British beef blues

Curious cause

Down deer, ill elk

Can't happen here?

Laughing death in New Guinea

Identifying disease agents

Menacing microbes

Glossary

Photo by Brian Prechtel. Courtesy Agricultural Research Service, USDA

Mad cow disease is one of several fatal brain diseases called transmissible spongiform encephalopathies, or TSEs. (Want The Why Files guide to mad cow lingo?)

The jargon says it all: These infectious diseases shoot the brain full of holes, making it look like a sponge.

The TSEs were once considered unlikely to infect other species, but some seem to move rather easily among animals. Most glaringly, many scientists believe people can get vCJD (variant Creutzfeldt-Jakob disease) from eating mad cows. The awkward name reflects the similarity to Creutzfeldt-Jakob disease (CJD), a deadly brain illness that strikes about one person per million per year, due to genetic or unknown causes.

While CJD mainly afflicts the elderly, vCJD appears among younger people, almost certainly from eating mad cow meat. The gruesome death starts with mood swings, numbness and uncontrolled body movements. Eventually the mind is destroyed, somewhat like Alzheimer's, another brain-wrecking disease.

The newer variety of CJD usually kills in about 18 months after symptoms appear, compared to four to six months for regular CJD. There is no treatment and both diseases are uniformly fatal.

Mad with concern
The first known TSE appeared in sheep, but now people, cows, elk, deer, mink, rats, mice, hamsters and possibly monkeys all get various types of the disease.

Although neither mad cow nor vCJD has been seen in the United States, vigilance and concern are both mounting.

Drugs and vaccines, including those given to millions of American children, have been made with products that could carry mad cow disease, in defiance of repeated requests from the Food and Drug Administration, the New York Times reported:

"The nine vaccines include some regularly given to millions of American children, including common vaccines to prevent polio, diphtheria and tetanus," the paper wrote. "They also include the anthrax vaccine, which the government requires for soldiers serving in the Persian Gulf."

Federal officials said the practice was still safe, and that nobody is known to have caught CJD from vaccine.

On Feb. 1, the government banned beef imports from Brazil, which had received cattle from Britain in the 1980s. The action followed a December ban on all animal protein imports from Europe, and represented a further tightening of restrictions to prevent infections in the United States.

At the end of January, a blunder in a Texas feed mill showed that regulations on feed are not foolproof. Despite quick corrective action, regulators and industry officials, to say nothing of food safety activists, were upset that the mill supplied a Texas feedlot with feed containing parts of slaughtered cattle -- the exact recipe that distributed mad cow across the United Kingdom more than 10 years ago.

An old TSE epidemic continues among deer and elk in Colorado and Wyoming, exposing hunters, and cattle that graze the same terrain, to disease. Neither human nor bovine infections have been documented, but the long incubation of TSEs and their mysterious habits are still causing concern.

The federal government is expanding its ban on blood donations to include people who lived for 10 years or more in France, Portugal or Ireland since 1980. People who lived at least 6 months in Britain are already on the no-donate list.

European epidemic The picture in Europe is much more distressing.

More than 80 Britons are already dead from eating mad-cow meat. Most probably got infected while their government was assuring the nation that the fearsome cow disease could not infect people.

Three people in France have died of vCJD, also presumably contracted from eating meat from diseased animals.

On Jan. 31., after the detection of 25 mad cows, Germany announced plans to slaughter and destroy 400,000 elderly cows, which, due to the long incubation period, are most prone to the disease. Beef consumption in Germany plunged 50 percent since November, and 34 countries have banned German beef imports.

Italian farmers have protested in Rome, demanding government compensation for losses caused by Italy's country's mad cow scare.

Beef sales have dropped in Spain, where 12 cows showed characteristic holes in their brains.

Mad cow has also appeared in Portugal, Switzerland, The Netherlands, Belgium, Denmark, Ireland, Luxembourg, Liechtenstein and France (see "Bovine Spongiform... " in the bibliography).

Messed up in Texas
The alarm bells rang in Texas after 1,200 cows were fed protein-rich byproducts of other cows. Until a few years ago, this was standard practice in the United States, and was considered a smart way to recycle slaughterhouse offal -- brains, spinal cords, spleens that wouldn't do too well in the butcher shop -- unless you love head cheese.

But exactly this "like to like" feeding technique lay at the heart of the United Kingdom epidemic. Long after cows began going mad and dying of a brain-destroying disease, the government allowed their byproducts to be fed to other cows.

The Texas bovine blunder was probably caught in time. Purina Mills, Inc., owner of the mill, said it would buy the 1,200 cattle that ate the questionable feed and remove them from the food chain, to an undetermined destination.

The FDA stressed other reasons for believing that the mistake was unlikely to spark a mad cow outbreak: "The prohibited material was domestic in origin (therefore not likely to contain infected material because there is no evidence of BSE in U.S. cattle), fed at a very low level, and fed only once. The potential risk of BSE to such cattle is therefore exceedingly low, even if the feed were contaminated."

Could a feed mill be the source of a deadly bovine epidemic?

That opinion, however, was not universal. "It is unfortunate that there has been a failure to comply with FDA regulations," says Judd Aiken, a prion researcher at the University of Wisconsin-Madison. "The key to the whole thing is that we stop the feeding of sheep and cattle to cattle."

Four or five years after the British stopped feeding cattle to cattle, there was, he says, a "precipitous drop" in the mad cow rate. Every mistake, he warns, sets back the date for ensuring that the slow-acting disease is removed from the food chain.

The U.S. cattle industry proudly says no cases of BSE have been found in this country, and it aims to keep it that way. "We're not taking any chances. We're very intent on keeping this disease out of the country," says Rick McCarty, a spokesman for the National Cattlemen's Beef Association.

Curious about the cost of complacency? Just glance across the Atlantic.