Submitted to: American Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: 10/9/2003
Publication Date: 10/9/2003
Citation: Hamir, A.N., Miller, J.M., Cutlip, R.C., Stack, M.J., Chaplin, M.J., Bartz, J., Jenny, A.L., Williams, E.S. 2003. Experimental inoculation of TME, scrapie, and CWD to raccoons (procyon lotor) and the utilization of raccoons for strain-typing of unknown TSEs in the United States [Abstract]. 46th Annual Meeting of the American Association of Veterinary Laboratory Diagnosticians. p. 211. Interpretive Summary:
Technical Abstract: Raccoons (Procyon lotor) are omnivorous and their diet may include carrion. It is therefore possible that in the wild they may get exposed to carcasses of animals with transmissible spongiform encephalopathies (TSEs). To determine the susceptibility of raccoons to transmissible mink encephalopathy (TME), scrapie, and chronic wasting disease (CWD), each of these agents was inoculated intracerebrally into a group of 4 kits. Three uninoculated kits served as controls. All raccoons in the TME-inoculated group developed neurologic signs and were euthanized within 6 months post inoculation (PI). In the scrapie-inoculated group, 3 animals became sick and were euthanized between 18 - 22 months PI. Although the fourth raccoon in this group did not show any clinical signs, it was euthanized at 24 months PI. At necropsy all clinically affected raccoons had extensive microscopic lesions of spongiform encephalopathy and protease-resistant prion protein (PrP**res) was detected in the CNS by immunohistochemistry and Western blot. In the CWD-inoculated group, 1 raccoon was euthanized at 39 months PI because of severe cystitis. Its brain was negative for PrP**res. At present, 4 years PI, the 3 remaining CWD-inoculated raccoons are alive and apparently healthy. These preliminary findings demonstrate that TME and scrapie can be transmitted to raccoons within 6 months and 2 years, respectively, whereas CWD cannot. Based on these incubation periods, it may be possible to differentiate these 3 TSEs should they occur in non-host species. Such a laboratory model would be relatively simple and inexpensive for characterization of unknown TSEs in the United States.