Molecular epidemiology of hepatitis C infections in Ningxia, China: genotype, phylogeny and mutation analysis

Current prevalence and genotype distribution of hepatitis C virus (HCV) infection remain unknown in Ningxia, northwest China.

From June to December 2013, 13,022 individuals were screened in Ningxia HIV/AIDS Sentinel Surveillance System, with their demographic features collected and serum samples tested for HCV antibody. Sero-positive drug users were further subjected to sequencing of NS5B and Core regions of HCV.

The anti-HCV prevalence was 0.34 % among individuals without history of drug use, while it was 15.80 % among drug users. Of 79 NS5B sequences amplified from drug users, 64 (81.0 %) were male and 51 (64.0 %) were injection drug users (IDUs). Subtype 3a (40.5 %) and 1b (25.3 %) were the most predominant subtypes, followed in frequency by 3b (10.1 %) and 2a (7.6 %). Subtype distribution has no significant difference between injection and non-injection drug users. Based on phylogeographic analysis, HCV strains in Ningxia IDUs were mainly originated from two sites, Yunnan province (in southwest China bordering Myanmar, also known as Burma) and Xinjiang Autonomous Region (in northwest China on the border of Central Asia), which are the two major drug trafficking originates in China. Previously reported drug-resistance mutations were also scanned in this treatment-naïve population. Amino acid substitutions (C316N) associated with direct anti-viral agents (DAA) resistance were identified in the NS5B region in seven samples.

This study is the first to reveal the existence of multiple genotypes of HCV in Ningxia, an inland province in northwest China, suggesting the rapid spreading of the virus.