Attenuation of a Novel Goose Parvovirus Strain NMG21 via Serial Cell Passage.

The novel goose parvovirus (N-GPV), responsible for beak atrophy and dwarfism syndrome (BADS), has caused significant economic losses in China's duck-raising industry. In this study, a highly virulent N-GPV strain NMG21 was serially passaged in duck embryo fibroblast cells (DEFs). The virus titers and virulence of selected passages were evaluated in 1-day-old ducklings. An increased virus titer was observed at the 5th passage (P5). Compared with the parent strain NMG21, the P35 (NMG21-35 strain) has a clear decrease in pathogenicity for ducklings, with less tissue damage. The NMG21-35 also exhibited relatively lower tissue replication rates and higher antibody levels. Collectively, the virulence of N-GPV strain NMG21 was reduced via serial passage in DEFs for 35 passages. Our research successfully prepared a N-GPV attenuated variant which might serve as a potential live vaccine candidate against N-GPV infection. Developing a live attenuated vaccine candidate against N-GPV infection in China is crucial for mitigating the economic impact of N-GPV on the duck industry.