Herpes simplex virus 2 (HSV2)

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The virus structure

Herpes simplex virus 2 belongs to the alpha herpesvirus group. HSV possesses an internal core with a linear double-stranded DNA. The capsid of herpes viruses consists of 162 consumers. The virus is wrapped in a lipid envelope with viral glycoproteins on the surface. Its molecular weight is approximately 100×106 units and diameter of approximately 160 nm.

Epidemiology

HSV2 is more common for females than males. Usually the HSV-2 infection is associated with the onset of sexual activity. The global prevalence of HSV-2 was about 11,3% as of 2012. About 23 million of new cases of HSV-2 are observed every year.

HSV2 infection is common among HIV-1-infected individuals and those who are at risk  for HIV-1 infection.

Transmission

HSV-2 infection is considered to a sexually transmitted disease. Unlike bacterial sexually transmitted diseases HSV-2 is commonly transmitted within long-term couples rather than accidental sexual relationships.

See also: Herpes zoster infection

Risk factors

  • Sexually active lifestyle;
  • Females are generally at higher risk for HSV-2;
  • Negroid race;
  • Big number of sexual partners;
  • Poverty or low income;

Symptoms

The incubation period of primary genital herpes may last from 2 to 12 days. Primary genital herpes tends to have a prolonged symptom duration.

The first episode of genital herpes manifests with fever, headache, general malaise, and muscular pain. Pain, itching, dysuria, vaginal and urethral discharge, and the painful enlargement of the local lymph nodes are characteristic. These symptoms occur between day 7 and 11 of the illness.  

Widely spaced bilateral lesions on the genitalia are observed on examination, including vesicles, pustules, painful erythematous ulcers, and crusting. The lesions persist for approximately 21 days. The painful lesions quickly become ulcers and are covered with a gray-white exudate.

The onset of primary herpes genitalis in males appears as a cluster of vesicles on the red surface of the skin on the glans or shaft of the penis.In females the lesions appear on the two sides of the vulva.  The labia minora, labia majora, and perineum are commonly affected.

HSV-2 causes cervicitis characterized by the purulent or bloody vaginal discharge. During the examination the cervical ulceration or necrosis is observed.

The virus is able to cause symptomatic or asymptomatic rectal and perianal infections.Proctitis due to herpes simplex virus is related to rectal intercourse. The symptoms of proctitis include pain in the anorectal area, discharge from the rectum, constipation and tenesmus.

HSV-2 may also affect the pharynx, causing the ulcers or the lesions of the pharynx or the tonsils.

Viral meningitis is much more common for HSV-2.

The HSV-2 infection tends to recur more frequently in the genital tract than  HSV-1 infection.

Diagnosis

The diagnosis is made based upon clinical features and laboratory tests such as DNA or PCR tests and virus cultures.

Treatment

Acyclovir, valacyclovir or famciclovir may be used in the treatment of genital herpes. Acyclovir 200 mg orally 5 times per day for 7-14 days or intravenously at dose of 5 mg/kg every 8 hours. Topical administration of acyclovir is not recommended, although approved as a treatment method.

For recurrent infection, valacyclovir is usually taken at 500 mg twice daily for 3 days, and famciclovir – at 1 g twice daily for 1 day. Daily administration of acyclovir was reported to prevent genital herpes recurrence. However, long-term application of antiviral medications is used only in individuals with immunosuppression.

Prevention

Knowledge of a partner’s infection, diagnosis and treatment reduces the risk of HSV-2 transmission. Chemoprophylaxis and consistent condom use are known to decrease the transmission rates as well. Male circumcision decreases both HIV-1 and HSV-2 acquisition risk in males, but does not affect the transmission rates among females.