Sheep with scrapie may be able to pass a kind of mad cow disease to humans, a new study shows. Cattle get bovine spongiform encephalopathy -- BSE or mad cow disease -- from a dangerous prion (an abnormal form of normal cell protein) called PrPsc. When humans eat PrPsc in contaminated beef, it can give them the human version of mad cow disease called variant Creutzfeldt-Jakob disease (vCJD). Scientists say vCJV comes from eating nerve tissue (such as that in the brain and spinal cord) from cattle infected with mad cow disease.