title: HCV subtype characterization among injection drug users: implication for a crucial role of Zhenjiang in HCV transmission in China.
abstract: BACKGROUND
  HCV transmission is closely associated with drug-trafficking routes in China. However, the transmission route of HCV in Eastern China remains unclear. Here, we investigate the role of Zhenjiang city of Jiangsu province, an important transportation hub linking Shanghai with other regions of China, in HCV transmission.
  
  
  RESULTS
  A total of 141 whole blood samples were collected from injection drug users (IDUs) in Zhenjiang and then tested for HCV infection. Of them, 115 HCV positive plasmas were subjected to RNA extraction, RT-PCR amplification, and sequencing. The subtype characterization and the evolutionary origin of HCV strains circulating in Zhenjiang were determined using polygenetic or phylogeographic analyses. Seven HCV subtypes 1b, 2a, 3a, 3b, 6a, 6e and 6n were detected among Zhenjiang IDUs, showing a complex HCV epidemic. The most predominant subtypes were 3a (38%) and 1b (26.8%). Among these subtypes, subtypes 3b, 6n and 6e originated from Southwestern China (i.e., Yunnan and/or Guangxi), subtypes 2a and 6a from Southern China (i.e., Guangdong), subtype 1b from Central (i.e., Henan) and Northwestern (i.e., Xinjiang) China, and subtype 3a from Southwestern (i.e., Yunnan) and Northwestern (i.e., Xinjiang) China. From Zhenjiang, subtypes 1b and 2a were further spread to Eastern (i.e., Shanghai) and Northern (i.e., Beijing) China, respectively.
  
  
  CONCLUSIONS
  The mixing of seven HCV subtypes in Zhenjiang from all quarters of China indicates that as an important middle station, Zhenjiang plays a crucial role in HCV transmission, just as it is important in population migration between other regions of China and Eastern China.
authors.affiliation: Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, China. zhangcy1999@hotmail.com
authors.forename: Chiyu
authors.initials: C
authors.lastname: Zhang
authors.forename: Nana
authors.initials: N
authors.lastname: Wu
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Qinjuan
authors.initials: Q
authors.lastname: Ge
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Qian
authors.initials: Q
authors.lastname: Ren
authors.forename: Qingchuan
authors.initials: Q
authors.lastname: Feng
authors.forename: Guangli
authors.initials: G
authors.lastname: He
mesh_terms: D002681:China; D002947:Cities / Q000453:epidemiology; D055030:Drug Users / Q000706:statistics & numerical data; D004641:Emigration and Immigration / Q000706:statistics & numerical data; D005838:Genotype; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006526:Hepatitis C / Q000150:complications / Q000453:epidemiology / Q000635:transmission* / Q000821:virology*; D006801:Humans; D021141:Nucleic Acid Amplification Techniques; D010802:Phylogeny; D011153:Population; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D015819:Substance Abuse, Intravenous / Q000150:complications / Q000453:epidemiology / Q000821:virology*
chemical_list: D012367:RNA, Viral