Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/29/2004
Publication Date: 10/14/2004
Citation: Hamir, A., Miller, J., Cutlip, R., Stack, M., Chaplin, M., Bartz, J., Jenny, A., Williams, E. 2004. Experimental inoculation of TME, scrapie, and CWD to raccoons: an update [abstract]. Animal Prion Diseases and the Americas. p. 79. 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 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 (PrPres) 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 PrPres. At present, 5 years PI, the 3 remaining CWD-inoculated raccoons are alive and apparently healthy. They will be kept under observation for further period of 1 year (i.e 6 years PI) when the experiment will be terminated. 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. Such a laboratory model would be relatively simple, fast and inexpensive for strain-typing of unknown TSEs in the United States. Now that the relative susceptibiity to IC transmission of each TSE has been established, oral transmission studies of TSEs to raccoons are planned.