Chronic Wasting Disease Causes and Effects

Original photo by Ennette Martin


  • Caused by a mis-folded protein known as a prion, not a bacterium or virus.
  • Similar to diseases found in other animals — scrapie in sheep, mad cow disease in cattle, and Creutzfeldt-Jakob disease in humans.
  • There is no practical live test for CWD. Almost all testing for this disease has to be conducted on dead animals.
  • Causative agent, the prion, is both transmissible and infectious.v
  • Transmission of CWD prions can be direct or indirect via body secretions and excretions—saliva, urine, and feces—and via the environment contaminated with prions shed in the above materials or present in decomposing carcasses.
  • CWD prions are extremely resistant to deactivation, and therefore remain infectious in the environment indefinitely.


  • 100% fatal — no cure
  • Occurs in cervidae (deer family)
  • Shown to affect cervids from age of 17 months to more than 15 years
  • Infects male and female cervidae
  • No strict seasonality
  • The minimal incubation period is approximately 17 months with no known maximum
  • Produces behavioral changes and wasting in symptomatic animals
  • Can reach remarkably high prevalence rates
  • Appears to infect male cervids at a higher prevalence