山东部分地区猪瘟病毒感染情况调查及其基因变异分析

Infection Investigation and Genetic Variation Analysis of Classical Swine Fever Virus in Parts of Shandong Province

为了解山东地区猪瘟病毒(CSFV)的感染和变异情况,应用RT-PCR方法对2018年从无害化处理场和屠宰场采集的756份猪的组织样品进行CSFV检测,并对阳性毒株的5′UTR、E0和E2基因进行扩增、克隆和序列分析。结果显示,756份样品中有59份为CSFV阳性,阳性率为7.8%。根据测序结果选取有代表性的9株CSFV病毒进行序列分析,对E2基因序列分析显示,与兔化弱毒(HCLV)疫苗株相比,在可造成免疫逃逸的关键氨基酸位点这9株毒株均存在相同的3个氨基酸位点的突变,而E0基因在密码子程度上一直向着远离经典毒株Shimen株和HCLV疫苗株方向发展。以5′UTR和E2基因为基础进行分型,发现这9株病毒均属于2.1d亚群,与Shimen株、HCLV疫苗株亲缘关系较远。综上说明,山东地区猪瘟病毒已经朝着远离疫苗株的方向进化。

To study the infection and genetic variation of classical swine fever virus(CSFV)in Shandong,a total 756 tissue samples were collected from harmless disposal field and slaughter house.All these samples were subjected to RT-PCR,and the positive samples were amplified and cloned,then sequenced to obtain the 5′UTR gene,E2 gene and E0 gene of CFSV.The results showed that positive rate of CSFV was 7.8%(59/756).The E2 gene of the 9 CSFV isolates with HCLV strain all showed the same 3 key amino acid sequence substitutions that may cause immune escape.Homology of E0 gene of 9 CSFV isolates were far from the classical strains such as Shimen strain and HCLV vaccine strain.Based on 5′UTR gene and E2 gene,phylogenetic analyses revealed that all of the 9 CSFV isolates were clustered into genetic subgroup 2.1 d.In summary,Shandong province CSFV virus has been evolving towards the direction away from vaccine strain.