Border Deer Study

About CWD

Chronic wasting disease (CWD) is only known to affect members of the deer family, including mule deer, white-tailed deer, wapiti (elk), and moose. The origins of the disease are currently unknown. Although identified in the 1970ís, CWD probably occurred in a localized area of Colorado/ Wyoming/ Nebraska for quite some time. It may be the result of local mutation of a similar agent that causes scrapie in domestic sheep. There is also the possibility that CWD has always been present in wild deer populations at very low levels, but the majority of biologists working on the disease do not support this idea.

CWD is a prion disease associated with protein changes in the brain. Damage to the brain results in changes to behaviour, attitude, and metabolism. Some of these changes include excessive salivation, lethargy, incoordination, and drooping head and ears. Individuals cannot maintain weight and slowly waste away. There is no known cure or treatment for CWD, and all infected individuals eventually die.

 In the short term, mortality due to CWD does not seem to affect overall productivity in infected populations. However, theoretical models suggest that mule deer populations in Colorado, at the heart of the affected area, will decline in 40-100 years and eventually die out. Thus the disease has the potential for large ecological and economic impacts.

The exact mode of transmission is still unknown, but the disease can be transmitted between individuals both directly via contact with an infected individual and indirectly via exposure to soils contaminated with the infectious prions. Infectious material survives in the environment for an unknown period. Management therefore focuses on the rapid elimination of new outbreaks and the prevention of spread from existing disease areas.

For more information on chronic wasting disease, please visit one of the following websites:



Alberta Sustainable Resource Development


Alberta Agriculture$department/deptdocs.nsf/all/agdex3594?opendocument


Saskatchewan Environment (search for CWD)





Canada Cooperative Wildlife Health Centre


Canadian Food Inspection Agency



CWD Alliance




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