Emergence of new forms of human immunodeficiency virus type 1 intersubtyperecombinants in central myanmar

We have previously shown that HIV-1 env subtypes B' (a Thai-B cluster withi n subtype B) and E (CRF01_ AE) are distributed in Yangon, the capital city of Myanmar. However, HIV strains from the rest of country have not yet been genetically characterized. In the present study, we determined env (C2/V3) and gag (p17) subtypes of 25 specimens from central Myanmar (Mandalay). Ph ylogenetic analyses identified 5 subtype C (20%), in addition to 10 CRF01_ AE (40%) and 4 subtype B' (16%). Interestingly, the remaining six specimens (24%) showed discordance between gag and env subtypes; three gag subtype B '/env subtype C, one gag subtype B'/env subtype E, one gag subtype C/env su btype B', and one gag subtype C/env subtype E. These discordant specimens w ere found frequently among injecting drug users (4 of 12, 33%) and female c ommercial sex workers (2 of 8, 25%) engaging in high-risk behaviors. The re combinant nature of these HIV-1 strains was verified in three specimens, in dicating the presence of new forms of HIV-1 intersubtype C/B' and C/B'/E re combinants with different recombination breakpoints. The data suggest that multiple subtypes of B', C, and CRF01_ AE are cocirculating in central Myan mar, leading to the evolution of new forms of intersubtype recombinants amo ng the risk populations exhibiting one of the highest HIV infection rates i n the region.