encephalopathy, bovine spongiform

Bovine spongiform encephalopathy

Bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, is an incurable and always fatal neurodegenerative disease of cattle. Symptoms include abnormal behavior, trouble walking, and weight loss. Later in the course of the disease, the cow becomes unable to function normally. There is conflicting information about the time between infection and onset of symptoms. In 2002, the World Health Organization suggested it to be approximately four to five years. Time from onset of symptoms to death is generally weeks to months. Spread to humans is believed to result in variant Creutzfeldt–Jakob disease (vCJD). As of 2024, a total of 233 cases of vCJD had been reported globally. BSE is thought to occur due to an infection by a misfolded protein, known as a prion. Cattle are believed to have been infected by being fed meat-and-bone meal that contained either the remains of cattle who spontaneously developed the disease or scrapie-infected sheep products. The United Kingdom was afflicted with an outbreak of BSE and vCJD in the 1980s and 1990s. The outbreak increased throughout the UK due to the practice of feeding meat-and-bone meal to young calves of dairy cows. Cases are suspected based on symptoms and confirmed by examination of the brain, which typically has reduced mass because of the degeneration caused by prion, which causes the brain to become spongy with holes. Cases are classified as classic or atypical, with the latter divided into H- and L types. It is a type of transmissible spongiform encephalopathy. Efforts to prevent the disease in the UK include n...