Human alphaherpesvirus 2

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Human alphaherpesvirus 2
Herpes simplex virus TEM B82-0474 lores.jpg
Transmission electron micrograph of herpes simplex virus
Virus classification Red Pencil Icon.png
(unranked): Virus
Realm: Duplodnaviria
Kingdom: Heunggongvirae
Phylum: Peploviricota
Class: Herviviricetes
Order: Herpesvirales
Family: Herpesviridae
Genus: Simplexvirus
Species:
Human alphaherpesvirus 2
Synonyms

Herpes simplex virus

Human alphaherpesvirus 2 (HHV-2) is a species of virus in the genus Simplexvirus , subfamily Alphaherpesvirinae , family Herpesviridae , and order Herpesvirales . [1]

Contents

Evolution

Human alphaherpesvirus 2 can be divided into two clades: one is globally distributed and the other is mostly limited to sub Saharan Africa. [2]

Pathology

Human alphaherpesvirus 2 infects humans, most often as genital herpes. In the United States more than one in six people have the virus. [3] It is primarily a sexually transmitted infection. [4] Human alphaherpesvirus 2 tends to reside in the sacral ganglia. Human alphaherpesvirus 2 is periodically shed in the human genital tract, most often asymptomatically. Most sexual transmissions occur during periods of asymptomatic shedding. [5] Asymptomatic reactivation means that the virus causes atypical, subtle, or hard-to-notice symptoms that are not identified as an active herpes infection, so acquiring the virus is possible even if no active blisters or sores are present.

In one study, daily genital swab samples found Human alphaherpesvirus 2 at a median of 12–28% of days among those who have had an outbreak, and 10% of days among those suffering from asymptomatic infection, with many of these episodes occurring without visible outbreak ("subclinical shedding"). [6] In another study, 73 subjects were randomized to receive valaciclovir 1 g daily or placebo for 60 days each in a two-way crossover design. A daily swab of the genital area was self-collected for Human alphaherpesvirus 2 detection by polymerase chain reaction, to compare the effect of valaciclovir versus placebo on asymptomatic viral shedding in immunocompetent, seropositive subjects without a history of symptomatic genital herpes infection. The study found that valaciclovir significantly reduced shedding during subclinical days compared to placebo, showing a 71% reduction; 84% of subjects had no shedding while receiving valaciclovir versus 54% of subjects on placebo. About 88% of patients treated with valaciclovir had no recognized signs or symptoms versus 77% for placebo. [7] For Human alphaherpesvirus 2, subclinical shedding may account for most of the transmission. [6] Studies on discordant partners (one infected, one not) show that the transmission rate is approximately 5 per 10,000 sexual contacts. [8] Atypical symptoms are often attributed to other causes, such as a yeast infection. [4] [9]

See also

Related Research Articles

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Varicella-zoster virus (VZV), also known as human herpesvirus 3 or Human alphaherpesvirus 3 (taxonomically), is one of nine known herpes viruses that can infect humans. It causes chickenpox (varicella) commonly affecting children and young adults, and shingles in adults but rarely in children. VZV infections are species-specific to humans. The virus can survive in external environments for a few hours.

<span class="mw-page-title-main">Aciclovir</span> Antiviral medication used against herpes, chickenpox and shingles

Aciclovir (ACV), also known as acyclovir, is an antiviral medication. It is primarily used for the treatment of herpes simplex virus infections, chickenpox, and shingles. Other uses include prevention of cytomegalovirus infections following transplant and severe complications of Epstein–Barr virus infection. It can be taken by mouth, applied as a cream, or injected.

<span class="mw-page-title-main">Valaciclovir</span> Anti-herpes virus drug

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<span class="mw-page-title-main">Herpetic gingivostomatitis</span> Medical condition

Gingivostomatitis is a combination of gingivitis and stomatitis, or an inflammation of the oral mucosa and gingiva. Herpetic gingivostomatitis is often the initial presentation during the first ("primary") herpes simplex infection. It is of greater severity than herpes labialis which is often the subsequent presentations. Primary herpetic gingivostomatitis is the most common viral infection of the mouth.

