Beware of catching mad fish disease, say scientists

Louisville, (KY) – A University of Louisville neurologist has warned of the potential risks of eating farmed fish.

Writing in the Journal of Alzheimer’s Disease, Robert P. Friedland suggests that farmed fish could transmit Creutzfeldt Jakob disease – the human form of mad cow disease – if they are fed with pellets rendered from cows. He is urging government regulators to ban feeding cow meat or bone meal to fish until the safety of this widespread practice can be confirmed.

“We have not proven that it’s possible for fish to transmit the disease to humans,” says Friedland. “Still, we believe that out of reasonable caution for public health, the practice of feeding rendered cows to fish should be prohibited. Fish do very well in the seas without eating cows.”

Although the risk of transmission of bovine spongiform encephalopathy (BSE) to humans who eat farmed fish would appear to be low because of perceived barriers between species. But, according to the research, it is possible for a disease to be spread by eating a carrier that is not itself infected.

It is also possible that eating diseased cow parts could cause fish to experience a pathological change that allows the infection to be passed between the two species.

Creutzfeldt Jakob disease is an untreatable, universally-fatal disease that can be contracted by eating parts of an animal infected with BSE. An outbreak in England attributed to infected beef prompted most countries to outlaw feeding rendered cow material to other cattle because the disease is so easily spread within the same species. 

“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,” adds Friedland. “The incubation period of these diseases may last for decades, which makes the association between feeding practices and infection difficult. Enhanced safeguards need to be put in place to protect the public.”

There have been 163 deaths from Creutzfeldt Jakob disease in the United Kingdom attributed to eating infected beef. Bovine spongiform encephalopathy has so far been identified in nine Canadian and three US cattle.