Risk of mad cow disease from farmed fish?

Since I do not eat fish or cows I'm not too worried for myself about getting mad cow disease. 

Three U.S. scientists are concern about the potential of people contracting Creutzfeldt Jakob disease -- the human form of "mad cow disease" -- from eating farmed fish who are fed byproducts rendered from cows.

Mad cow disease, also called bovine spongiform encephalopathy is a fatal brain disease in cattle, which scientists believe can cause Creutzfeldt Jakob disease in humans who eat infected cow parts.

In the latest issue of the Journal of Alzheimer's Disease, Dr. Robert P. Friedland, a neurologist at University of Louisville in Kentucky and colleagues suggest that farmed fish fed contaminated cow parts could transmit Creutzfeldt Jakob disease.

More at link.