Epidemiology of HIV-1 Infection in Opiate Users in Northern Thailand

Characterizing the epidemiology of HIV-1 infection in Northern Thai opiate users is important in developing control strategies in this ethnically diverse and culturally distinct region. A cross-sectional survey of drug users first admitted between 1993 and 1995 at the Northern Drug Dependence Treatment Center, Mae Rim, Thailand, was conducted. Patients (n = 4197) were interviewed at intake about their history of drug use when they provided serum specimens for HIV-1 antibody testing. The HIV-1 prevalence was 18.6%, with men having a fourfold higher prevalence than women. Wide diversity in HIV-1 prevalence was seen by ethnicity; the HIV-1 prevalence among Thai lowlanders was four times greater than that among ethnic minorities (hill tribes). Differences in HIV-1 prevalence were the result of differences in opiate use; hill tribes frequently smoked or ingested opium, whereas Thai lowlanders injected heroin. The high HIV-1 prevalence suggests that preventive interventions for risk reduction are urgently needed in these populations. Education about the risks of injection drug use (IDU) as well as information concerning needle disinfection and expansion of drug treatment are required to reduce the risk of HIV-1 transmission associated with sharing injection equipment. Further, increasing sources of sterile needles should be considered for active users, especially for those in more remote settings.