Chronic Wasting Disease (CWD) is a contagious neurological disease affecting deer and elk. It causes a characteristic spongy degeneration of the brains of infected animals resulting in emaciation, abnormal behavior, loss of bodily functions and death. The infectious agents are consider to be neither bacteria or virus but rather are thought to be prions. Prions are considered to be infectious proteins with out associated nucleic acids. 

Distribution 

The disease was long thought to be limited in the wild to a relatively small endemic area in northeastern Colorado, southeastern Wyoming and southwestern Nebraska, but it has recently been found in new areas of these states, as well as in wild deer and elk in Illinois, Kansas, Maryland, Minnesota, New Mexico, New York, South Dakota, Utah, Virginia, West Virginia, Wisconsin and the Canadian provinces of Saskatchewan and Alberta.  

The disease also has been diagnosed in commercial game farms in Colorado, Nebraska, Minnesota, South Dakota, Montana, Oklahoma, Kansas, Wisconsin, New York,  Missouri, Saskatchewan and Alberta. The disease was confirmed on 8/25/2008 in a captive white-tailed deer in Kent County at facility in Michigan. It has not been found in any free-ranging deer in the state.