We report a novel HIV-1 circulating recombinant form (CRF64_BC) that was 
isolated from five epidemiologically unlinked HIV-infected persons in Yunnan 
province. CRF64_BC was composed of subtype B and subtype C, with five short 
subtype B segments inserted into the subtype C backbone. Phylogenetic analysis 
demonstrated that the C subregion was correlated with the India C lineage, which 
was transmitted into China in the early 1990s. The evolutionary history of the B 
subregion was not as clear as the C subregion, as the short length of this 
region yielded poor phylogenetic results. Dehong is considered the epicenter of 
HIV-1 in China, and recombinant strains such as CRF07_BC and CRF08_BC, which 
also originated from this region, have spread widely in China. The newly emerged 
CRF64_BC increases the complexity of the HIV epidemic in China and complicates 
the development of subtype-specific tools against HIV transmission.