EXPERIMENTAL ADENOVIRUS HEMORRHAGIC-DISEASE IN YEARLING BLACK-TAILED DEER

An apparently novel adenovirus was associated with an epizootic of hem orrhagic disease that is believed to have killed thousands of mule dee r (Odocoileus hemionus) in California (USA) during 1993-1994. A system ic vasculitis with pulmonary edema and hemorrhagic enteropathy or a lo calized vasculitis associated with necrotizing stomatitis/pharyngitis/ glossitis or osteomyelitis of the jaw were common necropsy findings in animals that died during this epizootic. Six black-tailed yearling de er (O. hemionus columbianus) were inoculated with purified adenovirus isolated from a black-tailed fawn that died of acute adenovirus hemorr hagic disease during the epizootic. Three of six inoculated deer also received intramuscular injections of dexamethasone sodium phosphate ev ery 3 days during the study Eight days post-inoculation, one deer (wit hout dexamethasone) developed bloody diarrhea and died. Necropsy and h istopathologic findings were identical to lesions in free-ranging anim als that died of the natural disease. Hemorrhagic enteropathy and pulm onary edema were the significant necropsy findings and there was micro scopic vascular damage and endothelial intranuclear inclusion bodies i n the vessels of the intestines and lungs. Adenovirus was identified i n necrotic endothelial cells in the lungs by fluorescent antibody stai ning, immunohistochemistry and by transmission electron microscopy. Ad enovirus was reisolated from tissues of the animal that died of experi mental adenovirus hemorrhagic disease. Similar gross and microscopic l esions were absent in four of six adenovirus-inoculated deer and in th e negative control animal which were necropsied at variable intervals during the 14 wk study. One deer was inoculated with purified adenovir us a second time, 12 wk after the first inoculation. Fifteen days afte r the second inoculation, this deer developed severe ulceration of the tongue, pharynx and rumen and necrotizing osteomyelitis of the mandib le which was associated with vasculitis and thrombosis of adjacent lar ge vessels and endothelial intranuclear inclusions. Transmission elect ron microscopy demonstrated adenovirus within the nuclei of vascular c ells and immunohistochemistry demonstrated adenovirus antigen within t onsilar epithelium and in rare vessels.