Although no cases of mad cow disease have been confirmed in people or cattle in the United States, a Purdue specialist believes that individuals have died as a result of the disease. Although there is no scientific evidence to back up these claims, they have had an impact. Mad cow disease has never been found in any animal in the United States, so there is no risk of it spreading here. People can become infected with bovine spongiform encephalopathy (BSE) or "mad cow disease" when they eat products such as meat and dairy products that contain the brain tissue of cows, sheep, and humans. BSE was first discovered in 1986. Since then, more than 10 million animals have been killed to prevent the spread of the disease. In 1996, a human case of BSE was reported for the first time. The patient showed symptoms similar to those seen in people with Alzheimer's disease - mainly memory problems and loss of judgment. He was a 67-year-old man who lived in England and had eaten meat and bone meal before he became ill. This material is used as a fertilizer and contains parts of animals' bodies such as bones, horns, skin, and viscera. It has been suggested that this case may have been caused by contact with this material, but further studies are needed to confirm this hypothesis. In 2003, a second case of BSE was reported.