戊型肝炎病原学研究进展

Research progress in the etiology of hepatitis type E virus

戊型肝炎是由戊型肝炎病毒(HEV)引起的一种重要的人畜共患性传染病。该病主要由被污染的水或食物经粪口传播途径扩散,且可跨种属间传播。该病致病原HEV为肝炎病毒科成员,是单正链RNA病毒。其7.2 kb基因组主要包含三个开放阅读框(ORF):ORF1编码介导病毒复制和转录的非结构多聚蛋白;ORF2编码诱导中和抗体的衣壳蛋白和游离抗原;ORF3与ORF2部分重叠,编码参与病毒粒子形成和释放的多功能小蛋白。HEV具有独特的双重生命周期:以裸病毒粒子形式排入粪便,但以"准囊膜"粒子形式在血液中循环。两种病毒粒子以不同方式吸附、穿入宿主细胞,随后内化脱壳,进行基因组复制,产生更多病毒粒子释放至胞外,介导病毒扩散传播。现对HEV的病毒粒子形态特征、基因组结构、编码蛋白及其功能进行论述,以期为该病的基础研究和综合防控提供理论基础。

Hepatitis type E virus(HEV)is a significant infectious zoonotic disease that causes hepatitis E.The disease is primarily transmitted via the fecal-oral route through contaminated water or food and is transmissible between species and genera.The causative agent for the disease is the hepatitis type E virus,which is a member of the Hepadnaviridae family and a single-stranded RNA virus.Its 7.2 kb genome mainly contains three open reading frames(ORFs):ORF1 encodes a non-structural polyprotein that mediates viral replication and transcription;ORF2 encodes a capsid protein and free antigen that induce neutralizing antibodies;ORF3 partially overlaps with ORF2 and encodes a small multifunctional protein involved in virion formation and release.HEV has a unique dual life cycle:it is excreted into feces in the form of naked virions but circulates in the blood in the form of"quasi-enveloped"particles.The two kinds of virus particles adsorb and penetrate the host cell in distinct ways,then internalize and decapsulate to replicate the genome,thereby producing more virion and releasing it outside the cell to mediate the virus’s spread.This paper reviews the morphological characteristics,genome structure,encoded proteins,and function of HEV virus-like particles in order to provide a theoretical basis for basic research and comprehensive disease prevention and control.