For Keny Medical Research Institute/Walter Reed Project Clinical Research Center (KEMRI/WRP CRC)/Kenya site: HIV-1 infection will initially be diagnosed based upon two, serial rapid HIV tests according to Kenya Ministry of Health (MOH) guidelines. Volunteers entering this study will have HIV infection confirmed by two serial rapid HIV test in accordance with Kenya MOH guidelines and testing algorithm followed by a confirmation with a Western Blot using FDA approved-kits. Samples from participants with discrepant results (between the results from other institution and KEMRI/WRP-CRC laboratory) and/or indeterminate/negative Western Blot will be subjected to a nucleic acid assay i.e. DNA or RNA PCR. For Thailand, HIV-1 screening and confirmatory testing will be based on 3, HIV tests according to the Thai Ministry of Public Health guidelines. The subjects will initially be tested with a chemiluminescent microparticle immunoassay (CMIA) method that detects both HIV antigen and antibody. Confirmatory testing of HIV reactive samples by two different antibody detection methods will follow. Positive results by all three methods confirm HIV diagnosis. Discrepancy between the tests will require a nucleic acid detection method to confirm HIV diagnosis.