Bovine spongiform encephalopathy (BSE) or “mad cow disease” is a progressive brain disease of cattle. It is associated with inclusion in cattle feed of ruminant-derived protein contaminated with the infectious agent of BSE.

It is generally accepted that the infectious agent is a prion, a "self-replicating" protein, rather than a conventional bacterium or virus. The disease has a long incubation period (5 years on average) and is always fatal. BSE causes the brain to become sponge-like. Brain, central nervous system tissue, and parts of of the small intestine can carry the infective agent, so measures have been taken to exclude these tissues from the animal feed supply and from human food.

BSE is often referred to as "mad cow" disease because animals infected with the disease are often irritable and incoordinated and can react violently to humans and to other animals.

Occurrence

The most extensive outbreak of BSE has been in the United Kingdom where more than 180,000 cases have been recorded, starting in 1986. As of December 2007, 10 cases of BSE have occurred in Canada and the United States.

Clinical Signs

• Disorientation
• Ataxia (incoordination)
• Irritability
• Decreasing ability to walk
• Unexplained down cattle

Treatment

There is no treatment for BSE. Any cow suspected of having BSE should be reported to the State Veterinarians or USDA Area Veterinarian in Charge immediately.

Prevention

The FDA has taken steps to prevent to introduction of BSE into U.S. beef herds by adopting a ruminant-to-ruminant feed ban in 1997 preventing use of ruminant parts as feed for cattle. In addition, the USDA restricts the entry of cattle and cattle products from countries with BSE to protect the national herd and human health.

Public Health

There is evidence that consumption of brain and spinal cord tissue from cows with BSE can lead to variant Creutzfeldt-Jakob disease(vCJD) in people. The symptoms of vCJD are similar to those of BSE and include progressive disorientation, personality changes, and progressive paralysis. There is no cure for vCJD and it is fatal.

Since the discovery of a BSE-infected cow in Washington State in 2003, the federal government has adopted measures to ensure that meat coming from a cow suspected of having BSE will not be allowed to enter the food supply. Visit the EDEN BSE Issues Pageto learn more about BSE and the measures in place to safeguard our food supply.

Links

Confirmed BSE cases in North America -EDEN Extension Disaster Education Network

Facts about Bovine Spongiform Encephalopathy (BSE) - University of Wisconsin

BSE FAQs -North Dakota State University

Bovine Spongiform Encephalopathy -USDA-Foreign Agricultural Service

Bovine Spongiform Encephalopathy - "Mad Cow Disease" -Food Safety and Inspection Service