Decline in sexually transmitted disease prevalence in female Bolivian sex workers: impact of an HIV prevention project.
OBJECTIVE: To implement an HIV prevention intervention among female commercial sex workers (CSW), and to monitor key outcomes using routinely collected clinical and laboratory data. DESIGN: Cross-sectional and longitudinal analysis of data from an open-enrollment cohort. SETTING: One public sexually transmitted disease (STD) clinic and about 25 brothels in La Paz, Bolivia. PARTICIPANTS: A total of 508 female CSW who work at brothels and attend a public STD clinic. INTERVENTION: Improved STD clinical care, supported by periodic laboratory testing, and behavioral interventions performed by a local non-governmental organization. MAIN OUTCOME MEASURES: Prevalence of gonorrhea, syphilis (reactive plasma reagin titer > or = 1 : 16), genital ulcer disease, chlamydial infection, and trichomoniasis; self-reported condom use in the previous month; and HIV seroprevalence. RESULTS: From 1992 through 1995, prevalence of gonorrhea among CSW declined from 25.8 to 9.9% (P < 0.001), syphilis from 14.9 to 8.7% (P = 0.02), and genital ulcer disease from 5.7 to 1.3% (P = 0.006); trends in prevalence of chlamydial infection and trichomoniasis were not significant. Self-reported condom use during vaginal sex in the past month increased from 36.3 to 72.5% (P < 0.001). In a multivariate analysis, condom use was inversely associated with gonorrhea [odds ratio (OR), 0.63; 95% confidence interval (Cl), 0.41-0.97], syphilis (OR, 0.39; 95% Cl, 0.23-0.64), and trichomoniasis (OR, 0.44; 95% Cl, 0.32-0.71). In 1995, HIV seroprevalence among CSW was 0.1%. CONCLUSION: Effective prevention interventions for female CSW can be implemented through public services and non-governmental organizations while HIV rates are still low, and key outcomes can be monitored using data obtained from periodic screening examinations.