鸡新城疫病毒强毒株的分离鉴定及其生物学特性的研究

Isolation, identification and biological characterization of velogenic Newcastle disease virus isolated from chicken

为了探索湖北省黄冈市某鸡场在2016年9月自然发病的大批量鸡死亡的原因,为临床诊断新城疫病毒感染提供病理学依据。采集病死鸡的组织样品,经9日龄SPF鸡胚接种传代分离病毒后,利用HA和HI试验、RT-PCR扩增F基因,对分离株进行鉴定,并通过测定鸡胚最小致死剂量的平均死亡时间、1日龄雏鸡脑内接种指数及组织病理学观察评估分离株的毒力和致病性。结果,从送检的病死鸡中分离到1株NDV,命名为Chicken-China-Hubei0901-2016,简称HB0901。HB0901株F基因裂解区域氨基酸序列为112R-RQ-K-R-F117,符合强毒株特征。HB0901株与F17株同处于基因Ⅶ型分支上,其核苷酸序列同源性高达99.4%。该分离株的MDT和ICPI分别为47.8 h和1.96。显微镜下可见新城疫典型的组织病理学变化。结果表明,基因Ⅶ型新城疫毒株是导致该批鸡大量发病死亡的原因。

The study aims to explore the causes of the death of large quanlities of chickens,naturally occurring in a farm in Huanggang,Hubei in 2016,to provide a pathologic basis for the clinical diagnosis of NDV.The tissue samples of dead chickens were collected and the virus was isolated by9-day-old SPF chicken embryos.The isolate was identified by hemagglutination （HA） and hemagglutination-inhibition （HI） test,RT-PCR,and sequencing of F gene of the virus.The virulence and the pathogenicity of the isolate were determined by the mean death time （MDT）,the intracerebral pathogenicity index （ICPI） and pathological morphology observation.A NDV strain was isolated from dead chickens and named as Chicken-China-Hubei0901-2016 （HB0901）.The amino acid sequence of F protein cleavage site was112R-R-Q-K-R-F117,which was consistent with the characteristic of the virulent strain.The nucleotide sequence homology of the F gene between HB0901 and F17 was 99.4%,and they both located the same branch in the phylogenetic tree and fell into the genotype Ⅶ.The MDT and ICPI of the HB0901 were 47.8h and 1.96,respectively.The typically histopathological changes in New-castle disease were seen under microscope.The results showed that the chick＇s death was caused by NDV.