<span class="mw-page-title-main">Famciclovir</span> Chemical compound

Famciclovir is a guanosine analogue antiviral drug used for the treatment of various herpesvirus infections, most commonly for herpes zoster (shingles). It is a prodrug form of penciclovir with improved oral bioavailability. Famciclovir is marketed under the trade name Famvir (Novartis).

Bovine alphaherpesvirus 1 (BoHV-1) is a virus of the family Herpesviridae and the subfamily Alphaherpesvirinae, known to cause several diseases worldwide in cattle, including rhinotracheitis, vaginitis, balanoposthitis, abortion, conjunctivitis, and enteritis. BoHV-1 is also a contributing factor in shipping fever, also known as bovine respiratory disease (BRD). It is spread horizontally through sexual contact, artificial insemination, and aerosol transmission and it may also be transmitted vertically across the placenta. BoHV-1 can cause both clinical and subclinical infections, depending on the virulence of the strain. Although these symptoms are mainly non-life-threatening it is an economically important disease as infection may cause a drop in production and affect trade restrictions. Like other herpesviruses, BoHV-1 causes a lifelong latent infection and sporadic shedding of the virus. The sciatic nerve and trigeminal nerve are the sites of latency. A reactivated latent carrier is normally the source of infection in a herd. The clinical signs displayed are dependent on the virulence of the strain. There is a vaccine available which reduces the severity and incidence of disease. Some countries in Europe have successfully eradicated the disease by applying a strict culling policy.

<span class="mw-page-title-main">Herpes simplex virus</span> Species of virus

Herpes simplex virus1 and 2, also known by their taxonomical names Human alphaherpesvirus 1 and Human alphaherpesvirus 2, are two members of the human Herpesviridae family, a set of viruses that produce viral infections in the majority of humans. Both HSV-1 and HSV-2 are very common and contagious. They can be spread when an infected person begins shedding the virus.

<span class="mw-page-title-main">Genital herpes</span> Infection by herpes simplex viruses of the genitals

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<span class="mw-page-title-main">Duck plague</span> Disease caused by Anatid alphaherpesvirus 1

Duck plague is a worldwide disease caused by Anatid alphaherpesvirus 1 (AnHV-1) of the family Herpesviridae that causes acute disease with high mortality rates in flocks of ducks, geese, and swans. It is spread both vertically and horizontally—through contaminated water and direct contact. Migratory waterfowl are a major factor in the spread of this disease as they are often asymptomatic carriers of disease. The incubation period is three to seven days. Birds as young as one week old can be infected. DEV is not zoonotic.

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The Central Nervous System controls most of the functions of the body and mind. It comprises the brain, spinal cord and the nerve fibers that branch off to all parts of the body. The Central Nervous System viral diseases are caused by viruses that attack the CNS. Existing and emerging viral CNS infections are major sources of human morbidity and mortality. Virus infections usually begin in the peripheral tissues, and can invade the mammalian system by spreading into the peripheral nervous system and more rarely the CNS. CNS is protected by effective immune responses and multi-layer barriers, but some viruses enter with high-efficiency through the bloodstream and some by directly infecting the nerves that innervate the tissues. Most viruses that enter can be opportunistic and accidental pathogens, but some like herpes viruses and rabies virus have evolved in time to enter the nervous system efficiently, by exploiting the neuronal cell biology. While acute viral diseases come on quickly, chronic viral conditions have long incubation periods inside the body. Their symptoms develop slowly and follow a progressive, fatal course.

<span class="mw-page-title-main">Herpes simplex</span> Viral disease caused by herpes simplex viruses

Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected.

Neonatal herpes simplex is a rare but serious condition, usually caused by vertical transmission of the herpes simplex virus from mother to newborn. Around 1 in every 3,500 babies in the United States contract the infection.

<span class="mw-page-title-main">Herpesviral encephalitis</span> Encephalitis associated with herpes simplex virus

Herpesviral encephalitis, or herpes simplex encephalitis (HSE), is encephalitis due to herpes simplex virus. It is estimated to affect at least 1 in 500,000 individuals per year, and some studies suggest an incidence rate of 5.9 cases per 100,000 live births.

