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{{Herpes simplex}}
{{Herpes simplex}}


{{CMG}}, '''Associate Editor(s)-In-Chief:''' {{CZ}}; [[Lakshmi Gopalakrishnan, M.B.B.S.]]
{{CMG}}; {{AE}} {{CZ}}, [[Lakshmi Gopalakrishnan, M.B.B.S.]]


==Recurrences and triggers==
==Overview==
Following active infection, herpes viruses become quiescent to establish a latent infection in sensory and autonomic [[ganglia]] of the nervous system.  The double-stranded DNA of the virus is incorporated into the cell physiology by infection of the [[cell nucleus]] of a nerve's [[Soma (biology)|cell body]]. HSV latency is static - no virus is produced - and is controlled by a number of viral genes including Latency Associated Transcript (LAT).<ref name="pmid12409612">{{cite journal |author=Stumpf MP, Laidlaw Z, Jansen VA |title=Herpes viruses hedge their bets |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=99 |issue=23 |pages=15234–7 |year=2002 |pmid=12409612 |doi=10.1073/pnas.232546899}}</ref>
[[HSV-1]] and [[HSV-2]] can be found in and released from the sores that the viruses cause, but they also may be released between [[outbreaks]] from [[skin]] that does not appear to have a [[sore]]. Generally, a person can only acquire [[HSV-2]] infection during sexual contact with someone who has a genital [[HSV-2]] infection. Transmission can occur from an infected partner who does not have a visible sore and may not know that he or she is infected. [[HSV-1]] can cause [[genital herpes]], but it more commonly causes infections of the mouth and lips, so-called fever blisters. [[HSV-1]] infection of the genitals can be caused by oral-genital or genital-genital contact with a person who has HSV-1 infection. Genital HSV-1 outbreaks recur less regularly than genital HSV-2 outbreaks.


The causes of reactivation from latency are uncertain but several potential triggers have been documented. Physical or psychological stress can trigger an outbreak of herpes.<ref name="pmid11359358">{{cite journal |author=Sainz B, Loutsch JM, Marquart ME, Hill JM |title=Stress-associated immunomodulation and herpes simplex virus infections |journal=Med. Hypotheses |volume=56 |issue=3 |pages=348–56 |year=2001 |pmid=11359358 |doi=10.1054/mehy.2000.1219}}</ref>  Local injury to the face, lips, eyes or mouth, trauma, surgery, wind, [[radiotherapy]], [[ultraviolet light]] or sunlight are well established triggers.