Final answer:
The cause of Chronic Wasting Disease is b) abnormally misfolded protein or prion. Prions are misfolded proteins that propagate by inducing normal proteins to also misfold, leading to diseases known as transmissible spongiform encephalopathies.
Step-by-step explanation:
Chronic Wasting Disease is an infectious disease affecting deer and elk. The etiology of Chronic Wasting Disease is an abnormally misfolded protein known as a prion, making option b) the correct answer. Prions are unique infectious agents, distinct from bacteria, viruses, and other pathogens, in that they are simply proteins with an incorrect three-dimensional structure. This misfolded version of the protein can convert normal proteins into the misfolded state, leading to a chain reaction that damages brain tissue. The characteristic spongy degeneration of the brain tissue caused by the accumulation of these prions is a hallmark of transmissible spongiform encephalopathies (TSEs), a group of diseases that also includes scrapie in sheep and bovine spongiform encephalopathy (BSE) in cows, which can be transmitted to humans as Creutzfeldt-Jakob disease.