<span class="mw-page-title-main">Herpes labialis</span> Herpes simplex virus infection of the lip

Herpes labialis, commonly known as cold sores or fever blisters, is a type of infection by the herpes simplex virus that affects primarily the lip. Symptoms typically include a burning pain followed by small blisters or sores. The first attack may also be accompanied by fever, sore throat, and enlarged lymph nodes. The rash usually heals within ten days, but the virus remains dormant in the trigeminal ganglion. The virus may periodically reactivate to create another outbreak of sores in the mouth or lip.

The epidemiology of herpes simplex is of substantial epidemiologic and public health interest. Worldwide, the rate of infection with herpes simplex virus—counting both HSV-1 and HSV-2—is around 90%. Although many people infected with HSV develop labial or genital lesions, the majority are either undiagnosed or display no physical symptoms—individuals with no symptoms are described as asymptomatic or as having subclinical herpes.

Herpes simplex research includes all medical research that attempts to prevent, treat, or cure herpes, as well as fundamental research about the nature of herpes. Examples of particular herpes research include drug development, vaccines and genome editing. HSV-1 and HSV-2 are commonly thought of as oral and genital herpes respectively, but other members in the herpes family include chickenpox (varicella/zoster), cytomegalovirus, and Epstein-Barr virus. There are many more virus members that infect animals other than humans, some of which cause disease in companion animals or have economic impacts in the agriculture industry.

HSV epigenetics is the epigenetic modification of herpes simplex virus (HSV) genetic code.

<i>Human alphaherpesvirus 1</i> Species of virus

Human alphaherpesvirus 1 (HHV-1) is a species of virus in the genus Simplexvirus, subfamily Alphaherpesvirinae, family Herpesviridae, and order Herpesvirales.

References

  1. "ICTV Master Species List 2018b.v2". International Committee on Taxonomy of Viruses (ICTV). Archived from the original on March 30, 2019. Retrieved 19 June 2019.
  2. Burrel S, Boutolleau D, Ryu D, Agut H, Merkel K, Leendertz FH, Calvignac-Spencer S (2017) Ancient recombination events between human herpes simplex viruses. Mol Biol Evol doi : 10.1093/molbev/msx113
  3. "STD Facts - Genital Herpes". www.cdc.gov. December 11, 2017. Retrieved September 22, 2018. Genital herpes is common in the United States. More than one out of every six people aged 14 to 49 years have genital herpes.
  4. 1 2 Gupta R, Warren T, Wald A (2007). "Genital herpes". Lancet. 370 (9605): 2127–37. doi:10.1016/S0140-6736(07)61908-4. PMID   18156035.
  5. Schiffer JT, Mayer BT, Fong Y, Swan DA, Wald A (2014). "Herpes simplex virus-2 transmission probability estimates based on quantity of viral shedding". J R Soc Interface. 11 (95): 20140160. doi:10.1098/rsif.2014.0160. PMC   4006256 . PMID   24671939.
  6. 1 2 Johnston C, Koelle DM, Wald A (Dec 2011). "HSV-2: in pursuit of a vaccine". J Clin Invest. 121 (12): 4600–9. doi:10.1172/JCI57148. PMC   3223069 . PMID   22133885.
  7. Sperling RS, Fife KH, Warren TJ, Dix LP, Brennan CA (March 2008). "The effect of daily valacyclovir suppression on herpes simplex virus type 2 viral shedding in HSV-2 seropositive subjects without a history of genital herpes". Sex Transm Dis. 35 (3): 286–90. doi: 10.1097/OLQ.0b013e31815b0132 . PMID   18157071.
  8. Effect of Condoms on Reducing the Transmission of Herpes Simplex Virus Type 2 From Men to Women. A Wald, AGM Langenberg, K Link, et al. JAMA. 2001;285(24):3197
  9. Koelle DM, Corey L (2008). "Herpes simplex: insights on pathogenesis and possible vaccines". Annual Review of Medicine. 59: 381–95. doi:10.1146/annurev.med.59.061606.095540. PMID   18186706.