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Herpes simplex virus 1 and 2 (HSV-1 and HSV-2), also known as human herpesvirus 1 and 2 (HHV-1 and HHV-2), are two members of the herpesvirus family, Herpesviridae, that infect humans. Both HSV-1 (which produces most cold sores) and HSV-2 (which produces most genital herpes) are ubiquitous and contagious. They can be spread when an infected person is producing and shedding the virus. Herpes simplex can be spread through contact with saliva, such as sharing drinks. Symptoms of herpes simplex virus infection include watery blisters in the skin or mucous membranes of the mouth, lips or genitals.〔 Lesions heal with a scab characteristic of herpetic disease. Sometimes, the viruses cause very mild or atypical symptoms during outbreaks. However, as neurotropic and neuroinvasive viruses, HSV-1 and -2 persist in the body by becoming ''latent'' and hiding from the immune system in the cell bodies of neurons. After the initial or ''primary'' infection, some infected people experience sporadic episodes of viral ''reactivation'' or ''outbreaks''. In an outbreak, the virus in a nerve cell becomes active and is transported via the neuron's axon to the skin, where virus replication and shedding occur and cause new sores. It is one of the most common sexually transmitted infections. ==Transmission== (詳細はIn another study, seventy-three subjects were randomized to receive valaciclovir 1 g daily or placebo for 60 days each in a 2-way crossover design. A daily swab of the genital area was self-collected for HSV-2 detection by polymerase chain reaction, in order to compare the effect of valaciclovir 1 g once daily for 60 days versus placebo on asymptomatic viral shedding in immunocompetent, HSV-2 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. 88% of patients treated with valaciclovir had no recognized signs or symptoms versus 77% for placebo. For HSV-2, subclinical shedding may account for most of the transmission, and one study found that infection occurred after a median of 40 sex acts.〔 Atypical symptoms are often attributed to other causes such as a yeast infection.〔 HSV-1 is often acquired orally during childhood. It may also be sexually transmitted, including contact with saliva, such as kissing and mouth-to-genital contact (oral sex). HSV-2 is primarily a sexually transmitted infection, but rates of HSV-1 genital infections are increasing.〔 Both viruses may also be transmitted vertically during childbirth, although the real risk is very low. The risk of infection is minimal if the mother has no symptoms or exposed blisters during delivery. The risk is considerable when the mother is infected with the virus for the first time during late pregnancy. Herpes simplex viruses can affect areas of skin exposed to contact with an infected person. An example of this is herpetic whitlow which is a herpes infection on the fingers. This was a common affliction of dental surgeons prior to the routine use of gloves when conducting treatment on patients. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Herpes simplex virus」の詳細全文を読む スポンサード リンク
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