Mad Cow Disease - The beef about this cattle catastrophe
For the last several years, we have heard a lot about mad cow disease in the news. I still remember when Oprah scared us all about the prospect of eating beef! But what is mad cow disease and should we be worried?
Bovine spongiform encephalopathy (BSE) is the scientific name for this condition. It is a fatal neurodegenerative condition of cattle. While never having killed cattle on a scale comparable to other dreaded livestock diseases, such as foot and mouth and rinderpest, mad cow disease has received wide attention because it seems that people can contract it as well. It is thought to be the cause of variant Creutzfeldt-Jakob (vCJD) a human brain-wasting condition.
Unlike the other kinds of infectious diseases which are spread by microbes, the infectious agent in mad cow disease is a specific type of protein. Misshapen prion proteins carry the mad cow disease between individuals and causes deterioration of the brain. It is a type of transmissible spongiform encephalopathy (TSE). Transmission can occur when healthy animals consume tainted tissues from others who are infected. It progresses to the appearance of holes in the brain, degeneration of physical and mental abilities and ultimately death.
The British BSE epidemic in cattle was recognized in 1986. It was first believed to have originated in sheep, in which the related condition, scrapie, is common. Prior to the mad cow disease epidemic, cattle were fed with meat and bone meal, a high-protein substance obtained from the remains of butchered animals, including cows and sheep. This practice allowed the accumulation of prions over many generations. As more animals became ill, more infectious tissue got into the feed, and so the number of cases reached epidemic proportions. The tissues that contain most of the pathogenic molecules are those of the brain and the nervous system, although infectious amounts have been shown experimentally to be present elsewhere, such as in blood.
The use of meat and bone meal as a protein supplement in cattle feed was widespread in Europe prior to 1987. Worldwide, soybean meal is the primary plant-based protein supplement fed to cattle and is widely used in the United States. However, soybeans do not grow well in Europe, so cattle raisers throughout Europe turned to the less expensive animal byproduct feeds as an alternative. A contributing factor seems to have been a change in British laws that allowed a lower temperature sterilization of the protein meal. While other European countries like Germany required the animal byproducts to undergo a high temperature steam boiling process, this requirement had been eased in Great Britain as a measure to keep prices competitive.
Following an epidemic of mad cow disease in England, 157 people as of 2004 acquired and died of a condition with similar neurological symptoms to mad cow disease. For many of these patients, direct evidence exists that they had consumed tainted beef, and this is assumed to be the way by which all affected individuals contracted it. As of 2004, there have only been three cases of mad cow disease in the United States and no cases of (vCJD) the human form of the condition.
For more information and precautions about mad cow disease, do some research online.