Transmission of raccoon passaged chronic wasting disease agent to white-tailed deer

Authors: Cassmann, Eric; FRESE, ALEXIS - Oak Ridge Institute For Science And Education (ORISE); MOORE, S - Oak Ridge Institute For Science And Education (ORISE); Greenlee, Justin

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2022
Publication Date: 7/20/2022
Citation: Cassmann, E.D., Frese, A.J., Moore, S.J., Greenlee, J.J. 2022. Transmission of raccoon passaged chronic wasting disease agent to white-tailed deer. Viruses. 14(7). Article 1578. https://doi.org/10.3390/v14071578.
DOI: https://doi.org/10.3390/v14071578

Interpretive Summary: Prion diseases are invariably fatal neurologic diseases for which there is no known prevention or cure. Chronic wasting disease (CWD) is the prion disease of deer and elk and is present in farmed and free ranging herds throughout North America. We are currently unsure of the potential host range of CWD and what role other animals in the environment may have in spreading or maintaining CWD. This manuscript demonstrates that CWD prions that have been passaged through raccoons are able to reinfect deer by the oronasal route. Moreover, the molecular profile of the CWD agent is altered by passage through raccoons and these molecular features are maintained when returned to the deer host. The unique molecular features of this isolate suggest that additional studies will be needed to determine if these changes are associated with a broadened host range of this CWD prion. This information will be of interest to wildlife biologists, the farmed cervid industry, and regulatory officials involved in making policy for farmed cervids and wildlife.

Technical Abstract: The transmission characteristics of prion diseases are influenced by host prion protein sequence and therefore the host species. Chronic wasting disease (CWD), a TSE of cervids, has widespread geographical distribution throughout North America and occurs in both wild and farmed populations. CWD prions contaminate the environment through scattered excrement and decomposing carcasses. Fresh carcasses with CWD prions are accessible by free ranging mesopredators like raccoons and may provide a route of exposure. Previous studies demonstrated the susceptibility of raccoons to CWD from white-tailed deer. In this study, we demonstrate that white-tailed deer replicate raccoon passaged CWD prions that results in clinical disease similar to intraspecies CWD transmission. Six white-tailed deer were oronasally inoculated with brain homogenate from a raccoon with CWD. All six deer developed clinical disease, had widespread lymphoid distribution of misfolded CWD prions (PrPSc), and had neuropathologic lesions with PrPSc accumulation in the brain. The presence of PrPSc was confirmed by immunohistochemistry, enzyme-linked immunoassay, and western blot. The glycoform migration of raccoon passaged CWD was different from white-tailed deer CWD. The new molecular phenotype was maintained after transmission of raccoon CWD back to white-tailed deer.