Wildlife Habitat_Content Page_Disease Chronic wasting disease

Chronic wasting disease

Chronic wasting disease (CWD) is a fatal nervous system disease affecting deer, elk, moose and caribou/reindeer. CWD belongs to a group of diseases known as transmissible spongiform encephalopathies (TSEs) thought to be caused by prions. The prions cause abnormal folding of specific normal proteins in the tissue cells which causes a characteristic spongy degeneration of the brains of infected animals.

TRANSMISSION

CWD transmission occurs when disease prions are shed by infected animals through saliva, urine, feces and natural decomposition after death. Because CWD prions bind to the substrate and are extremely resistant to the environment, the transmission may be both direct and indirect. This means that not only is CWD spread through contact between deer and their saliva, urine and feces, but also through contact between deer and contaminated environments. For more information, please see the department’s Recommendations For Reducing the Spread of CWD. [PDF]

CLINICAL SIGNS

Clinical signs of CWD include no fear of humans, teeth grinding, notable weakness, drooping of head and ears, excessive thirst, difficulty swallowing, rough dull coat, walking in set patterns, nervousness, loss of coordination, excessive salivation, diminished tone of facial muscles, excessive urination, severe emaciation and dehydration and inability to stand.

DISEASE MANAGEMENT

The Wisconsin Department of Natural Resources began monitoring the state's wild white-tailed deer for chronic wasting disease (CWD) in 1999. The first positives were found in 2002 through testing of hunter-harvested deer in November 2001. For information on the management of CWD in Wisconsin, please visit Wisconsin's Chronic Wasting Disease Response Plan.

PUBLIC HEALTH

The U.S. Centers for Disease Control and Prevention states that to date, there have been no reported cases of CWD infection in people. Nonetheless, as a precaution, the Wisconsin Department of Health Services (DHS) recommends that people only consume venison from healthy-appearing deer with test results indicating that CWD was not detected. This is consistent with recommendations from the Centers for Disease Control (CDC) [exit DNR] and World Health Organization (WHO) [exit DNR]. Information from the Wisconsin Division of Public Health is available through Venison and CWD: What Hunters Should Know. [PDF]

ADDITIONAL INFORMATION