<ref name="pmid18083428">{{cite journal |author=Chambers A, Perry M |title=Salivary mediated autoinoculation of herpes simplex virus on the face in the absence of "cold sores," after trauma |journal=J. Oral Maxillofac. Surg. |volume=66 |issue=1 |pages=136–8 |year=2008 |pmid=18083428 |doi=10.1016/j.joms.2006.07.019}}</ref><ref name="pmid2821086">{{cite journal |author=Perna JJ, Mannix ML, Rooney JF, Notkins AL, Straus SE |title=Reactivation of latent herpes simplex virus infection by ultraviolet light: a human model |journal=J. Am. Acad. Dermatol. |volume=17 |issue=3 |pages=473–8 |year=1987 |pmid=2821086 |doi=}}</ref><ref name="pmid1323616">{{cite journal |author=Rooney JF, Straus SE, Mannix ML, ''et al'' |title=UV light-induced reactivation of herpes simplex virus type 2 and prevention by acyclovir |journal=J. Infect. Dis. |volume=166 |issue=3 |pages=500–6 |year=1992 |pmid=1323616 |doi=}}</ref><ref name="pmid9377190">{{cite journal |author=Oakley C, Epstein JB, Sherlock CH |title=Reactivation of oral herpes simplex virus: implications for clinical management of herpes simplex virus recurrence during radiotherapy |journal=Oral Surg Oral Med Oral Pathol Oral Radiol Endod |volume=84 |issue=3 |pages=272–8 |year=1997 |pmid=9377190 |doi=}}</ref><ref name="pmid15603217">{{cite journal |author=Ichihashi M, Nagai H, Matsunaga K |title=Sunlight is an important causative factor of recurrent herpes simplex |journal=Cutis |volume=74 |issue=5 Suppl |pages=14–8 |year=2004 |pmid=15603217 |doi=}}</ref> Some studies suggest changes in the immune system during [[menstruation]] may play a role in HSV-1 reactivation.<ref name="pmid11022124">{{cite journal |author=Myśliwska J, Trzonkowski P, Bryl E, Lukaszuk K, Myśliwski A |title=Lower interleukin-2 and higher serum tumor necrosis factor-a levels are associated with perimenstrual, recurrent, facial Herpes simplex infection in young women |journal=Eur. Cytokine Netw. |volume=11 |issue=3 |pages=397–406 |year=2000 |pmid=11022124 |doi=}}</ref><ref name="pmid4526372">{{cite journal |author=Segal AL, Katcher AH, Brightman VJ, Miller MF |title=Recurrent herpes labialis, recurrent aphthous ulcers, and the menstrual cycle |journal=J. Dent. Res. |volume=53 |issue=4 |pages=797–803 |year=1974 |pmid=4526372 |doi=}}</ref> In addition, concurrent infections, such as viral [[upper respiratory tract infection]] or other febrile diseases, can cause outbreaks, hence the historic terms "cold sore" and "fever blister".
The surest way to avoid transmission of genital herpes, is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected. [[Genital ulcer]] diseases can occur in both male and female genital areas that are covered or protected by a latex [[condom]], as well as in areas that are not covered. Correct and consistent use of latex condoms can reduce the risk of genital herpes. Persons with herpes should abstain from sexual activity with uninfected partners when lesions or other symptoms of herpes are present. It is important to know that even if a person is asymptomatic, he or she can still infect sex partners. A positive HSV-2 [[blood test]] most likely indicates a genital herpes [[infection]].


