Raccoons accumulate PrPSc after intracranial inoculationof the agents of chronic wasting disease or transmissible mink encephalopathybut not atypical scrapie

摘要

Prion diseases are neurodegenerative diseases characterized by the accumulationof misfolded prion protein (PrP ) in the brain and other tissues.Animal prion diseases include scrapie in sheep, chronic wasting disease (CWD) incervids, and transmissible mink encephalopathy (TME) in ranch-raised mink. Weinvestigated the susceptibility of raccoons to various prion disease agents andcompared the clinicopathologic features of the resulting disease. Raccoon kitswere inoculated intracranially with the agents of raccoon-passaged TME(TME ), bovine-passaged TME (TME ),hamster-adapted drowsy (TME ) or hyper TME (TME ), CWDfrom white-tailed deer (CWD ) or elk (CWD ), oratypical (Nor98) scrapie. Raccoons were euthanized when they developed clinicalsigns of prion disease or at study endpoint (<82 mo post-inoculation). Brainwas examined for the presence of spongiform change, and disease-associatedPrP was detected using an enzyme immunoassay, western blot, andimmunohistochemistry. All raccoons inoculated with the agents ofTME and TME developed clinical disease at~6.6 mo post-inoculation, with widespread PrP accumulation incentral nervous system tissues. PrP was detected in the brain of 1of 4 raccoons in each of the CWD -, CWD -, andTME -inoculated groups. None of the raccoons inoculated withTME or atypical scrapie agents developed clinical disease ordetectable PrP accumulation. Our results indicate that raccoons arehighly susceptible to infection with raccoon- and bovine-passaged TME agents,whereas CWD isolates from white-tailed deer or elk and hamster-adaptedTME transmit poorly. Raccoons appear to be resistant toinfection with hamster-adapted TME and atypical scrapie agents.