Isolation, Identification And Biological Study Of Canine Parvovirus

Canine parvovirus (CPV) emerged in 1978 and spreaded all over the word. Since then this disease becomes endemic wordwide. This study aims to obtain CPV strains in the middle of China and study their genotypes, epidemiology, biological characteristics and pathogenicity.42 feces swabs that were positive in colloidal gold test were collected from pet clinics in Wuhan. Then they were passaged in Feline kidney 81 (F81) and observation by transmission electron microscopic.2 pairs primers were designed according to conservative Capsid protein2 (VP2) and the other pair were synthesized according to reference. Another 4 pairs primers were designed to clone the ORF of CPV. The strains were purified by plaque assay, and then one-step growth curves were obtained. Subsequently TEN sections were made. At the end animal experiment was carried out.28 CPV strains were isolated.390bp,583bp and 1755bp nucleotide Sequences were acquired. After sequencing and analyzing the gene fragments, the result shows that all the isolates were CPV while 25 were CPV-2a and 3 were CPV-2b. The system phylogenetic analysis explores the isolates 5 and 10 were close to the Chinese isolates, farther from the isolates in Europe and the Americas, farthest from the earliest isolate. The curves show the growth of CPV at different stages after infection. The reproductive activity could reach or beyond 105.5 PFU/ml. The result also shows that the two curves were slightly different at the beginning. The curve according to the experiment that the cells were infected when the cell had passaged 8 hours showed descending at the beginning Howere, another curve was rising. All the isolates could agglutinate red blood cells of swine under certain conditions and the agglutination can be inhibited. The photographs of TEN show that mitochondria are swelling. The ORFs of the 2 isolates were obtained. Finally, animal experiment shows that every dog had clinical symptoms in different degrees, such as vomiting and bloody excrement. After we tested the anus swabs collected at different time, we found that the dogs had discharge virus and the highest quantity can reach 102.5TCID50. The results of dissection reflect that there are necrosis in the small intestine and the myocardium becomes thinner. After pathological sections were made, observation were taken up and the result shows that myocardial cells are metamorphic and necroticThis study provides groundwork for further study of molecular biology and pathopoiesia of CPV.