Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/1996
Publication Date: N/A
Interpretive Summary: Chronic wasting disease (CWD) has been reported in captive mule deer in Colorado and Wyoming. This paper reports a similar disease in free ranging mule deer, elk and white-tailed deer in the Fort Collins, Colorado area. The clinical signs and histologic lesions resemble scrapie, a transmissible spongiform encephalopathy of sheep and goats. The causative agent of this group of diseases is unknown. This paper describes the histopathology associated with the disease and reports the presence of the disease- associated isoform of the prion protein in brain tissue from infected deer. The possible origin of the disease in free-ranging animals, a proposed route of infection, and management implications are discussed.
Technical Abstract: Between March 1981 and March 1995, 44 cases of a transmissible spongiform encephalopathy were diagnosed in 37 mule deer (Odocoileus hemionus), 6 Rocky Mountain elk (Cervus elaphus nelsoni) and a white-tailed deer (O. virginianus) from northcentral Colorado. Clinical signs included emaciation, excessive salivation, behavioral changes, ataxia and weakness. Severe emaciation with a total loss of subcutaneous and abdominal adipose tissue and serous atrophy of remaining fat depots were the only consistent gross finding. Spongiform encephalopathy characterized by microcavitation of grey and white matter, intraneruonal vacuolation and neuronal degeneration was found microscopically in all cases. Scrapie-associated prion protein (PrPSc) was found in brain of 12 animals with histologic lesions of spongiform encephalopathy, 6 using an immunohistochemical staining procedure and in another 6 by Western blot. Prevalence estimates, ,host range (including domestic animals), distribution, origins, and management implications of this transmissible spongiform encephalopathy in free-ranging wild deer and elk remain undetermined.