Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/1999
Publication Date: N/A
Interpretive Summary: Chronic wasting disease is a transmissible spongiform encephalopathy or prion disease of deer and elk. CWD is a member of the family of diseases that includes sheep scrapie and bovine spongiform encephalopathy (BSE). The natural route of transmission of these diseases in ruminant animals is unknown but oral exposure to contaminated feeds, bedding, or tissues is presumed to be a major source of infection. In this study, mule deer fawns were orally fed an infectious homogenate and sacrificed at intervals to examine the lymphoid tissue of the alimentary tract for signs of infection. Prion protein was detected as early as 42 days and was evident in all fawns after 53 days. This paper provides an improved procedure for detecting prions in early infection, establishes a protocol for accelerated study of transmission routes, and supports the hypothesis that oral exposure may reflect the initial pathway of CWD infection in deer.
Technical Abstract: Mule deer fawns were inoculated orally with a brain homogenate prepared from mule deer with naturally occurring chronic wasting disease (CWD), a prion induced transmissible spongiform encephalopathy. Fawns were necropsies and examined for PrP-res, a protein marker for infection, at 10, 42, 53, 77, 78 and 80 days post inoculation using an immunohistochemistry assay modified to enhance sensitivity. PrP-res was detected in alimentary-tract- associated lymphoid tissues as early as 42 days post inoculation and in all fawns after 53 days. These results indicated that CWD PrP-res can be detected at least 16 months before clinical signs would be expected to appear and may reflect the initial pathway of CWD infection in deer.