山东蛋鸡群马立克病临床病例的综合诊断及流行毒株的分子特征分析  

Comprehensive diagnosis of Marek’s disease clinical cases and analysis of molecular characteristics of epidemic strains from layers in Shandong Province

作　　者：张会霞 张慧 曹胜亮 李悦 姜胜男 宋一诺刘 思当 ZHANG Hui-xia;ZHANG Hui;CAO Sheng-liang;LI Yue;JIANG Sheng-nan;SONG Yi-nuo;LIU Si-dang(College of Animal Science and Technology,Shandong Agricultural University,Tai'an,Shandong 271018,China)

机构地区：[1]山东农业大学动物科技学院,山东泰安271018

出　　处：《中国兽医学报》2020年第8期1468-1473,1490,共7页Chinese Journal of Veterinary Science

基　　金：国家自然科学基金资助项目(3167130369)。

摘　　要：2019年5月份以来,山东省各地蛋鸡场送诊的疑似鸡马立克病(Marek's disease,MD)的临床病例明显增多,为明确诊断并探究其发病原因,本试验采用病理剖检、组织病理学观察、病毒分离鉴定等实验室诊断方法进行综合诊断并对分离毒株的分子生物学特性进行分析。剖检病死鸡的心脏、肝脏、肺脏、肾脏表面均见灰白色肿瘤病灶,脾脏颜色变淡、显著肿大。镜检发现在各器官组织内浸润性生长的肿瘤组织为大小不等的淋巴样瘤细胞并多见核分裂象。分离到3株马立克病病毒(MDV),分别命名为SDHZ1、SDLC1、SDTA1,采用PCR方法扩增分离毒株的Meq、gE及gI基因,并与参考毒株相应序列比对,结果显示分离毒株的Meq基因编码的氨基酸在77E、80Y、115A和176R位点均有相同的氨基酸突变,与中国的参考强毒株GX0101、Js201801相同,且Meq基因编码的氨基酸的176位氨基酸突变(P→R)改变了原有的Pro重复序列,这可能与vvMDV的毒力有关。分离毒株MDVs与已报道的中国毒株的gE和gI基因突变位置相同,具有明显的地域性遗传特点。经过遗传进化分析,分离株MDVs与GX0101的同源性最高,属血清1型MDV且极有可能是超强毒株。但MDV分离株的致病性及鸡群免疫失败的原因有待于进一步研究探讨。Since May 2019,the suspected chicken Marek’s disease(MD)cases from the layer farm in Shandong Province has increased obviously.In this study,laboratory methods,including pathological autopsy,histopathological examination and pathogen molecular biological detection were used to diagnose and explore the cause of the disease and analyze the molecular biological characteristics of the isolated strains.From autopsy observation,the heart,liver,lungs,and kidney surface of the sick chickens were all found with gray and white tumor lesions on the surface,and the spleen became pale and significantly enlarged.Histopathology revealed that the tumors were composed of lymphoid tumor cells of varying sizes,in which mitotic figures were observed.Three Marek’s disease viruses(MDV)were isolated and named as SDHZ1,SDLC1,and SDTA1.Sequence detection analysis was performed on the Meq,gE and gI genes amplified by PCR of the 3 new MDVs isolated which compared with reference strains.The results showed that the Meq of the isolated strain had the same amino acid mutations at locations 77 E,80 Y,115 A and 176 R sites,which were identical to the Chinese reference very virulent MDVs(vvMDVs)GX0101 and Js201801.Moreover,176 amino acid mutations of Meq gene(P→R)changed the original Pro repeat sequence,which may be related to the virulence of vvMDV.The isolated MDVs have the same mutation location as the gEand gI gene of the reported Chinese strains,which has clear regional genetic characteristics.After genetic evolution analysis,the 3 new isolated MDVs had the greatest homology with GX0101,a serotype1 MDV and most likely vvMDVs.The pathogenicity of MDV isolates and the reasons for the failure of chicken immune suppression need to be further studied.

关 键 词：马立克病病毒 蛋鸡 MEQ gE gI 遗传进化分析 

分 类 号：S852.65[农业科学—基础兽医学]