The frequency and severity of recurrent outbreaks may vary greatly depending upon the individual.
==Pathophysiology==
Outbreaks may occur at the original site of the infection or in close proximity to nerve endings that reach out from the infected ganglia.  In the case of a genital infection, sores can appear near the base of the spine, the buttocks, back of the thighs, or they may appear at the original site of infection. Immunocompromised individuals may experience episodes that are longer, more frequent and more severe. The human body is able to build up an immunity to the virus over time and antiviral medication has been proven to shorten the duration and/or frequency of the outbreaks.<ref name="pmid18192785">{{cite journal |author=Martinez V, Caumes E, Chosidow O |title=Treatment to prevent recurrent genital herpes |journal=Curr Opin Infect Dis |volume=21 |issue=1 |pages=42–48 |year=2008 |pmid=18192785 |doi=10.1097/QCO.0b013e3282f3d9d3}}</ref>
===Mode of Transmission===
 
*Herpes can be contracted through direct contact with an active [[lesion]] or [[body fluid]] of an infected person.<ref name="titleAHMF: Preventing Sexual Transmission of Genital Herpes">{{cite web |url=http://www.ahmf.com.au/health_professionals/guidelines/preventing_gh_transmission.htm |title=AHMF: Preventing Sexual Transmission of Genital Herpes |accessdate=2008-02-24 |format= |work=}}</ref> Infected people that show no visible symptoms may still shed and transmit virus through their skin, and this asymptomatic shedding may represent the most common form of HSV-2 transmission.<ref name="pmid16238897">Leone P (2005) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=16238897 Reducing the risk of transmitting genital herpes: advances in understanding and therapy.] ''Curr Med Res Opin'' 21 (10):1577-82. [http://dx.doi.org/10.1185/030079905X61901 DOI:10.1185/030079905X61901] PMID: [http://pubmed.gov/16238897 16238897]</ref>
==Transmission and prevention==
====Mode of Transmission====
*Herpes can be contracted through '''direct contact''' with an active lesion or body fluid of an infected person.<ref name="titleAHMF: Preventing Sexual Transmission of Genital Herpes">{{cite web |url=http://www.ahmf.com.au/health_professionals/guidelines/preventing_gh_transmission.htm |title=AHMF: Preventing Sexual Transmission of Genital Herpes |accessdate=2008-02-24 |format= |work=}}</ref> Infected people that show no visible symptoms may still shed and transmit virus through their skin, and this asymptomatic shedding may represent the most common form of HSV-2 transmission.<ref name="pmid16238897">Leone P (2005) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=16238897 Reducing the risk of transmitting genital herpes: advances in understanding and therapy.] ''Curr Med Res Opin'' 21 (10):1577-82. [http://dx.doi.org/10.1185/030079905X61901 DOI:10.1185/030079905X61901] PMID: [http://pubmed.gov/16238897 16238897]</ref>


*There are no documented cases of infection via an inanimate object (e.g. a towel, toilet seat, drinking vessels).   
*There are no documented cases of infection via an inanimate object (e.g. a towel, toilet seat, drinking vessels).   


*To infect a new individual, HSV travels through tiny breaks in the skin or mucous membranes in the mouth or genital areas. Even microscopic abrasions on mucous membranes are sufficient to allow viral entry.  
*To infect a new individual, HSV travels through tiny breaks in the skin or mucous membranes in the mouth or genital areas. Even microscopic abrasions on [[mucous membranes]] are sufficient to allow viral entry.  


====Population At Risk====
===Population At Risk===
*Herpes transmission occurs between discordant partners and a person with a history of infection (HSV seropositive) can pass the virus to an HSV seronegative person.<ref name="pmid18156035">Gupta R, Warren T, Wald A (2007) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=18156035 Genital herpes.] ''Lancet'' 370 (9605):2127-37. [http://dx.doi.org/10.1016/S0140-6736(07)61908-4 DOI:10.1016/S0140-6736(07)61908-4] PMID: [http://pubmed.gov/18156035 18156035]</ref> Antibodies that develop following an initial infection with that type of HSV prevents reinfection with the same herpes type - a person with a history of a cold sore caused by HSV-1 cannot contract a [[Herpetic whitlow|herpes whitlow]] or [[Herpes simplex anogenital infection|genital infection]] caused by HSV-1. In a [[monogamy|monogamous]] couple, a seronegative female runs greater than 30% per year risk of contracting an HSV-1 infection from a seropositive male partner. If an oral HSV-1 infection is contracted first, seroconversion will have occurred after 6 weeks to provide protective antibodies against a future genital HSV-1 infection.
*Herpes transmission occurs between discordant partners and a person with a history of infection ([[HSV]] [[seropositive]]) can pass the virus to an HSV [[seronegative]] person.<ref name="pmid18156035">Gupta R, Warren T, Wald A (2007) [http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&retmode=ref&cmd=prlinks&id=18156035 Genital herpes.] ''Lancet'' 370 (9605):2127-37. [http://dx.doi.org/10.1016/S0140-6736(07)61908-4 DOI:10.1016/S0140-6736(07)61908-4] PMID: [http://pubmed.gov/18156035 18156035]</ref> Antibodies that develop following an initial infection with that type of HSV help prevent reinfection with the same herpes type. In a [[monogamy|monogamous]] couple, a [[seronegative]] female runs greater than 30% per year risk of contracting an HSV-1 infection from a [[seropositive]] male partner. If an oral HSV-1 infection is contracted first, [[seroconversion]] will have occurred after 6 weeks to provide [[Antibodies|protective antibodies]] against a future genital [[HSV-1]] infection.


