The causes of reactivation are uncertain, but several potential triggers have been documented. A 2009 study showed the protein VP16 plays a key role in reactivation of the dormant virus.[71] Changes in the immune system during menstruation may play a role in HSV-1 reactivation.[72][73] Concurrent infections, such as viral upper respiratory tract infection or other febrile diseases, can cause outbreaks. Reactivation due to other infections is the likely source of the historic terms 'cold sore' and 'fever blister'.
Herpes antiviral therapy began in the early 1960s with the experimental use of medications that interfered with viral replication called deoxyribonucleic acid (DNA) inhibitors. The original use was against normally fatal or debilitating illnesses such as adult encephalitis,[92] keratitis,[93] in immunocompromised (transplant) patients,[94] or disseminated herpes zoster.[95] The original compounds used were 5-iodo-2'-deoxyuridine, AKA idoxuridine, IUdR, or(IDU) and 1-β-D-arabinofuranosylcytosine or ara-C,[96] later marketed under the name cytosar or cytarabine. The usage expanded to include topical treatment of herpes simplex,[97] zoster, and varicella.[98] Some trials combined different antivirals with differing results.[92] The introduction of 9-β-D-arabinofuranosyladenine, (ara-A or vidarabine), considerably less toxic than ara-C, in the mid-1970s, heralded the way for the beginning of regular neonatal antiviral treatment. Vidarabine was the first systemically administered antiviral medication with activity against HSV for which therapeutic efficacy outweighed toxicity for the management of life-threatening HSV disease. Intravenous vidarabine was licensed for use by the U.S. Food and Drug Administration in 1977. Other experimental antivirals of that period included: heparin,[99] trifluorothymidine (TFT),[100] Ribivarin,[101] interferon,[102] Virazole,[103] and 5-methoxymethyl-2'-deoxyuridine (MMUdR).[104] The introduction of 9-(2-hydroxyethoxymethyl)guanine, AKA aciclovir, in the late 1970s[105] raised antiviral treatment another notch and led to vidarabine vs. aciclovir trials in the late 1980s.[106] The lower toxicity and ease of administration over vidarabine has led to aciclovir becoming the drug of choice for herpes treatment after it was licensed by the FDA in 1998.[107] Another advantage in the treatment of neonatal herpes included greater reductions in mortality and morbidity with increased dosages, which did not occur when compared with increased dosages of vidarabine.[107] However, aciclovir seems to inhibit antibody response, and newborns on aciclovir antiviral treatment experienced a slower rise in antibody titer than those on vidarabine.[107]
The risk of transmission from mother to baby is highest if the mother becomes infected around the time of delivery (30% to 60%),[54][55] since insufficient time will have occurred for the generation and transfer of protective maternal antibodies before the birth of the child. In contrast, the risk falls to 3% if the infection is recurrent,[56] and is 1–3% if the woman is seropositive for both HSV-1 and HSV-2,[56][57] and is less than 1% if no lesions are visible.[56] Women seropositive for only one type of HSV are only half as likely to transmit HSV as infected seronegative mothers. 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.[14] 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.[14]
Herpes antiviral therapy began in the early 1960s with the experimental use of medications that interfered with viral replication called deoxyribonucleic acid (DNA) inhibitors. The original use was against normally fatal or debilitating illnesses such as adult encephalitis,[92] keratitis,[93] in immunocompromised (transplant) patients,[94] or disseminated herpes zoster.[95] The original compounds used were 5-iodo-2'-deoxyuridine, AKA idoxuridine, IUdR, or(IDU) and 1-β-D-arabinofuranosylcytosine or ara-C,[96] later marketed under the name cytosar or cytarabine. The usage expanded to include topical treatment of herpes simplex,[97] zoster, and varicella.[98] Some trials combined different antivirals with differing results.[92] The introduction of 9-β-D-arabinofuranosyladenine, (ara-A or vidarabine), considerably less toxic than ara-C, in the mid-1970s, heralded the way for the beginning of regular neonatal antiviral treatment. Vidarabine was the first systemically administered antiviral medication with activity against HSV for which therapeutic efficacy outweighed toxicity for the management of life-threatening HSV disease. Intravenous vidarabine was licensed for use by the U.S. Food and Drug Administration in 1977. Other experimental antivirals of that period included: heparin,[99] trifluorothymidine (TFT),[100] Ribivarin,[101] interferon,[102] Virazole,[103] and 5-methoxymethyl-2'-deoxyuridine (MMUdR).