HCV Subtype Characterization among Injection Drug Users: Implication for a Crucial Role of Zhenjiang in HCV Transmission in China

Abstract

BackgroundHCV 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.Methodology/Principal FindingsA 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/SignificanceThe 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.

The Current Hepatitis C Virus Prevalence in China May Have Resulted Mainly from an Officially Encouraged Plasma Campaign in the 1990s: a Coalescence Inference with Genetic Sequences

“…Figure 2B depicts an ML tree including the E1 sequences from 82 subtype 3a isolates. In addition to the 14 in this study, 53 were from our previous reports (25,26) and 10 were recently described (30). In this tree, five clusters were observed, and four exhibited significant bootstrap support.…”

“…Figure 2C shows an ML tree including E1 sequences from 104 subtype 3b isolates. In addition to the 13 in this study, 20 were from our previous studies (24)(25)(26) and 71 were from reference reports, and all were from intravenous drug users (IDUs); 44 were from Guangxi Province (27), 24 from Hubei (29), and 3 from Jiangsu (30). Two monophyletic clusters were observed, but they did not show significant bootstrap support.…”

“…To estimate the HCV epidemic history, five sequence data sets were assembled, which comprised the sequences of subtypes 1b, 2a, 3a, 3b, and 6a. The majority of these sequences were from this study and our previous reports (24)(25)(26), while a small portion were from the reference literature (27)(28)(29)(30). Among the latter, many were from our collaborators, with whom we communicated about the sequencing procedures and sampling dates.…”

“…To estimate the HCV epidemic history in China, Bayesian MCMC analyses were performed using the sequences determined in this study combined with those from our previous studies (24)(25)(26) and those reported by others (27)(28)(29)(30). These analyses resulted in five BSPs, each representing one subtype.…”

“…To test these hypotheses, we determined the HCV sequences in the samples collected from 423 patients in Guangzhou city, one of the major cities in China, where a considerable portion of the residents are immigrants or migrants from across the country (25). Based on the determined sequences, we performed phylogenetic analyses for a standard HCV classification, followed by subjecting them to BEAST inferences, in combination with the sequences from our previous studies (24)(25)(26) and those reported by others (27)(28)(29)(30). Because the last two sequence collections were sampled in different provinces, they represent the HCV strains prevalent in the country.…”