Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease, degenerative
brain disorder of cattle. Symptoms in cows include loss of coordination and a typical
staggering gait. Affected animals also show signs of senility, for example, lack of
interest in their surroundings, the abandonment of routine habits, disinterest in
feed and water, or unpredictable behavior. Affected cattle show symptoms when
they are three to ten years old.
First identified in Britain in November 1986, over 170,000 cases have since
been recorded there. Sporadic incidences have been confirmed in other European
countries, with Switzerland (over 260 cases) and Ireland (over 260 cases)
identifying the largest number. It has also been recognized in Canada, where cases
are confined to dairy cows imported from Britain. BSE has not been officially
confirmed in the United States or any other major milk-producing country.
Autopsies of affected cattle reveal holes in the brain tissue that give it a spongy, or
Similar spongiform diseases have been recognized in humans
(for example, Creutzfeldt-Jakob disease or CJD) for over a century and in sheep
(scrapie) for over 200 years. The cause of BSE is unproven, although there is strong
evidence that prions, which may be ineffective proteins, are the agent. Other
hypotheses suggest that prions work with an as yet undetected virus to cause the
Recycled animal tissue, which had been routinely fed to British dairy cows as
a protein supplement, was identified as the source of the infection. The European
Commission's Scientific Veterinary Committee and the world control body, the
FÃÂ©dÃÂ©ration Internationale des Epizooties (FNE) believes that BSE was originally
spread from sheep's brains infected with scrapie and that its spread was
accidentally accelerated by the ingestion of brain tissue taken from cows that had
become infected with BSE.
Following through with this fodder transmission theory, the...