OBJECTIVETo analyze the molecular epidemiological characteristics of HIV-1 subtype CRF01_AE strains being prevailed among HIV/AIDS in Zhejiang province in 2009.

METHODSA total of 303 subjects were identified by stratified random sampling among HIV infected individuals in Zhejiang province in 2009. Gag fragments of the HIV-1 strains were amplified by nested polymerase chain reaction from the DNA extracted from whole blood of HIV-1 infected individuals. PCR products were sequenced and analyzed by phylogenetic method.

RESULTSA total of 132 HIV-1 subtype CRF01_AE sequences were identified from the 225 samples that sequenced successfully, accounting for 58.67% (132/225). A total of 90.91% (120/132) CRF01_AE strains infected HIV/AIDS were transmitted mainly by sexual contacts. A total of 65.91% (87/132) of the cases infected by heterosexual route and 25.00% (33/132) by homosexual route. There were three main clusters in the phylogenetic tree. Pairwise DNA distance within three groups was 0.037 ± 0.011, 0.034 ± 0.008 and 0.047 ± 0.010, which has statistical significance (P < 0.05). Distribution of the sequence of homosexual behavior infected individuals was relatively concentrated in clusters one (96.97%, 32/33), and crossed with heterosexual behavior infectors, and presented the close relations with strains from Jiangsu province, Zhengzhou of Henan province, Liaoning province, Shijiazhuang of Hebei province.

CONCLUSIONThe CRF01_AE strains were the dominant subtypes among HIV infected individuals. The majority of the CRF01_AE infected cases had high risk sexual behavior. The heterosexual infected cases were more than homosexual cases. The circulating status of CRF01_AE strains in homosexual population was relatively independent, but also had evidence of transmission from man who have sex with man to heterosexual population.