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. Blood samples from four locations in Cameroon were collected to determine the molecular epidemiology of HIV-1. The C2-V5 region of envelope was sequenced 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 recombinant form CRF02_AG (IbNG) was the most common strain (22/39, 56%). Two of these were confirmed by full genome analysis. Four samples (4/39, 10%) clustered with the sub-subtype F2 and one of these was confirmed by full genome sequencing. Recombinant forms, each different but containing subtype A, accounted for the next most common form (7/39, 18%). Among these recombinants, those combining subtypes A and G were the most common (4/7, 57%). Also found were 3 subtype A, 2 subtype G, and 1 subtype B strain. Many recombination break points were shared between IbNG and the other AG recombinants, though none of these other AG recombinants included IbNG as a parent. This suggests that there was an ancestral AG recombinant that gave rise to CRF02_AG (IbNG), the successful circulating recombinant form, and to others that were less successful and are now rare. © 2001 Academic Press.