Chronic wasting disease (CWD) is a prion disease affecting deer, elk, and moose across North America. It causes progressive neurological deterioration and a prolonged, distressing death in affected animals.
CWD inflicts one of the most prolonged and distressing deaths documented in wildlife. The months-long course of neurological deterioration involves progressive loss of normal behavior, inability to eat effectively, and increasing vulnerability to predation and secondary infections. Animals in late-stage CWD are suffering significantly and visibly — the "zombie deer" description used in media captures the profound behavioral abnormality. The inability to treat or cure CWD, combined with environmental persistence of prions, means that once established in a population the disease becomes an ongoing welfare burden. Population management through hunting to reduce deer density can slow spread and thereby reduce the number of animals experiencing this prolonged death.