Isolation and Pathogenicity Analysis of a Novel Orthoreovirus Caused the Outbreak of Duck Viral Arthritis in China

Novel duck orthoreovirus can infect various hosts, mainly causing spleen necrosis and hemorrhagic necrotizing hepatitis, leading to immunosuppression and growth impairment. Infectious diseases characterized by swollen hock joints, movement disorders, and impaired growths have recently occurred in significant duck breeding areas in China. Infected ducks from Shandong Province were selected, and N-DRV-LY20 was isolated from the swollen joints. Next-generation sequencing (NGS) of N-DRV-LY20 and homology analysis showed that all ten fragments had the highest homology to N-DRV and the closest affinity to Duck/N-DRV-XT18/China/2018. After artificial inoculation with N-DRV-LY20 virus solution, Cherry Valley ducks showed the same symptoms of leg swelling and hock joint deformation, which were not explored in previous studies. A long history of evolution has led to significant variation in DRV and altered its pathogenicity. In this study, we confirmed the ability of N-DRV to cause viral arthritis in ducks and clarified this isolate's genetic characteristics and level of variation, providing a basis for the control and variation detection of N-DRV.