What is mad cow disease (bovine spongiform encephalopathy)?

Answer: Mad Cow disease, or bovine spongiform encephalopathy (BSE), is a prion disorder that causes neurodegeneration in cattle.


Mad cow disease is a progressive, neurodegenerative disease in cattle that causes irrational behavior and a loss of voluntary locomotor control. There is no diagnostic tests available other than a pathological examination post mortem that examines nervous tissue. Mad cow disease is restricted to bovine - the related human disorder that arises from consumption of infected cattle is called the variant Creutzfeld-Jakob disease, or vCJD.

Prions are misshapen proteins that have the capability to affect the shape of other proteins. Prions cannot be destroyed by exposing them to ordinary cooking temperatures; they remain viable at temperatures as high as 1000F. The misshapen prion associated with mad cow disease is PrPSc.

In order to decrease the occurrence of human cases of vCJD, slaughterhouses implement strict control of nervous tissue, intestines, and eyes. These body parts are disposed of separately and segregated from the rest of the food processing workspaces.

Although scientists are unsure of the origin, some scientists believe that it related to the neurodegenerative disorder scrapie seen in sheep. The prions may have jumped species at some point.