EVALUATION OF THE PATHOGENIC POTENTIAL OF CERVID ADENOVIRUS IN CALVES

Authors: WOODS, LESLIE - UNIVERSITY OF CALIFORNIA; Lehmkuhl, Howard; PARKER, JACKIE - UNIVERSITY OF CALIFORNIA; MANZER, MIKE - UNIVERSITY OF CALIFORNIA

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2007
Publication Date: 1/21/2008
Citation: Woods, L.W., Lehmkuhl, H.D., Parker, J.C., Manzer, M. 2008. Evaluation of the Pathogenic Potential of Cervid Adenovirus in Calves. Journal of Veterinary Diagnostic Investigation. 20(1):33-37.

Interpretive Summary: Respiratory and enteric disease is an important cause of economic loss to the livestock industry. We report the experimental inoculation of a deer adenovirus into groups of colostrum-fed and colostrum-deprived calves. The deer adenovirus produces die-offs of free-ranging deer and if pathogenic for domestic species, such as cattle, could cause significant disease because of intermingling of wild deer with domestic cattle in natural pasture settings. We show that following experimental mucosal inoculation of the deer adenovirus neither colostrum-fed nor colostrum-deprived calves developed typical lesions of adenovirus infection or replicated or shed virus in vivo. Low antibody titers to deer adenovirus developed only in colostrum-deprived calves inoculated with deer adenovirus and did not develop in colostrum-fed calves. We concluded that deer adenovirus does not induce clinical disease in calves or grow in the respiratory tract or kidneys of calves.

Technical Abstract: Four 3-month-old Jersey calves and three 3-month-old Holstein calves were inoculated with deer adenovirus and monitored for clinical signs until necropsied between 10 and 42 days post-inoculation. The neonatal Jersey calves had received colostrum and the Holstein calves were colostrum-deprived. Pre-inoculation and post-inoculation serum samples were tested for antibody to the deer adenovirus, bovine adenovirus type 6, bovine adenovirus type 7 and goat adenovirus type 1. Virus isolation was performed on kidney, nasal secretion and/or lung homogenates in fetal white-tailed deer lung cells. Negatively stained preparations of feces from Jersey calves were examined weekly using an electron microscope and weekly blood samples were collected for CBCs. Full necropsies were performed on all calves. A complete selection of tissues was evaluated for microscopic changes, and immunohistochemistry was performed on all tissues using a polyclonal antibody to deer adenovirus. No clinical signs were observed in the calves during the study period. Following inoculation, colostrum-deprived calves developed low antibody titers to deer adenovirus while the Jersey calves that had received colostrum did not. Calves that had received colostrum had high antibody titers to bovine adenovirus type 7 and goat adenovirus type 1. No consistent gross or microscopic lesions were seen. Adenovirus was not observed in negatively stained preparations of feces. Immunohistochemistry results did not demonstrate virus in all tissues examined microscopically and virus was not isolated from lungs, nasal secretions and kidneys.