貂、狐、貉源犬瘟热病毒分离株H和N基因的遗传多样性分析

Phylogenetic characterization of H gene and N gene of canine distemper virus detected in naturally infected raccoon dogs,foxes and minks

为研究鼬科动物犬瘟热病毒（CDV）毒株的变异特性,对来自不同地区的貉、狐、貂的5个CDV分离株（其中HD-m、LN-m为貂源,HTp-r、THD1-r为貉源,HB-f为狐源）和1个CDV国内弱毒疫苗株（vCh）的N基因和部分H基因进行了核苷酸测序,并构建系统发生树。结果表明,5个分离株之间H基因核苷酸序列同源性均达到97.5%以上,而N基因为94.5%-99.8%。vCh与5个分离株的H基因和N基因核苷酸序列同源性普遍较低（H基因：90.5%-91.8%;N基因：90.9%-93.5%）,而与国外疫苗株vCon和vOnder的H基因核苷酸同源性达96.8%和97.2%。分离株之间H蛋白氨基酸同源性差别不大（97.1%-100%）,而N蛋白氨基酸同源性差别较大（91.6%-100%）。5个CDV分离株与vCh疫苗株H蛋白和N蛋白同源性均普遍较低,H蛋白为89.7%-91.8%,N蛋白为92.8%-96.8%。vCh与vOnder、vCon有很高的同源性,其H蛋白氨基酸同源性分别为97.1%和95.6%,vCh与vOnder N蛋白氨基酸同源性达97.3%。结果显示,最近犬瘟热的流行和免疫失败现象的发生与国内所用疫苗毒株和野毒株的遗传关系甚远有关。

To characterize the variability of recent field isolates of 5 canine distemper virus （CDV） strains from different hosts and geographical areas, nucleotide sequence analysis of the H gene and the N gene encoding the haemagglutinin and the nucleocapsid protein were conducted, respectively. Pronounced differences between 5 field isolates were revealed in comparison to the attenuated vaccine strains vCh, vCon and yOnder. Phylogenetic trees were constructed with H/N gene of 5 CDV isolates, vaccine strain vCh and 12/ll CDV strains in GenBank. Results： The homology of nucleic acid sequences among the 5 isolates was high （H gene： 97.6%-99.9% and N gene： 94.5%-99. 8% ）. While the homology of nucleic acid sequences between vCh and 5 isolates was low （H： 90.5%-91.8%; N： 90.9%-93.5%）, but high with foreign vaccines, vCon （H： 96. 8%） and vOnder （H： 97. 2% ）. The difference of amino acid homology of H protein among 5 isolates was not high （97. 1% - 100% ）, but high of the N protein between 5 isolates （91.6%- 100% ）. All the homology of H protein and N protein between vCh and 5-isolates were low, with H protein 89.7%-91.8% and N protein 92. 8%-96. 8%. vCh, yOnder and vCon had high homology of amino acid both H protein and N protein （ H protein 97. 1% and 95.6% , respectively, N protein of vCh and yOnder 97.3% ）. Conclusion ： the canine distemper prevalenced in several provinces of China may be due to the far heredity between vaccine strain and field strains.