What causes mad cow disease?
Reporter: Dan BjarnasonThe story of mad cow disease is in large measure a classic detective yarn. It began in England in 1984 when a cow developed strange symptoms and soon died. Then the bodies started to pile up, and scientists were soon chasing down clues. It took two years, to 1986, before the British made their first diagnosis of what is technically known as bovine spongiform encephalopathy. Eventually, almost five million cattle were slaughtered, but not before almost a million had made it into the food supply.Initially the public was assured there was no danger to people, but soon a new strain of the disease was detected in humans and as many as 140 people have died. BSE gets its scientific name from the microscopic holes in the brains of affected animals, giving the tissue a sponge-like appearance.Mad cow disease is still full of mystery. BSE is but one of a group of brain diseases affecting various animals, such as chronic wasting disease in farmed elk and deer in North Americ
“Mad cow disease” is a fatal and communicable brain disease of cows that has a very long incubation period. Decades after infection, the brains of infected cattle develop numerous small cavities as nerve cells die. The holes produce a marked spongy appearance that gives the disease its scientific name, bovine spongiform encephalopathy (BSE). Central nervous system function is progressively degraded, until death eventually occurs. There is no cure. Mad cow disease is remarkable in that it is not transmitted by a virus or other microbe. Instead, a protein molecule spreads it from one individual to another! Proteins are made as long strings, like spaghetti, each then folding itself up into a compact shape. The shape it assumes determines how the protein functions in an organism. BSE is thought to have started when a key brain protein called a prion made a mistake and folded itself up incorrectly. Tragically, this protein, when it encounters others of the same sort, is able to induce them
