摘要
[Objective] This study aimed to investigate the genetic variation of g E gene of an epidemic pseudorabies virus（PRV） strain and its pathogenicity to piglets. [Method] By serial passage in Vero cells, a PRV strain was isolated from the brain tissues of stillborn fetuses delivered by sows with suspected PRV infection and preliminarily identified by PCR. g E gene of the isolated PRV strain was amplified and sequenced for phylogenetic analysis. In addition, the pathogenicity of the isolated PRV strain to 6-week-old piglets was evaluated. [Result] A PRV strain was successfully isolated and named PRV N5 B strain, which could proliferate in Vero cells and TCID50 of the 15 thgeneration virus liquid reached 10^7.125/0.1 ml. Specific bands could be amplified by PCR. g E gene in the isolated PRV strain was 1 740 bp in length. A phylogenetic tree was constructed based on full-length g E sequences, which showed that PRV N5 B strain and PRV strains isolated since 2012 were clustered into the same independent category and shared 99.7%-100% homology of nucleotide sequences. Compared with related sequences published previously, there were insertions of three consecutive bases at two loci. Animal experiments showed that intranasal inoculation of 6-week-old piglets with 2 ml of PRV N5 B strain（10^6/0.1 ml） led to a mortality rate of 100%. [Conclusion] In this study,genetic variability of g E gene in PRV N5 B isolate and its pathogenicity to piglets were analyzed, which provided a theoretical basis for the development of new vaccines to prevent and control porcine pseudorabies.
[目的]了解我国猪伪狂犬病病毒流行株g E基因的遗传变异特性以及其对仔猪的致病性。[方法]利用Vero细胞从疑似伪狂犬病病毒（PRV）引起的流产死胎猪的脑组织进行病毒分离。通过PCR进行初步鉴定,对分离株g E基因序列进行系统进化树分析以及该病毒对6周龄左右仔猪的致病性试验。[结果]成功分离到1株PRV毒株,命名为PRV N5B株,该病毒能在Vero细胞上增值,在15代TCID50达到10^7.125/0.1 ml;PCR检测可扩增出特异性条带;g E基因全长1 740 bp,系统进化树分析表明分离株与2012年以来新流行的毒株属于同一个相对独立的分支,核苷酸同源性高达99.7%～100%;而与以往发表的国内外相关序列比较,在2个不同的位置分别有3个连续碱基的插入。动物试验表明,2 ml的该病毒（10^6/0.1 ml）滴鼻接种能使6周龄左右仔猪100%死亡。[结论]该研究中的PRV N5B分离株g E基因的遗传变异特性以及其对仔猪的致病性试验对于目前流行的猪伪狂犬病的防控及新的疫苗的研发提供理论依据。
基金
Supported by Natural Science Foundation of Jiangsu Province(BK20131334)
Fund for Independent Innovation of Agricultural Science and Technology in Jiangsu Province[CX(13)3069]~~
