title: Dominance of HIV-1 subtype CRF01_AE in sexually acquired cases leads to a new epidemic in Yunnan province of China.
abstract: BACKGROUND
  Dating back to the first epidemic among injection drug users in 1989, the Yunnan province has had the highest number of human immunodeficiency virus type 1 (HIV-1) infections in China. However, the molecular epidemiology of HIV-1 in Yunnan has not been fully characterized.
  
  
  RESULTS
  Using immunoassays, we identified 103,015 accumulated cases of HIV-1 infections in Yunnan between 1989 and 2004. We studied 321 patients representing Yunnan's 16 prefectures from four risk groups, 11 ethnic populations, and ten occupations. We identified three major circulating subtypes: C/CRF07_BC/CRF08_BC (53%), CRF01_AE (40.5%), and B (6.5%) by analyzing the sequence of p17, which is part of the gag gene. For patients with known risk factors, 90.9% of injection drug users had C/CRF07_BC/CRF08_BC viruses, whereas 85.4% of CRF01_AE infections were acquired through sexual transmission. No distinct segregation of CRF01_AE viruses was found among the Dai ethnic group. Geographically, C/CRF07_BC/CRF08_BC was found throughout the province, while CRF01_AE was largely confined to the prefectures bordering Myanmar. Furthermore, C/CRF07_BC/CRF08_BC viruses were found to consist of a group of viruses, including C, CRF08_BC, CRF07_BC, and new BC recombinants, based on the characterization of their reverse transcriptase genes.
  
  
  CONCLUSIONS
  This is the first report of a province-wide HIV-1 molecular epidemiological study in Yunnan. While C/CRF07_BC/CRF08_BC and CRF01_AE are codominant, the discovery of many sexually transmitted CRF01_AE cases is new and suggests that this subtype may lead to a new epidemic in the general Chinese population. We discuss implications of our results for understanding the evolution of the HIV-1 pandemic and for vaccine development.
authors.affiliation: Yunnan Center for Disease Control and Prevention, Kunming, Yunnan, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
authors.forename: Lei
authors.initials: L
authors.lastname: Ba
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Manhong
authors.initials: M
authors.lastname: Jia
authors.forename: Haibo
authors.initials: H
authors.lastname: Wang
authors.forename: Qing
authors.initials: Q
authors.lastname: Fang
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Shi
authors.forename: Wenyun
authors.initials: W
authors.lastname: Yan
authors.forename: Guangcai
authors.initials: G
authors.lastname: Chang
authors.forename: Linqi
authors.initials: L
authors.lastname: Zhang
authors.forename: David D
authors.initials: DD
authors.lastname: Ho
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology / Q000635:transmission / Q000821:virology; D000293:Adolescent; D000328:Adult; D002681:China / Q000453:epidemiology; D003710:Demography; D004196:Disease Outbreaks; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D011995:Recombination, Genetic; D015229:Sexually Transmitted Diseases, Viral / Q000453:epidemiology* / Q000821:virology*; D015819:Substance Abuse, Intravenous