青海岩羊源小反刍兽疫病毒N、F基因的遗传进化分析

Diagnosis of peste des petits ruminants and genetic evolution analysis of N and F genes of Pseudois nayaur in Qinghai

2021年1月19日,青海省海西州都兰县巴隆乡伊克高里村发生岩羊不明原因的死亡,表现为离群独处、卧地不起、体质虚弱、觅食困难、肛门周围黑色附着物等现象。通过临床症状、病理学解剖及实时荧光RT-PCR诊断,为小反刍兽疫病毒(PPRV)感染。采用RT-PCR技术从病死岩羊病料组织中扩增出了PPRV N、F基因的部分片段。采用MegAlig、NT1和MEGA6.0软件对岩羊PPRV株N、F基因序列进行了比对和分析,绘制系统进化树,结果显示:此次岩羊感染的PPRV株N、F基因片段与新疆株(China/Xinjiang/2015/16)序列片段的同源性分别为99.43%和99.73%。遗传进化分析,该病原属于基因Ⅳ系。在N、F基因核酸序列水平上,与国内新疆地区分离毒株亲缘关系最近,同在一个小的分支;与国外毒株相比,N基因与塞内加尔和尼日利亚分离毒株亲缘关系较远,F基因与国外分离毒株亲缘关系较远。综上所述,青海岩羊源PPRV株属于基因Ⅳ系,与当前我国流行的野毒株属于同一个谱系。

On January 19, 2021, an unexplained death of a Pseudois nayaur occurred in the Yikegaoli area, Balong Town‐ship, Dulan County, Haixi Prefecture, Qinghai Province. The animal was characterized by being alone, lying on the ground, physical weakness, difficulty in foraging, and black attachments around the anus. It was diagnosed as peste des petits ruminants virus (PPRV) infection by clinical symptoms, pathological autopsy, and qRT-PCR. Part of PPRV N and F genes were amplified from the diseased tissues of the dead P. nayaur by RT-PCR. Megalig, NT1, and MEGA 6. 0 software were used to compare and analyze the N and F gene sequences of P. nayaur PPRV and the phylogenetic tree was constructed. The results show that the homology between the N and F genes of PPRV infecting the P. nayaur from Qinghai and the Xinjiang strain (China/Xinjiang/2015/16) was 99. 43% and 99. 73% respectively. Phylogenetic analysis showed that it belonged to the lineage Ⅳ. At the nucleic acid sequence level of N and F genes, it has the closest genetic relationship with the strains isolated in Xinjiang. Compared with foreign strains, the N gene is more related to the strains isolated from Senegal and Nigeria and the F gene is distantly related to foreign strains. In conclusion, Qinghai P. nayaur PPR strains belong to the gene Ⅳ lineage, which is the same pedigree as the wild virus strains currently prevalent in China.