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How the Cows Turned Mad

How the Cows Turned Mad: Unlocking the Mysteries of Mad Cow Disease

Translated by Edward Schneider
Copyright Date: 2004
Edition: 1
Pages: 256
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  • Book Info
    How the Cows Turned Mad
    Book Description:

    Fear of mad cow disease, a lethal illness transmitted from infected beef to humans, has spread from Europe to the United States and around the world. Originally published to much acclaim in France, this scientific thriller, available in English for the first time and updated with a new chapter on developments in 2001, tells of the hunt for the cause of an enigmatic class of fatal brain infections, of which mad cow disease is the latest incarnation. In gripping, nontechnical prose, Maxime Schwartz details the deadly manifestations of these diseases throughout history, describes the major players and events that led to discoveries about their true nature, and outlines our current state of knowledge. The book concludes by addressing the question we all want answered: should we be afraid? The story begins in the eighteenth century with the identification of a mysterious illness called scrapie that was killing British sheep. It was not until the 1960s that scientists understood that several animal and human diseases, including scrapie, were identical, and together identified them as transmissible spongiform encephalopathy (TSE). The various guises assumed throughout history by TSE include an illness called kuru in a cannibalistic tribe in Papua New Guinea, an infectious disease that killed a group of children who had been treated for growth hormone deficiencies, and mad cow disease. Revealing the fascinating process of scientific discovery that led to our knowledge of TSE, Schwartz relates pivotal events in the history of biology, including the Pasteurian revolution, the birth of genetics, the emergence of molecular biology, and the latest developments in biotechnology. He also explains the Nobel Prize-winning prion hypothesis, which has rewritten the rules of biological heredity and is a key link between the distinctive diseases of TSE. Up-to-date, informative, and thoroughly captivating,How the Cows Turned Madtells the story of a disease that continues to elude on many levels. Yet science has come far in understanding its origins, incubation, and transmission. This authoritative book is a stunning case history that illuminates the remarkable progression of science.

    eISBN: 978-0-520-93151-0
    Subjects: Health Sciences

Table of Contents

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  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-viii)
    (pp. ix-xviii)
    Marion Nestle

    READERS OF THIS fine book, which so clearly recounts the scientific and social history of “mad cow” disease and related spongiform encephalopathies, should not be too surprised by the spread of the bovine form of the disease to North America in 2003. In May of that year, Canadian officials announced the discovery of mad cow disease—formally known as bovine spongiform encephalopathy (BSE)—in an eight-year-old Black Angus cow from Alberta. In October, however, the Harvard Center for Risk Analysis downplayed concerns about the disease and reassured the U.S. government and beef industries that the actions they had already taken...

    (pp. 1-3)

    UNKNOWN TO THE public at large until recently, Creutzfeldt-Jakob disease (CJD) is now the subject of daily media attention, especially in western Europe. What exactly is this disease that seems to pose a threat to us all? What is the meaning of terms we hear, such as “sporadic,” “inherited,” “iatrogenic,” and “new variant”? What is CJD’s relationship to “mad cow diseasen—bovine spongiform encephalopathy (BSE)—and to the sheep disease known as scrapie? If it can be transmitted from cattle to humans, why not from sheep to humans? As an infectious disease, can it be transmitted from human to human?...

    (pp. 4-12)

    THE EIGHTEENTH CENTURY, which was to conclude with the American and French Revolutions, was also the Age of Enlightenment. The conviction was growing that scientific progress was intended to enable humans to control the world around us: Had we not learned to control thunderbolts, thanks to the lightning rod? This was the era of Linnaeus, Buffon, and Diderot, and we began cataloguing nature’s riches and seeking to employ them in a more rational way.

    This approach was seen particularly in the areas of agriculture and animal husbandry. Improved productivity was the order of the day. Landowners organized and agricultural societies...

    (pp. 13-17)

    PASTEUR’S EARLY WORK related to what we now call physical chemistry. Before Pasteur, chemists had established that substances—solids, liquids, and gases alike—were in general composed of molecules, which were in turn composed of atoms. A so-called pure substance contains molecules of a single kind, each containing a particular number of atoms linked by very specific bonds. As Antoine Lavoisier (1743–1794) demonstrated in his work during 1783–1785, for example, a molecule of water consists of one oxygen atom and two hydrogen atoms. However, in studying a compound somewhat more complex than water—tartrate, which is deposited in...

    (pp. 18-23)

    PASTEUR AND KOCH had established that anthrax was caused by a bacterium, but how was it transmitted within a flock? That would also be the question a century later for scrapie and BSE.

