Bovine Spongiform Encephalopathy

Bovine spongiform encephalopathy or mad cow disease is a fatal brain disease of cattle. The brain of affected animals appears sponge-like under a microscope.

Bovine Spongiform Encephalopathy is of great importance because:
*Its causative agent can overcome the species barrier and became very dangerous to man
*Cattle are significant source of human food, and an undiagnosed Bovine Spongiform Encephalopathy infection is a danger to man.

The first appeared in the United Kingdom in 1986. Scientists believed the disease may have first been transmitted though feeding cattle protein made from sheep carcasses infected with scrapie, the sheep form of the disease.

In the early 1980s, a change in the manufacturing process that limited steam heat treatment may have played a role in the appearance of the disease.

Bovine Spongiform Encephalopathy developed into an epidemic as a consequence of an intensive farming practice – the recycling of normal protein in ruminant feed.

The human form is Creutzfeldt Jakob disease (CJD). It is a rare disease that occurs in approximately one person per million.

A new type of CJD, new variant or nvCJD has been linked to Bovine spongiform encephalopathy exposure. It is believed that eating Bovine spongiform encephalopathy infected meat can cause variant Creutzfeldt Jakob disease.

For this reason, it is important that cattle are regularly tested for BSE and that contaminated meat is prevented from getting into food products for human consumption.

The origin, transmission and nature of spongiform encephalopathies theory is that the causative agent is a prion, a type of pathogenic protein.

Prion proteins is a minute proteinaceous infectious particles 4-6 nm in diameter. They occur in normal and pathogenic forms on the surface of nerve cells and various cells of lymphatic tissue.

Infective prions are thought to be found only in the brain tissue, spinal cord and retina of infected animals, not in meat or milk products.
Bovine Spongiform Encephalopathy