First isolation report of bovine adenovirus type 10 in Japan: virological and pathological characteristics.

Bovine adenovirus type 10 (BAdV-10) was isolated for the first time in Japan from a calf with severe hemorrhagic diarrhea at a farm in Gifu Prefecture. Histopathologically, lesions were mainly in the colon, with pseudomembrane formation accompanied by extensive fibrosis and viral inclusion bodies in the nuclei of vascular endothelial cells. The isolated virus showed cytopathic effect in bovine testicular cells and was genetically confirmed to be BAdV-10. Although the BAdV-10 gene was not detected in the rectal stools of cohabiting calves, an increase in antibody titers was observed. Involvement of BAdV-10 in lesion formation was suspected, but extensive fibrosis was not reported overseas. Further investigation is needed to clarify the prevalence and epidemiological significance of BAdV-10 in Japan.