Location: Virus and Prion ResearchTitle: Experimental oronasal transmission of chronic wasting disease agent from white-tailed deer to Suffolk sheep
Submitted to: Emerging Infectious Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2021
Publication Date: 12/20/2021
Citation: Cassmann, E.D., Moore, S., Greenlee, J.J. 2021. Experimental oronasal transmission of chronic wasting disease agent from white-tailed deer to Suffolk sheep. Emerging Infectious Diseases. 27(12). https://doi.org/10.3201/eid2712.204978.
Interpretive Summary: Transmissible spongiform encephalopathies (TSEs) are a group of fatal diseases caused by the accumulation of misfolded prion protein in the brain. Several livestock species including sheep, deer, and elk are afflicted by prion diseases. In sheep the disease is called scrapie. In deer and elk, the disease is called chronic wasting disease (CWD). The source of CWD is unknown, but it is speculated that the origin of CWD may have been due to a species jump of scrapie in sheep to deer. Due to the human consumption of cervid meat products and intermingling of various livestock species with wild cervid populations, there is significant interest in characterizing the possible host range of CWD. This study reports preliminary results of an ongoing multi-year experiment on the oronasal transmission of CWD from white-tailed deer to sheep. After a five-year period, 1/7 sheep had detectable CWD prions in the retropharyngeal lymph nodes and tonsil. Infectivity of these prions was confirmed using a bioassay with transgenic mice expressing cervid prion protein. These results demonstrate the susceptibility of sheep to the agent of CWD after a prolonged incubation period. Since the original experiment ended after five years, it is unknown if the sheep would have remained asymptomatic or developed clinical prion disease given a longer incubation period. It is also unknown if sheep are capable of shedding or transmitting CWD prions. Additional work is necessary to further characterize the transmission properties of the CWD agent in sheep and other species.
Technical Abstract: CWD is a fatal prion disease of cervids. This study examined the host range of CWD by orally inoculating Suffolk sheep with brain homogenate from a CWD positive white-tailed deer. Sixty-months after oronasal inoculation, 1/7 sheep had immunoreactivity against PrPSc in the lymphoid tissue that was confirmed by mouse bioassay.