Farmed fish that eat rendered animals could pose risk of mad cow disease

June 23, 10:26 PMSacramento Nutrition ExaminerAnne Hart

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Farmed fish are being fed too high on the food chain. Instead of fish eating fish and seaweed, farmed fish commonly are being fed rendered cows and bone meal from animals that never lived in the oceans. See the article, "You Are What They Eat" on animal feed at the Consumer Reports.org site.

There are a lot more details to know regarding animal feed. Some cows may be born with a gene variation that gives them a higher risk of later developing mad cow disease or of being carriers, passing that gene to other animals, or the prions to humans, without being infected with outward symptoms.

The quick solution to this dilemma is for government regulators to ban the feeding of cow meat byproducts or bone meal to farmed fish (and to other animals) until the safety or danger of this common practice can be ascertained. The basic problem is that farmed fish are not being fed what they normally would eat.

When restaurants buy farmed fish, or when you buy farmed fish from supermarkets, are there prions in the farmed fish that could cause mad cow disease in humans? According to a Science News article, published June 17, 2009, "Farmed Fish May Pose Risk For Mad Cow Disease," University of Louisville neurologist Robert P. Friedland, M.D., questions the safety of eating farmed fish in Journal of Alzheimer’s Disease, adding a new worry to concerns about the nation’s food supply.

For those people anywhere in the world that have been diagnosed with fatal mad cow disease, did they get it from previous farmed fish meals or from beef? Are other prion-caused diseases of the brain, including Creutzfeldt Jakob disease caused by eating meat from infected animals?

Most consumers know it's not safe to eat fish that ate bonemeal. How long will it take to prove it? And is Alzheimer's also linked to what people eat? Who's studying prions in the brain related possibly to diet?

A press release on neurologist Robert P. Friedland's  research results, titled, "Farmed Fish May Pose Risk for Mad Cow Disease," appeared in the Journal of Alzheimer's Disease  on June 16, 2009. Based on his research, he and his team question the safety of eating farmed fish that are fed byproducts rendered from cows.

Recently, Dr. Friedland also has been working on the patterns of disease occurrence, including risk and protective factors, with studies of the Kikuku in Kenya, Jews and Arabs in Israel, and Caucasian and African-American subjects in Cleveland.  Friedland and his co-authors suggest farmed fish could transmit Creutzfeldt Jakob disease--commonly known as mad cow disease--if the farmed fish are fed byproducts rendered from cows. The scientists researching the question of whether there are prions in farmed fish urge government regulators to ban feeding cow meat or bone meal to fish until the safety of this common practice can be confirmed.

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

Creutzfeldt Jakob disease is an untreatable, universally-fatal disease that can be contracted by eating parts of an animal infected with bovine spongiform encephalopathy (BSE or mad cow disease). 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 risk of transmission of BSE to humans who eat farmed fish would appear to be low because of perceived barriers between species. But, according to the authors, it is possible for a disease to be spread by eating a carrier that is not infected itself. It’s 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.

“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. 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,” Friedland said.

There have been 163 deaths from Creutzfeldt Jakob disease in the United Kingdom attributed to eating infected beef. Bovine spongiform encephalopathy has been identified in nine Canadian and three U.S. cattle. There's a food safety problem with feeding animal by-products that contain mad cow disease prions in meat and bone meal. Yet rendered cow meat and bone meal is routinely fed to farmed fish. A few years ago people even fertilized vegetable gardens and fruit trees with bovine bone meal.

You'll still see calcium or mineral supplements containing bone meal from animals. How do you know the animals didn't carry a gene for mad cow disease or had been infected with it or some other disease fatal to humans? You've seen flu jump species from bird and pig to human, why not mad cow disease prions from cows to humans? Of course the mad cow prions jumped species from cow to human.

Can they jump from cow to fish to human? Prions for mad cow disease can't be killed by cooking. Research will eventually confirm or deny whether fish can pass along mad cow disease based on whether the fish ate rendered meat or bone meal from cows infected with mad cow disease. Meanwhile, the nation's food supply is at risk as evidence mounts.

How do farmed fish get the prions in their flesh that are then eaten by humans so that the fish and the human comes down with mad cow disease? It's a genetic mutation within a gene called the Prion Protein Gene that causes mad cow disease. 

Prion proteins are proteins expressed abundantly in the brain and immune cells of mammals. The questions researchers are trying to answer is whether prions are found in farmed fish after the fish consume meat or bone meal containing prions from cows that are carriers but not infected themselves.

Another issue being researched is whether the meals that the fish are fed contain prions that the fish pass on to human consumers. And is it possible or not that humans can get mad cow disease from consuming farmed fish? If mad cow disease actually is a genetic  mutation in the cow, can a cow that doesn't become infected with mad cow disease act as a carrrier, and still pass on the prions to humans to cause mad cow disease in people or other animals--from farmed fish to chickens?

