Herpes in the time of AIDS: A comparison of the epidemiology of HIV-1 and HSV-2 in young men in northern Thailand

Objectives: To compare the epidemiologic pattern of HIV-1, a recently introduced sexually transmitted disease (STD) agent in Thailand, with the pattern of HSV-2, a well-established STD agent, so that future trends for both viruses can be better understood. Methods: We obtained questionnaire data and determined HSV-2 (by specific gG-2) and HIV-1 seroreactivity in a cohort of 1,115 young male army conscripts who entered service in northern Thailand in 1991, Results: Seroprevalence of HIV-1 and HSV-2 was 6.9% and 14.9%, respectively, For HSV-2-seropositive men who reported previous genital ulcers, HIV-1 seroprevalence was 32%. For most variables, there was a close correspondence between the prevalence ratios for HIV-I and for HSV-2, except that prevalence ratios for HIV-1 tended to be greater than the corresponding ratios for HSV-2, The seroprevalence of both viruses was strongly related to early and frequent contact with female sex workers (FSWs), infrequent use of condoms with FSWs, and residence in the upper north region of Thailand, When differences in sexual behavior between the upper north and lower north were controlled for, the seroprevalence of both viruses still differed significantly by region. Conclusions: Although the seroprevalence levels of HSV-2 and HIV-1 were quite different in this cohort of Thai army conscripts in 1991, the patterns of infection in terms of demographic, residential, and behavioral variables were similar. Seroprevalence studies of HSV-2 in other populations, particularly where the HIV-1 epidemic is just beginning, may be useful in predicting which subgroups might be most vulnerable to the epidemic and could therefore benefit the most from public health intervention. Where differences in the patterns of the two viruses have been noted, we hypothesize that the pattern for HIV-1 will evolve toward that seen for HSV-2.