Feb
24
2005

Do you worry about mad cow disease?

"Mad cow disease"-also known as bovine spongiform encephalopathy (BSE)-is a fatal brain disorder in cows. It's spread by contact with brain or other nervous-system tissue from an animal with the disease. An animal can be infected but not have any symptoms for years. But once the disease is active, it kills brain cells, leaving large, spongy holes. It also causes large clumps of abnormal proteins in the brain and quickly kills the victim.

Scientists still don't know for sure what causes mad cow disease. But the most likely theory is that abnormal proteins called prions (PREE-ons) damage nerve cells, causing loss of brain function and eventual death.

You can read more about prions and how scientists think they might cause mad cow disease:
click here

Scientists think mad cow disease came from a similar disease in sheep called scrapie. We used to feed cows meat and bone meal-from other cows, but also animals such as sheep-leftover after processing for human consumption. Cows ate food contaminated with scrapie and developed BSE. At the time, people thought that neither scrapie nor BSE affected us, so meat from BSE-infected cows got into the human food supply. People who ate the infected meat-probably hamburger or other processed meats-developed a disease similar to the cows'.

You can find out a lot more about mad cow disease and its human manifestation:
click here

The US government has made some rules to try and protect people here from the disease. It has banned the import of cud-chewing animals (cows, sheep, goats) and products made from them from Europe. It prohibits the use of any mammal products in food for cows. Cows with unidentified neurological disorders cannot be eaten. Drug companies can't use animal tissues from countries with mad cow disease when they make vaccines or other products. And people who spent more than six months in the UK (where the mad cow disease epidemic was first identified) between 1980 and 1986 are not allowed to donate blood.

Do the new rules make you feel safer about eating meat? Have you changed any of your eating habits since mad cow reports came out in the media?

Your Comments, Thoughts, Questions, Ideas

Anonymous's picture
Anonymous says:

i think that you can solve the mad cow desise is by making the cow happy and maybe give it some ice cream

posted on Mon, 04/03/2006 - 12:44pm
Liza's picture
Liza says:
The results of an experiment published in the April issue of Journal of Pathology suggest that abnormal prion proteins may not be infectious at all, and that the prion protein may just be an indication that whatever causes the disease is present. The bummer, however, is that scientists still don't know what the infectious agent is.
posted on Fri, 04/14/2006 - 11:26am
Liza's picture
Liza says:

National Institutes of Health (NIH) scientists announced in the 6/2 issue of Science that the prions that cause mad cow disease and its relatives have to attach themselves to the outside of cell membranes to destroy brain tissue. Their research suggests that if they can devise a way to break the bond that anchors the prions to the cell membranes, they may be able to treat the deadly disease.

Virologist Dr. Bruce Chesebro and a team of researchers bred genetically-engineered mice that lack the anchor that usually binds prions to the surfaces of cells. Then they injected both the experimental and regular mice with prions that cause scrapie, a relative of mad cow disease. All of the regular mice immediately got sick. But the engineered mice showed no signs of the disease. Chesebro looked at their brains; they had lots of the plaques that are a hallmark of the disease, but their brain cells hadn't died.

Chesebro says,

"We need to focus on [this] as a target for drug therapy."

posted on Sat, 06/04/2005 - 2:22pm
Liza's picture
Liza says:

Researchers at the Salk Institute for Biological Studies reported in this week's Nature that prions can be rendered harmless in the laboratory by changing the three-dimensional shape of the prion protein's structure. Altered prions can't infect normal prions.

Scientist Roland Riek and his colleagues used fungal prions instead of human prions because they're easier to isolate and work with. Riek said,

"It's a fantastic system to study the structural components of prions and measure infectivity. ... This discovery is very interesting from a basic scientific point of view because it shows that a specific conformation of the prion protein is the infectious entity, and also that we can easily destroy the prion's infectivity by altering its shape. We now need to find out if this is also the case in mammalian prions."

posted on Mon, 06/13/2005 - 1:05pm
Liza's picture
Liza says:

The United States Department of Agriculture (USDA) has possibly discovered the second American case of mad cow disease.

In 2004, inspectors started testing cattle that show neurological symptoms, can't walk, or are found dead for the disease. They use a test called ELISA, which is prone to false positives.

This particular cow tested positive in November, 2004. A second round of testing, using a different test (immunohistochemistry, or IHC), showed no antibodies to the protein that causes BSE, and the cow was declared disease-free. But a third round of testing, using a "western blot" test, came back positive.

The cow is still has not been officially diagnosed with BSE. Instead, samples are being re-tested at two other labs.

(No part of this cow ever entered the US food supply, by the way.)

