The AG recombinant IbNG and novel strains of group M HIV-1 are common in Cameroon

The genetic diversity of group M HIV-1 is highest in west central Africa. B lood samples from four locations in Cameroon were collected to determine th e molecular epidemiology of HIV-1. The C2-V5 region of envelope was sequenc ed from 39 of the 40 samples collected, and 7 samples were sequenced across the genome. All strains belonged to group M of HIV-1, The circulating reco mbinant form CRF02_AG (IbNG) was the most common strain (22/39, 56%). Two o f these were confirmed by full genome analysis. Four samples (4/39, 10%) cl ustered with the sub-subtype F2 and one of these was confirmed by full geno me sequencing. Recombinant forms, each different but containing subtype A, accounted for the next most common form (7/39, 18%). Among these recombinan ts, those combining subtypes A and G were the most common (4/7 57%). Also f ound were 3 subtype A, 2 subtype G, and 1 subtype B strain. Many recombinat ion break points were shared between IbNG and the other AG recombinants, th ough none of these other AG recombinants included IbNG as a parent. This su ggests that there was an ancestral AG recombinant that gave rise to CRF02_A G (IbNG), the successful circulating recombinant form, and to others that w ere less successful and are now rare. (C) 2001 Academic Press.