*As with almost all [[STD|sexually transmited infections]], women are more susceptible to acquiring genital HSV-2 than men.<ref> {{cite news | author=Carla K. Johnson | title=Percentage of people with herpes drops | url=http://www.newsobserver.com/150/story/477928.html | publisher=Associated Press | date=  August 23, 2006}}</ref> On an annual basis, without the use of antivirals or condoms, the transmission risk of HSV-2 from infected male to female is approximately 8-10%. This is believed to be due to the increased exposure of mucosal tissue to potential infection sites. Transmission risk from infected female to male is approximately 4-5% annually.
*As with almost all [[STD|sexually transmited infections]], women are more susceptible to acquiring genital [[HSV-2]] than men.<ref> {{cite news | author=Carla K. Johnson | title=Percentage of people with herpes drops | url=http://www.newsobserver.com/150/story/477928.html | publisher=Associated Press | date=  August 23, 2006}}</ref> On an annual basis, without the use of antivirals or condoms, the transmission risk of HSV-2 from infected male to female is approximately 8-10%. This is believed to be due to the increased exposure of mucosal tissue to potential infection sites. Transmission risk from infected female to male is approximately 4-5% annually.


*HSV seropositive individuals practising unprotected sex with HIV positive persons pose a high risk of [[HIV]] transmission, and are even more susceptible to HIV during an outbreak with active sores.<ref name="pmid18186706">{{cite journal |author=Koelle DM, Corey L |title=Herpes Simplex: Insights on Pathogenesis and Possible Vaccines |journal=Annu Rev Med |volume=59 |issue= |pages=381–395 |year=2008 |pmid=18186706 |doi=10.1146/annurev.med.59.061606.095540}}</ref>
*[[HSV]] [[seropositive]] individuals practicing unprotected sex with HIV positive persons pose a high risk of [[HIV]] transmission, and are even more susceptible to HIV during an outbreak with active sores.<ref name="pmid18186706">{{cite journal |author=Koelle DM, Corey L |title=Herpes Simplex: Insights on Pathogenesis and Possible Vaccines |journal=Annu Rev Med |volume=59 |issue= |pages=381–395 |year=2008 |pmid=18186706 |doi=10.1146/annurev.med.59.061606.095540}}</ref>


