The Identification Of Pathogens Of Gosling New Type Viral Enteritis And The Development And Applications Of Its PCR Detection Technique

Gosling new type viral enteritis (GNTVE) is a new disease, whose epizootiology, the clinical symptoms and lesions are quite similar with those of gosling plague(GP), and causes a serious economy lose for geese industry. Therefore, it is important and necessary to study the etiology, to develope a rapidly diagnosis technique, and to search the prevention and control measure of the disease.The viral agents of six samples from typical cases of GNTVE were isolated by using cell cultures with goose embryo fibroblast (GEF), duck embryo fibroblast (DEF) and chick embryo fibroblast (CEF), and by inoculating the allantoic cavity and yolk sac of the embryoed eggs. GEF is the optimal laboratory host of GNTVE pathogens with 100% (6/6) successfulness of the isolation. 7 cloned viruses were obtained from one of the isolates by plaque technique.A fragment of 58()bp of Hexon gene were successfully amplified by polymerase chain reaction (PCR) technique from both Guangxi isolate FAV-GX1 and Sichuan isolate FAV-SCY. The PCR products were then cloned, sequenced and compared with the corresponding sequence of fowl adenovirus (FAV) reference strains in GenBank. The results suggested that two isolates belong to group I FAV. The isolates were further classified as serotype 1 FAV (FAV-1) by the sequences homologus analysis of ITR and Fiber genes with FAV-1 reference strain CELO.Two sets of PCR primers were designed to amplify specific DNA fragment from the genomes of GPV and FAV-1 respectively for the detections of both viruses. 32 liver samples and 70 cloaca swabs samples from the health gosling and the health breeding geese respectively, and liver samples of 33 clinic diseased geese with typical signs and lesions of GNTVE from different areas of Guangxi were detected. All the clinic samples were positive of both GPV and FAV-1, 44.29% and 37.14% of the cloaca swab samples were positive of GPV and FAV-1 respectively, while none of the liver samples from the health geese were positive of either GPV or FAV-1.An inactivated oil-emulsion (IOE) vaccine consisted of both GPV and FAV-1 was developed. And the breeder flock was vaccinated twist before breeding for the passive immunity for their progenies, and the health adult geese were hyperimmunized (inoculated 4 times) to obtained high level of antibody for the production of immune serum. The experimental and field applications results proved that both means of the passive immunity can provided very good prevention for gosling against GNTVE.The results of the study demonstrated that the pathogens of GNTVE are consisted of GPV and FAV-1, and GEF is the optimal laboratory host for the of pathogens. The the developed duplex PCR-based protocol is useful for the rapid diagnosis of GNTVE. The developed IOE vaccine and immune serum can provided very good passive immunity for gosling against GNTVE.