On March 20, 1996, the gruesome story finally broke into the mainstream press: bovine spongiform encephalopathy (BSE), or "mad cow disease", was indeed very likely transmissible to human beings. This frightening admission by the British government was made after public disclosure that ten Britons had been diagnosed with an unusual variant of the rare human form of this fatal affliction called Creutzfeldt-Jakob disease. Of course, the real story began to unfold years ago and was dutifully covered up by the British government and mainstream press to avoid any disruption in the multi-billion dollar British beef industry.
Spongiform encephalopathy has been recognized since 1755 when it was first identified in sheep. It was then named "scrapie" for the afflicted animals' tendency to rub their hides raw. Upon autopsy of these animals, their brains looked like sponges filled with holes tangled with protein fibrils; hence the medical term spongiform encephalopathy. The cause was unknown.
In the mid-20th century, as a measure to increase profits, cattlemen began the practice of feeding a gruel made from offal (the waste parts cut from dead animals) to their herds. Such creative farming not only made use of a former waste product but also provided a cheap source of highly concentrated protein; never mind the fact that as ruminants, cattle are strict herbivores. Initially this offal brew, including the brains and nerve tissues of scrapie-infected sheep, was seasoned with noxious solvents and cooked at high temperatures to kill disease-causing bacteria and viruses; but then, in the 1970s, a new, cheaper, no solvent, low temperature rendering process came into favor. As early as 1979, six years before the first case of BSE was identified, the Royal Commission on Environmental Pollution warned the British government that low temperature rendering might spread diseases throughout the food chain, but their warning fell on deaf ears.
Then, in 1985, a formerly healthy Holstein dairy cow suddenly became edgy and uncoordinated. Its brain was later found to be riddled with holes similar to those found in scrapie-infected sheep. By 1989, over 11,000 cases of this new disease, dubbed "mad cow disease", had appeared in British cattle herds and the Agriculture Ministry banned the use of offal in animal feed. The epidemic continued to spread, however, peaking at over 36,000 head in 1992 alone. So far, over 160,000 British cattle have been felled by mad cow disease and 70 cases per week are still reported. All the while, the British government steadfastly maintained that transmission to human populations was inconceivable.
But when 10 cases of a new variant of Creutzfeldt-Jakob disease (CJD) appeared in the human population, all bets were off. The classic form of CJD afflicts about one in a million people worldwide each year. It appears to develop in three distinct ways: heredity; tissue transplants from infected donors; and "sporadic" generation (i.e., of unknown origin) which accounts for, by far, the largest number of cases (an estimated 75%). Familiar symptoms include loss of coordination, speech impairment, visual failure and rapid onset of dementia. The 10 newly reported cases of CJD vary from this classic form in significant ways, possibly indicating a link to the eating of beef from infected cattle. Classic CJD usually strikes people over 60 years of age; none of the 10 recent victims was over 42, with an average age of only 27. The younger victims also took, on average, a year to die from this always fatal disease, more than twice the time it takes older patients. Furthermore, in the new cases, nerve cells in the brain were more liberally scarred with amyloid plaques, which are gummy deposits usually associated with Alzheimer's disease. An additional disconcerting fact is that each of the 10 victims was British, and Britain is the only country which has sustained a mass outbreak of BSE. The announcement of this new strain of CJD finally forced the British government into its March 20th capitulation on the possibility of cross-species transmission of BSE from cattle to humans.
The family of spongiform encephalopathy diseases - including CJD, Kuru (another human form affecting New Guinea tribesmen who, until the 1950s, ate the brains of their deceased relatives), BSE, scrapie, and many other forms infecting animals from cats to ostriches - has presented a confounding puzzle to research scientists. Unlike every other infectious disease known to man and beast, spongiform encephalopathies produce no host immune system response or inflammation of tissue, and no bacteria or virus has been isolated as a causative factor.
Enter Dr. Stanley Prusiner, neurologist and biochemist at the University of California at San Francisco. From his methodical study of scrapie and CJD victims beginning in 1972, Dr. Prusiner was able to identify rogue proteins which he named "prions" (pronounced PREE-ons, short for proteinaceous infectious particles) as the infectious agent causing these diseases. Prions differ from bacteria and viruses in one remarkable aspect - they contain no DNA! Needless to say, Dr. Prusiner was nearly laughed out of the neuro-research community when he first proposed this theory, but few are laughing now; the existence of prions is no longer denied by the scientific establishment. But how do prions reproduce and spread without DNA? This trick was formerly thought impossible and, indeed, prions don't reproduce in the normal biological sense.
