江西省某猪场育肥猪群出现高热、呼吸困难和死亡等症状,为确定疫病病原,本实验室从发病猪场随机采取20份病死猪血样和组织,用RT-PCR的方法进行病原检测.结果显示,19份临床样品呈现猪繁殖与呼吸综合征病毒(Porcine reproductive and respiratory syndrome virus,PRRSV)阳性.随后对病死猪肺组织进行病毒分离,结果显示分离的第1代病毒感染后48 h即可出现典型的致细胞病变效应(cytopathic effect,CPE),对传至第5代的病毒进行RT-PCR检测和间接免疫荧光鉴定,结果证实我们分离获得的病毒为PRRSV,命名为JX14T2.将JX14T2 P5代次的病毒与高致病性PRRSV强、弱毒代表株进行生长特性比较分析,结果显示,JX14T2在Marc-145细胞上形成的细胞病变、病毒噬斑形态以及病毒增殖动态均与HP-PRRSV毒株相似.对JX14T2进行全长基因测序和序列比较分析,结果表明JX14T2基因组全长14960 bp,属于北美型毒株,其NSP2除存在的1+29个氨基酸的缺失而外,在598~717 aa还存在120个氨基酸的缺失,与HP-PRRSV亲缘关系较近.本研究结果为掌握PRRSV流行情况以及致病机制提供了科学依据.%To investigate the etiological agent causing high fever, dyspnea and death of fattening pigs on a pig farm in Jiangxi province, a total of 20 blood and tissue samples were collected from dead pigs and examined in RT-PCR. As a result, 19 out of 20 samples were positive for Porcine reproductive and respiratory syndrome virus (PRRSV). Then, one lung sample that was positive in RT-PCR was inoculated to Marc-145. The typical PRRSV-induced cytopathic effect (CPE) developed after 48 hours of inoculation. The viruses at the fifth passage were demonstrated to be PRRSV in RT-PCR and IFA. Therefore, the isolate was confirmed to be PRRSV designate as strain JX14T2. In addition, the strain JX14T2 showed similar characters to the highly pathogenic strains in formation of CPE and plague and growth curve in Marc-145. The sequence analysis of the strain JX14T2 showed that its complete genome was 14960 bp and belonged to North American genotype. A continuous deletion of 120 aa between residues 598-717 was identified in NSP2 protein, in which the 1+29 aa deletion existed that was typically found in HP-PRRSV. The characterization of the strain JX14T2 added new information for further understanding of epidemiology of PRRSV.
展开▼
