Spatial clusters of HIV-1 genotypes in a recently infected population in Yunnan, China

Abstract

Background: As a gateway for HIV-1 in China, Yunnan has experienced dramatic changes in HIV-1 epidemics, during which HIV-1 genotypes have become complex. To track dynamic changes in HIV-1 genotypes, an HIV-1 molecular epidemiological study was implemented in the recently infected population in Yunnan. Methods: From 6,357 HIV-1-positive samples diagnosed during the first half of 2015 in Yunnan, 586 samples were identified as recent infections with BED-capture enzyme immunoassay (CEIA) and were subjected to phylogenetic analyses. Spatial scanning analyses for the main HIV-1 genotypes were also performed. Results: Among the 439 specimens successfully genotyped, more than ten genotypes were detected, including CRF08-BC (45.3%), CRF07-BC (19.4%), unique recombinant forms (URFs) (18.2%), CRF01-AE (11.4%), subtype C (2.1%), CRF85-BC (1.1%), CRF55-01B (0.9%), subtype B (0.5%), CRF64-BC (0.5%), CRF59-01B (0.2%), CRF83-cpx (0.2%) and CRF87-cpx (0.2%). Females, Chinese, heterosexual contact and intravenous drug injection were significantly associated with CRF08-BC infection; homosexual contact was significantly associated with CRF01-AE and CRF07-BC infection; males and non-Chinese had a higher risk of URF infection than females. Among all HIV-1 genotypes, the geographic coverage of CRF08-BC was the largest. For CRF08-BC, CRF07-BC, URFs and CRF01-AE, spatial clusters were detected. The two CRF08-BC clusters and one URF cluster were associated with heterosexual transmission, and two of CRF01-AE clusters were associated with homosexual transmission. Transmitted drug resistance (TDR)-associated mutations were detected in 2.4% of individuals. Conclusions: The diversity of HIV-1 genotypes increased in recent infections because of a long-term HIV-1 epidemic in Yunnan. The predominant HIV-1 strains showed distinct demographic characteristics and formed spatial clusters. These findings improved our understanding of the evolution of HIV-1 in Yunnan and provided information for further HIV-1 control and prevention.