Chronic Wasting Disease (CWD) is a prion disease, similar to bovine spongiform encephalopathy (mad cow disease), that affects cervids such as deer, elk, moose, caribou, and reindeer. CWD has been detected in cervids living in Canada, the United States, Norway, Finland, Sweden, and South Korea. CWD has also been detected in farmed deer and elk. As of June 2022, there were 391 counties in 29 states of the United States with reported CWD in free-ranging cervids. Most recently, CWD has been detected at deer breeding farms in five counties in central and south Texas.
Scientists believe CWD proteins (prions) likely spread between animals through body fluids like feces, saliva, blood, or urine, either through direct contact or indirectly through environmental contamination of soil, food or water. Once introduced into an area or farm, CWD prions are highly contagious and can spread quickly. Experts believe CWD prions can remain in the environment for a long time,
More than a year might pass before an infected animal develops symptoms which include drastic weight loss (wasting), stumbling, listlessness and other neurologic symptoms. CWD is fatal and there are no treatments or vaccines.
So far, CWD has not been detected in humans, but health officials recommend against eating meat from infected animals.
References
Osterholm MT, Anderson CJ, Zabel MD, et al. Chronic Wasting Disease in Cervids: Implications for Prion Transmission to Humans and Other Animal Speciesexternal icon . MBio.2019 Jul 23;10(4). pii: e01091-19. doi: 10.1128/mBio.01091-19.
Centers for Disease Control and Prevention, Chronic Wasting Disease, https://www.cdc.gov/prions/cwd/index.html