一株犬细小病毒CPV-2a变异株的分离鉴定及生物学特性研究

Isolation and biological characterization of a canine parvovirus mutant isolates

为研究犬细小病毒(CPV)地方分离株的变异情况,本研究从洛阳市某宠物医院临床表现为出血性肠炎的患犬肛拭子样品中分离到一株病毒,对其进行血凝试验、间接ELISA试验、PCR试验及动物回归试验。结果表明该病毒分离株能够凝集猪红细胞;利用兔抗CPV血清进行检测,结果呈阳性。采用CPV检测引物进行PCR扩增,获得大小为559 bp的特异性片段,并且利用针对CPV VP2基因设计的特异性引物能够扩增到大小为1 755 bp的特异性片段。同源性比较和进化树分析均表明该分离株为一株CPV,将其命名为CPV-henan32-2013。氨基酸序列分析表明该分离株为CPV-2a型,并且发生了T322S、Y324I、P333A、A334G、S348C 5个位点突变。动物回归试验复制出了CPV典型症状的出血性肠炎、心包液增多及肺脏水肿充血。病理切片观察可见心肌细胞、肠粘膜上皮细胞和肺脏均有出血、坏死或脱落等特异性病变。本实验结果为进一步了解CPV的变异规律、疫苗株的选择和CPV病的有效防控奠定了基础。

In order to study the variation of canine parvovirus （CPV） local isolates, a virus was isolated from rectal swabs of a canine suspected to be suffering from severe hemorrhagic enteritis in Luoyang city. The isolate was idetified as CPV by red cell agglutination assay and indirect ELISA, desgnated CPV-henan32-2013. In addition, the VP2 gene of the isolate was 1,755 bp in length, which shared high homology to CPV-2a, but 5 deduced amino acid mutations of T322S, y324I, p333A, A334G and S348C were found in VP2 of the isolate. Moreover, artifical infection showed that the infected dogs had typical clinical symptoms such as hemorrhagic enteritis, increased pericardial fluid, pulmonary edema and hyperaemia. Pathological examinations showed that myocardial cells, intestinal epithelial cells and pulmonary were hyperemic, hemorrhaging, necrosis or shedding. This study provides the groundwork for further exploration of CPV variation.