Shock waves rocked Europe during the late 1980’s and the 1990’s as a result of “mad cow” disease. In Britain and France in particular, there was widespread concern when people were informed that the disease could be passed to humans through consumption of contaminated beef. On December 23, 2003, U.S. government sources revealed that a dairy cow in Washington state was infected with mad cow disease, also called bovine spongiform encephalopathy. The American publication of Maxime Schwartz’s How the Cows Turned Mad is therefore very timely.
This remarkable scientific detective book traces the origin of what Schwartz calls The Disease back to the eighteenth century, when a mysterious disease called scrapie began to infect large numbers of sheep in England. The fascinating story which follows gives great insight into how scientific theories are developed. In this case, it is a patchwork of false trails, flawed hypotheses, conventional wisdom that turns out to be wrong, guesswork, intuition, patience, hard work, determination, and a touch of genius. The story also shows what a cunning and resilient adversary The Disease has been (and perhaps still is), manifesting in a variety of disguised forms in several species over a period of three hundred years.
The story begins with scrapie, a disease so named because infected sheep would be tormented by itching skin and would try in vain to alleviate it by frantic scratching. Scrapie was always fatal, and there was no knowledge of how to protect sheep from it. Veterinarians were divided as to whether the disease was contagious or hereditary. Some believed the disease arose spontaneously. It was not until the end of the nineteenth century, following the groundbreaking work of Louis Pasteur in showing the role of microbes in contagious disease, that scrapie was studied in a scientific manner. A French scientist, Charles Besnoit, discovered the presence of bubblelike “vacuoles” in the brains of infected sheep. Although this provided an accurate diagnosis, knowledge of the cause and nature of the disease remained tantalizingly out of reach.
From 1920 to 1923, German neurologists Hans Gerhard Creutzfeldt and Alfons Maria Jakob published papers describing a rare, fatal disease of the nervous system in humans. It was christened Creutzfeldt-Jakob disease (CJD). This was, in fact, another manifestation of The Disease, but no one realized it at the time, and for forty years there was no followup to Creutzfeldt and Jakob’s work.
More progress was made on scrapie in the 1930’s, when French veterinarians Jean Cuillé and Paul Louis Chelle demonstrated that scrapie was inoculable—that is, it could be transmitted from one sheep to another, which meant that it had to be viewed as an infectious disease. Work still had to be done to identify the infectious agent. Progress was made in 1961, when British researcher Richard Chandler succeeded in transmitting scrapie to mice and from mouse to mouse. He found that the infectious agent was concentrated in the brain of the sick animal.
In the meantime, another part of the puzzle had been identified. In 1955 Vincent Zigas, a German doctor, discovered a strange, fatal disease called kuru among the Fore people of Papua New Guinea. In 1957 he was joined in his research by Carleton D. Gajdusek, an American pediatrician. Given the blood and other samples collected by Zigas and Gajdusek, Igor Klatzo, a researcher at the United States’ National Institutes of Health, noted the similarity between the cerebral lesions in kuru and those in Creutzfeldt-Jakob disease. None of the researchers, however, could say what caused kuru.
Two years later, in 1959, American veterinarian William Hadlow noted the similarities between kuru and scrapie. This was the first time anyone had noticed the similarities between the animal and human manifestations of The Disease. In the 1960’s, the...
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