犬细小病毒BJ5株分离和VP2序列分析

从北京地区疑似犬细小病毒感染的病死犬血样粪便中分离1株犬细小病毒并进行VP2基因扩增和序列分析，命名为CPV—BJ5株。应用CrFK细胞分离病毒，经2次传代后出现稳定的血凝特性（HA）；免疫荧光试验表明，感染分离毒的细胞与抗CPV单克隆抗体反应并出现特异性的胞浆荧光；试验犬接种分离病毒后14d内均表现为体温升高、食欲减退、腹泻及血便等典型发病症状；序列测定结果表明分离病毒的VP2基因与CPV-15、CPV-020、CPV-NJ、CPV—HLJ-JQ株的核苷酸相似性分别为99．2％、99．5％、99．1％、99．9％，氨基酸相似性分别为99．5％、100％、100％、99．3％；与CPV—Northern、CPV-39株的VP2基因核苷酸相似性为98．9％、98．1％，氨基酸相似性为98．8％、99．5％。表明该分离病毒与CPV-15、CPV-020、CPV—NJ、CPV—HU—JQ株在基因型上同属于CPV-2a毒株。

Isolation of Canine Parvovirus B J5 strain (CPV-BJ5) and Sequence Analysis of the VP2 Gene

A canine parvovims, CPV-BJ5 strain, was isolated from bloody stool of a dead dog in Beijing, characterized by growth in cell culture and infection in host animals, and analyzed for the sequence of the VP2 gene. After 2 passages in CrFK cells, CPV-BJ5 strain induced regular haemagglutination （HA）. Direct immunofluorescent assay （FA）, using CPV specific monoclonal antibody, revealed specific fluorescent staining in the cytoplasm of infected cells. Pups were experimentally infected with the virus strain, and typical clinical symptoms of CPV infection, including, fever, loss of appetite, depression, vomiting and hemorrhagic diarrhea were observed during 14 days course after infection. Sequence analysis on its VP2 gene and comparison to other CPV strains were conducted. The results showed that the VP2 gene of CPV-BJ6 shares 99.2%、99.5%、99.1%、and 99.9% of sequences with CPV-15, CPV-020, CPV-NJ, and CPV-HLJ-JQ strains, respectively at nucleotide level; the similarity at amino acids level was 99.5%、100%、100% 、and 99.3 % respectively to these strains,respectively at nucleotide level; the similarity at amino acids level was 99.5%, 100% ,100% ,and 99.3 % respectively to these strains. Comparison was also made to other 2 CVP strains, CPV-Northern and CPV-39. Nucleotide sequence similarity was 98.9% and 98.1%, and amino acid similarity was 98.8% and 99.5%, respectively. These results indicated that this isolate, CVP-BJS, together with CPV-15, CPV-020, CPV-NJ, and CPV-HLJ-JQ strains, belongs to CPV-2a type.