昆明市静脉注射吸毒人群丙型肝炎病毒基因型分析

Analysis on genotypes of hepatitis C virus among intravenous drug users in Kunming, Yunnan

目的研究云南省昆明市静脉注射吸毒人群（IDUs）中丙型肝炎病毒（HcV）基因型的流行特点。方法2014年4—7月在昆明市连续收集276份IDUs的血浆，其中199份样品为HCV抗体阳性，提取RNA后用巢式PCR对EIE2基因和NS5B基因的部分片段进行扩增。扩增产物经基因序列测定，所得序列通过构建系统进化树确定HCV的分子亚型。结果结合2个基因片段，共有125份样品获得了分型结果，3b为主要的亚型，占48．8％（61／125）；其他亚型按照比例依次为3a（30．4％，38／125）、6n（14．4％，18／125）、6a（3．2％，4／125）和1b（3．2％，4／125）。各HCV亚型按性别、婚姻、民族和HIV-1抗体是否阳性差异无统计学意义，按年龄分布差异有统计学意义，45岁以下组亚型多样化。分别计算不同亚型在EIE2和NS5B基因区的基因距离，结果显示3a、3b和6a亚型的基因距离大于1b和6n亚型的基因距离。3a、3b、6a3种亚型中3b亚型毒株的基因距离大于3a亚型毒株。结论昆明市IDUs人群中HCV存在5种亚型，3b和3a是主要毒株且在该人群中具有较长的流行时间。

Objective To investigate the distribution of hepatitis C virus （HCV） subtypes among intravenous drug users （IDUs） in Kunming, Yunnan province, in 2014. Methods A total of 276 plasma samples were collected from IDUs in Kunming during April 2014 - July 2014, in which 199 plasma samples were tested to be HCV antibody positive. For the HCV antibody positive samples, HCV E1E2 genes and NS5B genes were amplified by using nested-polymerase chain reaction （PCR）. After sequencing, the HCV subtypes were determined through phylogenetic analysis. Results Based on the phylogenetic trees of E1E2 gene and NS5B gene fragments, a total of 125 samples were genotyped. 3b was the predominant subtype （48.8%, 61/125）, followed by 3a （30.4%, 38/125）, 6n （ 14.4%, 18/125）, 6a （3.2%, 4/125） and lb （3.2%, 4/125）. The distributions of HCV subtypes by sex, marital status, ethnic group and HIV-1 infection status showed no statistical differences. However, the distribution of HCV subtypes by age showed statistical difference, the diversity of HCV subtypes was found in age group 〈45 years. The genetic distances of 3a, 3b and 6a on EIE2 and NS5B were larger than those of lb and 6n. For genotype 3, the genetic distances of 3b on E1E2 and NSSB were larger than those of 3a. Conclusion Five HCV subtypes were found among IDUs in Kunming, HCV subtypes 3b and 3a were predominant, which have circulated in this population for long time.