Comparative pathogenicity of six avian adenovirus isolants in the liver

The comparative pathogenicity of six avian adenovirus isolants for chickens was determined. The most virulent isolant was DPI-1, causing focal to massive hepatic necrosis with hemorrhage, while Tipton (Conn), Tipton (Purdue), GAL-1, and DPI-2 isolants were considered less pathogenic and produced only mild focal hepatic necrosis. The Indiana-C isolant was the least pathogenic and failed to produce any significant hepatic lesions. Intranuclear inclusions were observed in hepatocytes of all but the Indiana-C inoculated chickens on the third day postinoculation (PI), disappearing by the seventh day PI.