摘要
Abstract
In order to investigate the genetic variation of canine distemper virus(CDV),lesions of a sick dog suspected of infecting with CDV were collected from a pet hospital in Beijing for CDV isolation and culture,biological characterization,RT-PCR assay and animal regression experiment,followed by homology comparison based on H genes and analysis on its coding protein locus.The results showed that one strain of CDV was successfully isolated,and typical cytopathic effect(CPE)of Vero cells could be caused by inoculation of the isolated pathogen,and the viral titer reached 10-4.33 TCID50/0.1 mL after 96 hours of incubation,indicating a strong specificity and high purity;typical characteristics of paramyxovirus were observed under the electron microscope.The animal regression experiment showed that 100%(5/5)challenged dogs presented clinical symptoms of distemper;the H gene,with the length of 1 824 bp,encoded 607 amino acids,was 97.37%-99.67%identical to the strain prevalent in China,and 90.68%-91.12%to the vaccine strain,indicating a relatively distant genetic relationship.Genetic evolutionary tree showed that the isolate was located in Asia-1 branch,amino acids Y,D,R,G and Y were located at the loci 525,526,529,530 and 549 of the receptor binding sites,respectively,with 7 potential N-glycosylation sites,which was fully different from those of the vaccine strain.In conclusion,the isolate,possibly with strong virulence,was highly identical to the domestic epidemic strain,and far away from the vaccine strain,indicating a necessary to adjust the genotype of the vaccine strain and to change current vaccination strategy,as appropriate.A reference was provided by the study for the prevention and control of canine distemper and development of corresponding vaccines.关键词
犬瘟热病毒/分离鉴定/H基因Key words
CDV/isolation and identification/H gene分类
畜牧业
