The Andean CIPRA U19 proposal represents a consortium of researchers, primarily from the Peruvian research NGO, Impacta Salud y Educacion, from the School of Public Health at Universidad Peruana Cayetano Heredia and from the US Naval Medical Research Center Detachment and the U. of Washington and the U. of California San Francisco CFAR-affiliated faculty are partners in the proposal. The theme of this CIPRA is Pathogenesis, Prevention, and Treatment of HIV in the Andean Region. The overall aims of the Andean CIPRA are to: 1) Further develop regional, institutional, and investigator capacity for HIV prevention, vaccine and treatment research through Core A: Administrative and developmental (which includes a community education and development sub-core); Core B: Biostatistics, Data Management and Informatics; Core C: Laboratory; and Core D: Research Development and Training; and to 2) Support specific research projects of particular importance to the Andean region. The Andean CIPRA will directly support three major research projects and developmental projects. The major research projects proposed build on four recently funded HIV research programs in Peru: the NIH-funded HPTN, HVTN, and IACTG Units, and a community randomized trial (CRT), funded by Wellcome Trust and by USAID-Peru, of a hybrid STD/HIV Prevention Intervention. Project 1 will quantify the increase in anorectal and cervical HIV shedding associated with HSV-2 reactivation among HIV and HSV co-infected men and women, and will assess the reduction in genital HIV shedding with daily suppressive acyclovir; Project 2 will test immunologic and virologic outcomes, adherence, and rate of emergence of ARV resistance with a once daily antiretroviral regimen in HIV (+) persons, comparing directly-observed vs. self-directed therapy in the first 6 months of ARV initiation, and comparing intensive vs. less intensive laboratory monitoring; Project 3 will evaluate repeated cross-sectional sampling of high risk, bridging, and low risk urban populations to assess population-level impact of the hybrid intervention CRT, and to monitor the impact of Peru's new $29 million Global Health Fund program on antiretroviral resistance of HIV, on risk behaviors and incidence of HIV; and will conduct multilevel analyses of risk determinants for HIV and STD infections at the level, and of the impact of behavioral and biologic interventions on STD and HIV infection rates. The Andean CIPRA has an External Advisory Committee of experts and collaborators from other Andean countries, and the U.S. [An Andean CIPRA coordination system based upon three pronged branches (the Andean government's health coordination system, the Pan American Health organization, and existing HIV research networks) will be use for expanding CIPRA activities.]