ARS | Publication request: 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

Submitted to: American Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: April 29, 2002
Publication Date: October 17, 2002

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 and 22 PI. Although the fourth raccoon in this group did not show any clinical signs, it was euthanized at 24 months PI. At present, 3 years PI, all CWD-infected raccoons are alive and apparently healthy. 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. 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.