January 5, 2004

BSE Frequently Asked Questions
December 31, 2003

BSE or bovine spongioform encephalopathy is a transmissible spongiform encephalopathy. There are at least five recognized TSEs in humans and at least five recognized TSEs in animals. BSE is an infectious disease of the central nervous system of cattle. The disease is sometimes referred to as “mad cow disease”, but this name is scientifically inaccurate. Bovine refers to cattle, spongioform refers to a sponge-like appearance, and encephalopathy is disease of the brain. The disease is thought to be caused by a prion, which is very different from a virus, bacteria or protozoa, the common causes of infectious diseases.

Scientists believe prions are naturally occurring, self-replicating proteins that fold upon themselves. Under this theory, how the proteins fold determines whether the prions are infectious and how infectious they are. Prions cause BSE by causing metabolic changes in cattle, most importantly metabolism in the brain. Prions prevent the brain from functioning as it should. These metabolic changes result in “vacuoles” or voids in the brain, leading to the name spongioform encephalopathy. BSE has a relatively long incubation period (4-6 years). Typically, only adult cattle show clinical symptoms of BSE.

Scientists believe prions are primarily in the brain and spinal cord of adult cattle.

Research in Britain suggests that BSE is spread when affected tissue, primarily central nervous system tissue from infected animals, is consumed by other ruminants early in life. Animal to animal spread through close contact has not been documented.

The U.S. system for detecting and controlling BSE is based on what’s been learned about the disease in Britain and other countries. The U.S. implemented multiple hurdles to prevent the entry and spread of BSE. These include: import restrictions on cattle, import restrictions on ruminant meat and bone meal, and other materials from countries with BSE; a ban on feeding most rendered ruminant protein back to ruminants; and a surveillance program. These measures are designed to prevent the entry and multiplication of BSE in the United States.

On Dec. 30, 2003, the USDA announced additional safeguards to bolster the U.S. protection systems against BSE including a ban on downer animals in the food supply, changes in how animals that are tested for BSE are handled, and new regulations for meat processors to provide additional safeguards to prevent central nervous system tissue from entering the food supply. (www.usda.gov)

Non-ambulatory or “Downer” cows are cattle presented for slaughter that are unable to stand. As of December 30, 2003 the USDA has ruled that non-ambulatory cattle will no longer be allowed in the food supply. Previously, non-ambulatory cattle could enter the food supply after they passed USDA Food Safety Inspection Service inspection.

To date, USDA reports testing 20,526 animals for BSE in 2003. Most testing focuses on older animals because of the relatively long incubation period associated with BSE.

Because the primary theory on the spread of BSE focuses on the feeding of infected meat and bone meals, the FDA implemented a ban on the feeding of most mammalian protein to ruminants in 1997. This effort was to stop the potential spread of BSE by banning the feeding of meat and bone meal which may contain central nervous system tissues such as brain and spinal cord. The law states that meat and bone meal produced from ruminant animals (cattle, sheep, bison, deer, elk) cannot be fed to ruminants.

• Non-mammalian tissues including marine (fish), poultry and vegetable proteins
• Non-protein or non-tissue feedstuffs such as grease, tallow, amino acids, dicalcium phosphate, fats and oils
• Protein from pigs and horses
• Blood and blood products
• Milk and milk products

• Meat
• Glandular meal
• Meat and bone meal
• Meat by-products
• Meat and bone meal tankage
• Hydrolyzed hair
• Cooked or steamed bone meal
• Bone marrow
• Leather meal

Producers are required to keep records of purchased feedstuffs as part of the federal regulation. Sales invoices and feed labels should be kept for at least one year after purchase. These will be valuable in the event of an audit or traceback situation involving BSE.

Some researchers theorize that BSE is linked to a human disease called new variant (nv) Creutzfeldt-Jakob disease. Pathological similarities exist between the two conditions which lead scientists to speculate that the two conditions are related. However, a definitive link between BSE and nv-CJD has not been established. The risk of acquiring nv-CJD from eating beef in the United States is extremely low. There have been no cases of nv-CJD reported in the United States. Another transmissible spongiform encephalopathy afflicting humans is CJD. It is important to note that CJD and nv-CJD are two different conditions and their only link is a similarity in name.

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