中国内地地区埃可病毒25型全基因组进化与重组分析

Whole Genome Evolution and Recombination Analysis of Echovirus 25 in Chinese Mainland

埃可病毒25型(Echovirus 25,E25)属于肠道病毒B组(Enterovirus B,EV⁃B),其在临床上可引起包括手足口病(Hand,foot,and mouth disease,HFMD),无菌性脑膜炎(Aseptic meningitis,AM),急性弛缓性麻痹(Acute flaccid paralysis,AFP)等在内的多种疾病。本文从全国HFMD监测网络选取了2009⁃2018年的18株E25毒株进行全基因组测序,将所得全长序列及GenBank上目前已发表的E25全长序列,以及EV⁃B组其它原型株全长序列分别构建全基因组和各编码区的亲缘进化树,并依据不同进化分支选取具有代表性的两株E25毒株进行重组分析。结果显示,中国内地地区E25在P1区具有更高的亲缘关系,而P2和P3区建树中各出现了两个分支,且在每个分支上,与多个EV⁃B组的原型株具有较高的核苷酸同源性,提示E25可能存在多种重组模式。此外所选的两株毒株均与EV⁃B的其它血清型流行株在P2及P3不同区域发生重组,且重组的模式不相同,因此中国内地地区的E25至少存在两种重组模式,并且致病力可能与基因的重组有关。通过本研究的分析,进一步的揭示中国内地地区E25的重组特征,对其进化变异及后续的预防与治疗具有重要意义。

Echovirus 25(E25)belongs to Enterovirus B(EV⁃B),which can cause many diseases including hand,foot,and mouth disease(HFMD),aseptic meningitis(AM),acute flaccid paralysis(AFP)and so on.In this paper,18 strains of E25 virus from 2009 to 2018 were selected from the National Hand⁃foot⁃mouth Disease Detection Network for whole⁃genome sequencing.The full⁃length sequence obtained and the full⁃length sequence of E25 currently published on GenBank,as well as the full⁃length sequence of other prototype strains of EV⁃B group,were selected to construct phylogenetic trees of the whole genome and each coding region,and two representative strains of E25 virus were selected according to different evolutionary branches for recombination analysis.The results showed that E25 in Chinese Mainland was relatively conservative in P1 region,but two branches appeared in P2 and P3 regions,and showed higher nucleotide similarity with different types of prototype strains,suggesting that E25 may have multiple recombination patterns.In addition,two selected strains were recombined with other serotype epidemic strains of EV⁃B group in different regions of P2 and P3,and the recombination mode was different.Therefore,E25 in Chinese Mainland has at least two recombination modes,and its pathogenicity may be related to gene recombination.Through the analysis of this study,we can further reveal the recombination characteristics of E25 in Chinese Mainland,which is of great significance for its evolutionary variation and subsequent prevention and treatment.