Prions cause Creutzfeldt-Jakob disease (or “mad cow disease” in cattle) by rearranging the structure of normal proteins in their own image.

Prions cause a number of fatal diseases such as mad cow disease in cattle, scrapie in sheep and kuru and Creutzfeldt-Jakob disease (CJD) in humans.

The fact that no cases of Creutzfeldt Jakob disease have been linked to eating farmed fish does not assure that feeding rendered cow parts to fish is safe.