    In some flocks, anthrax is endemic; from time to time, an animal will succumb to it. In other flocks, it affects a large number of ainimals within a short space of time, thus becoming epidemic. Furthermore, it can flare up periodically or remain dormant for many years. Koch reported two important facts that advanced our understanding of these phenomena: First, he observed that in conditions not conducive...

    (pp. 24-30)

    IN 1898, THREE YEARS AFTER Pasteur’s death, Professor Charles Besnoit of the École Vétérinaire d’Alfort learned that for several years an unknown disease had been ravaging flocks in the Tarn, in southwest France. Mortality had reached 15 to 20 percent, devastating for a region where sheep were important not only for wool and meat, but also for milk used in cheese production. Besnoit soon realized that this “unknown” disease was scrapie, and he decided to study it—becoming the first to do so in a genuinely scientific way. His principal achievement would be to resolve a question that had baffled...

    (pp. 31-37)

    THE POSTHUMOUS LEGACY of Hans Gerhard Creutzfeldt is a strange one. He died in 1964 virtually unknown, but two decades later his name was to be world famous—although some today question whether his renown is really justified. In any event, that fame is due to an obscure paper published in 1920 in a German neurological-psychological journal.

    Creutzfeldt was an exceptional human being: an original, independent thinker, and a man whose brusque manner concealed great kindness and profound humility. “Knowledge makes you arrogant, but education makes you humble.”Those words, spoken during his speech at the opening of the new University...

    (pp. 38-44)

    ON DECEMBER 28, 1936, the French veterinarians Jean Cuilli and Paul-Louis Chelle presented to the Acadtmie des Sciences a communication titled “Is the Disease Known as Scrapie Inoculable?” They reported having used a variety of techniques to inoculate nine sheep of both sexes with cerebral or medullar matter from a number of animals in the latter stages of scrapie. In the course of the nine months following the inoculation, seven died or were sacrificed—for reasons beyond the control of the experimenters—and showed no sign of scrapie. Despite those discouraging beginnings, Cuillé and Chelle continued their observation of the...

    (pp. 45-50)

    THINGS CHANGED IN THE EARLY 1950s. By then scrapie had turned up in Canada, the United States, and Australia in the wake of importation of sheep from the United Kingdom. Those countries, along with New Zealand, imposed an embargo on such sheep unless they could be guaranteed scrapie-free. Now, finding the source of the disease became an economic issue. Motivated and well financed, British veterinarians resumed large-scale experimentation at two major research centers: the Agricultural Research Council’s institute in Compton, Berkshire, and the Moredun Research Institute in Edinburgh. Although they were unable to identify the mysterious scrapie virus, they made...

    (pp. 51-57)

    THE WORK OF CUILLE AND CHELLE, now fully confirmed by British researchers, indisputably established that scrapie was transmissible. Once introduced into an animal’s body, the causative agent multiplied, so that after the proper incubation period the tissues of the animal could be used to infect other animals, and so on. But was scrapie contagious? Was it transmitted spontaneously from animal to animal?

    MacFadyean’s observations seemed to demonstrate that it could be: Think of Mr. A (introduced in Chapter 4), whose flock had been contaminated by ewes bred by Mr. X. Many similar observations had been published in the scientific literature....

    (pp. 58-66)

    SOME PLANTS AND ANIMALS ARE so-called living fossils. They seem to have survived since time immemorial while their contemporaries fell by the wayside, yielding to new species better adapted to a changing world. As of the mid-twentieth century, the human species too included its share of well-adapted survivors: groups cut off from the rest of the world, who lived as our distant ancestors had lived. Among them were a number of ethnic groups on a huge island to the north of Australia, which had been “discovered” in the sixteenth century by Portuguese and Spanish navigators, who named it New Guinea....

    (pp. 67-72)

    NOT THE BERLIN WALL—this was 1959, and that structure would not rise for another two years—but the wall that segregated physicians and veterinarians was toppling. That year saw the first suggestion of a similarity between a human form of The Disease—kuru—and its animal form, scrapie.

    Let us return to the Compton research center in England, where Iain Pattison and his colleagues were at work. When the issue of scrapie in sheep that were exported to the United States arose, an American veterinary scientist, William Hadlow, was sent to Compton in 1958. On September 5,1959, Hadlow published...

    (pp. 73-80)

    IT WAS THE LATE 1960s. In Paris, the United States, and throughout the developed world, students were taking to the streets to protest war, intolerance, and other social ills.

    How was the hunt for The Disease going? A composite sketch was emerging: In very similar guises, it attacked sheep and goats as scrapie; it affected the Fore people of Papua New Guinea as kuru; and it threatened the rest of the human world as Creutzfeldt-Jakob disease. It could be transmitted experimentally both within a species and between species, so it had to be caused by an infectious agent. In nature,...

