Mad Cow Disease

Microbiologists became aware of bovine spongiform encephalopathy, also known as, mad cow

disease in 1986. The disease originated in the United Kingdom, when cattle feed was prepared from

sheep infected with their own version of the disease (Tortora, Funke, & Case, 20). In 1996, countries

all over the world began to refuse beef imported from the United Kingdom because hundreds of

thousands of cattle born after 1988 had to be killed for fear they may had been infected with the

disease (Tortora, Funke, & Case, 20).

Mad Cow disease is caused by an infectious protein called a prion. Prions are the cause

of neurological diseases (Tortora, Funke, & Case, 203). This can result in an organism losing its ability

to mentally and physically function properly (Hirsch). These prions are considered to be mutated and

cause transmissible spongiform encephalopathies (TSEs). TSEs are so named because the brain becomes

spongy (full of holes), the brain tissue withers, and uncoordinated movements develop in the affected

person or animal (Timby & Smith, 114).

People aren't, technically, diagnosed with mad cow disease, but with a variant called

Creutzfeldt-Jakob disease (vCJD). Similarly, vCJD is caused by prions. Those that have tested positive of

the bovine variant gradually began to lose the ability to function properly, just as the organisms who

were diagnosed with mad cow. By October 2009, there had been 217 vCJD cases reported worldwide,

and all had spent some time in the United Kingdom (Hirsch). The research have linked that the bovine

variant was transmitted to humans who ingested undercooked beef from the infected cattle (393), and

as previously mentioned the mutated prions were transmitted from sheep to cattle when the cows were

fed waste parts of slaughtered infected sheep (Timby & Smith, 114).

The United States has taken drastic measures to prevent any outbreaks of bovine spongiform

encephalopathy in the country. It is prohibited from using any animal that has fallen and is unable to

rise and walk for any purpose, and the use of animal protein as a feed supplement. The FDA has, also,

banned