广东地区犬瘟热病毒血凝素基因的克隆与序列分析

Cloning and sequence analysis of haemagglutinin gene of canine distemper virus in Guangdong area

【目的】对广州和东莞市宠物犬感染犬瘟热病毒(CDV)的情况进行病原鉴定和分析,为监测CDV的遗传变异情况和防治犬瘟热(CD)提供数据基础。【方法】从表现CD症状的犬只中鉴定了17份CDV阳性样本,采用RT-PCR的方法克隆得到这些野毒株的血凝素(H)基因序列,采用生物信息学方法进行序列比对分析。【结果】17株CDV的H基因核苷酸与氨基酸序列的相似性分别为97.4%~100.0%和97.5%~100.0%,与Onderstepoort、Lederle和Convac等疫苗株相比,其核苷酸与氨基酸序列相似性分别为90.3%~91.5%和89.4%~90.8%。进化树分析结果显示,17株CDV野毒株均属于AsiaⅠ型,与疫苗株的分支较远;本研究鉴定的野毒株已进化形成9个潜在的N-糖基化位点。【结论】AsiaⅠ型CDV仍为该地区的流行基因型,基因型较稳定,但与疫苗株相比形成了一定的进化距离和出现了大量的变异。因此,继续监控CDV在犬群中的进化,掌握其遗传变异状况具有重要意义。

【Objective】To perform etiological investigation of canine distemper virus(CDV)infection in dogs from Guangzhou and Dongguan,moniter the genetic evolution of canine CDV,and provide a data basis for the prevention and control of canine distemper(CD).【Method】Seventeen CDV positive samples were identified from dogs with CD symptoms.The haemagglutinin(H)genes of these wild strains were obtained by RT-PCR,and the H gene sequences were compared and analyzed through bioinformatics approach.【Result】The similarities of nucleotide and amino acid sequences of H genes from 17 CDV strains were 97.4%to 100.0%and97.5%to 100.0%,respectively.Compared with vaccine strains such as Onderstepoort,Lederle and Convac,the similarities of nucleotide and amino acid sequences of H genes from these CDV strains were 90.3%to 91.5%and 89.4%to 90.8%,respectively.Phylogenetic tree analysis showed that 17 CDV wild strains belonged to Asia I subtype and were distant from the vaccine strains.The identified wild strains had evolved to containing nine potential N-glycosylation sites.【Conclusion】Asia I CDV is still an epidemic subtype in this region and this subtype is stable,but it has formed a certain evolutionary distance and a large number of mutations compared with vaccine strains.Therefore,it is of great significance to continue to monitor the evolution of CDV in dog populations.