What is Mad Cow Disease?

Eliminating nervous system tissues in ground meat used in hamburgers and sausage has reduced the risk of mad cow disease.
Mad cow disease attacks the central nervous system of cattle.
By-products from slaughtered sheep infected with a similar disease may have been fed to cattle, leading to mad cow disease.
Contaminated cattle feed is thought to have led to mad cow disease.
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  • Written By: Jane Harmon
  • Edited By: Niki Foster
  • Last Modified Date: 31 August 2014
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Mad cow disease, officially known as bovine spongiform encephalopathy (BSE), is a cattle disease that attacks the central nervous system. That is, it moves through the spinal cord and brain, literally killing brain cells and leaving holes in the brain. The visible effects of this disease are erratic, or insane, behavior in the infected cow, hence the name mad cow disease. Mad cow disease can be transmitted to humans who eat contaminated meat from a 'mad cow'. This makes the disease doubly threatening - it endangers the food supply as well as individual human lives.

In the late 1980s, mad cow disease was first seen in British cattle. It is thought to have entered the cattle population through a similar disease affecting sheep. At that time, byproducts from slaughtered sheep and cows were added to cattle feed to increase the amount of protein they consumed, and this practice is believed to have led to the disease in cattle.

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Humans who eat contaminated beef acquire a related disease, called new variant Creutzfeldt-Jakob disease (nvCJD), a neurological disease with a progression and effects similar in humans to mad cow disease in cattle. Over 150 people in Europe, mainly in Britain, were infected and died of the human form of the disease. Because the infectious agent that causes mad cow disease can lie dormant for a number of years, putting the pieces of the puzzle together took some time, but it is now believed that mad cow disease is transmitted via a misshapen protein called a prion. This agent exists in nervous system tissues, so meat that does not come from these tissues - that is, from animal brain and spinal tissue - is probably safe.

Mad cow disease has been controlled over the past several decades by eliminating the use of nervous system tissues in cattle feed and ground meat products such as hamburger and sausage. There have been several cases of mad cow disease in the US recently, but they were isolated and are thought to have been contained. There is currently no treatment for mad cow disease or the human nvCJD. In areas where the food chain is suspicious, avoid eating ground meat or dishes that include animal brains.

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KoiwiGal
Post 3

To some extent I can't believe people were surprised when a disease resulted from them feeding the carcasses of cows to other cows. I know they say that part of the reason the infection happened was that they had lowered the regulation temperature the feed had to be cooked at.

But really, the reason cannibalism never caught on is because it is really bad for you. People in areas that did practice it are some of the only people who suffer from the other kind of prion disease (the laughing disease). We read about it in my anthropology class.

And who knows what other diseases might have infected them that aren't only transmitted by eating brains?

Cannibalism is gross and taboo to us because it is incredibly dangerous. And it is just as dangerous for cows.

pleonasm
Post 2

@clyn - I've come across that question when I was giving blood and I was always grateful I didn't live in England around that time. Hopefully they will eventually come up with a way to detect the latent disease. I know that for the people around that time who may have been exposed, the worst aspect was not knowing when or if they might find out about it.

You could live a perfectly normal life for years afterward and not realize you had it until you eventually started displaying mad cow disease symptoms.

I can see why they'd want to be cautious about people donating blood, but it is very frustrating for all concerned.

clyn
Post 1

I lived in England briefly in the late 1990s. Now, I can no longer donate blood, since there isn't a test to detect if I was exposed or if my blood could transmit the disease. It's very, very frustrating.

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