Bovine Spongiform Encephalopathy

BSE Post-Canadian Discovery Facts - 5/27/03

Background Information
Bovine spongiform encephalopathy (BSE), widely referred to as "mad cow disease" is a chronic, slowly progressive, degenerative disease affecting the central nervous system of cattle. The majority of BSE cases have been found in the United Kingdom and recent cases have been identified in European Union countries. BSE has not been found in the United States. Affected cattle die. Currently there is no test to detect the disease in a live animal; veterinary pathologists confirm BSE by examining the brain tissue of dead animals or by detecting the abnormal form of the prion protein. BSE has been linked to a variant form of Creutzfeldt-Jakob disease (CJD) in humans.

Related Animal and Human Diseases
BSE is a transmissible spongiform encephalopathy (TSE); other TSE's include scrapie in sheep, chronic wasting disease in deer and elk, and "classic" CJD and "variant" CJD in humans.

In 1996, the committee investigating BSE in the United Kingdom identified 10 unusual cases of CJD. These cases differed from classic CJD and were termed variant CJD. Variant CJD cases are characterized by: a younger age at onset of symptoms (29 years of age vs. 60); early behavioral changes; longer duration of illness; unique EEG patterns; and, under microscopic examination, different pathogen lesions. Classic CJD occurs each year at a rate of 1 to 2 cases per million people throughout the world, including the United States and Minnesota.

According to the U.S. Centers for Disease Control and Prevention, no cases of variant CJD have been identified in the United States.

Safeguarding the United States food supply
Since 1989, the USDA has prohibited the importation of live hoofed animals from countries where BSE is known to exist in native cattle and products derived from these animals, including bone meal. In 1990, the USDA initiated an active surveillance program to examine the brains of U.S. cattle for BSE. In 1997, the restrictions were extended to include all of the countries in Europe. As of December 2000, the USDA prohibited all imports of rendered animal protein products, regardless of species, from Europe.

For more information:
Extension Contact: Jan Swanson, 800-380-8636/612-624-2268, swans032@umn.edu
Minnesota Board of Animal Health: 651-296-2942 or www.bah.state.mn.us
Minnesota Department of Agriculture: 1-800-967-AGRI
U.S. Department of Agriculture website at www.aphis.usda.gov/oa/bse.