Abstract: 【Objective】 The aim of this study was to explore the genetic variation and genetic diversity of Canine distemper virus in Huaihua district and clarify its genetic evolutionary relationship.【Method】 Thirty Canine distemper virus samples were collected from Huaihua district and H and F gene sequences were amplified by PCR.The H and F gene sequences were analyzed by DNAStar software.Clustal X and MegAlign software were used to analyze variation sites and genetic diversity.Clustal X and PhyML 3.0 software were used to analyze the genetic evolution of Canine distemper virus in Huaihua area by maximum likelihood method (ML),and the genetic evolution tree was constructed by FigTree v 1.3.1 software.【Result】 Thirty Canine distemper viruses in Huaihua were Asian-type Ⅰ,and the H and F gene sequences were 1 778 and 1 850 bp,respectively.The contents of AT were 56.8%-57.9% and 54.9%-56.1%,and the contents of GC were 42.2%-43.0% and 44.1%-44.9%,respectively.The intraspecific and interspecific differences of H gene ranged from 0 to 3.1% and from 51.36% to 60.15%.The intraspecific difference of F gene was 0-2.4%,and the interspecific difference was 39.60%-53.09%.Based on the genetic evolutionary tree constructed by H and F gene sequences,it was found that 30 Canine distemper viruses from Huaihua were all located in the same branch of the genetic evolutionary tree.【Conclusion】 Canine distemper viruses from Huaihua were closely related to each other although there was a certain degree of genetic variation and genetic diversity among them.In addition,the H and F gene sequences of Canine distemper virus showed little intraspecific difference but great interspecific difference,which was an important genetic marker for studying gene variation,genetic diversity and genetic evolution of Canine distemper virus.

Key words: Canine distemper virus; H gene; F gene; gene variation; genetic diversity