mad cow disease

mad cow disease: see prion.

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mad cow disease

 or bovine spongiform encephalopathy (BSE)

Fatal neurodegenerative disease of cattle. Symptoms include behavioral changes (e.g., agitation), gradual loss of coordination and locomotive function, and, in advanced stages, weight loss, fine muscular contractions, and abnormal gait. Brain tissue becomes pitted with holes and spongy. Death usually follows within a year. The disease is similar to the neurodegenerative disease of sheep called scrapie. No treatment is known. A BSE epidemic in Britain that began in the mid-1980s is believed to have been caused by the use of cattle feed containing supplements made from ruminant carcasses and trimmings. Hundreds of thousands of infected cattle were slaughtered and the use of animal-derived protein supplements ended. The cause of both BSE and scrapie is attributed to an infectious aberrant protein called a prion. The unusual occurrence of Creutzfeldt-Jakob disease, another prion-related illness, in young people beginning in the mid-1990s may be linked to eating meat from cattle with BSE.