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Facts on Mad Cow

Mad cow disease is the common name for bovine spongiform encephalopathy (BSE). This disease is fatal in all breeds of cows and can also kill people who eat beef from an infected cow. Eating BSE-infected cows gives humans the lethal variant Cruetzfelt-Jakob disease. According to the U.S. Centers for Disease Control and Prevention (CDC), 1993 saw the most deaths in cows and people but occurrences have fallen steadily since that year.

  1. Cause

    • Although no one is entirely sure what causes mad cow disease, the most prevalent theory is that it was from contaminated feed made with sheep infected with scrapie. Ground up sheep meat and bone meal was a common additive to cattle feed in the United Kingdom. Both dairy and beef cattle are used for meat. Dairy cattle calves are separated from their mothers soon after birth in order to increase the cow's milk production. Calf feed used to include ground-up meat and bones from cows. If a calf ate feed made from a cow infected with BSE, then the calf would also get BSE.

    History

    • Although mad cow disease was first identified in 1986, the CDC believes that the disease began in cows during the 1970s. The cause of mad cow disease was not identified until the 1990s. By that time, BSE had spread throughout herds in the United Kingdom. The first case of BSE in the United States was in 1993. It wasn't until 1996 that mad cow disease was found to be responsible for variant Cruetzfelt-Jakob disease in people. The U.K.'s Department for Environment, Food and Rural Affairs estimates that as of January 2010, there are fewer than four suspected cases of BSE per week.

    Symptoms in Cows

    • Cows infected with BSE stagger about and eventually cannot stand. Sometimes cows will thrash as if in a seizure trying to stand, hence the common name "mad cow disease." According to the U.S. Food and Drug Administration (FDA), it can take anywhere from four to six years for a cow to begin showing symptoms once it is infected.

    Significance

    • BSE decimated the beef industry in the United Kingdom. Many countries, including the United States and countries in the European Union, refused to import U.K. beef starting in 1997, until the cattle feed ban was strengthened and any cows suspected of eating contaminated feed were culled by government health inspectors. Any calf born within two years by a culled cow was also culled. The European Union refused to lift the ban until 2006.

    Losses

    • Although millions of cattle were culled, BBC News estimates that only 183,000 cows were diagnosed with BSE. The British National Farmers Union estimates that mad cow disease cost farmers about 675 million pounds sterling per year from 1996 -- 2006. It is unknown how many people died of variant Cruetzfelt-Jakob disease, but the CDC estimates that there were 217 people in 11 countries from 1996 to 2009. There is no cure for the disease.

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