Mad Cow Disease

Mad cow disease, or bovine spongiform encephalopathy (BSE), is a degenerative disease of the nervous system in cattle. It is always fatal. Cattle with BSE develop minute holes in their brains, have difficulty standing and walking, produce less milk, become irritable, and lose weight. The disease has an extended incubation period. Symptoms usually appear four to five years after infection, and death often occurs within weeks of symptom onset.

BSE belongs to a group of diseases called transmittable spongiform encephalopathies (TSEs). Other TSEs include scrapie in sheep, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob Disease in humans. TSEs can spontaneously arise in individual animals or can occur due to genetic mutations. They are believed to occur when certain cellular proteins, called prions, become misshapen. ...