SUMMARY
Originally discovered and characterized in 1998, the pigeon adenovirus 1 (PiAdV-1) has received little attention because of its low contagiousness and lethality or misperception by scientists. Consequently, the virus's pathogenic properties are still unknown. Here, we describe an outbreak of PiAdV-1 in a flock of farmed pigeons. Twenty-five percent of adults and 40% of young pigeons died suddenly without presentations in the outbreak. The dead pigeons’ gross pathology and histological examination revealed severe liver and kidney inflammatory damage, presenting as extensive liver necrosis and swollen and congested kidneys. The courses of PiAdV-1 infection matched those classified as pigeon adenovirosis type 2, according to clinical presentations. Furthermore, we attempted to isolate the virus strain using different cell lines. The PiAdV-1 strain could proliferate in chicken embryo fibroblast, chicken liver hepatocellular carcinoma, and pigeon embryo primary fibroblast cell lines; it specifically infected liver and kidneys as its target organs, and could proliferate effectively in pigeon embryo kidney and liver cells. This offers us a fresh viewpoint to reconsider and comprehend the pathophysiology of PiAdV-1, as well as a novel concept for large-scale PiAdV-1 proliferation.