If the cow is positive for BSE, it will be the first case in a cow born in the US. However, the animal was nine years old, born just before the US banned the use of cattle remains in cattle feed--a practice that can spread the disease.

posted on Mon, 06/13/2005 - 1:18pm
Anonymous's picture
Anonymous says:

Can't scientist make a vaccine for the deadly prions? I mean have our immune cells detect the mis-shaped proteins,while the natural prion protein made in our body goes about doing what it does without the immune system detecting it as foreign. I don`t know what the natural protein does in our body,but I read somewhere it takes excess cholesterol out of the cell. I don`t know if this is true or not?

posted on Wed, 03/22/2006 - 5:07pm
Liza's picture
Liza says:

Two cows are standing around in a field. One cow says to the other, "So, what do you think of this mad cow disease?" The second cow says, "Mooooooo! What do I care? I'm a helicopter!"

posted on Sun, 06/19/2005 - 7:18pm
Liza's picture
Liza says:

This New York Times article explains what went wrong in previous rounds of testing.

posted on Mon, 06/27/2005 - 9:18am
Liza's picture
Liza says:

After two years, Japan has lifted an import ban on American and Canadian beef, as long as it's from cattle less than 21 months old. (Those cows are considered too young to catch mad cow disease.)

The ban was imposed in December 2003 after a Washington dairy cow tested positive for BSE. Until then, Japan was the largest market for American beef exports, buying $1.4 billion worth in 2003. But a survey of Japanese consumers last week showed that a whopping 75% of them are still unwilling to eat American beef.

posted on Tue, 12/13/2005 - 10:58am
Liza's picture
Liza says:

From Mary Roach's "Stiff: the curious lives of human cadavers":

"According to the Kind & Knox Web site, other products made with cow-bone-and-pigskin-based gelatin include marshmallows, nougat-type candy bar fillings, liquorice, Gummi Bears, caramels, sports drinks, butter, ice cream, vitamin gel caps, suppositories, and that distasteful whitish peel on the outside of salamis. What I am getting at here is that if you're going to worry about mad cow disease, you probably have more to worry about than you thought. And that if there's any danger, which I like to think there isn't, we're all doomed, so relax and have another Snickers."

posted on Fri, 02/17/2006 - 5:50pm
Anonymous's picture
Anonymous says:

what can prevent mad cow desese???????

posted on Wed, 03/01/2006 - 10:55am
Anonymous's picture
Anonymous says:

just don't eat it

posted on Fri, 04/14/2006 - 12:06pm
bryan kennedy's picture

Scientists, the government, and farmers are taking two approaches. They are preventing the cows from getting Mad-Cow and are working to prevent humans from getting sick from an infected cow. When this happens in a human it is called Creutzfeldt-Jakob's disease.

If your a cow

One of the best things to do is to not feed cows brain tissue. As gross as it sounds, the food cows eat on factory farms regularly includes ground up parts of mammals (including brain and nervous tissue) in their food. You can also not import animals from countries where lots of cows have the disease. The US is trying to regulate both of these things.

So what if you are a human?

If you avoid all contact with beef products you are pretty safe. We aren't super sure how humans get sick from this disease (see Liza's posts above). But we do know that if you eat or touch meat that includes nervous tissue from an infected cow you can become sick. Hamburger is the most likely to cause this problem since it is generally butchered from the cow's body near the spinal column where the nervous tissue is located.

Should I become a veggie?

You probably don't need to become a vegetarian just yet (even though it is a great lifestyle that worked for me for 10 years). This quote from the Massachusets Department of Health states it best:

There have been 153 cases of vCJD reported in the world since the first case was identified in 1995, with 143 of these in the UK. Although many millions of people in the UK and around the world have been exposed to UK beef, and approximately 200,000 cases of BSE in cattle were reported and removed from the food supply over the past twenty years, the number of cases of vCJD remains low.

So your risk of catching this disease is pretty low.

posted on Wed, 03/01/2006 - 3:38pm
Anonymous's picture
Anonymous says:

The ironic thing is that UK beef now has to undergo so many BSE checks its probably now the safest in the world.....

posted on Thu, 03/09/2006 - 5:52pm
Anonymous's picture
Anonymous says:

i like meat\r\n

posted on Fri, 03/10/2006 - 11:46am
Anonymous's picture
Anonymous says:

Mad Cow Desis sounds NASTY

posted on Wed, 09/19/2007 - 3:51pm
Anonymous's picture
Anonymous says:

Can you get it by touching meat? Although I am a vegetarian I work at a restaurant and have to make sandwiches with roast beef. What if you cut yourself with knife used for cutting the sandwiches?

posted on Sat, 10/22/2011 - 3:31pm

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