The purpose of this study is to collect data on the HIV strains currently circulating among female sex workers (FSWs) and their clients. In addition, this study will identify potential participants for future studies.

The overwhelming majority of HIV/AIDS patients live in the developing world. The rate of HIV infection in China has been consistently and steadily increasing over the past few years. Commercial sex workers and their clients are at highest risk for HIV infection and transmission. Yunnan Province is reported to be home to about half of China's HIV infected population. Honghe Prefecture accounts for 14% of the total reported HIV infections in Yunnan Province. Even though the incidence of HIV is important in tracking the HIV epidemic, there are little data on HIV incidence among FSWs in China. Estimates of HIV incidence are essential for optimally monitoring the HIV epidemic, knowing where to focus prevention efforts, and evaluating the success of vaccines and other prevention strategies. The purpose of this study is to estimate the incidence of and risk factors for HIV infection among FSWs and miners in Honghe Prefecture, Yunnan Province, China. In addition, this study will identify and describe the different HIV clades currently circulating among FSWs and miners. Four cross-sectional surveys will be conducted: three among FSWs and one among miners. In addition, a 12-month cohort study will be conducted among a subgroup of FSWs enrolled in the baseline cross-sectional survey in Kaiyuan City, Honghe Prefecture, Yunnan Province, China.

FSWs will complete cross-sectional surveys at study entry, Month 6, and Month 12. FSWs will complete two study visits: one to complete the survey and another to receive test results and participate in post-test counseling. Physical and gynecologic exams and blood collection will occur at both study visits. Each survey will include general participant information and sexual activity and drug use habits.

Pre-test counseling will be provided to all FSWs; those who elect to donate specimens for laboratory testing will have an additional appointment within 6 weeks of donation to receive test results and post-test counseling. Multiple counseling sessions may be provided to some participants based on their individual needs. FSWs found to be either infected with HIV or another sexually transmitted disease (STD) will be referred for further medical evaluation and treatment.

Every fourth participant enrolled in the FSW cross-sectional survey, all FSWs found to be HIV infected, and all FSWs who are intravenous drug users will participate in a substudy lasting 12 months. Study staff will contact each participant once a month for 12 months and ask them for location information and about their current behaviors.

Participants enrolled as FSW clients (miners) will participate in two study visits. The first visit will include completing a questionnaire and counseling. The second study visit will include post-test counseling to inform participants of their test results and will occur about one month after the first visit. A physical exam and blood and urine collection will occur at both visits.

Inclusion Criteria for FSWs Completing Cross-sectional Survey:

• Self-reported to have sold sex for money within the 3 months prior to study entry
• Works at one of the study sites

Inclusion Criteria for FSW Cohort Study:

• Participated in the baseline cross-sectional survey in Kaiyuan City, Honghe Prefecture, Yunnan Province, China
• Willing to provide updated contact information (and a cell phone number, if available)
• Willing to be contacted by study staff once a month for 12 consecutive months

Inclusion Criteria for FSW Client (Miner) Study:

• Male
• Works at one of the selected mine sites

Inclusion Criteria for All Participants:

• Parent or guardian willing to provide informed consent, if applicable

Female sex workers and their clients in Hinghe Prefecture, Yunnan Province, China