The Agriculture Department said that additional checks were needed after an initial screening proved inconclusive for Mad Cow Disease in a single animal. The announcement raised fears that the U.S. might have its second case of the fatal brain-wasting disease and rattled the cattle industry, meat companies and hamburger restaurant chains.
Mad cow disease, bovine spongiform encephalopathy (BSE), attacks an animal's nervous system. People who eat food contaminated with BSE can contract a rare disease that is nearly always fatal -- variant Creutzfeldt-Jakob disease.