American study finds KS-associated herpesvirus is highly prevalent among gay men

Infection with Kaposi’s sarcoma-associated herpesvirus (KSHV) is common among men who have sex with men (MSM), according to a study by researchers in Seattle, USA.

The incidence of KSHV among the gay and bisexual men studied is even higher than the incidence of genital herpes, the researchers report in the 1 April issue of the Journal of Infectious Diseases.

The study, aimed at determining the correlates of infection, assessed 578 HIV-negative MSM by serologic assays, questionnaires, and physical examinations. Of those, 474 were studied for 12 months. At baseline 76 (16%) were KSHV seropositive.

The researchers from the University of Washington Department of Medicine did not find any sexual behaviour particularly associated with having antibodies to KSHV, but multivariate analysis revealed that a history of hepatitis A, serology suggesting hepatitis B or HSV-2 infection, and a history of more than four sex partners in the previous six months were all independent predictors.

The researchers, led by Dr Corey Casper, report that prevalent KSHV infection was significantly associated with hepatitis A (odds ratio [OR], 3.3; 95% confidence interval [CI], 1.5-7.5), hepatitis B seropositivity (OR, 2.6; 95% CI, 1.4-4.8), herpes simplex virus (HSV)-2 (OR, 2.4; 95% CI, 1.3-4.4), and more than four male partners in the previous six months (OR, 1.9; 95% CI, 1.1-3.2).

Fifteen KSHV seroconversions (4%) were observed for an incidence of 3.8/100 person-years, similar to HSV-1 incidence in this cohort and more frequent than incidence of HIV and HSV-2.

Reporting >/=1 HIV-positive partner (OR, 5.9; 95% CI, 1.8-19.3), amyl nitrite use (OR, 7.0; 95% CI, 2.1-23.0), and lymphadenopathy in the past six months (OR, 7.7; 95% CI, 1.9-31.0) correlated with KSHV seroconversion.

Dr Casper says the study is the largest prospective study looking at incident infection but still there were only 15 men who had new infections. He said the fact that there wasn’t statistical significance did not mean there wasn’t an association.

The researchers believe the virus may be transmitted through saliva and in a large study of almost 1,000 participants they are starting to ask questions not only relating to whether or not the participants have anal, oral, protected and unprotected sex but also questions about the exchange of saliva.