====Prevention of Transmission====
===Prevention of Transmission===
*For genital herpes, [[condom|condoms]] are a highly effective in limiting transmission of herpes simplex infection.<ref name=Wald>{{cite journal | author=Wald A, Langenberg AG, Link K, Izu AE, Ashley R, Warren T, Tyring S, Douglas JM Jr, Corey L. | title=Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women | journal=JAMA | year=2001 | pages=3100-3106 | volume=285 | issue=24 | id=PMID 11427138}}</ref><ref name=Casper>{{cite journal | author=Casper C, Wald A. | title=Condom use and the prevention of genital herpes acquisition. | journal=Herpes | year=2002 | pages=10-14 | volume=9 | issue=1 | id=PMID 11916494}}</ref> Condom use reduce the risk of transmission by 50%. The use of condom is much more effective in the prevention of male to female transmission than vice-versa. However, condoms are by no means completely effective.  The virus cannot get through latex, but their effectiveness is somewhat limited on a [[public health]] scale by the limited use of condoms in the community,<ref name=Visser>{{cite journal | author=de Visser RO, Smith AM, Rissel CE, Richters J, Grulich AE. | title=Sex in Australia: safer sex and condom use among a representative sample of adults | journal=Aust. N. Z. J. Public Health. | year=2003 | pages=223-229 | volume=27 | issue=2 | id=PMID 14696715}}</ref> and on an individual scale because the condom may not completely cover blisters on the penis of an infected male, or base of the penis or testicles not covered by the condom may come into contact with free virus in vaginal fluid of an infected female.  
*For [[genital herpes]], [[condom|condoms]] are a highly effective in limiting transmission of herpes simplex infection.<ref name=Wald>{{cite journal | author=Wald A, Langenberg AG, Link K, Izu AE, Ashley R, Warren T, Tyring S, Douglas JM Jr, Corey L. | title=Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women | journal=JAMA | year=2001 | pages=3100-3106 | volume=285 | issue=24 | id=PMID 11427138}}</ref><ref name=Casper>{{cite journal | author=Casper C, Wald A. | title=Condom use and the prevention of genital herpes acquisition. | journal=Herpes | year=2002 | pages=10-14 | volume=9 | issue=1 | id=PMID 11916494}}</ref> Condom use reduce the risk of transmission by 50%. The use of condom is much more effective in the prevention of male to female transmission than vice-versa. However, condoms are by no means completely effective.  The [[virus]] cannot get through latex, but their effectiveness is somewhat limited on a [[public health]] scale by the limited use of condoms in the community,<ref name=Visser>{{cite journal | author=de Visser RO, Smith AM, Rissel CE, Richters J, Grulich AE. | title=Sex in Australia: safer sex and condom use among a representative sample of adults | journal=Aust. N. Z. J. Public Health. | year=2003 | pages=223-229 | volume=27 | issue=2 | id=PMID 14696715}}</ref> and on an individual scale because the condom may not completely cover blisters on the penis of an infected male, or base of the penis or testicles not covered by the condom may come into contact with free virus in vaginal fluid of an infected female.  
:*In cases where condom use is ineffective, abstinence from sexual activity, or washing of the genitals after sex, is recommended.  
:*In cases where condom use is ineffective, abstinence from sexual activity, or washing of the genitals after sex, is recommended.  
:*The use of dental dams also limits the transmission of herpes from the genitals of one partner to the mouth of the other (or vice versa) during [[oral sex]].   
:*The use of dental dams also limits the transmission of herpes from the genitals of one partner to the mouth of the other (or vice versa) during [[oral sex]].   
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*Topical [[microbicide|microbicides]] contain chemicals that directly inactivate the virus and block viral entry are currently being investigated.<ref name="pmid18156035"/>  
*Topical [[microbicide|microbicides]] contain chemicals that directly inactivate the virus and block viral entry are currently being investigated.<ref name="pmid18156035"/>  


*When one partner has herpes simplex infection and the other does not, the use of antiviral medication, such as [[valaciclovir]], in conjunction with a condom, further decreases the chances of transmission to the uninfected partner.<ref name="pmid18156035"/>   
*When one partner has herpes simplex infection and the other does not, the use of [[antiviral medication]], such as [[valaciclovir]], in conjunction with a condom, further decreases the chances of transmission to the uninfected partner.<ref name="pmid18156035"/>   


*[[Herpes simplex genitalis antiviral treatment of first episode genital herpes#First Clinical Episode of Genital Herpes|Antivirals]] also help to prevent the development of symptomatic HSV infection in approximately 50%, indicating that the infected partner may be seropositive but symptom free. The effects of combining antiviral and condom use is roughly additive, thus resulting in approximately a 75% combined reduction in annual transmission risk. These figures reflect experiences with subjects having frequently-recurring genital herpes (greater than 6 recurrences per year). Subjects with low recurrence rates and those with no clinical manifestations were excluded from these studies.
*[[Herpes simplex genitalis antiviral treatment of first episode genital herpes#First Clinical Episode of Genital Herpes|Antivirals]] also help to prevent the development of symptomatic [[HSV]] infection in approximately 50%, indicating that the infected partner may be [[seropositive]] but symptom-free. The effects of combining [[antiviral]] and condom use is roughly additive, thus resulting in approximately a 75% combined reduction in annual transmission risk. These figures reflect experiences with subjects having frequently recurring genital herpes (greater than 6 recurrences per year). Subjects with low recurrence rates and those with no clinical manifestations were excluded from these studies.


