Abstract
Background: In 2022, a new infectious disease characterized by severe acute hepatitis, sudden death, and high mortality among breeding pigeons, was reported in China. Results: In naturally infected pigeons, key necropsy findings comprised hepatic swelling with patchy hemorrhage and pericardial effusion. Histopathological examination further revealed degeneration, necrosis, and basophilic intranuclear inclusion bodies affecting hepatocytes, cardiomyocytes, and vascular endothelial cells. Transmission electron microscopy revealed a typical icosahedral virus structure and crystal-like arrangement of viral particles in the nucleus. Metagenomic next-generation sequencing (mNGS) of pericardial effusion samples revealed the presence of pigeon adenovirus. Sequencing analysis of the hexon and fiber-2 genes suggested that it constituted pigeon adenovirus 1 (PiAdV-1). The complete genome of CH/BJ/1/2022 was determined to be 48,071 nucleotides in length, with a 10-amino acid deletion in the fiber-2 gene at residues 627-636 and a 95-animo acid insertion in the 100 K gene at residue 75. The same disease was reproduced in pigeons by experimental infection. Conclusion: Collectively, our analyses confirmed that the etiological agent was PiAdV-1, an emerging pathogen that causes severe acute hepatitis and high mortality in pigeons. This virus merits close attention because it could be catastrophic for the pigeon industry.