Follow-up visits are scheduled infrequently, so participants may be contacted periodically between visits to stay in touch and provide updated locator information. Visits will include the completion of a questionnaire, HIV testing for those who were not infected at the prior visit, with confirmation and follow-up tests if necessary. A viral load test will be performed for HIV-infected participants at the time of diagnosis and again at 52 weeks. All participants will receive STI counseling and testing at 26 and 52 weeks. Participants will receive counseling to include risk reduction counseling and pre- and post- test counseling, as needed. Participants will also be counseled for issues such as mental health and substance use and referred for care as appropriate. Participants will be asked to report any STI or HIV diagnoses they receive between visits and to provide documentation of diagnoses. Plasma specimens for testing will also be collected from all participants at all visits.