Bovine Spongiform Encephalopathy (BSE), also known as Mad Cow Disease, is a chronic degenerative disease affecting the nervous system in cattle. It was first diagnosed in Great Britain in 1986. BSE is one of several transmissible spongiform encephalopathies (TSE).

Scientists don't know the exact cause of the disease and there are no known treatments or vaccines for it. Many believe the disease agent is a prion (abnormal protein) that is partially protease-resistant after infection. There are currently no methods to test live animals for the disease. The only way scientists are able to detect the disease is through examination of brain tissue of slaughtered animals.

No one is sure where the BSE pathogen originated, but the most widely-accepted theory is that the disease originated in Great Britain through cattle that ate feed containing products made from the carcasses of animals having some form of TSE (possibly sheep having scrapie). It is believed that BSE is not capable of being transmitted from one live animal to another.

Why are people concerned about this livestock disease?

Evidence suggests BSE may be linked to a variant of the fatal human brain illness Creutzfeldt-Jakob Disease (CJD). This BSE-related form of CJD is known as "variant" Creutzfeldt-Jakob Disease (vCJD). Scientists suspect eating BSE-contaminated beef can lead to vCJD.

This variant form is not the same as the classical form of CJD that occurs sporadically at the rate of one case per million in the United States. Classical CJD has been around for many years, and it is not believed to be connected to consumption of BSE-contaminated beef.

Although no cases of vCJD have ever been detected in Minnesota, the Minnesota Department of Health monitors the state for cases. Some clinical signs of vCJD are neurological disorders, such as loss of muscle coordination and dementia.

Are Minnesota's beef consumers safe from Mad Cow Disease?

The United States Department of Agriculture (USDA), the Food and Drug Administration and dozens of state agencies, including the Minnesota Department of Agriculture and the Minnesota Board of Animal Health, have worked together to establish an aggressive prevention and monitoring program to keep Mad Cow Disease out of the United States food supply. Here's a look at what these efforts have done to keep the risk of Mad Cow Disease very low:

• To keep BSE contaminated products out of the U.S., the USDA started restricting the importation of live ruminants and certain ruminant products from the United Kingdom in 1989. More recently, the USDA banned the importation of any rendered animal protein products, regardless of species, from all of Europe and any other country known to have BSE.
• In 1990, the United States initiated active BSE surveillance efforts. Since then, more than 60 veterinary diagnostic laboratories across the country and USDA's National Veterinary Services Laboratories examine hundreds of cattle brains each year submitted from animals displaying signs of neurological disorders either at slaughter or on the farm.
• Because evidence suggests BSE might have developed in Great Britain as a result of the use of animal feed containing contaminated meat and bone meal as a protein source, the Food and Drug Administration has established regulations prohibiting the feeding of most mammalian proteins to cattle. To ensure this federal rule is being followed locally, state agriculture officials conduct inspections of feed manufacturers.
• The Minnesota Department of Agriculture, the USDA and the Minnesota Board of Animal Health work cooperatively to monitor the state's livestock for BSE warning signs. When cattle show warning signs, their brains are sent to the USDA for testing. To date, no Minnesota cattle have tested positive for BSE.
• The United States government has a monitoring program that trains veterinarians in the clinical signs and diagnosis of BSE. Federal Foreign Animal Disease diagnosticians have trained in Great Britain in BSE recognition. In addition, BSE fact sheets, risk assessments, and reviews have been sent to state and federal veterinarians, private practitioners, other industries, and producers to keep them updated and educated on the latest BSE research.

What can Minnesota cattle producers do?

• Minnesota cattle producers have one of the most important roles to play in BSE prevention. If you have cattle showing signs of any neurological disorder, contact your local veterinarian or the Minnesota Board of Animal Health at 651-296-2942 immediately. BSE-affected animals may display changes in temperament, such as nervousness or aggression, abnormal posture, incoordination and difficulty in rising, decreased milk production, or loss of body weight despite continued appetite. Don't just assume any of the listed symptoms are from a common disease.
• If you think or know you have fed your cattle feed containing animal rendered products, contact the Minnesota Department of Agriculture at 1-800-967-AGRI or the Minnesota Board of Animal Health immediately. For more feeding precautions and information see the Food and Drug Administration's web site.
• If you would like additional information on how to identify neurological disorders in cattle or would like more information on Mad Cow Disease, please contact the Minnesota Department of Agriculture at 1-800-967-AGRI.