BackgroundAs one of prevalence HIV-1 strains in IDUs in Asia, the origination and full transmission map of CRF07_BC is of great interested and remains unclear. In the study, we collected 769 CRF07_BC derived sequences (including 45 sequences generated in our laboratory) from 12 provinces in China for reconstructing transmission map. Meanwhile, ample historic epidemic evidences were also reviewed to assist sequences analysis.Methodology/Principal FindingsIn the study, we collected 769 CRF07_BC derived sequences and identified 138 independent sequences from 12 provinces in China for subsequent phylogeographic tree analysis, Bayes Factor test and the estimation of state tMRCA. The analyses demonstrated that CRF07_BC was originated in 1993 in IDU in Yunnan province and then initially spread to Guangxi (eastern neighbor to Yunnan) in 1994, to Xinjiang (northwest) in 1995 and to Sichuan (northern neighbor to Yunnan) in 1996. The subsequent transmissions occurred from Yunnan to Liaoning (northeast) in 1997 and to Jiangsu in 1998. Interestingly, after the early introduction of CRF07_BC into Guangxi, Xinjiang and Sichuan, these three regions served as secondary epicenters for further spreading into Gansu, Ningxia, Qinghai, Beijing and Hunan during 1999–2001. These analyzed results are in accordance with early epidemic investigations.Conclusions/SignificanceOur data not just reconstructed the migration map of CRF07_BC, but also firstly revealed the active roles of these secondary epicenters in the dynamic migration of CRF07_BC in China.

BackgroundHIV-1 CRF01_AE accounts for an important fraction of HIV infections in Asia including China, but little is known about the phylogenetic and evolutionary history of this CRF (circulating recombinant form). In the current study, we collected a large number of 1,957 CRF01_AE gag p17 sequences with known sampling year (1990-2010) from 5 global regions representing 15 countries to better understand the phylogenetic relationships and epidemic history of CRF01_AE strains in China.Methodology/Principal FindingsCRF01_AE gag p17 sequences were retrieved from public databases to explore phylogenetic relationships and phylogeographic dynamics of CRF01_AE in Asia by using maximum-likelihood phylogenetics and Bayesian coalescent-based analyses. We found close phylogenetic relationships between sequences from Thailand, Vietnam and China. Moreover, at least 5 independent introductions and 5 independent autochthonous clades of CRF01_AE, which descended from Thailand or Vietnam were identified in China from 1991 through 2003.Conclusion/SignificanceThe current study not only defines the migration of CRF01_AE clades to/in Asia, but also demonstrates the criticalness of identifying the circulating strains in the population for the development of vaccine and microbicides.

The main heroine traffic from Yunnan province to the Xinjiang Autonomous Region is believed to initiate the transmission of CRF07_BC which is the predominant strain in intravenous drug users (IDUs) in China. However, the great distances between Yunnan and Xinjiang lead to an unclear and elusive diffusion process of CRF07_BC due to the absence of an important middle site such as Sichuan province. Moreover, in recent years the rapidly increasing infection rate among IDUs in the Liangshan region of Sichuan made it necessary to characterize the genetic character of the circulating strain of Sichuan IDUs. In this study, we characterized the genetic character of seven newly isolated CRF07_BC genomes (five from Sichuan and two from Xinjiang) and analyzed the transmission linkage among strains from IDUs in different regions. By conducting Markov chain Monte Carlo (MCMC) analysis and reconstruction of neighbor-joining trees and maximum-likelihood trees, our results revealed the genetic variation and important role of Sichuan-derived CRF07_BC strains during the transmission of CRF07_BC.