Isolation And Identification Of Duck Parvovirus 04Nb Strain And Sequence Analysis Of Genome Coding Region And Expression Of VP2 Protein

Duck parvovirus is causative agents of Derzsy's disease, which is characterized by high mortality in young muscovy ducklings, stunting, diarrhea and grasping. The clinical symptom is enteritis, and the mortality is about 50% to 80 %. In 1989 this disease is first reported in France, subsequently, reported in Hungary, America and China. It caused significant economic losses in duckery all over the world. Duck parvovirus has been classified as a autonomous member of Parvoviridae, which has the linear single-stranded DNA genome approximately 5kb in length.Isolation and identification of DPV-04Nb Strain:A severe contagious disease broke out in several duckeries in Ningbo, Zhejiang province with the symptoms of diarrhea and grasping. The liver tissue from the dead ducks was collected and inoculated into the allantoic cavity of the 11-day-old embryos. Through purification by the sucrose density gradient centrifugation, a kind of 20nm virions with typical duck parvovirus (DPV) characters was observed by electron microscopy. In the test of agar-gel immunodiffusion, the reaction between the stuff from dead embryos and positive serum is obvious. Through SDS-PAGE, three main segments were visible that coincided with DPV. And in animal test, similar symptoms were observed. Using the primers designed according to DPV genome, we acquired an anticipative 600bp DNA fragment, which was cloned into E.coli and sequenced. The sequence shared 98% identity with the representative DPV strain. From all above results, the pathologic agent was diagnosed as Duck Parvovirus, and named it DPV-04Nb strain.