Genital herpes: epidemiology and pathophysiology. Update and new perspectives.

Genital Herpes simplex virus (HSV) is a sexually transmitted disease (STD) which affects millions of people worldwide and is mainly due to HSV type 2. Seroprevalence rates as high as 60-90% have been reported in developing countries. In developed countries, 20% of the general population is HSV2 seropositive. Recent epidemiological surveys employing type-specific antibody assays show that the prevalence of HSV-2 infections is rising at an alarming rate. Also, the epidemiology is changing with an increasing incidence of first episodes caused by HSV-1. The natural history of HSV infection includes acute or subclinical first episode mucocutaneous infection, establishment of neuronal latency, and intermittent virus reactivation with or without associated symptoms. Although this sequence of events has been recognized for more than five decades, little is known about the exact mechanism of latency and reactivation. Almost all persons with HSV2 infection will have recurrences. Recent data show that many of these infections are subclinical: subclinical shedding can be documented in over 80% of HSV2 seropositive individuals who deny subclinical lesions. This suggests that patients shed virus and transmit it even in the absence of clinical signs and that genital herpes should be redefined as a chronic rather than an intermittent disease.