Isolation And Identification Of A Parvovirus Strain From A Giant Panda And Phylogenetic Analysis

Since before the1920s, FPV (Feline panleukopenia virus, FPV) has been knownand studied as a major cause of diseases of cats. Since the1940s, it has beenrecognized as a natural pathogen of minks, foxes, raccoons, and some other carnivores,including mink enteritis virus, blue (Arctic) fox parvovirus, and raccoon parvovirus.In1978, CPV (Canine parvovirus, CPV) was first observed when two new diseases ofdogs were seen，since then, CPV has remained an endemic pathogen of dogsthroughout the world. Although vaccination can frequently protect puppies, this hashad no effect on containment of the virus in the wild.In the study, a strain of parvovirus was isolated from feces of a dead giantpanda and labeled as PV/GP/SC/1/12, which was the focus of the study. The maincontents are as follows:1. Isolation and identification of the parvovirus isolated from a giant pandaAfter chloroform treatment, hemagglutination assay titer of the feces of thegiant panda was1:64. Frozen intestinal tissue sample was tested byimmunohistochemistry, positive results could be found. Intestinal contents wasdirectly done by electron microscopy negative staining, with parvovirus-likeparticles being observed. The virus was isolated by F81with CPE. By PCRamplification of the virus in F81the parvovirus-specific strip was observed. Thehemagglutination titer of the3rd generation of virus was1:1024. The test resultsshowed that a parvovirus was successfully isolated from a giant panda namedPV/GP/SC/1/12.2. Phylogenetic analysis of NS1and VP2of the parvovirus isolated from a giantpanda The VP2and NS1genes of the parvovirus were amplified by PCR and theirnucleotide and amino acid sequences were analyzed. The results showed that the232th amino acid was I, and the323th amino acid remanant base was N on the VP2protein of PV/GP/SC/1/12, the564th is S, and the other key amino acid sites werealso the same with FPV. The amino acid homologies of NS1protein and VP2proteinbetween PV/GP/SC/1/12and published sequences of CPV and FPV were98.7%~99.6%for NS1protein,98.3%~99.5%for VP2protein. Phylogeneticanalysis showed that the NS1gene of PV/GP/SC/1/12was found to bephylogenetically closely related to CPV, and the VP2gene formed a monophyleticbranch in the FPV cluster. The result showed that PV/GP/SC/1/12were characteristicof the recombination virus.3. Artificial infection of kittens by the parvovirus isolated from a giant pandaIn order to study the pathogenicity of PV/GP/SC/1/12toward kittens, in the test,two60-day-old kittens with CPV HI antibody less than1:2were artificially infectedby PV/GP/SC/1/12via oral cavity. The results showed that the PV/GP/SC/1/12couldinfect60-day-old kittens, causing typical symptom of parvovirus; the two testsubjects died on the10th and15th day post-infection, respectively. The results ofimmunohistochemistry showed that PV/GP/SC/1/12had replicated in many organsof kittens. It was showed that PV/GP/SC/1/12was infectious and pathogenic tokittens.