|
March 1, 2001
|
Corralling Mad Cow Disease
| U.S. Outbreak Seen as Unlikely |
|
The symptoms are frightening, to say the least. As the disease bores holes into the brain, victims become depressed, hallucinatory, mute, and finally, they die. Ninety people, mostly in England, have died of "new variant Creutzfeldt-Jakob disease" (nvCJD)—the human version of "mad cow disease," which is officially known as bovine spongiform encephalopathy (BSE). The victims apparently became ill after eating BSE-contaminated beef. Since the disease came to light in 1989, governments and industry insiders have been working to prevent an epidemic. An outbreak of mad cow disease in the United States seems unlikely, according to an upcoming report by the Harvard Center for Risk Analysis. The team of scientists bases its findings on the prevention measures adopted in this country 10 years ago. Those measures ban imported European cattle and the feeding of ground-up cattle parts to other cattle, a practice blamed for the recent spread of mad cow disease to some European countries. Some chinks in the U.S.'s armor have appeared. The U.S. Food and Drug Administration (FDA) recently announced that Purina Mills provided feed containing the banned meat-and-bone meal (MBM) to 1,200 Texas cattle. The company has agreed to buy and destroy the cows. Also, about 1,000 European cows have entered the country since the ban was enacted a decade ago, although none were found to be diseased.
|
|
| Transmission Fears |
|
When mad cow disease was first discovered in England, millions of cows were slaughtered in an attempt to squelch the disease. However, England continued to sell animal-based feed to other European countries. This practice has apparently led to recent occurrences of mad cow disease in Ireland, France, Germany, Denmark, Belgium, and Italy. Scientists have found that the highest risk to humans comes from eating tissues from a diseased cow's brain and spinal cord. Medium-risk tissues include a cow's spleen, lymph nodes, and pituitary and adrenal glands. People have begun to wonder if BSE could be spread through other products made from at-risk cows. Milk has been tested extensively. Some European candy containing gelatin (which is made from beef parts) has come under scrutiny, as has cheese and nutritional supplements. One candy manufacturer has decided to start making candy with vegetable starch instead of gelatin. Scientists have also been monitoring the human blood supply. Although there is no proof that the disease is spread by blood, the United States does not accept blood donations from those who have lived in England for more than six months. Some scientists have also advised the FDA to ban blood donations from people who take nutritional supplements containing cow tissues. Several U.S. supplement makers produce pills containing cow brains and adrenal glands, which the companies claim can improve people's thinking and energy levels. By law, supplement manufacturers are not required to inform consumers whether their products contain cow organs, and if they do, what country the bovine matter came from.
|
| Origins of a Disease |
|
Mad cow disease originated when British cattle were fed animal-based feed that included the remains of sheep who had been sick with scrapie, a disease similar to BSE. Not knowing that the cows were diseased, manufacturers used them to make cattle feed. CNN recently reported that "as many as 500,000 contaminated beef carcasses are thought to have entered the human food chain." BSE spreads through a mutated protein known as a prion, which can be passed along to humans who eat infected beef. Researchers do not know how many people are infected with the human version of mad cow disease because of its lengthy incubation period. Researchers believe that symptoms may not occur for years or even decades after contracting the disease.
|
||
|
|
|
|
|