犬细小病毒河南方城株分离及VP2基因序列分析

Isolation and Sequence Analysis of VP2 Gene of Canine Parvovirus from Fangcheng,Henan

为了解犬细小病毒的临床流行及变异情况,本研究于河南省方城县采集了8份疑似CPV感染犬粪便样品,经过PCR检测、CRFK细胞增殖培养、透射电镜观察和病毒滴度测定后,对其VP2基因进行序列分析。结果表明5株分离株为犬细小病毒,病毒滴度分别为10^(-4.22)/0.1 mL(China-HN-01株)、10^(-3.56)/0.1 mL(China-HN-02株)、10^(-3.78)/0.1 mL(China-HN-05株)、10^(-4.4)7/0.1 mL(China-HN-06株)、10^(-4.4)/0.1 mL(China-HN-07株)。VP2基因序列比对和遗传进化树分析结果显示,4株分离株基因型为New CPV-2a,1株分离株基因型为CPV-2c,5株分离株与疫苗株的同源性为97.8%~98.7%,与国内外参考毒株的同源性为94.0%~99.0%,4株New CPV-2a基因型毒株与四川的Canine/China/24/2017株亲缘关系最近,CPV-2c基因型毒株与蒙古国5-MGL分离株位于同一分支,与我国河南地区的3株CPV-2c毒株亲缘关系较远。对河南方城地区CPV毒株的分析,为研究CPV变异株在河南地区的传播和宠物疫病防控提供了理论依据。

In order to investigate the prevalence and variation of Canine parvovirus,8 fecal samples were collected from dogs suspected of CPV infection from Fangcheng county,Henan province.Five CPV isolates were obtained based on PCR amplification,growth on CRFK cells,transmission electron microscopy and virus titration.The TCID50 titers of these isolates were 10^(-4.22)/0.1 mL(China-HN-01 strain),10^(-3.56)/0.1 mL(China-HN-02 strain),10^(-3.78)/0.1 mL(China-HN-05 strain),10^(-4.4)7/0.1 mL(China-HN-06 strain)and 10^(-4.4)/0.1 mL(China-HN-07 strain),respectively.The VP2 gene of these isolates were then sequenced for phylogenetic analysis.Four isolates belonged to new CPV-2a subtype and 1 isolate belonged to CPV-2c subtype.These 5 isolates were 97.8%-98.7%identical to the vaccine strains and 94.0%-99.0%to the domestic and foreign reference strains.4 isolates of new CPV-2a subtype had the closest genetic relationship with Canine/China/24/2017 strains from Sichuan.The isolate of CPV-2c subtype was clustered in the same branch with the Mongolian 5-MGL isolate and distantly related to 3 CPV-2c subtype isolates from Henan province.These results provided a theoretical basis for the epidemiology of CPV mutant strains in Henan province and prevention and control of pet disease.