Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/1998
Publication Date: N/A
Interpretive Summary: Adenovirus infection was the cause of an epizootic of hemorrhagic disease that is believed to have killed thousands of mule deer in California during the latter half of 1993. In order to study transmission of adenovirus infection in deer and susceptibility of black-tailed fawns to adenovirus infection, six 3- to 6-month old black-tailed fawns were either inoculated with the adenovirus or placed in contact with inoculated fawns. Between 4 and 16 days post-inoculation, 8 of 10 black-tailed deer fawns developed infection with lesions identical to lesions seen in animals with natural disease that died during the epizootic. Adenovirus was reisolated from tissues of experimentally infected deer, thus fulfilling Koch's postulates. Therefore, to make accurate diagnoses of future outbreaks of hemorrhagic disease in black-tailed deer diagnosticians need to differentiate between hemorrhagic disease caused by orbiviruses and the newly described disease caused by adenovirus. Serum virus neutralization test results suggest this deer adenovirus is a new serotype adenovirus.
Technical Abstract: Adenovirus infection was the cause of an epizootic of hemorrhagic disease that is believed to have killed thousands of mule deer in California during the latter half of 1993. A systemic vasculitis with pulmonary edema and hemorrhagic enteropathy, or a localized vasculitis were common necropsy findings in animals that died during this epizootic. In order to study infection and transmission of the adenovirus in black-tailed fawns, two groups were inoculated with virus. One group was inoculated intravenously and the other through the mucous membranes of the eyes, nose and mouth to study infection. Two additional fawns were added to each treatment group to study transmission. One fawn served as a negative control. Between 4 and 16 days post-inoculation, 8 of 10 fawns developed systemic or localized infection with lesions identical to lesions seen in deer with natural disease. The route of inoculation did not affect the incubation period and there was transmission by direct contact. There was immunohistochemical labeling for adenovirus antigen in endothelial cells of vessels subtending necrotic foci in the upper alimentary tract in fawns with the localized form of the disease. All inoculated or exposed fawns had labeling in the tonsillar epithelium. Transmission electron microscopic examination of the lungs and the ileums from 2 fawns with pulmonary edema and hemorrhagic enteropathy had endothelial necrosis and adenovirus virions in endothelial cell nuclei. Adenovirus was reisolated in back-tailed deer pulmonary artery endothelial cells using lung homogenate of the first fawn that developed systemic adenovirus infection. Serum virus neutralization test results suggest this deer adenovirus is a new serotype adenovirus.