*[[Herpes simplex genitalis antiviral treatment of recurrent genital herpes#Suppressive Therapy for Recurrent Genital Herpes|Suppressive antiviral therapy]] reduces the risk of transmission by 50%. Suppressive antiviral therapy with [[valaciclovir]] 500 mg once daily reduces the rate of acquisition of HSV-2 infection and clinically symptomatic genital herpes in serodiscordant couples. In a randomised trial involving 1,484 patients treated for 8 months, 0.5% valaciclovir recipients developed symptomatic infection compared with 2.2% of placebo recipients, and 1.6% compared with 3.2% acquired HSV-2 infection. Although valaciclovir reduced the risk of acquiring symptomatic infection by 75%, approximately 60 people needed to be treated to prevent one transmission.
*[[Herpes simplex genitalis antiviral treatment of recurrent genital herpes#Suppressive Therapy for Recurrent Genital Herpes|Suppressive antiviral therapy]] reduces the risk of transmission by 50%. Suppressive antiviral therapy with [[valaciclovir]] 500 mg once daily reduces the rate of acquisition of HSV-2 infection and clinically symptomatic genital herpes in serodiscordant couples. In a randomised trial involving 1,484 patients treated for 8 months, 0.5% valaciclovir recipients developed symptomatic infection compared with 2.2% of placebo recipients, and 1.6% compared with 3.2% acquired HSV-2 infection. Although valaciclovir reduced the risk of acquiring symptomatic infection by 75%, approximately 60 people needed to be treated to prevent one transmission.
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*[[Herpes simplex primary prevention|Vaccines]] for HSV are currently undergoing trials. Once developed, they may be used to help with prevention or minimize initial infections as well as treatment for existing infections. <ref>{{cite news  | last =Seppa  | first =Nathan  | title =One-Two Punch: Vaccine fights herpes with antibodies, T cells  | pages =5  | language =English  | publisher =Science News  | date=  2005-01-05 | url =http://www.sciencenews.org/articles/20050101/fob6.asp  | accessdate = 2007-03-29}}</ref>
*[[Herpes simplex primary prevention|Vaccines]] for HSV are currently undergoing trials. Once developed, they may be used to help with prevention or minimize initial infections as well as treatment for existing infections. <ref>{{cite news  | last =Seppa  | first =Nathan  | title =One-Two Punch: Vaccine fights herpes with antibodies, T cells  | pages =5  | language =English  | publisher =Science News  | date=  2005-01-05 | url =http://www.sciencenews.org/articles/20050101/fob6.asp  | accessdate = 2007-03-29}}</ref>


*To '''prevent neonatal infections''', seronegative women are recommended to avoid unprotected oral-genital contact with an HSV-1 seropositive partner and conventional sex with a partner having a genital infection during the last trimester of pregnancy. Mothers infected with HSV, are advised to avoid procedures that would cause trauma to the infant during birth (e.g. fetal scalp electrodes, forceps and vacuum extractors) and, should lesions be present, to elect [[caesarean section]] to reduce exposure of the child to infected secretions in the birth canal.<ref name="pmid18156035"/>  The use of antiviral treatments, such as aciclovir, given from the 36th week of pregnancy limits HSV recurrence and shedding during childbirth, thereby reducing the need for caesarean section.<ref name="pmid18156035"/>
*To prevent neonatal infections, [[seronegative]] women are advised to avoid unprotected oral-genital contact with an [[HSV-1]] [[seropositive]] partner and conventional sex with a partner having a genital infection during the last trimester of pregnancy. Mothers infected with [[HSV]] are advised to avoid procedures that would cause trauma to the infant during birth (e.g. fetal scalp [[electrodes]], [[forceps]] and vacuum extractors) and, should [[lesions]] be present, to elect [[caesarean section]] to reduce exposure of the child to infected secretions in the birth canal.<ref name="pmid18156035"/>  The use of antiviral treatments, such as [[aciclovir]], given from the 36th week of pregnancy limits [[HSV]] recurrence and shedding during childbirth, thereby reducing the need for caesarean section.<ref name="pmid18156035"/>


==References==
==References==
{{reflist|2}}
{{reflist|2}}
{{WH}}
{{WS}}


[[Category:Sexually transmitted diseases]]
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Latest revision as of 16:53, 3 October 2022

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2], Lakshmi Gopalakrishnan, M.B.B.S.

