Outbreak of hepatitis-hydropericardium syndrome in blue-breasted quail (Excalfactoria chinensis) reveals a novel cross-species transmission of fowl adenovirus serotype 4

Notably, the newly identified HNSQ2023 from Excalfactoria chinensis, and other five epidemic FAdV-4 viruses isolated separately from peacocks, chickens, ducks or pigeons during 2018-2023 have formed a closely evolutionary sub-branch, distinct from the main branch composed of the vast majority of Chinese FAdV-4 strains originated from chickens. Furthermore, animal experiments demonstrated that HNSQ2023 retained highly pathogenicity to chickens and Excalfactoria chinensis, with a same 100% morbidity and over 90% mortality in both species.

Our data have shed new light on the high risk of cross-species transmission of FAdV-4 in domestic poultry and ornamental pet birds, stressing the great importance of stricter biosecurity measures and necessary vaccinations for future control of disease.