subject: Genital Herpes- Natural History [print this page] Aetiology Aetiology
Herpes simplex virus type 1 (HSV-1, the usual cause of oro-labial herpes) or
Herpes simplex virus type 2 (HSV-2, historically associated with sexual transmission
Natural History
Infection may be primary or non-primary. Disease episodes may be initial or recurrent (figure 1) and symptomatic or asymptomatic. It is likely that the majority of infections are acquired subclinically as at least 80% of persons seropositive for HSV type-specific antibodies are unaware of that they have been infected.
Prior infection with HSV-1 modifies the clinical manifestations of first infection by HSV-2 1.
After childhood, symptomatic primary infection with HSV-1 is equally likely to be acquired in the genital area or oral areas 2,2A.
Primary genital herpes in the UK is equally likely to be caused by HSV-1 as by HSV-2.
Following primary infection, the virus becomes latent in local sensory ganglia, periodically reactivating to cause symptomatic lesions or asymptomatic, but infectious, viral shedding.
The median recurrence rate after a symptomatic first episode is 0.34 recurrences/ month for HSV-2 and is four times more frequent than the recurrence rate for HSV-13. Recurrence rates decline over time in most individuals, although this pattern is variable 4.
The majority of individuals found to be seropositive for HSV-2 type-specific antibodies subsequently develop symptomatic lesions 5. In some of these individuals, the number of days when virus is shed asymptomatically exceeds the number of days of symptomatic shedding associated with lesions. Virus can be shed asymptomatically from the external genitalia, the anorectum, the cervix, and urethra.
In HIV positive HSV-2 seropositive individuals, both symptomatic and asymptomatic shedding are increased, especially in those with low CD4 counts and those who are also seropositive for HSV-16,7.
2
Clinical Features
Symptoms
The patient may be asymptomatic, and the disease unrecognised.
Local symptoms consist of painful ulceration, dysuria, vaginal or urethral discharge.
Systemic symptoms are much more common in primary than in initial or recurrent disease.
Systemic symptoms consist of fever and myalgia.
Rarely, systemic symptoms may be the only evidence of infection.
Signs
Blistering and ulceration of the external genitalia (+/- cervix/rectum)
