Chronic wasting disease (CWD) is a contagious prion disease of free-ranging and captive deer, elk, and moose. The cellular prion protein (PrP C ) serves as the normal host-encoded cellular prion protein. It is when PrP C directly binds to the misfolded isoform PrP Sc that PrP C adopts the diseaseassociated conformation. Normal prion proteins can be found most abundantly in the brain and spinal cord.