HIV-1 and other sexually transmitted infections in a cohort of female sex workers in Chiang Rai, Thailand

Objectives: To determine demographic and behavioural factors and sexually t ransmitted infections (STIs) associated with prevalent HIV-1 infection amon g brothel based and other female sex workers (FSWs) in Chiang Rai, northern Thailand. Methods: Data were collected Gum questionnaires, physical examinations, and laboratory evaluations on Thai FSWs enrolled in a prospective cohort study in Chiang Rai, Thailand, from 1991 to the end of 1994. Results: HIV-1 seroprevalence was 32% among 500 women: 47% for 280 brothel workers and 13% for 220 other FSWs (p<0.001); 96% of infections were due to HIV-1 subtype E. At enrolment, other STIs were common: chlamydia, 20%; gon orrhoea, 15%; active syphilis (serological diagnosis), 9%; genital ulcer, 1 2%; seroreactivity to Haemophilus ducreyi, 21%, and herpes simplex virus ty pe 2 (HSV-2), 76%. On multiple logistic regression analysis, HIV-1 was asso ciated with brothel work, birth in upper northern Thailand, initiation of c ommercial sex at <15 years of age, syphilis, HSV-2 seropositivity, and geni tal ulcer. Conclusions: Young Thai FSWs working in brothels in northern Thailand in th e early phase of the HIV epidemic have been at very high risk for HIV-1 inf ection and several other STIs. Programmes are needed to prevent girls and y oung women from entering the sex industry and to reduce the risk of infecti on with HIV-1 and other STIs.