a disease of cattle first reported in 1986 in Great Britain; characterized clinically by apprehensive behavior, hyperesthesia, and ataxia, and histologically by spongiform changes in the gray matter of the brain stem; caused by a prion, like spongiform encephalopathies of other animals (e.g., scrapie) and human beings (Creutzfeldt-Jakob disease [vCJD]). SYN: mad cow disease.In the middle 1990s, an unusual number of cases of Creutzfeldt-Jakob disease (CJD) were reported in people under 30 years of age in Great Britain. These patients displayed typical clinical features but not the EEG changes characteristic of CJD, and autopsy specimens showed unusual amyloid plaques resembling those of kuru but not previously observed in CJD. This so-called variant Creutzfeldt-Jakob disease (vCJD) has been traced to consumption of beef products contaminated by central nervous system tissues of a cow infected with bovine spongiform encephalopathy (mad cow disease). An epizootic of this disease killed more than 150,000 cattle in Britain between 1986 and 1996. Since July 1989 the importation of cattle and cattle products from the U.K. has been banned by the U.S. Department of Agriculture. The discovery late in 2003 of a single dairy cow infected with BSE in Washington state prompted a revision of screening procedures in the U.S. and a tightening of restrictions on the use of meat products as human food. WHO consultants have condemned the practice of feeding ruminant-derived meat-and-bone meal to cattle and urged the adoption of measures to ensure that no part of any animal that shows signs of a spongiform encephalopathy enters any human or animal food chain. Milk, dairy products, gelatin, and lard are considered safe. see also Creutzfeldt-Jakob disease.