What is CWD?
Chronic wasting disease (CWD) is a fatal neurological disease of deer, elk, and moose that has been classified in the group of diseases called transmissible spongiform encephalopathies (TSEs). The disease is infectious, communicable, and always fatal. Other TSEs include Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease in cattle, scrapie in sheep and goats, and Creutzfeldt-Jakob Disease (CJD) in humans. TSEs are believed to be the result of the transformation of normal prions (proteinaceous infectious particles) into infectious, self-propagating, abnormal prions. Their shape is transformed in such a way that they cause disease. These abnormal prions are found throughout the deer’s body, but concentrate in the brain, other tissues of the nervous system, and some lymph tissues. They eventually cause degeneration of brain cells, creating microscopic holes in the brain.
What animals are affected?
CWD affects several species in the deer family (cervids). White-tailed deer, mule deer, elk, red deer, moose, sika deer, and reindeer have all been found to be susceptible to the disease. Although a variety of species can be experimentally infected with CWD, there is currently no evidence that the disease can be spread naturally from cervids to livestock.
Where does CWD occur?
CWD was first recognized as a disease syndrome in 1967 in captive mule deer at a wildlife research facility in Fort Collins, Colorado, and was recognized as a TSE in 1978. CWD was diagnosed in free-ranging deer and elk in the 1980s. To date, CWD has been diagnosed in free-ranging or captive cervids in 26 states and three Canadian provinces including: Alberta, Arkansas, Colorado, Illinois, Iowa, Kansas, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Mexico, New York, North Dakota, Ohio, Oklahoma, Pennsylvania, Quebec, Saskatchewan, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, and Wyoming. CWD also has been detected in South Korea (elk) and Norway (reindeer and moose).