山东省猪圆环病毒2型的分离鉴定及其ORF2基因遗传进化分析

Isolation, Identification and Analysis of ORF2 Gene Evolution of Porcine Circovirus Type 2 in Shandong Province

该研究对山东省某猪场疑似患有断奶仔猪多系统衰竭综合征(postweaning multisystemic wasting syndrome,PMWS)的病猪进行了临床病理学检测和病理组织切片观察。PCR检测阳性的病料处理后接种PK-15细胞,通过连续传代培养分离到一株猪圆环2型病毒(porcine circovirus type 2,PCV2)(SDWF20107),并对其进行ORF2基因扩增、遗传进化分析以及氨基酸突变位点分析。序列分析表明,该毒株与其他参考毒株的核苷酸相似性介于77.2%~99.6%之间,氨基酸相似性介于82.1%~99.6%之间;分离株与2.1d亚型的毒株位于同一分支,表明分离毒株属于2.1d亚型。根据流行毒株的特征,该猪场改用高效圆环2型病毒疫苗并调整了免疫程序,使该猪场患病猪群症状很快消失,恢复正常生产水平。该研究结果为猪场中PCV2的基因分型及其变异情况提供了参考资料,也为今后PMWS的流行病学研究和防控提供理论依据。

In this study, we made a pathological diagnosis of swine which suspected of suffering from postweaning multisystemic wasting syndrome（PMWS） in one swine farm in Shandong province, by pathological examination and histopathological section observation. Then, PK15 cells were inoculated with the samples that were positive for PCV2 by PCR, and a strain of PCV2（SDWF20107） was isolated by continous subculture. The results of similarity analysis of the ORF2 gene showed that the nucleotide similarity between this strain and other reference strains ranged from 77.2% to 99.6%, and the amino acid similarity ranged from 82.1% to 99.6%. Phylogenetic analysis based on ORF2 genes indicated that the isolated strain belongs to the 2.1 d subtype. According to the characteristic of the epidemic strain, the swine farm switched to a highly efficientive and adjusted the immune program. As a result, the symptoms of the diseased swine soon disappeared and the normal production levels were restored. The present study provided reference data for the genotyping and variation of PCV2 in swine farms, and provided theoretical basis for future epidemiological studies and prevention and control of PMWS.