江西省猪伪狂犬病原流行病学调查及其gB、gE及TK基因遗传变异分析

Epidemiological Survey of Pseudorabies in Jiangxi Province and Analysis of Genetic Variation of gB,gE and TK Genes

为了解江西省猪伪狂犬病原流行情况及遗传变异情况,对2017—2018年收集的疑似伪狂犬样品,以1对针对猪伪狂犬病毒gE基因的检测引物进行病原检测,并随机挑选15株PRV阳性样品,对PRV病毒复制必需的糖蛋白gB基因和主要毒力基因gE与TK基因克隆测序及遗传进化分析,用以探究其遗传变异关系。临床结果显示:猪伪狂犬病毒检出率由2017年的4.76%PRV gB/gE/TK全基因序列遗传进化分析结果表明:调查的15株伪狂犬病毒毒株与中国株处于同一分支,与美国株Bartha差异较大。核苷酸同源性分析结果表明:15株PRV gB基因相互间同源性为98.9%～100%;与参考毒株的gB基因的同源性96.7%～100%;gE基因相互间同源性为99.1%～100%;与参考毒株的gE基因的同源性98.1%～100%;TK基因变异相对较小,相互间同源性为100%,与参考PRV毒株的gE基因的同源性99.1%～100%。研究结果表明,gB基因和gE基因存在较多的变异,可能是当前流行毒株抗原变异及毒力增强从而使现有疫苗免疫保护力不佳的主要原因。

To study the epidemic and genetic variation of pseudorabies virus(PRV)in Jiangxi Province, PRV in clinical samples collected during 2017-2018 were detected by PCR based on gE gene,and fragments of 15 sequences were analyzed to explore the variation of gB/gE/TK gene.The results showed that the PRV clinical detection rate increased from 3.7% in 2017 to 7.54% in 2018,the detection rate was low across Jiangxi Province and there was no obvious seasonal change.Sequencing analysis showed that the gB/gE gene of detected 15 PRV strains had a low identity with PRV strains in US.The result of phylogenetic tree analysis of gB/gE gene showed that the 15 isolates and PRV strain of China belonged to the same cluster and with the US strain separated into two main groups;indicating that the current epidemic strain probably made the mutation of gB/gE gene, which would influence the immunogenicity and immune evasion of virus,and might be the reason for low immune protection of the currently applied vaccine strain.