    (pp. 81-86)

    IN FEBRUARY 1966 Gajdusek published his findings on the transmission of kuru to chimpanzees. As William Hadlow had predicted (see Chapter IO), kuru thus proved to be similar to scrapie. The same month saw the publication of an article that would puzzle the scientific community. We will address that in a moment, but first: What was known at that point about the “virus” or “viruses” responsible for these diseases? Let us focus on the one that causes scrapie, about which more complete information was available. In many respects, the scrapie “virus” was already known to be highly unusual—in its...

    (pp. 87-92)

    HERE IS WHERE THE HUNT for The Disease stood in 1959: British veterinary researchers had transmitted scrapie to goats, but not yet to mice. The writings of Creutzfeldt and Jakob were gathering dust on library shelves. Gajdusek had left the Fore people and had learned of Hadlow’s theory positing a parallel between scrapie and kuru. The year 1959 also saw the early triumphs of molecular biology. Watson and Crick had published their historic article six years before, and Jacob and Monod would publish their initial work on the regulation of gene expression.

    That was the context in which certain types...

    (pp. 93-97)

    AS A RARE, POSSIBLY GENETIC AILMENT, Creutzfeldt-Jakob disease was of interest to only a handful of doctors and researchers between 1920 and 1960. But there had been enough interest to ensure the gathering of data on patients who had been treated in several countries. During the 1960s, the question of whether CJD was a single disease became a matter of increasing controversy. Citing the diversity of clinical symptoms and of the lesions observed in nervous system tissues, some were convinced that several different diseases were gathered under the Creutzfeldt-Jakob umbrella, and they came up with as many as sixteen names...

  19. 15 PRIONS
    (pp. 98-103)

    DESPITE THE AVALANCHE OF THEORIES loosed by the observations of Alper and her colleagues, nothing spectacular was published during the: 1970s about the nature of the mysterious “virus” that was seemingly without nucleic acid.

    Enter a man who continues to occupy center stage to this day: Stanley Prusiner, a neurologist and biochemist who since 1974 has diviaed his time between the San Francisco and Berkeley campuses of the University of California. Starting in 1978, but primarily in the early 1980s, he published an impressive series of articles that identified what some say is the causative agent of scrapie and what...

  20. 16 APRIL 1985
    (pp. 104-109)

    APRIL 1985 WAS A KEY MONTH. It seemed as though The Disease had been flushed out. But it counterattacked on two fronts, launching deadly offensives whose effects would still be felt fifteen years later.

    As described in Chapter 15, Prusiner believed that The Disease was caused by a kind of protein, which he named a prion. It is not hard to imagine a toxic protein, for there are many precedents. The toxins produced by the bacteria that cause diphtheria, anthrax, and botulism are proteins, and they can kill humans and animals in extremely low doses. But they do not reproduce;...

  21. 17 THE “KISS OF DEATH”
    (pp. 110-118)

    LET US LEAVE THE DOCTORS and veterinarians to their confusion and concern, and return for a moment to the guilty party—the causative agent of The Disease, the prion. As we have seen, this appeared to be a protein encoded by a gene that was present, with very similar sequences, in all mammals. Normally, this gene would encode a protein containing 240 amino acids that, like most other proteins, was protease-sensitive. But in animals with scrapie or humans with Creutzfeldt-Jakob disease, the protein would take a different form, one highly resistant to proteases. This other form was infectious; inoculating animals...

    (pp. 119-127)

    SCRAPIE IS TRANSMISSIBLE. We have known this since the 1936 experiments of Cuillé and Chelle and the accidental contamination of thousands of sheep in Scotland by a louping ill vaccine around the same time. Human spongiform encephalopathies—kuru and Creutzfeldt-Jakob disease—are infectious as well, as Gajdusek’s team demonstrated in the late 1960s by transmitting them to chimpanzees. So if you accept the orthodox Pasteurian “contagionist” view, these diseases can be contracted only through contagion.

    If spongiform encephalopathies were infectious, the next task was to find out how they were transmitted. For scrapie, there were very convincing arguments in favor...

    (pp. 128-135)

    GROW . . . AND DIE: That was the sad fate of at least 140 children treated with human growth hormone and infected with the causative agent of Creutzfeldt-Jakob disease. The final outcome of this tragedy remains to be known; owing to the lengthy incubation period of CJD, additional cases appear every year.

    The announcement of the first cases, in April 1985, took specialists by surprise; the vast majority of them had not seriously contemplaled the possibility of such infection. Although in the period 1974–1977 Gajdusek and his team had signaled the risk of transmitting the CJD agent during...

    (pp. 136-141)

    COULD THE TRAGEDY have been averted? In theory, perhaps, but only at the cost of abandoning the treatment of pituitary dwarfism.

