title: A new migration map of HIV-1 CRF07_BC in China: analysis of sequences from 12 provinces over a decade.
abstract: BACKGROUND
  As 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.
  
  
  RESULTS
  In 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
  Our 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.
authors.affiliation: Shanghai Public Health Clinical Center and Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health at Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Zhefeng
authors.initials: Z
authors.lastname: Meng
authors.forename: Ruolei
authors.initials: R
authors.lastname: Xin
authors.forename: Ping
authors.initials: P
authors.lastname: Zhong
authors.forename: Chiyu
authors.initials: C
authors.lastname: Zhang
authors.forename: Yassir F
authors.initials: YF
authors.lastname: Abubakar
authors.forename: Jingyun
authors.initials: J
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhang
authors.forename: Jianqing
authors.initials: J
authors.lastname: Xu
mesh_terms: D001499:Bayes Theorem; D002681:China / Q000453:epidemiology; D058872:Epidemics / Q000706:statistics & numerical data; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000235:genetics* / Q000502:physiology*; D063426:Human Migration / Q000706:statistics & numerical data; D006801:Humans; D017421:Sequence Analysis; D013997:Time Factors