Attenuation of an original novel goose parvovirus strain NMG21 via serial cell passage

In China, drastic losses in the economy have been caused by the novel goose parvovirus (N-GPV), the causative agent of the beak atrophy and dwarfism syndrome (BADS), to the duck-raising industry. In this study, an original, highly virulent N-GPV strain NMG21 was serially passaged in duck embryo fibroblast cells (DEFs). The virus titers and virulence of selected passages in 1-day-old ducklings were examined. Increased virus titer was observed at the 5th passage (P5). Compared with the parent strain NMG21, P35 (NMG21-35 strain) has a clear decrease in pathogenicity for ducklings, with less tissue damage. The NMG21-35 also had relatively low tissue replication rates and higher antibody levels. Collectively, the virulence of N-GPV strain NMG21 was reduced via serial cell passage. Our research successfully prepared a N-GPV attenuated variant which might serve as a potential attenuated live vaccine candidate against N-GPV infection. Producing a live attenuated vaccine candidate against N-GPV infection in China is essential to reducing the economic impact of N-GPV on the duck-raising industry.