    By the late 1960s—even before the foundation of L’Association France Hypophyse—the scientific literature contained information that could have signaled the danger of administering growth hormone derived from human pituitaries. But pediatricians and endocrinologists treating pituitary dwarfism either did not know of that information or did not fully appreciate it. Remember that it was in 1968 thai Gajdusek’s team succeeded in transmitting Creutzfeldt-Jakob disease to chimpanzees, thus demonstrating its close resemblance to scrapie and gathering both diseases together...

    (pp. 142-152)

    ALTHOUGH THE FIRST CASES of bovine spongiform encephalopathy were recorded in April 1985, they were not identified as such until two years later. That may seem surprising, but we must recall that a single cow in a herd dying, even of a murky cause, is not so extraordinary as to justify an in-depth investigation. The animal is written off as a loss on the balance sheet, its carcass is sent to the processing plant, and nothing more is said of it. Things become more serious when there are several deaths within a herd from what appears to be a single...

    (pp. 153-162)

    THE POSSlBlLlTY THAT BSE could be transmitted to humans was considered as soon as the disease became known. In June 1988 the question was posed in aBritish Medical Journaleditorial: “[We] are faced with the fact that spongiform encephalopathy, whether or not we are at risk from it ourselves, is now established in the cattle of this country. . . . There is no way of telling which cattle are infected until features develop, and if transmission has already occurred to man it might be years before affected individuals succumb.”¹ And in September of that year an editorial in...

    (pp. 163-168)

    AS THOUGH FEARS ABOUT EATING BEEF and other cattle products were not enough, some people began to worry about the possible risks of eating products from other animals—first and foremost sheep. The fact is that cows were not the only animals to have been given potentially contaminated animal-based feeds; these had been fed also to sheep, hogs, chickens, and even fish. Could it not be risky to eat meat or other products from those animals as well—especially since, for some of them, animal-based meals had still been a part of their diet until recently? Let us look first...

    (pp. 169-175)

    WE HAVE BEEN ON THE TRAIL of The Disease for three centuries now. If it has managed to evade capture for so long, this is due in large part to its disturbing ability to alter its appearance. The closet in which this criminal stores its disguises seems to be infinitely deep. So what is its secret? Can prion theory help us figure it out?

    From the very outset we knew that The Disease could change its appearance. Think of how hard it was to realize that scrapie in all its forms was in fact a single disease-hence, the many names...

    (pp. 176-179)

    SO, THE DISEASE APPEARS to be caused by a molecule, a protein that is more or less the same in all species that fall victim to it. Does this hypothesis in its present form account for all the various characteristics of The Disease? Before saying that it does, we should look at a few more questions.

    One obvious question, which we addressed earlier, relates to the precise nature of the changes in conformation that turn the prion protein infectious. The conformation of the normal protein has been described, but not those of all the various infectious forms, whose insolubility makes...

    (pp. 180-183)

    IN NOVEMBER 2000 a French television network broadcast a program titled “Mad Cow: Running Scared.” The Disease—which had been lurking in the days of Louis XV and which we’ve been hunting down for the past three centuries—is still spreading fear today. Even if we have unmasked it, we have not conquered it. The public has been deeply shocked by images of young people, of mothers, unable to move about, speak, or even show any sign that they understand what is said to them, incontinent and awaiting a certain death. People are suspicious of the food they buy. The...

  31. 27 2001
    (pp. 184-198)

    AS THE FRENCH EDITION of this book went to press toward the end of 2000, Europe’s mad cow crisis was at its height. A year later, the crisis was still with us but seemed less intense. Beef consumption had picked up somewhat in France, but concerns about lamb and mutton emerged. In countries that had been BSE-free, the first cases of the disease triggered panics like those that had been experienced in the United Kingdom and then in France. In the scientific arena, many—and often extremely interesting—findings were announced, but their impact remained uncertain.

    One particularly active area...

    (pp. 199-204)

    WE HAVE NOT YET BEATEN The Disease. By possessing many characteristics that run completely counter to orthodox scientific thinking, it has long managed to evade the pursuit mounted by veterinarians, physicians, and researchers.

    The Disease is transmissible, but its incubation period is far longer than anything ever seen before. It is infectious, but it triggers no defensive reaction in the body—a strange characteristic that for years led researchers down the garden path. It is caused by an infectious agent that is resistant to all the usual decontamination processes; this is what inspired the heretical hypothesis of an infectious agent...

  33. NOTES
    (pp. 205-214)
    (pp. 215-216)
    (pp. 217-224)
    (pp. 225-226)
  37. INDEX
    (pp. 227-238)
  38. Back Matter
    (pp. 239-241)