Submitted to: American College of Veterinary Pathologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 12, 2009
Publication Date: December 5, 2009
Citation: Greenlee, J.J., Nicholson, E.M., Kunkle, R.A., Hamir, A.N. Susceptibility of Cattle to First-Passage Intracerebral Inoculation with Chronic Wasting Disease Agent from Elk [abstract]. American College of Veterinary Pathologists Annual Meeting. Veterinary Pathology. 46(5):1058. Technical Abstract: Cattle could be exposed to chronic wasting disease (CWD) from infected farmed or free-ranging cervids. The purpose of this study was to assess the transmissibility of CWD derived from elk to cattle. Intracerebral inoculation of calves (n=14) of approximately 3 months of age was done with 1 ml of a 10% brain homogenate derived from farmed elk with CWD to determine the potential for transmission and define the clinicopathologic features of disease. Non-inoculated calves (n=5) were maintained as controls. Cattle were observed twice daily and necropsies were performed as clinical signs occurred or at the termination of experiment (49 months). Clinical signs of poor appetite, weight loss, circling and bruxism occurred in two cattle (14%) at 16 and 17 months post-inoculation, respectively. The rate of transmission was lower than in cattle inoculated with CWD derived from mule deer (38%) or White-tailed deer (86%). Accumulation of abnormal prion protein (PrPd) in these cattle was confined to the central nervous system and was similar in distribution to cattle inoculated with CWD from mule deer with the most prominent immunoreactivity in midbrain, brainstem, and hippocampus with lesser immunoreactivity in the cervical spinal cord. Additional studies are required to fully assess the potential for cattle to develop CWD through a more natural route of exposure, but a low rate of transmission after intracerebral inoculation suggests that risk of transmission through other routes is low.