Overview

HSV-1 and HSV-2 can be found in and released from the sores that the viruses cause, but they also may be released between outbreaks from skin that does not appear to have a sore. Generally, a person can only acquire HSV-2 infection during sexual contact with someone who has a genital HSV-2 infection. Transmission can occur from an infected partner who does not have a visible sore and may not know that he or she is infected. HSV-1 can cause genital herpes, but it more commonly causes infections of the mouth and lips, so-called fever blisters. HSV-1 infection of the genitals can be caused by oral-genital or genital-genital contact with a person who has HSV-1 infection. Genital HSV-1 outbreaks recur less regularly than genital HSV-2 outbreaks.

The surest way to avoid transmission of genital herpes, is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected. Genital ulcer diseases can occur in both male and female genital areas that are covered or protected by a latex condom, as well as in areas that are not covered. Correct and consistent use of latex condoms can reduce the risk of genital herpes. Persons with herpes should abstain from sexual activity with uninfected partners when lesions or other symptoms of herpes are present. It is important to know that even if a person is asymptomatic, he or she can still infect sex partners. A positive HSV-2 blood test most likely indicates a genital herpes infection.

Pathophysiology

Mode of Transmission

  • Herpes can be contracted through direct contact with an active lesion or body fluid of an infected person.[1] Infected people that show no visible symptoms may still shed and transmit virus through their skin, and this asymptomatic shedding may represent the most common form of HSV-2 transmission.[2]
  • There are no documented cases of infection via an inanimate object (e.g. a towel, toilet seat, drinking vessels).
  • To infect a new individual, HSV travels through tiny breaks in the skin or mucous membranes in the mouth or genital areas. Even microscopic abrasions on mucous membranes are sufficient to allow viral entry.

Population At Risk

  • Herpes transmission occurs between discordant partners and a person with a history of infection (HSV seropositive) can pass the virus to an HSV seronegative person.[3] Antibodies that develop following an initial infection with that type of HSV help prevent reinfection with the same herpes type. In a monogamous couple, a seronegative female runs greater than 30% per year risk of contracting an HSV-1 infection from a seropositive male partner. If an oral HSV-1 infection is contracted first, seroconversion will have occurred after 6 weeks to provide protective antibodies against a future genital HSV-1 infection.
  • As with almost all sexually transmited infections, women are more susceptible to acquiring genital HSV-2 than men.[4] On an annual basis, without the use of antivirals or condoms, the transmission risk of HSV-2 from infected male to female is approximately 8-10%. This is believed to be due to the increased exposure of mucosal tissue to potential infection sites. Transmission risk from infected female to male is approximately 4-5% annually.
  • HSV seropositive individuals practicing unprotected sex with HIV positive persons pose a high risk of HIV transmission, and are even more susceptible to HIV during an outbreak with active sores.[5]

