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Keeping Mad Cow Out

Fifty-seven million pounds of beef will hit the grills this holiday as America enjoys its special independence--from mad cow disease. There is no such freedom in Europe.

Since January, mad cow disease in cattle has spread from Britain, across the continent, into Eastern Europe. And the human death toll has risen dramatically.

"This is an epidemic already," says Dr. David Heymann of the World Health Organization.

Dr. Heymann says 25 people have died of mad cow disease this year--the most ever. Most alarming, he says, is that scientists now know it take humans at least 10 years to get sick after exposure to infected beef products, meaning the true horror of the disease may be yet to come.

"If, as we understand it, this incubation of 10-13 years is a minimum, we may be at the beginning of a much larger epidemic," he says.

Meanwhile in the United States, the firewall against mad cow is based on a simple premise: Protect American cows, and you protect humans.

"What we look for in cows is something may be wrong with their brains," says Linda Detwiler, who heads the US Department of Agriculture (USDA) task force that checks cattle for any sign of brain disease. "They may walk in circles. They may press their head against a solid object."

This year, the agency is doubling the number of tests it performs on cow brains. The good news is, no cases of mad cow have been discovered. But the test now in use has its limits. It can only detect the disease years after a cow gets infected.

"The world is actually looking for that test for the live animal. That would be an improvement of what we have now. Not only do you not have to wait until the cow is dead, but you could also diagnose disease earlier in what they call the incubation period," says Detwiler.

So the race is on for a mad-cow blood test. At the University of California, San Francisco, Dr. Stanley Prusiner says a blood test for "prions," the infectious agent in animals, could halt the disease in humans.

"If we could, 3 days before slaughter, examine each cow that's about to be slaughtered, then we could eliminate those cows infected with prions," he says.

In essence, eliminate it from cows, and you eliminate it from the food chain.

But the greatest unknown in mad cow disease is how it jumps from cow to person. The source is thought to be some kind of food, especially hamburger or sausage. But other cow products like milk, cheese, and gelatin have not been ruled out, even though scientists think none of these are a likely source.

In Europe, the uncertainty still makes eating a burger a show of bravado.

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