In recent years, men who have sex with men (MSM) have been identified as the primary source of HIV-1 transmission in Hebei Province, China. Co-circulation of multiple subtypes in HIV-1 positive MSM populations may contribute to the emergence of the second generation of recombinant HIV-1 strains, indicating the occurrence of dual infections or superinfections in MSM populations. Thus, the discovery of new recombinant strains is important to indicate the appearance of multiple infected individuals and the prevalence caused by changes in the parent strains. In this study, we present two new unique recombinant forms (URFs) from two HIV-1-positive subjects (HB070052 and HB070056) infected through homosexual contact in Hebei Province, China. The near full-length genome of the two URFs revealed that HB070052 was divided into seven segments by six breakpoints in the gag, pol, vif, and vpr genes; HB070056 was separated into five fragments by four breakpoints, with two regions of CRF07_BC inserted into a CRF01_AE backbone's gag, pol regions. The subregion tree showed CRF01_AE segments were traced back to the cluster 4 and 6 of the CRF01_AE phylogenetic tree, which were prevalent among HIV-1 infections through MSM in China. The continued emergence of the novel CRF01_AE/CRF07_BC recombinant forms indicates the HIV-1 epidemic is complex and long-term surveillance of recombinant strains is necessary among MSM in this region.
Keywords: HIV; MSM; URF; phylogenetic analysis; recombinant form.