- Bovine spongiform encephalopathy (BSE),commonly known as mad cow disease.
- is a fatal neurodegenerative disease (encephalopathy) in cattle that causes a spongy degeneration of the brain and spinal cord.
- The disease may be most easily transmitted to humans by eating food contaminated with the brain, spinal cord or digestive tract of infected carcasses.
- However, the infectious agent, although most highly concentrated in nervous tissue, can be found in virtually all tissues throughout the body, including blood.
- In 1997, FDA published a final regulation that prohibits the use of most mammalian protein in the manufacture of animal feeds given to ruminant animals, such as cows, sheep, and goats.
- The rule does not prohibit the use of mammalian protein as an ingredient in feed for non-ruminants, but requires process and control systems to ensure that such use does not cause contamination of ruminant feed during feed manufacture or transport.
- FDA strengthened the 1997 rule in 2008 by prohibiting the use of the highest risk cattle tissues in ALL animal feed.
- These high risk cattle materials are the brains and spinal cords from cattle 30 months of age and older, and the entire carcass of cattle not inspected and passed for human consumption, unless the carcasses are shown to be from cattle less than 30 months of age, or the brains and spinal cords have been removed.
- The BSE agent, known as a prion, is an abnormal and infectious form of a normal protein that is abundant in the brain and spinal cord.
- The prion is able to convert the normal prion proteins in the infected animal to the infectious form by changing their conformation.
- Aggregations of these abnormal prions then accumulate to form plaques causing the microscopic appearance of holes in the brain (sponge-like) which is associated with clinical BSE disease in cattle.
- The spread of BSE was a result of feeding BSE contaminated meat and bone meal of ruminant (cattle, sheep and goats) origin to cattle
- As the disease affects the brain, the symptoms are the gradual lack of mental and physical ability. In cows this degeneration of the brain results in an ability to stand or walk straight, and has therefore given rise to the common term ‘mad cow disease’. BSE ultimately results in death.
