Albion Monitor /News

Efforts to Prevent U.S. Mad Cow Disease Are Too Little, Too Late

by Neal D. Barnard, M.D.

The Food and Drug Administration (FDA) has recently announced a new proposal to eliminate ome of the risk factors that could lead to an outbreak of "mad cow disease" in the United States. The FDA should be concerned about preventing an outbreak -- current evidence leads to the conclusion that mad cow disease is already here.

Last April, British authorities announced a connection between mad cow disease (a brain disease, formally known as bovine spongiform encephalopathy, or BSE) and a rare human brain disease, Creutzfeldt-Jakob Disease (CJD). British authorities have confirmed fourteen cases of a variant form of CJD and French doctors have reported one case. The U.S. held its collective breath, then exhaled, thinking, "It's horrible what's happening in the U.K., but we're safe in the United States, right?" Alarmingly enough, cattle in the U.S. may not be safe from the disease at all.

BSE may have been present in U.S. cattle for decades
Mad cow disease is primarily spread through animal feed contaminated with rogue proteins known as prions. Scientists put the blame for the BSE outbreak in Great Britain on the practice of feeding cattle the remains of sheep infected with scrapie, a disease with many similarities to BSE.

One-third of British sheep flocks are currently affected by scrapie. More than 165,000 cattle in Great Britain have been infected with BSE since it was first detected in 1986. Scrapie has been present in U.S. sheep flocks since 1947. Moreover, ten billion pounds of processed animal remains were "recycled" into animal feed in the U.S. in 1995, and, as late as 1993, 71 percent of renderers who process animal remains for feed were still processing adult sheep.

In addition, there is evidence that cattle feed has spread brain diseases to other animal species in the U.S. Mink fed remains from cattle have developed a disease called transmissible mink encephalopathy, which is remarkably similar to BSE. Since 1947, five outbreaks of transmissible mink encephalopathy have occurred. Department of Agriculture researchers estimate that the brain and spinal cord of a single BSE-infected cow could easily contain enough infective material to cause disease in 1,000 mink.

Moreover, University of Wisconsin researchers, noting that the mink disease was linked to the use of cattle remains in mink feed, concluded, "If this is true, there must exist an unrecognized bovine spongiform encephalopathy (BSE)-like infection in American cattle."

This finding indicates that BSE may have been present in U.S. cattle for decades.

Furthermore, there are presently 499 head of cattle from the U.K. in the U.S., imported primarily for breeding purposes. If scientists discover a definite genetic predisposition to acquiring BSE, the U.K. cattle may have passed the predisposing gene to U.S. cattle.

he USDA has tested only three-one-thousandths of one percent of all cattle in the U.S.
The FDA's proposed regulations don't go far enough to prevent the spread of BSE. They would only prohibit feeding any ruminant animal (animals that chew their cud) the tissues of other ruminant animals. Meanwhile, potentially dangerous animal feed ingredients, including other animal remains and manure, would not be covered by the regulations. These measures are not enough to prevent the spread of BSE in this country.

First, the FDA should expand the proposal to prohibit the use of all animal tissue in animal feed. At this time, there is no evidence that non-ruminant animals are not carriers of dangerous prions. While cattle have been considered the most likely species to have passed transmissible encephalopathies to humans, they are not the only species under suspicion.

As The Lancet reported on April 6, 1996, other animals have routinely been fed feed containing rendered cow and sheep remains: "[S]heep, pigs, and chickens have also been exposed to BSE and scrapie-contaminated feed. While there is no evidence of natural transmission of BSE to these species, it would be prudent to remain open-minded about dietary exposure." It is common practice on farms for chickens to be fed cattle remains, and then the chicken manure is fed directly back to cattle, thus increasing the potential for contamination and spread of disease. Until the prion diseases are more fully understood, all animal tissues (not just the tissues of ruminant animals) should be banned from livestock feed.

Secondly, the FDA should ban the practice of adding manure to livestock feed. In this technological age of livestock rearing, a cow is fattened for slaughter in just over a year. Volume is profit, and fattening enormous populations of animals as quickly and cheaply as possible is the name of the game. Believe it or not, that cheap feed often includes manure. Manure can carry a variety of pathogens, diseases, and parasites. In one case, prion-infectivity was found in manure. Feed products containing manure are only tested for salmonella and E.coli contamination, and if a livestock producer chooses to use manure produced on-farm, he or she is not required to process- - or even test -- it for disease-causing organisms. This means raw manure containing disease-causing organisms can be fed without regulation. The FDA should ban the practice.

Increased surveillance for BSE must be made a greater priority. Presently, no one is even looking for BSE in cattle in a systematic way. The USDA's Animal and Plant Health Inspection Service has tested only three-one-thousandths of one percent of all cattle in the U.S.

The urgency for action is underlined given that BSE and CJD are 100 percent fatal and 100 percent untreatable
The bottom line is this: Because brain diseases like BSE have long incubation periods, infected animals may be slaughtered and then fed to other animals before they reach an age where symptoms become evident. Combining all of the above mentioned factors, the prohibition of animal tissues and manure in feeds is a necessary step in preventing the spread of BSE in the U.S.

The line must be drawn, and it must be drawn soon. Based upon the prevailing evidence, the FDA must ban livestock feeding practices that present a public health risk. It is far better to err on the side of caution rather than to expose the American public to a health risk as serious as BSE and related prion diseases.

The urgency for action is underlined given that BSE and CJD are 100 percent fatal and 100 percent untreatable. Of course, we already know that meat-eating leads to the big three killers -- heart disease, stroke, and cancer. Americans shouldn't wait for a mad cow epidemic to erupt in this country to kick the meat habit; but while they are making the transition to healthier diets, Americans should not have to risk a fatal brain disease.

Neal D. Barnard, M.D., is the president of The Physicians Committee for Responsible Medicine

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Albion Monitor April 15, 1997 (

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