Bovine spongiform encephalopathy (BSE), is commonly known as mad-cow disease. It is a progressive neurological disorder of cattle that results from an infection by an unconventional transmissible agent. BSE is one of a group of diseases that affect a number of different mammals. These diseases, known as Transmissible Spongiform Encephalopathies (TSEs), or Prion Diseases, result from the build-up of abnormal prion proteins in the brain and nervous system. BSE attacks the brain and central nervous system of the animal and eventually causes death.
Research has shown that TSEs have two characteristics in common: they can be transmitted between animals, and they cause the same spongy decay of brain tissues. A commonly occurring prion disease is scrapie. The symptoms commonly associated with it are disorientation, clumsiness and occasionally, aggressive behavior towards other animals and humans.
What caused the disease? Most experts agree that the BSE was spread by cattle eating feed that contained meat-and-bone meal (MBM), which contained BSE infected parts of other grazing animals. MBM is produced in a process called rendering, this is where otherwise unused meat products are taken from the animal carcass and turned into cattle feed. Cattle can contract BSE if they are fed infected brain tissue. Thus, it is presumed that BSE was transmitted to cattle through their animal feed.