Mad Cow Disease

Jan. 22, 2004

Jeffrey Bender, College of Veterinary Medicine, discussed mad cow disease on the Jan. 22 KARE-11 Today show.

Q: What is Mad Cow Disease? Should I avoid eating beef?

Bender: Mad Cow disease has drawn a lot of attention since Dec. 23 when a single dairy cow in Washington state was found to have the disease. Mad cow, or bovine spongiform encephalopathy (BSE), is a fatal disease in cattle that causes degeneration of the brain.

The disease first made the news in the 1980s when there was an outbreak of BSE in Britain that forced the destruction of 190,000 animals. Scientists learned that feeding rendered animal proteins to cows and other animals spread the disease. There's speculation that a related degenerative brain disease in sheep called scrapie might have crossed the species in this fashion. That research has led to a ban on feeding animal proteins to grazing animals in several countries, including the United States.

The outbreak in Europe triggered concern because it appears that mad cow can cause a form of the disease in humans called variant Creutzfeldt-Jacob disease, which is a rare and progressive degenerative brain disease that has led to the deaths of more than 140 people in the United Kingdom and about a dozen others worldwide.

Mad cow and Creutzfeldt-Jacob disease are both believed to be caused by misshapen prion proteins that can affect normal proteins in human and animal brains. Researchers think that mad cow can cause Creutzfeldt-Jacob disease in humans if people consume tissue from the brain and nervous system of sick animals. Prion is not found in muscle tissue, such as steaks. In the case of the stricken cow in Washington, the brain and spinal cord were removed before slaughtering, meaning it is unlikely that meat processed from the cow was contaminated. Researchers think that meat products containing other tissue, such as bologna or hot dogs, might be at greater risk, although it's still low. Unlike bacteria, these proteins are not killed or altered when meat is cooked.

Key Points

I think the risk is extremely low. There are a number of firewalls put in place by the United States Department of Agriculture over the last 15 years, implemented in part because U.S. officials have carefully watched and learned from whats happened in the United Kingdom.

• The United States has banned importation of beef from countries where there have been outbreaks, including Britain, Japan, and Canada.

• The USDA has banned importation of animal feed products that include proteins derived from rendered animals as a way to prevent the spread of mad cow disease in the United States. In addition, they have restricted the type of animal proteins that can be fed to U.S. cattle to prevent a similar situation that occurred in the United Kingdom.

• The USDA has a program to educate veterinarians about mad cow, so they can recognize possible cases and alert appropriate authorities.

• The USDA has an active surveillance program in place, which targets downer animals considered at high-risk for carrying the disease.

As a result of the outbreak, there could be additional changes made to prevent sick animals from entering the food supply. Officials are closely watching to see if other cattle in the United States have contracted the disease.

There are some indications that organic beef could be safer. In general, however, should Americans be worried about eating beef? I dont think so.

Web Links

Center for Animal Health and Food Safety

http://www.cahfs.umn.edu

Center for Infectious Disease Research and Policy

http://www.cidrap.umn.edu

United States Department of Agriculture

http://www.usda.gov

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