Street youths are the only high-risk group for HIV in a low-prevalence South American country.

Objectives: To measure HIV prevalence in various subpopulations in Bolivia.

Design: In 2002 in Cochabamba, we offered voluntary counseling and testing to homeless street youths, registered and unregistered commercial sex workers, truck drivers, and prisoners. We examined surveillance data of pregnant women and blood donors.

Results: Among street youths over 15, overall HIV prevalence was 3.5% (11/313), higher among those recruited in the street, lower among those recruited in centers for homeless; prevalence was 0.6% (2/334) and 0.5% (1/189) in female registered and nonregistered sex workers, respectively, and below 0.3% in all other groups. All HIV cases were attributed to sexual transmission.

Conclusion: In a low-prevalence setting where intravenous drug use is uncommon, street youths are a threat for the expansion of the HIV epidemic. We argue that HIV prevention in this population requires a comprehensive approach to their health and social problems.