Isolation, Identification, Phylogenetic Analysis And Pathogenic Study Of A Feline Panleukopenia Virus(FPV-GZ01) In Cats

In order to understand the biological characters of feline virus in the Guangzhou area, PCR experiment was conducted to the collected faeces and the positive faeces were conducted by hemagglutination assay, physical and chemical properties test, and cell separation identification experiment. experiment results showed that two faecal samples were positively identified by PCR test from 11 faecal samples. Two positive faecal samples could agglutinate 1% porcine red blood cells and the HA titer was 1:128. Result showed that FPV could be isolated from the faece of FPV-GZ01, whereas another positive faecal sample FPV-GZ02 did not isolate FPV, which might be relevant to the virus titer of the faece. the result of physical and chemical properties test showed that FPV had the tolerance of acid, alkali, heat and lipid solvent, but not the DNA cytotoxicity material.For knowing natural recombination, cross host transmission and prevalence of FPV, PCR experiments was conducted to faece samples seemingly infected with FPV, genome DNAs were extracted from positive samples, and complete virus genome sequences were amplified by PCR and were compared with relevant reference sequences from Gen Bank to genetic analysis. Meanwhile, major amino acid sites were analyzed for the variation of VP2 gene and NS1 gene. Result showed that our experiments successfully obtained total genome of FPV from two positive faeceal samples. Genetic analysis indicated that one strain of FPV-GZ01 isolated from Guangzhou area had the same branch with the other isolated strains of FPV-XJ01 and FPV-HRB, and implied FPV-GZ01 and FPV-GZ02 evolved from FPV-XJ01. NS1 phylogenetic analysis demonstrated that FPLV may recombine with CPV-447. Major amino acid site analysis indicated that FPV was more conservative than CPV in genetic variation of VP2 gene. In NS1 gene analysis, FPV-GZ01 and FPV-GZ02 were various in amino acid mutation in some extent.For purpose of understanding the infectivity and pathogenicity of FPV in Guangzhou area, our study used the FPV-GZ01 strain to infect kittens by oral virus. Animal experiment result demonstrated that kittens infected with FPV got fever, and one of experiment group kittens occur with typically biphasic fever. In weight change aspect, kittens of experiment group got the situation of losing weight continually, which demonstrated that kittens infected with FPV lost appetite, weight and spirit. FPV-GZ01 could induce the various damage of tissue and the main diseased region was gastrointestinal tract. FPV mainly infect mucosal epithelial cells of gastrointestinal tract to result cellular degeneration, necrosis and shedding. Besides, FPV has a bad influence on cats and causes the cat death.Our study provided the reference of knowing epidemic conditions in Guangdong area and the basis of studying the FPV infectivity as well as pathogenicity to kittens, by isolation, identification, phylogenetic analysis and animal experiment.