Last month's discovery of a single Holstein infected with mad cow disease on a Mabton, Wash., dairy farm—the first confirmed case in the U.S.—terrified many Americans and sent the beef industry reeling. Properly known as bovine spongiform encephalopathy (BSE), mad cow is contracted by animals who are fed the infected meat and bone meal of other animals, and it can spread to humans who consume tainted meat. Always fatal, the disease destroys the brain and central nervous system. A 2000 outbreak in Britain infected thousands of cattle, which were killed and burned.
In the U.S., where animal feed has been banned since 1997, officials say the risk of catching BSE is minuscule. Still, a recall of 10,000 lbs. of beef is under way as a result of the discovery of the Mabton cow, which is believed to have been imported from Canada with 73 other animals in 2001.
How grave is the threat? Giuseppe Legname, a molecular biologist at the University of California at San Francisco and an expert on BSE, spoke about the risks with PEOPLE's Giovanna Breu.
What is mad cow disease?
It's the bovine form of a fatal illness that carries infectious proteins called prions that bore holes into the brain. The disease is believed to be spread by recycling the remains of slaughtered livestock into feed, which is consumed by other cows. We think infected tissue comes mainly from the nervous system, the brain, the spinal cord.
How do humans get mad cow?
There's evidence that in England and elsewhere in Europe people contracted a variant of Creutzfeldt-Jakob Disease [vCJD], a rare, fatal, degenerative brain disorder, by eating BSE-contaminated beef. We don't know for sure if these people died by eating standard cuts of beef or hamburger that was tainted or from specifically consuming infected bits of bone and brain. In any case, the disease can take years to manifest its symptoms.
What are the symptoms?
They include lack of memory, lack of ability to sleep and, finally, uncoordinated movements, loss of speech and a demented stage where muscle and brain function begins shutting down. A patient diagnosed with vCJD will
die within a year.
Are there any Americans infected?
Except for one person in Florida who had lived in England, there are no people in the United States infected with the disease. It's very important to stress that vCJD is extremely rare.
Can vCJD be treated?
There's a malaria drug called quinacrine that works to extend the survival of laboratory animals. Clinical studies are going on here in UCSF with Creutzfeldt-Jakob Disease. But we haven't been able to design a test that would let us tell if you have the disease before you have symptoms. At that point, it's too late.
What can be done to protect the consumer from infected cows?
Currently we have one confirmed case of mad cow disease in the United States, and we don't know how many other infected animals are out there. In contrast, countries like Japan screen every single cow that goes into the food supply. There's a kit on the market that would cost $40 or $50 per cow, or only a few cents per pound, and we have developed our own low-cost test here at UCSF that can efficiently check thousands of cows within a single day. That would greatly reduce the threat of even one infected cow finding its way into the food system. [Government officials say American beef is safe to eat but are considering changes in their testing regime.]
Do you think organic beef is safe?
I think it's better than nonorganic, because organic cows are generally grass-fed and can't be exposed to contaminated feed.
What about a T-bone steak?
Even though the risks of getting mad cow disease are very low, personally, I would be more cautious about consuming it.
Would you rather eat hamburger in a fast-food joint or roast beef in a regular restaurant?
With hamburger it's better if you grind it yourself. In general, whether you dine in or eat out, it helps if you know the cut of the meat and know where it comes from. Still, in some other countries, consumers gain added peace of mind when they eat beef because laws require the disclosure of information about where an animal was raised and how it was fed throughout its life. In Italy, for example, if you go to the butcher, you know not only the cut of the meat but you also have extensive information about the cow it came from. It's obviously good to know as much about the food you eat as possible. The most important thing is knowledge.
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