[104] The introduction of 9-(2-hydroxyethoxymethyl)guanine, AKA aciclovir, in the late 1970s[105] raised antiviral treatment another notch and led to vidarabine vs. aciclovir trials in the late 1980s.[106] The lower toxicity and ease of administration over vidarabine has led to aciclovir becoming the drug of choice for herpes treatment after it was licensed by the FDA in 1998.[107] Another advantage in the treatment of neonatal herpes included greater reductions in mortality and morbidity with increased dosages, which did not occur when compared with increased dosages of vidarabine.[107] However, aciclovir seems to inhibit antibody response, and newborns on aciclovir antiviral treatment experienced a slower rise in antibody titer than those on vidarabine.[107]
The causes of reactivation are uncertain, but several potential triggers have been documented. A 2009 study showed the protein VP16 plays a key role in reactivation of the dormant virus.[71] Changes in the immune system during menstruation may play a role in HSV-1 reactivation.[72][73] Concurrent infections, such as viral upper respiratory tract infection or other febrile diseases, can cause outbreaks. Reactivation due to other infections is the likely source of the historic terms 'cold sore' and 'fever blister'.

Although there is no cure for herpes, treatments can relieve the symptoms. Medication can decrease the pain related to an outbreak and can shorten healing time. They can also decrease the total number of outbreaks. Drugs including Famvir, Zovirax, and Valtrex are among the drugs used to treat the symptoms of herpes. Warm baths may relieve the pain associated with genital sores.
Human herpes virus 8 (HHV8) was recently discovered in the tumours called Kaposi's Sarcoma (KS). These tumours are found in people with AIDS and are otherwise very rare. KS forms purplish tumours in the skin and other tissues of some people with AIDS. It is very difficult to treat with medication. HHV8 may also cause other cancers, including certain lymphomas (lymph node cancers) associated with AIDS. The fact that these cancers are caused by a virus may explain why they tend to occur in people with AIDS when their immune systems begin to fail. The discovery also provides new hope that specific treatments for these tumours will be developed that target the virus.
The cell this virus targets is the B lymphocyte. These cells mature in the bone marrow and are a type of mononuclear leukocyte cells - white blood cells with a one-lobed nucleus. The incubation period for the Epstein – Barr Virus (EBV) is about 30 to 50 days, and patients typically have enlarged lymph nodes and spleens. Some patients have signs of hepatitis.
The frequency and severity of recurrent outbreaks vary greatly between people. Some individuals' outbreaks can be quite debilitating, with large, painful lesions persisting for several weeks, while others experience only minor itching or burning for a few days. Some evidence indicates genetics play a role in the frequency of cold sore outbreaks. An area of human chromosome 21 that includes six genes has been linked to frequent oral herpes outbreaks. An immunity to the virus is built over time. Most infected individuals experience fewer outbreaks and outbreak symptoms often become less severe. After several years, some people become perpetually asymptomatic and no longer experience outbreaks, though they may still be contagious to others. Immunocompromised individuals may experience longer, more frequent, and more severe episodes. Antiviral medication has been proven to shorten the frequency and duration of outbreaks.[79] Outbreaks may occur at the original site of the infection or in proximity to nerve endings that reach out from the infected ganglia. In the case of a genital infection, sores can appear at the original site of infection or near the base of the spine, the buttocks, or the back of the thighs. HSV-2-infected individuals are at higher risk for acquiring HIV when practicing unprotected sex with HIV-positive persons, in particular during an outbreak with active lesions.[80]
What's to know about eczema herpeticum? Eczema herpeticum occurs when the herpes virus meets an area of skin that is affected by herpes. This MNT Knowledge Center feature introduces eczema, the herpes simplex virus, and how they combine to produce the effects of eczema herpeticum. Learn also about the treatments available and how it may be prevented. Read now
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