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

Infectious bursal disease virus (IBDV) primarily triggers severe immunosuppression in birds and has resulted in substantial economic losses to the poultry industry globally. Here, a novel naturally reassortant IBDV strain, designated IBDV_G3, was isolated from quails during a disease outbreak in Jiangsu Province, China. Genome sequencing revealed that IBDV_G3 carried segment A derived from the serotype-2-related A0 lineage, while segment B clustered within the B1a classical-like lineage, and this genomic constellation was further confirmed in the original uncultured quail tissues. IBDV_G3 replicated efficiently in LMH cells without prior adaptation, and its VP2 was recognized by the serotype 1 VP2-specific monoclonal antibody 5G10. These findings suggest that quails may harbor reassortant IBDV strains and that the quail–chicken interface warrants continuous surveillance for IBDV reassortment and evolutionary variation.