【摘要】 2018年云南省边境地区某猪场猪群出现高热等症状,部分猪只死亡。为确认发病原因,采集死亡猪只肺脏组织样品进行猪繁殖与呼吸综合征病毒（PRRSV） RT-PCR检测,然后将阳性样品接种Marc-145细胞,连续传代3次后发现产生稳定的细胞病变效应（CPE）。经间接免疫荧光试验（IFA）、毒价测定及病毒全基因组测序,最终确定病原为PRRSV,将其命名为YNML-2018株,毒价测定为10^-4.88 TCID₅₀/0.1 mL。全基因组序列分析显示,YNML-2018毒株基因组全长15 357 bp,包含8个开放阅读框（ORF）,其中非结构蛋白2编码基因（NSP2）缺失90个碱基。病毒全基因组遗传进化分析显示,该毒株序列与国内分离的高致病性PRRSV同源性为95.3%～99.3%;其NSP2高变区序列与国内分离的高致病性PRRSV同源性为92.1%～97.8%;结构蛋白GP3、GP5氨基酸序列与国内分离的高致病性PRRSV毒株同源性分别为84.3%～99.6%和83.1%～99.0%。结果表明,YNML-2018株与近年来我国PRRSV流行株相比存在一定变异,但变异程度较低,仍与首次报道的高致病性毒株JXA1同属于亚群V。本研究为掌握云南省边境地区PRRSV流行毒株的遗传变异特征提供了技术支撑,并可为疫苗选用提供数据参考。更多还原

【Abstract】 In 2018,the symptoms including high fever were found in the pigs in a farm in the border area of Yunnan Province,leading to death of some pigs.In order to find out possible etiological factors, lung tissue samples from dead pigs were collected to detect porcine reproductive and respiratory syndrome virus（PRRSV） by RT-PCR,the positive samples were then inoculated into Marc-145 cells,after 3 consecutive passages,stable cytopathic effect（CPE） was observed.Through indirect immunofluorescence assay（IFA）,viral titer determination and whole genome sequencing,PRRSV was ultimately confirmed as the pathogen,and the isolate was named as YNML-2018,identified with the titer of 10^-4.88 TCID₅₀/0.1 mL.Whole genome sequence analysis showed that the total genome length of YNML-2018 was15 357 bp,8 open-reading frames（ORFs） were contained,and 90 nucleotides of NSP2 gene was missing.Genetic evolution analysis of the whole genome showed that the nucleotide sequences of the strain and its NSP2 hypervariable region as well as the amino acid sequences of structural proteins GP3 and GP5 were 95.3%-99.3%,92.1%-97.8%,94.3 %99.6% and 83.1%-99.0% re spectively identity to the highly pathogenic PRRSV isolated in China.In conclusion,compared to the PRRSV prevalent in China in recent years,YNML-2018 mutated at certain extent,but its level of variation was relatively low,and still clustered into the same subgenotype V as the highly pathogenic JXA1 reported for the first time.A technical support was provided by the study to investigate the genetic variation characteristics of PRRSV prevalent strain in border areas of Yunnan Province,and a reference to select appropriate vaccines.更多还原