The current proposal aims to fully integrate the researchers currently involved in HPTN pilot studies in different sites, in Rio de Janeiro and Rio Grande do Sul (southern Brazil), in a single team, in different areas including basic science, clinics, applied behavioral and social sciences and epidemiology. For such purpose I our team is requesting a CIPRA RO3 proposal to reinforce current activities carried out as part of HPTN pilot studies and other ongoing protocols in Rio de Janeiro. A second major area of the current proposal involves training of key personnel in different areas, defining standard guidelines and routines to be applied in the different sites involved in the future studies. The focus of our study is HIV/AIDS among women in two Brazilian regions. Such regions have been affected by sub-epidemics with different dynamics: whereas the epidemic in Rio de Janeiro is reaching a plateau, the southern sub-epidemics is still progressing under a fast pace. So, a first broad objective is to analyze in detail the underlying reasons of such contrastive dynamics, from different points of view. One main point refers to the distinct molecular epidemiology of HIV prevailing in such regions, to be thoroughly explored by analyses of HIV strains and drug resistant viruses circulating among HIV-infected pregnant women and newborns in reference hospitals of both regions. A second main point refers to the exploration of the different epidemiological patterns of HIV and major STDs in each region and center, carrying out preparedness studies of a cohort of women under particular risk to be infected with HIV and/or a major sexually transmitted pathogens. This cohort will also be of paramount importance to assess HIV sero-incidence and associated risk behaviors. A third main point refers to the implementation of comprehensive studies involving HIV positive women, highlighting co-infection of HIV and HPV, particularly relevant in the Brazilian context, where uterine cancer constitutes a major challenge and HIV/AIDS has been affecting in a large extent women from disenfranchised communities where uterine cancer is especially prevalent.