Robert P. Friedland from University of Louisville School of Medicine in Louisville, KY and colleagues published a report in 2008 to suggest that dietary consumption of farmed fish may provide a means of transmission of infectious prion from cows suffering from bovine spongiform encephalopathy to consumers, eventually causing variant Creutzfeldt Jakob disease – the human form of mad cow disease.
Recycled use of animal protein is a known dangerous practice. Parts of farmed animals like cows (some are downers that die from diseases rather than are slaughtered) are processed and re-used into animal feeds intended for cows, chicken and shellfish/fish. This cycled use of animal proteins, particularly parts with prion protein, is officially considered the risk for mad cow disease. The U.S. government has long ago stopped monitoring prion disease or mad cow disease in the U.S., because it assumes that the risk of mad cow disease is no longer existent.
Authors of the report supported by the National Institutes of Health reviewed 10 reports on the potential risk from fish fed on animal protein which can include prion protein. Prion protein is very resistant to heat and sterilizing agents and cannot be destroyed easily. They suggest that “current regulations should be revised to ban the feeding of rendered material from cows to fish, until further work establishes the safety of this
Ingested prion protein derived from animals will not immediately cause any disease. It takes decades for the human type of mad cow disease to manifest. The incubation time is so long that the association between prion protein consumption and the onset of mad cow disease could not be established. Also prion protein can not only result in mad cow disease, but also other neurodegenerative diseases like Alzheimer’s disease and Parkinson’s disease which many scientists believe have something to do with prion protein.
Eating animal foods – even fish – can be a risky business. The safe protein source should be the plants. Animal products like meats and cow milk are not just used as foods. Some like gelatin are commonly used in dietary supplements as a gelatinizing agent to form soft-gels. Gelatin is supposedly tested to make sure that prion protein does not show up. But there is no absolutely certainty to guarantee that a product is free of prion protein. (DR. Lu)
來自肯塔基州路易斯維爾路易斯維爾大學路易斯維爾大學醫學院的 Robert P. Friedland 及其同事在 2008 年發表了一份報告，認為養殖魚類的飲食消費可能提供一種將感染性朊病毒從患有牛海綿狀腦病的奶牛傳播給消費者的途徑，最終導致變異的克雅氏病——瘋牛病的人類形式。
由美國國立衛生研究院支持的該報告的作者審查了 10 份關於以動物蛋白餵養的魚的潛在風險的報告，其中可能包括朊病毒蛋白。朊病毒蛋白對熱和消毒劑具有很強的抵抗力，不易被破壞。他們建議“應修改現行法規，禁止將提煉過的材料從奶牛餵給魚，直到進一步的工作確定這種材料的安全性。
LOUISVILLE, Ky. –University of Louisville neurologist Robert P. Friedland, M.D., questions the safety of eating farmed fish in the June issue of the Journal of Alzheimer’s Disease, adding a new worry to concerns about the nation’s food supply.
Friedland and his co-authors suggest farmed fish could transmit Creutzfeldt Jakob disease–commonly known as mad cow disease–if they are fed byproducts rendered from cows. The scientists 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.