3株马立克氏病病毒的分离鉴定及其主要致病基因分析

Isolation and identification of three Marek's disease virus strains and sequence comparison of genes involved in pathogenesis

为了解国内鸡群马立克病(MD)毒株目前的流行情况,在我国3个已免疫MD疫苗的白羽肉种鸡场暴发MD的鸡群中,通过临床剖检,组织病理学变化,病毒分离,IFA检测从发病鸡的淋巴细胞中分离到3株马立克氏病毒(MDV),并分别命名为SDAU1501、SDAU1502和SDAU1503。采用PCR方法扩增3株MDV的vIL8、pp38、meq致病基因,所得氨基酸序列与已发表的参考毒株序列进行比较分析,结果显示SDAU1501和SDAU1502的致病基因与强毒株的同源性达到97%以上,具有强毒特征;而SDAU1503的meq基因在第194位具有与CVI988同样的缺失(P),但其没有CVI988中177个核苷酸的插入突变,其具有与弱毒疫苗株的特征。MDV新的变异在不断发生,出现了不同类型的变异株,因此,对MD的流行情况与基因监测应当继续下去;同时,在MDV疫苗的研制更新上还有待于进一步研究。

To understand epidemiological characteristics of Marek＇s disease virus （MDV） prevalent in china currently,3 Marek＇s disease （MD） strains were isolated and identified from white feather meat chickens vaccined with MDV CVI988 or 814 through necropsy, histopathological observation,virus isolation and IFA detection,named SDAU1501, SDAU1502 and SDAU1503, respective- ly. vIL8,pp38,MEQ gene of the three strains of MDV were amplified using PCR,and compared with reference strains. The homology between SDAU1501 and SDAU1502 and virulent strains was above 97% ,suggesting some features of virulent strainslwhile meq gene of SDAU1503 lost P amino acid at the 194 th site as that in CVI988,But the distinctive 177 nucleotide insertion mutations was not existed,predicting that it may be a attenuated vaccine strain. New variations of MDV con- tinued and different types of variants emerged,therefore,prevalence and genetic monitoring of MD should be proceeded - meanwhile , more attentions should be given to MDV vaccine development.