Mad Cow Disease: Spongiform Encephalopathy (Epidemics).

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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

spongiform, texture.

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

Fédération 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...