丙型肝炎病毒(Hepatitis C virus , HCV)是导致慢性肝炎的主要病原体之一, 全球感染人数大约为1.7亿。HCV基因组具有高度变异特性, 利用现代遗传分类方法, 可将HCV分为6个基因型和80多个基因亚型。不同HCV基因型、亚型的分布与流行具有明显地域特性：1型、2型呈全球流行态势, 3型主要流行于亚洲、北美及欧洲部分地区, 4型主要流行于中非、中东和欧洲地区, 5型主要发现于非洲和欧洲部分国家, 6型则主要在东南亚和北美地区流行。我国流行的HCV有1、2、3和6四种基因型, 北方仍以1b和2a型为主要流行基因型, 近年来3型和6型在华南、西南地区快速传播。据推断, 云南将可能成为我国HCV流行与传播的重要源头, 引起目前HCV基因型/亚型分布的较大变化, 并呈现多样化的传播方式。通过溯祖理论和进化分子钟等分析方法, 了解HCV不同基因型差异性流行与进化, 对研究HCV的分子流行病学特征, 对应性制定丙型肝炎的预防控制策略具有重要意义。
关键词：
HCV; 流行; 分子钟; 进化; 基因型
Hepatitis C virus (HCV) is a prevalent and globally distributed human pathogen that currently infects an estimated 170 million people. Chronic HCV infection significantly increases the risk of chronic hepatitis. The virus exhibits a very high degree of genetic diversity that is classified six genotypes and sub-classified more than 80 subtypes by phylogenetic analysis. The various genotypes and subtypes of HCV have been associated with different epidemiological and geographical spread patterns. Genotypes 1 and 2 are globally distributed; genotype 3 is predominant in Asia, North America and parts of Europe; similar regional patterns of endemic diversity have been found for genotype 4 in Europe, Middle East and Central Africa, for genotype 5 in parts of Africa and Europe, and for genotype 6 in Southeast Asia and North America. Up to date, four HCV genotypes, including genotype 1, 2, 3 and 6, were identified in China. Genotypes 1b and 2a were mainly found in Northern China. The fast spreading of genotypes 3 and 6 in Southern and South-Western China was reported by recent studies. It’s deduced that Yunnan may become an important source of HCV epidemic and spread, which will cause great changes in the distribution of HCV genotypes and subtypes, and a variety of transmission. With the development of evolution theory and related analysis methods, such as coalescent theory and evolutionary molecular, it is possible to understand the characters of virus evolution and migration. For HCV, the further understanding on the prevalence and evolution characters of various genotypes is very important for the deep investigation of HCV epidemic and the develop-ment of prevention strategy.
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