Diagnosis and epidemiology of human herpesvirus 8 infection.

There is consensus that human herpesvirus 8 (HHV-8) is a necessary, albeit not sufficient, causal agent of Kaposi's sarcoma (KS). In the past several years, there have been rapid advances in our understanding of HHV-8 infection. In diagnosis, antibody detection is more sensitive than nucleic acid-based techniques. While initial serologic assays have proven useful in epidemiologic work, their application to individual patient diagnosis is problematic. The major aspects of the epidemiology of HHV-8 infection have been described, but many questions remain. For example, it is not known why there are distinct differences in worldwide distribution, with high prevalence throughout Africa and the Middle East, moderate prevalence in the Mediterranean, and low prevalence in the United States and Northern Europe. There is more than one mode of transmission, and the importance of the type of transmission varies by region. In the United States and Northern Europe, sexual transmission among homosexual men is the most common route of spread, but the specific sexual act(s) responsible are not clear. In high prevalence areas, nonsexual horizontal transmission during childhood is dominant. While saliva is the likely conduit for transmission in highly endemic areas, the precise mechanism for person-to-person spread-and whether this is preventable-is not understood.