OBJECTIVEUsing molecular epidemiology method to characterize human immunodeficiency virus type 1 (HIV-1) subtype CRF01 _ AE strains being prevailed in Zhejiang province.

METHODSGag fragments of the HIV-1 strains were amplified by nested-polymerase chain reaction (nPCR) from the DNA extracted from whole blood of HIV-1 infected individuals in Zhejiang province. PCR products were sequenced and analyzed by phylogenetic method.

RESULTS81 HIV-1 subtype CRF01 _ AE sequences were identified from the 192 samples that sequenced successfully. As one of the dominant subtypes in Zhejiang, CRF01 _ AE was transmitted mainly by heterosexual or homosexual contact in local residents. In migrants living in Zhejiang, CRF01 _ AE were transmitted mainly by heterosexual contact or injecting drug use. There were three main clusters in the phylogenetic tree which bootstrap value was larger than 60. We named the clusters with group MIX (47 sequences), group SEX (7 sequences) and group MSM (12 sequences) based on the transmission. Pairwise DNA distances in the gag region within the three groups and between CM240 were different (P = 0.000). Data through the analyses of deduced amino acid sequences from the three groups showed that several signature amino acid sites were distinct from the same positions of the subtype reference strains.

CONCLUSIONThe CRF01 _ AE strain prevailing in Zhejiang province was from several sources, transmitted by more than three different transmission routes, and becoming the main subtypes circulating in homosexual population in this study. More attention needs to be paid to the epidemic characteristic of CRF01 _ AE.