Chronic Wasting Disease and Animal Agriculture

Abstract

Chronic wasting disease (CWD), a member of the transmissible spongiform encephalopathies (TSEs), is only known to naturally affect mule deer (Odocoileus hemionus), white-tailed deer (O. uirginianus), and Rocky Mountain elk (Ceruus elaphus nelsoni). It has been recognized in an endemic focus along the front range of the Rocky Mountains in northern Colorado and in the hills of southeastern Wyoming for more than 30 years. Since 1996, CWD has been identified in free-ranging and farmed cervids in 15 western and midwestern states and Canadian provinces and elk imported to Korea from Canada. Surveillance for a TSE in cattle sympatric with deer and elk with CWD began in the early 1990s and has been ongoing since then. Experiments to determine host range of CWD in livestock began in the 1980s. Since that time cattle, domestic sheep and domestic goats have been exposed to the CWD agent by various means. All of these species are susceptible to CWD by intracerebral inoculation but, to date, CWD has not been found to affect traditional domestic livestock species when exposed by natural routes. Chronic wasting disease is of concern in farmed elk and white-tailed deer. Control of this disease in the cervid industries is based in state, provincial, and federal regulations. Surveillance of domestic livestock for TSEs in parallel with surveillance for CWD in farmed and free-ranging cervids will need to be continued into the foreseeable future.