Submitted to: American Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: 6/3/2005
Publication Date: 11/2/2005
Citation: Hamir, A.N., Cutlip, R.C., Miller, J.M., Kunkle, R.A., Greenlee, J.J., Richt, J.A. 2005. Experimental transmission of transmissible spongiform encephalopathies (TSE) at the National Animal Disease Center, Ames, Iowa: an update [abstract]. American Association of Veterinary Laboratory Diagnosticians. p. 169.
Technical Abstract: Experimental transmission of TSE agents provides valuable information for identification of potential host ranges, and generates much needed prion-infected tissues for research. Such investigations have been conducted at NADC since 1990 and up-to-now have been confined to scrapie, chronic wasting disease (CWD), and transmissible mink encephalopathy (TME). Most of these cross-species transmission studies require long incubation periods and need BL-2 conditions for conducting the experiments. Initially our studies were restricted to farm livestock (cattle and sheep). However, as a result of increased demand from our stakeholders, we now also conduct research on wildlife (herbivores and carnivores). Following are some of the significant findings of past experiments at NADC: -Intracerebral inoculation of sheep scrapie into cattle resulted in a neurologic disease in that was distinct from bovine spongiform encephalopathy (BSE). -Oral inoculation of cattle with scrapie infected brain did not result in clinical disease during eight years of observation. -Sheep scrapie was transmissible to elk by intracerebral route and the resulting pathology could not be distinguished from CWD in elk. -Intracerebral inoculation of CWD was transmissible to 38% of cattle and 12.5% sheep inoculated with CWD from mule deer. -TME agent was transmissible to cattle by the intracerebral route and the resulting pathology could not be distinguished from published lesions of BSE. -TME and scrapie agents were transmissible to raccoons via intracerebral route, whereas CWD from mule deer was not. -Genetically susceptible sheep inoculated with scrapie by intracerebral and oral routes developed clinical disease within 19 and 32 months, respectively. Resistant sheep have not developed scrapie 30 months post inoculation. -Immunohistochemistry method utilized at this laboratory did not reveal prion in muscle tissues of animals (cattle, sheep, elk, raccoons) infected with TME, scrapie or CWD.