Maintaining low HIV type 1 env genetic diversity among injection drug users infected with a B/C recombinant and CRF01_AE HIV type 1 in southern China.

HIV-1 outbreaks in Guangxi Province, southern China were initiated from two separate border cities in 1996 and 1997. Drug users in Pingxiang City, which borders Vietnam, were infected with CRF01_AE HIV-1, and drug users in Baise City, which borders Yunan Province, were infected with a novel B/C recombinant HIV-1. Since 1997, HIV-1 has been rapidly spreading in Guangxi, including its capital city Nanning. Survey data indicated that HIV-1 prevalence among IDUs in new outbreak regions increased 8 to 42% within 1 year. The B/C recombinants obtained from five separate regions in Guangxi, which span a 4-year time frame, were remarkable for their low intersubject env V3 diversity, less than 0.2%. Similarly, the CRF01_AE from IDUs over a 3-year time frame had low intersubject env V3 diversity of less than 1.6%. Different patterns of sequence variations in the V3 and V4 regions were observed for the B/C recombinant and the CRF01_AE HIV1. The rapid spreading of homogeneous HIV-1 strains in Guangxi may have important implications for HIV transmission as well as vaccine development and evaluation.