ABSTRACT
<p><b>OBJECTIVE</b>To analyze the geographical distribution and risk factors of HIV-1 subtypes in Yunnan province.</p><p><b>METHODS</b>Blood samples from 1319 HIV positives were collected in Yunnan Province from 2001 to 2006. The nested polymerase chain reaction was used to amplify the gag (p24)-protease fragments from RNA extracted from plasma or sera. The sequences were used for subtype determination by phylogenetic tree analysis.</p><p><b>RESULTS</b>Among 1319 samples studied, the subtypes has been successfully obtained from 644 samples that were constituted of seven subtypes: CRF08_BC, CRF07_BC, CRF07/08_BC, CRF01_AE, C, B' and URFB/C. C/CRF07_BC/CRF08_BC were distributed in the whole province, but CRF01_AE were mainly distributed in the boarding areas with Myanmar such as Dehong, Baoshan, Xishuangbanna and Puer. Moreover, injecting drugs users accounted for 61.6% (270/438) among C/CRF07_BC/CRF08_BC infections, while only 8.5% (15/177) among CRF01_AE infections.</p><p><b>CONCLUSION</b>Our data indicated that at least seven subtypes were identified in Yunnan province, the relationship between subtypes and transmission routes were analyzed, and the geographic difference of subtypes was also observed.</p>