Chronic wasting disease: What is a prion?

Chronic wasting disease is a neurological disease that affects cervids such deer, elk and moose and is caused by a prion.

Deer with chronic wasting disease
Photo by Wisconsin Department of Natural Resources

Think back to your high school biology class. I can vividly picture my teacher saying, “Proteins are the building blocks of the body.” Proteins are critical components in every cell in a living creature. The term protein refers to a molecule encoded by genes and built of amino acids that then folds into a particular shape. Proteins truly are the building blocks in that they help build and repair tissues; make up enzymes and hormones; fight infections; transport and store nutrients; provide energy and the structural framework of bone, muscles, cartilage and skin. To say that proteins are important to bodies would be an understatement!

A prion is a type of protein that can trigger normal proteins to fold abnormally. Prions are found mostly in the brain. Several transmissible prion diseases exist in mammalian species: scrapie in sheep; bovine spongiform encephalopathy or mad cow disease; chronic wasting disease in deer; and Creutzfeldt-Jakob disease in humans. The prion is an infectious agent that is responsible for these neurodegenerative diseases that are found in mammals.


Unlike viruses, bacteria or fungus, there is no antidote or cure for a prion disease; prions are resistant to denaturation by chemical agents, such as disinfectants, or physical agents, such as incineration. Prions can be spread just like other infectious agents through direct contact and indirect contact such as saliva, feces, urine and other bodily fluids.

Continuing research is being conducted at several universities across the United States, including Michigan State University, to learn more about prions, how chronic wasting disease is spread, and how to reduce chronic wasting disease spread in the environment.

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