11 |accessdate=2008-02-25 }}</ref>
[[Category:Zoonoses]]
 
[[Category:Hemorrhagic fevers]]
==References==
[[Category:Disease]]
{{Reflist|2}}

Latest revision as of 17:37, 18 September 2017

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Guillermo Rodriguez Nava, M.D. [2]; João André Alves Silva, M.D. [3]

Overview

Ebola virus can be classified into 5 subtypes: Zaïre, Sudan, Reston, Tai (Ivory Coast) and Bundibugyo, according to the place of discovery.

Classification

The table below summarizes the ebola virus strains identified until now:

Ebola Virus Strain Place of Discovery Date Identified
Sudan ebolavirus Nzara and Maridi, Sudan Between June and November 1976
Zaire ebolavirus Yambuku, Democratic Republic of the Congo Between August and November 1976
Reston ebolavirus Reston, Virginia, US. November 1989
Ivory Coast ebolavirus Tai Forest, Ivory Coast. November 1994
Bundibugyo ebolavirus Bundibugyo District, Uganda November 2007
Zaïre Ebolavirus
  • It is found in the Democratic Republic of the Congo, Gabon, or the Republic of the Congo.
  • It has a genome with two or three gene overlaps (VP35/VP40, GP/VP30, VP24/L).
  • It has a genomic sequence that differs from the virus type by less than 30%.
Sudan Ebolavirus
  • It is endemic in Sudan and/or Uganda.
  • It has a genome with three gene overlaps (VP35/VP40, GP/VP30, VP24/L).
  • It has a genomic sequence different from Ebola virus by ≥30%, but different from that of Sudan virus by <30%.
Reston Ebolavirus
  • If its genome diverges from that of the prototype Reston virus, the Reston virus variant Pennsylvania, by ≤10% at the nucleotide level.
Tai (Ivory Coast) Ebolavirus
  • It is endemic in Côte d'Ivoire.
  • It has a genome with three gene overlaps (VP35/VP40, GP/VP30, VP24/L).
  • It has a genomic sequence different from Ebola virus by ≥30% but different from that of Tai Forest virus by <30%.
Bundibugyo Ebolavirus
  • It is endemic in Uganda.
  • It has a genome with three gene overlaps (VP35/VP40, GP/VP30, VP24/L).
  • It has a genomic sequence different from Ebola virus by ≥30%, but different from that of Bundibugyo virus by <30%.

References

  1. 1.0 1.1 1.2 1.3 1.4 Kuhn, Jens H.; Becker, Stephan; Ebihara, Hideki; Geisbert, Thomas W.; Johnson, Karl M.; Kawaoka, Yoshihiro; Lipkin, W. Ian; Negredo, Ana I.; Netesov, Sergey V.; Nichol, Stuart T.; Palacios, Gustavo; Peters, Clarence J.; Tenorio, Antonio; Volchkov, Viktor E.; Jahrling, Peter B. (2010). "Proposal for a revised taxonomy of the family Filoviridae: classification, names of taxa and viruses, and virus abbreviations". Archives of Virology. 155 (12): 2083–2103. doi:10.1007/s00705-010-0814-x. ISSN 0304-8608.


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