A Naturally Occurring Novel Reassortant Strain of Infectious Bursal Disease Virus from Quails

Abstract

Simple Summary Infectious bursal disease (IBD) is a highly contagious viral infection that causes severe immunosuppression and major economic losses in poultry worldwide. The causative agent, IBDV, infects a wide range of birds, including wild species that can spread the virus without showing symptoms. In this study, we isolated a new reassortant IBDV strain, IBDV_G3, from diseased quails during an outbreak in Jiangsu Province, China. Genetic analysis showed that this strain carries a unique combination of genome segments: its segment A is related to serotype 2 IBDV, while its segment B belongs to the B1a classical-like lineage. IBDV_G3 replicated efficiently in cell culture without prior adaptation, and the same genomic combination was verified directly in the original quail tissues. Our findings suggest that quails may harbor such reassortant IBDV strains and that the quail–chicken interface deserves continuous surveillance for IBDV reassortment and evolutionary variation. Whether IBDV_G3 could serve as a vaccine candidate requires comprehensive future studies.