What is cwd

Overview

Chronic Wasting Disease (CWD) is a transmissible spongiform encephalopathy (TSE) affecting wild and captive cervid populations across North America. Like its counterparts in other species—mad cow disease in cattle and Creutzfeldt-Jakob disease in humans—CWD causes progressive neurological deterioration and is invariably fatal.

Disease Mechanism

CWD is caused by prions, which are misfolded proteins that accumulate in neural tissue. These abnormal proteins trigger a chain reaction causing normal prion proteins to misfold. The accumulation creates characteristic sponge-like holes in brain tissue, leading to progressive neurological dysfunction.

Symptoms and Progression

Infected animals exhibit behavioral changes including aggression, excessive drooling, loss of fear of humans, and weight loss. As the disease progresses, animals show ataxia (loss of coordination), tremors, and decreased sensory awareness. Most infected animals die within months of symptom onset.

Transmission and Spread

CWD spreads through saliva, urine, feces, and blood contact. Prions are extremely resistant to environmental degradation and can persist in soil for years. Infected animals shed prions throughout their entire lifespan, even before symptoms appear, making control challenging.

Geographic Distribution and Management

CWD has spread steadily across North America since its discovery in 1967. Wildlife agencies implement culling programs, movement restrictions, and monitoring to slow transmission. However, the disease continues to expand its geographic range despite control efforts.