Submitted to: Diseases at the Interface between Domestic Livestock and Wildlife Species
Publication Type: Abstract Only
Publication Acceptance Date: 7/17/2003
Publication Date: 7/17/2003
Citation: HAMIR, A.N., MILLER, J.M., CUTLIP, R.C., RICHT, J., KUNKLE, R.A., OROURKE, K.I., JENNY, A.L., STACK, M.J., CHAPLIN, M.J. TRANSMISSION OF SHEEP SCRAPIE TO ELK (CERVUS ELAPHUS NELSONI) BY INTRACEREBRAL INOCULATION. DISEASES AT THE INTERFACE BETWEEN DOMESTIC LIVESTOCK AND WILDLIFE SPECIES. 2003. ABSTRACT NO. 6. Interpretive Summary:
Technical Abstract: To determine the transmissibility of scrapie to Rocky Mountain elk (Cervus elaphus nelsoni), 6 elk calves were inoculated intracerebrally with brain suspension from sheep naturally affected with scrapie. Two others were kept as uninoculated controls. A preliminary report of this study was published previously. During the first 2 years post inoculation (PI), 3 animals died or were euthanized because of injuries or infection other than spongiform encephalopathy (SE). In years 3 and 4 PI, 3 other elk died after brief terminal neurological episodes. Necropsy of these animals revealed moderate weight loss but no other gross lesions. Microscopically, characteristic lesions of SE were seen throughout the brains and spinal cords and these tissues were positive for PrPres by immunohistochemistry (IHC) and Western blot. Also, scrapie-associated fibrils (SAF) were observed by negative stain electron microscopy in the brains of elk with neurologic signs. PrPres and SAF were not detected in inoculated elk necropsied during the first 2 years or in the 2 control animals. Retrospective sequencing of gene encoding PrP in affected elk revealed MM or LM at codon 132. These findings confirm that intracerebral inoculation of sheep scrapie agent results in SE with accumulations of PrPres in the CNS of elk and that this condition cannot be distinguished from chronic wasting disease (CWD) of elk with currently available diagnostic techniques.