2021年~2022年我国猪盖塔病毒流行情况调查及其E2基因序列遗传变异分析

Epidemiological survey of porcine Getahvirus and genetic variation analysis of E2 gene of GETV strains in China from 2021 to 2022

为了解2021年~2022年我国猪盖塔病毒(GETV)的流行现状和遗传变异情况,本研究对我国16个省份采集2512份临床样品,采用荧光定量RT-PCR方法进行GETV的检测,按照省份和地区进行GETV流行病学调查分析;采用RT-PCR方法对部分GETV阳性样品经PCR扩增E2基因并连接至p MD18-T载体并测序,利用DNAStar软件分析E2基因及其编码氨基酸序列与GETV参考株相应序列的同源性及其氨基酸变异情况;利用MEGA6.0软件构建E2基因的进化树,分析GETV的基因型及遗传进化关系。结果显示,7个省份猪群样品中均检测出GETV阳性样品,阳性率为3.34%(84/2512)。其中,陕西省和黑龙江省为首次在猪中检测到GETV。不同生长阶段猪中,仔猪GETV的检出率最高,达9.52%。同源性分析显示,获得的32个猪源GETV E2基因序列之间的同源性为98.3%~100%,与马来西亚GETV MM2021株相应基因序列的同源性为94.4%~94.9%。氨基酸序列变异分析显示,与参考株相比,本研究测序的E2蛋白有9个氨基酸位点只出现于猪源GETV。遗传演化分析显示,32个GETV株均属于III亚群,与III亚群内早期中国M1株、韩国QIAG9301株、日本Kochi等病毒株相比,本研究鉴定的GETV形成了新的进化分支。本研究揭示了我国当前猪群中GETV的感染现状及流行株的遗传变异情况,为该病毒的分子生物学研究和相关疫病防控策略的制定提供基础数据和参考依据。

In order to understand the epidemic status and genetic variation of porcine Getah virus(GETV)in China from 2021 to 2022,a total of 2512 clinical samples collected from 16 provinces were detected by fluorescence quantitative RT-PCR,and epidemiological surveys were analyzed by province and region.The E2 gene was amplified by RT-PCR and cloned into pMD18-T vector for sequencing.Then the homology and amino acid variation were analyzed by DNAStar software,and the phylogenetic tree of E2 gene was generated by MEGA6.0 software for further genotype and evolutionary relationship analysis.The results showed that GETV was detected in pig samples from 7 provinces,and the positive rate was 3.34%(84/2512).Among them,Shanxi province and Heilongjiang Province for the first time detected GETV in pig herds.Among pigs at different growth stages,piglets had the highest detection rate(9.52%).Homology analysis showed that the nucleotide homology among the 32 E2 genes of Porcine-origin GETV ranged from 98.3%to 100%,and the nucleotide homology with the Malaysian prototype strain of GETV MM2021 was 94.4%to 94.9%,respectively.Amino acid variation analysis showed that nine amino acid sites only found in porcine-derived strains compared with the reference strains.Genetic evolution analysis showed that all 32 strains belonged to subgroup III,which formed a new evolutionary branch compared with the early Chinese M1 strain,Korean QIAG9301 strain,and Japanese Kochi strain within subgroup III.This study revealed the current situation of GETV infection and the genetic variation of epidemic strains in China,and provides basic data for molecular biology research and disease prevention and control strategies of the virus.