三株猫杯状病毒的分离鉴定及致病性研究

为了解猫杯状病毒(feline calicivirus,FCV)在广西地区的流行情况与致病性,本研究采集55份疑似FCV拭子,按常规方法分离鉴定得到3株FCV,以VP1基因进行同源性分析,在77.5%~85%之间,这3株分离株(2019)与广西株GX01(2013)、吉林株CH-JL4(2015)、上海株SH(2014)及英国株F65(1999)、哈尔滨株HRB-SS(2014)处于同一进化分支,具有相同的遗传起源,但与目前临床上使用的国内疫苗株255、国外疫苗株F9处于不同的进化分支,存在疫苗免疫失败的风险。为了解这3株FCV的毒力,进行动物致病性试验。结果显示,模拟自然感染的试验猫,FCV潜伏期最长为7 d,5~7 d为排毒的高峰期,FCV存在短暂病毒血症的情况。器官病变集中在肺部,会出现明显的淤血、出血现象。这3株的感染率均为100%,死亡率分别为50%、50%、75%,表明这3株FCV毒株均有致病性。综合剖检和HE染色结果分析,致病力最强的是GXN3株。

Isolation,identification and pathogenicity of three strains of feline calicivirus

To understand the epidemic situation and pathogenicity of feline calicivirus(FCV)in Guangxi,55 swabs of FCV were collected,out of which 3 FCV strains were obtained after isolation and identification.Phylogenetic analysis of VP1 gene showed that the 3 FCV strains(2019)fell into the same cluster as Guangxi strains GX01(2013),Jilin strains CH-JL4(2015),Shanghai strains SH(2014),British strains F65(1999)and Harbin Strain HRB-SS(2014),sharing a common genetic origin between77.5%—85%,but the 3 strains were on a different branch from the domestic vaccine strain 255 and foreign vaccine strain F9 currently in clinical use.This result suggests a potential risk of failure in vaccineimmunization.To understand the virulence of 3 FCV strains,catpathogenicity experiments were carried out.The results showed the cat with simulation infection had the longest FCV incubation period of 7 days,and the peak period of detoxification was between the 5 th and the 7 th day where there was a brief transient viremia.Organ lesions mainly occurred in the lungs,and there were obvious congestion and bleeding,displaying a 100%infection rate,while the mortality were 50%,50%,75%,inspectively,indicating pathogenicity in the 3 FCV strains.Analysis of comprehensive anatomy and HE staining results indicated that GXN3 had the strongest pathogenicity.