It's not only the ongoing research on whether farmed fish are transmitting diseases to humans--diseases that range from mad cow disease to possibly Alzheimer's or other brain diseases theoretically caused by prions. Think of commercial pet food also made up largely of meat by-products. It's easy for pet food to get into the human food chain by handling pet food and touching one's mouth, nose, or eyes, or handling human food in the same room, dishes, or dishwasher, or transfering fluids or dust from canned or dry pet foods to human foods.

For now, the question is whether farmed fish contain mad cow disease prions. That's what Dr. Friedland and his co-authors want consumers to know about as the research continues. The goal is to see whether it's safe or not to feed farmed fish rendered cows. The research team so far thinks it's not safe but will continue researching to confirm or not confirm safety beyond a doubt.

Dr. Friedland wants consumers to know that scientists have not proven that it’s possible for fish to transmit the disease to humans. But researchers want consumers to be cautious. The warning is out of reasonable caution for public health. Friedland believes rendered cows should not be fed to fish. Friedland explained, "feeding rendered cows to fish should be prohibited.” 

His group also is using animal models to better define the pathophysiology of Alzheimer’s disease and develop new treatments. Dr. Friedland has documented a series of important determinants of the disease, including physical and mental inactivity, smoking and diet. This work has focused on interactions of genetic and environmental lifestyle elements.

Who's studying the health of the rendered cows that are currently fed to farmed fish? Creutzfeldt Jakob disease is an untreatable, universally-fatal disease that can be contracted by eating parts of an animal infected with bovine spongiform encephalopathy (BSE or mad cow disease). According to "Farmed Fish May Pose Risk For Mad Cow Disease," the mosts recent 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.

Now people eating farmed fish have to worry not only about the hormones and antibiotics given to the farmed fish to make them grow faster, or the pollutants and insecticides in the farmed fish. Now consumers have to worry about the rendered cows, those meat byproducts fed to the fish that might be full of mad cow disease prions.

The barriers between species could be breaking down. But scientists will have to study how a disease jumps from one species to another. Rather than rely on a prion mutating, a person could get infected from a fish even if barriers between species are perceived as low.

Maybe the infection barrier between species is no longer low if the fish eats the sick mammal or infected cow as ground meal byproducts, and then the human eats the sick farmed fish? If a disease infects a fish that once infected a cow, could that disease also infect a human? It's easy for a disease to jump between a cow and a human. Mad cow disease spread to humans through infected cows that might even have a gene variant that makes them susceptable to mad cow disease.

The risk of transmission of mad cow disease, also known as BSE to humans who eat farmed fish could be higher than most people thought. According to the authors of the research, "it is possible for a disease to be spread by eating a carrier that is not infected itself. It’s 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."

According to the press release, Friedland notes, "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."

Scientists know it takes decades, sometimes up to 30 years, for certain brain diseases similar to mad cow disease infections to incubate in a human. Most people don't make the association between what meat they ate and what that animal or fish ate before it was cooked or sold in the market. When you go out to a restaurant for a fish sandwich, do you think that the farmed fish in the sandwich contains mad cow disease prions or similar infections?

 Dr. Friedland and the authors of the research studies would like consumers to know that "enhanced safeguards need to be put in place to protect the public.” People in Europe that came down with mad cow disease after eating infected beef never had to wait very long. Certainly not for decades.

Those people that caught mad cow disease in Europe didn't have to wait 30 years between the time they ate the beef and the time they came down with Creutzfeld Jakob, the human form of Bovine spongiform encephalopathy (mad cow disease). In recent years, mad cow disease, always fatal in humans and cows, also has been identified in nine Canadian and three U.S. cattle.

The moral compass of this finding is that farmed fish need to be fed safer foods, and in the meantime, eat wild-caught fish from some ocean areas that are relatively cleaner than others.

Even wild-caught fish can be bought in cans, without added salt, because they are canned from the overrun of wild-caught fish. Worse yet, some commercial chicken ranches feed their chickens rendered cow meat and bone meal. When you buy organic chicken, do you know what they were fed? All you know is that they weren't given hormones or anti-biotics if the label says so.

What are turkeys fed? You are told that they're not getting hormones. But what else is in the food animals eat if you're eating the animals? Think about whether cows were fed grass or grain. They should have been grazing on grass. Cows shouldn't be feeding on bone meal and rendered other cows. And dogs/cats shouldn't be eating meat byproducts that have been genetically altered and then injected with all types of chemicals, hormones, or antibiotics.

Be aware of what the animal ate and what hormones, antibiotics, and insecticides that animal absorbed before you ate it. If you're a vegetarian, ask what herbicides, genetic alterations, or insecticides went into the plants you eat. At least you'll know what's going into your body. And the research continues on whether farmed fish present a mad cow disease problem.

See the video below with English subtitles about mad cow disease in the USA. Are farmed fish being fed these rendered cows?