Prevention of Transmission

  • For genital herpes, condoms are a highly effective in limiting transmission of herpes simplex infection.[6][7] Condom use reduce the risk of transmission by 50%. The use of condom is much more effective in the prevention of male to female transmission than vice-versa. However, condoms are by no means completely effective. The virus cannot get through latex, but their effectiveness is somewhat limited on a public health scale by the limited use of condoms in the community,[8] and on an individual scale because the condom may not completely cover blisters on the penis of an infected male, or base of the penis or testicles not covered by the condom may come into contact with free virus in vaginal fluid of an infected female.
  • In cases where condom use is ineffective, abstinence from sexual activity, or washing of the genitals after sex, is recommended.
  • The use of dental dams also limits the transmission of herpes from the genitals of one partner to the mouth of the other (or vice versa) during oral sex.
  • Topical microbicides contain chemicals that directly inactivate the virus and block viral entry are currently being investigated.[3]
  • When one partner has herpes simplex infection and the other does not, the use of antiviral medication, such as valaciclovir, in conjunction with a condom, further decreases the chances of transmission to the uninfected partner.[3]
  • Antivirals also help to prevent the development of symptomatic HSV infection in approximately 50%, indicating that the infected partner may be seropositive but symptom-free. The effects of combining antiviral and condom use is roughly additive, thus resulting in approximately a 75% combined reduction in annual transmission risk. These figures reflect experiences with subjects having frequently recurring genital herpes (greater than 6 recurrences per year). Subjects with low recurrence rates and those with no clinical manifestations were excluded from these studies.
  • Suppressive antiviral therapy reduces the risk of transmission by 50%. Suppressive antiviral therapy with valaciclovir 500 mg once daily reduces the rate of acquisition of HSV-2 infection and clinically symptomatic genital herpes in serodiscordant couples. In a randomised trial involving 1,484 patients treated for 8 months, 0.5% valaciclovir recipients developed symptomatic infection compared with 2.2% of placebo recipients, and 1.6% compared with 3.2% acquired HSV-2 infection. Although valaciclovir reduced the risk of acquiring symptomatic infection by 75%, approximately 60 people needed to be treated to prevent one transmission.
  • Vaccines for HSV are currently undergoing trials. Once developed, they may be used to help with prevention or minimize initial infections as well as treatment for existing infections. [9]
  • To prevent neonatal infections, seronegative women are advised to avoid unprotected oral-genital contact with an HSV-1 seropositive partner and conventional sex with a partner having a genital infection during the last trimester of pregnancy. Mothers infected with HSV are advised to avoid procedures that would cause trauma to the infant during birth (e.g. fetal scalp electrodes, forceps and vacuum extractors) and, should lesions be present, to elect caesarean section to reduce exposure of the child to infected secretions in the birth canal.[3] The use of antiviral treatments, such as aciclovir, given from the 36th week of pregnancy limits HSV recurrence and shedding during childbirth, thereby reducing the need for caesarean section.[3]

References

  1. ↑ "AHMF: Preventing Sexual Transmission of Genital Herpes". Retrieved 2008-02-24.
  2. ↑ Leone P (2005) Reducing the risk of transmitting genital herpes: advances in understanding and therapy. Curr Med Res Opin 21 (10):1577-82. DOI:10.1185/030079905X61901 PMID: 16238897
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Gupta R, Warren T, Wald A (2007) Genital herpes. Lancet 370 (9605):2127-37. DOI:10.1016/S0140-6736(07)61908-4 PMID: 18156035
  4. ↑ Carla K. Johnson (August 23, 2006). "Percentage of people with herpes drops". Associated Press.
  5. ↑ Koelle DM, Corey L (2008). "Herpes Simplex: Insights on Pathogenesis and Possible Vaccines". Annu Rev Med. 59: 381–395. doi:10.1146/annurev.med.59.061606.095540. PMID 18186706.
  6. ↑ Wald A, Langenberg AG, Link K, Izu AE, Ashley R, Warren T, Tyring S, Douglas JM Jr, Corey L. (2001). "Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women". JAMA. 285 (24): 3100–3106. PMID 11427138.
  7. ↑ Casper C, Wald A. (2002). "Condom use and the prevention of genital herpes acquisition". Herpes. 9 (1): 10–14. PMID 11916494.
  8. ↑ de Visser RO, Smith AM, Rissel CE, Richters J, Grulich AE. (2003). "Sex in Australia: safer sex and condom use among a representative sample of adults". Aust. N. Z. J. Public Health. 27 (2): 223–229. PMID 14696715.
  9. ↑ Seppa, Nathan (2005-01-05). "One-Two Punch: Vaccine fights herpes with antibodies, T cells". Science News. p. 5. Retrieved 2007-03-29.

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