Changing epidemiology of HIV type 1 infections in India: Evidence of subtype B introduction in Bombay from a common source

India has experienced multiple introductions of diverse HIV-1 subtypes A, B , C, and E, along with subtype B of HIV-2 between the 1980s and early 1990s , In this study, we have carried out a molecular investigation of 21 hetero sexually and vertically acquired HIV-infected individuals from the New Bomb ay area, who tested positive for HIV-1 by commercial enzyme-linked immunoso rbent assay (ELISA) and Western blot assay, We have sequenced the proviral DNA segments from the uncultured PBIMCs in the hypervariable env V-3 region (286 bp) and a full-length vpr gene (291 bp), Overall, phylogenetic cluste ring of all Indian strains and also their clustering with subtype B strains were evident from both V-3- and vpr gene-based trees, strongly supporting their recent introduction from a common source. This is the first report on subtype B introduction in Bombay, a region where subtype C predominates. O verall, these subtype B strains from Bombay shared genetic closeness with s ubtype B strains from Europe, the United States, and Asia.