Abstract: Duck flavivirus(DFV)disease was a kind of new duck disease. It had brought great economic losses to the duck industry in recent years. In order to study thoroughly and prevent the disease,it was isolated and identified as follows.The bacterial infection was initially ruled out from the samples by bacteria isolation. The samples showed DFV positive by RT-PCR detection. Then they were inoculated into DEF cells and healthy duck embryo for virus isolation and passages. Cytopathic effect (CPE) in DEF cells were observed in the first generation in the 48 h after inoculation, CPE was more evident with the extension of the time, and the typical CPE were observed as from 72 to 96 h after inoculation. Each generation of inoculated duck embryo appeared to be death, and the time of death were more concentrated in 60 to 72 h after inoculation. The dead duck embryo body were observed as edema, hemorrhage, dysphasia, severe hepatic hemorrhage, swelling or necrosis mottled. The virus isolated in DEF cells and duck embryo were detected and identified by hemagglutination test, titer determination, virus neutralization test, RT-PCR and artificial infection test. The results showed that the virus isolated was DFV and named as DFV SDbz strain.

Key words: duck flavivirus; virus isolation; identification