Bovine spongiform encephalopathy is a brain disease that affects cattle. It’s also known as mad cow disease. The complete nature of this disease is not fully understood, but scientists believe it is caused by a protein called a prion rather than some kind of bacterial infection or virus. This protein gradually causes the tissue in the brain to become spongy, eventually leading to death. Bovine spongiform encephalopathy can be spread to humans who eat the meat of infected cattle, and it is always deadly in both animals and humans.
When cattle are infected with this disease, the first thing that changes is their behavior. They may become aggressive or nervous. After a while, they start to develop motor difficulties, and they might have trouble walking or standing up. Eventually, they start to lose weight and waste away.
When people have the disease, their motor skills deteriorate, and they may begin to gradually lose their memory. When the disease is first starting, they often have emotional or psychiatric problems and changes in their demeanor. Sometimes they can become depressed, or they might be angry with their family members.
It can take years after exposure for symptoms to appear in both humans and animals. Scientists believe the disease is transmitted by eating the brain tissue of an infected animal. Small amounts of brain tissue can sometimes show up in ground beef, and this is usually how people contract the disease. It is very difficult for bovine spongiform encephalopathy to be passed on to humans, even if they eat contaminated tissue.
Cows also contract bovine spongiform encephalopathy by eating diseased brain tissue, and this happened because a lot of animal feed was made using leftover cattle parts. Laws have been passed to restrict the use of this kind of feed, and these measures have been fairly successful in decreasing occurrences of bovine spongiform encephalopathy worldwide.
Most cases have been reported in Great Britain, and at one point there was a huge epidemic with thousands of new infected cattle being reported every week. The first cows to ever get this disease were infected in the 1970s, but they didn’t become sick until the mid 1980s. The British bovine spongiform encephalopathy epidemic peaked during 1992 and 1993.
Most human cases have also been British citizens. Scientists say that people can limit their chances of developing the disease by focusing on steaks and roasts rather than ground beef, because those meats are much less likely to be contaminated. There is no way to test for the disease until after someone dies, but scientists can usually zero in on it as a probable diagnosis based on the symptoms.