To evaluate the association between sexually transmitted diseases that commonly may cause genital ulceration and prevalent and incident HIV infections, we conducted three case control studies in a cohort of 21-year-old male military conscripts in northern Thailand. The men were evaluated at baseline in 1991 and semiannually until their discharge 2 years later. Serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and HIV were more frequent at baseline in 83 men with a history of genital ulcer than in 97 men without such a history. Seropositivity to H. ducreyi (odds ratio [OR] = 3.46), HSV-2 (OR = 3.83), and syphilis (OR = 1.53) were more common in HIV-positive than HIV-negative men. Men (N = 45) who seroconverted to HIV while in the military were more often seropositive for H. ducreyi and HSV-2 before HIV seroconversion and also were more likely to seroconvert to HSV-2 and H. ducreyi during the same interval as their HIV seroconversion compared with men who remained HIV-negative. These data suggest that HSV-2 and H. ducreyi may be both markers for high-risk sexual behavior and risk factors for HIV infection among young men in Thailand.
PIP: Three case-control studies conducted in 1991-93 in a cohort of 21-year-old male military conscripts in northern Thailand investigated the association between HIV infection and three sexually transmitted diseases (STDs) commonly associated with genital ulceration: herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and Treponema pallidum. The studies compared 83 men with a history of genital ulcer disease (GUD) at baseline and 97 men without such a history, 103 men who were HIV-positive at baseline and 110 randomly selected HIV-negative conscripts, and 45 men who seroconverted to HIV while they were in the military and 124 men who remained HIV-negative throughout military service. The first study detected a significant dose-response association between number of commercial sex worker visits in the past year, lifetime number of sexual partners, and a history of GUD. Among men with GUD at baseline compared with those without GUD, the odds ratios were 2.52 for HSV-2, 2.02 for H. ducreyi, 0.97 for syphilis, and 2.14 for HIV. In the second study, HIV-infected men were significantly more likely than HIV-negative men to have antibodies to HSV-2 and H. ducreyi and a history of syphilis or gonorrhea. In the third study, men who converted to HIV were significantly more likely to have antibodies to H. ducreyi and HSV-2 at the visit before seroconversion than those who remained HIV-negative. Two independent predictors of seroconversion--HSV-2 seropositivity before conversion and 10 or more lifetime sexual partners--were identified. In northern Thailand, GUD, especially H. ducreyi and HSV-2, may be both a marker for increased HIV risk and a cofactor for HIV transmission.