What Are the Causes of Mad Cow Disease?

N. Madison
N. Madison

There aren't many known causes of mad cow disease. In fact, this disease has just one known cause, which is called a prion. A prion is a type of protein that is capable of causing infection. Some people compare prions to viruses, but the two are dramatically different; viruses are alive and can be killed using certain types of drugs, disinfectants, and heat generated during cooking. Prions, however, are not living organisms and are very difficult to destroy. Unfortunately, there are no effective treatment options for a person or animal diagnosed with this disease.

Veterinarians and government inspectors routinely inspect livestock for signs of BSE.
Veterinarians and government inspectors routinely inspect livestock for signs of BSE.

When a person talks about the causes of mad cow disease, he may actually mean the methods of transmission, as there is really only one known cause of the disease. The root of mad cow disease is a substance referred to as a prion, which is a unique type of protein. Most people think of healthy substances when they hear about proteins, but prions are the opposite. They are infectious and capable of causing deadly brain diseases.

Mad cow disease attacks the central nervous system of cattle.
Mad cow disease attacks the central nervous system of cattle.

While there aren't multiple causes of mad cow disease, there is more than one method of transmission. Both methods involve animals. Animals develop the disease when they consume feed that is contaminated with these unique proteins. For example, this may happen when animals are fed feed that contains parts of other animals. The second method of transmission occurs when a person consumes meat that contains prions capable of causing mad cow disease.

Interestingly, only certain animals seem to be vulnerable to mad cow disease. Usually, cows develop the disease, which is scientifically referred to as Bovine Spongiform Encephalopathy (BSE). Humans then contract the disease from these infected cows when they consume the infected beef. Unfortunately, cooking doesn't destroy the infectious proteins, so even properly handled and cooked beef can contain the proteins and spread the disease.

Unfortunately, people cannot destroy prions in the same way as they can other infectious agents. If viruses and bacteria were among the causes of the disease, dealing with it might be easier; disinfectants, drugs, and cooking at high temperatures destroy many disease causers. These methods are not effective against prions, however. Additionally, there is no effective treatment for mad cow disease — it is fatal.

In time, scientists may discover other causes of mad cow disease. Scientists are studying other possible methods of transmission as well and trying to learn whether animals can inherit the infectious proteins. For now, however, prions and transmission through food are the known culprits.

N. Madison
N. Madison

Nicole’s thirst for knowledge inspired her to become a wiseGEEK writer, and she focuses primarily on topics such as homeschooling, parenting, health, science, and business. When not writing or spending time with her four children, Nicole enjoys reading, camping, and going to the beach.

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Discussion Comments


I know a couple of ranchers who produce large amounts of beef each year. They have large herds of cows. You might be surprised at how closely they are regulated. I know that the agencies that monitor and inspect the food we eat sometimes get a lot of criticism for not being strict enough, but there are a large number of ranchers and farmers who believe these agencies have gone too far in some of the ways they go about their jobs.

If one animals in a herd gets sick from some type of virus or other infection then the the rancher may be required to dispose of hundreds if not thousands of animals. And this doesn't have to be for a condition as serious as mad cow disease.

I think mad cow disease is terrible, and I understand the need to be vigilant in protecting people from the condition, but when you look at the numbers, there are few cases of the disease in humans-- a low percentage anyway. So, we must be doing something right, and we don't want to go overboard. Like it or not, there is a risk you take when you eat beef or any food.


When you think about it, isn't it a wonder that mad cow disease in humans is not more common than it actually is at this time. Just think about how much beef people, especially Americans, eat. With all of the steaks and hamburgers we consume, and with the beef coming from so many different sources, seems like keeping the deadly protein out of our food supply would be a very difficult job.


I've seen pictures of cows with mad cow disease. The animals look like they are drunk or dazed. They have a difficult time keeping their balance, and they walk in circles when they are able to stay on their feet. This is so sad to watch. And it is so scary to read this article and see that there is no cure for the disease, and that the disease can be spread to humans.

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