Prions actually come in two varieties. One is healthy and produced by normal nerve cells in the brain, but the other is ominously mis- shapen. These mis-shapen prions proceed to wrap themselves around healthy prions converting them into the mis-shapen form. This begins a chain reaction that destroys healthy proteins eventually rotting the brain. Where these rogue prions come from and how and why they become aggressive remains a mystery.
And now to the question on the still lucid minds of all you dear readers out there - are American beef eaters at risk of contracting CJD? The answer to this question is none too reassuring - no one knows for sure; but strong evidence suggests the answer may well be yes.
Dr. Richard Marsh, an expert on animal encephalopathies at the University of Wisconsin, has reported on experiments conducted in Mission, Texas and Ames, Iowa in which brain matter from scrapie- infected American sheep was injected into the brains of cows. The infected cows developed BSE but their symptoms differed from the "mad cows" found in Britain. While BSE-infected cows in Britain went "mad" before dying, BSE-infected cows in America simply fell down and died. The sudden death of these American BSE-infected cows is remarkably similar to the symptoms of cows with a condition known as "downer cow syndrome" which affects about 100,000 U.S. cattle each year. Downer cows are either sent to the slaughterhouse where they are disassembled for human consumption or to the rendering plant where they are boiled down into protein supplements that are fed to cattle and other animals. In 1985, at a Stetsonville, Wisconsin mink farm where 95% of the feed came from downer cows, the entire ranch was wiped out by an outbreak of mink encephalopathy. Though circumstantial, Dr. Marsh believes this evidence appears to show that a form of BSE manifesting itself as downer cow syndrome has infected U.S. cattle herds.
Other evidence draws a possible link to human CJD infection in the United States. A study conducted at the University of Pittsburgh in 1989 sought to test the accuracy of the clinical diagnosis of dementia. In this study, 54 demented patients were autopsied. Most had Alzheimer's disease or other central nervous system disorders, but 3 were found to have CJD. It was further noted that, while alive, the symptoms of these 3 patients resembled Alzheimer's much more so than the classic symptoms of CJD. If these findings are representative of the general population, then literally thousands of cases of CJD have gone undetected among Americans who have been diagnosed with dementia.
Dairy cows are most at risk for contracting BSE because they are kept alive longer than beef cattle which allows the infecting prions more time to incubate. Dairy cows are also fed larger portions of rendered animal protein supplements as an effective means of increasing milk production. And, when dairy cows are injected with the genetically engineered bovine growth hormone - rBGH - to further increase milk production, they must be fed even larger quantities of animal protein supplements. Thus far, milk is not suspected as a vector for CJD, but in the United States over 2.6 billion pounds of hamburger meat each year is made from ground- up "retired" dairy cows. The biggest buyers of this possibly prion- infected meat are fast food joints like McDonald's and Burger King.
Despite full knowledge of the dangers of feeding rendered animal protein to cattle, the U.S. Department of Agriculture and the Food and Drug Administration have refused to ban this practice. According to government documents released through a Freedom of Information request by the Foundation on Economic Trends, these agencies, responsible for protecting animal and human health, have deliberately decided to ignore any evidence suggesting U.S. cattle may be infected with BSE. Instead, they have devised a public relations plan to quell public fears. The plan flatly states that "The mere perception that BSE might exist in the United States could have devastating effects on our domestic markets for beef and dairy products." It goes on to state that the British made a PR mistake by initiating a public health registry for CJD which "...appeared to legitimize concern about a link between BSE and human health." Clearly, USDA and FDA sensitivity to the economic concerns of the beef, dairy and rendering industries, all of whom have put tremendous pressure on these government agencies to maintain business as usual, is much greater than their sensitivity to the health concerns of the American people. And of course, the American mainstream press, like their British cousins, are only too willing to go along with the cover-up.
One final note. CJD can incubate in an infected person for up to 30 years before symptoms become apparent, so it will be quite some time before we know the full extent of a CJD epidemic in the human population. In the meantime, anyone care for a veggie burger?
Copyright Mendocino Environmental Center 1997
Permission granted to excerpt or use this article if source is cited