Air Date: Week of March 9, 2001

Transcript

CURWOOD: It's Living on Earth. I'm Steve Curwood. Since 1986, the European Union has seen nearly 200,000 cattle come down with the transmissible spongiform encephalopathy called TSE, or mad cow disease. So far, the United States has escaped mad cow disease and its human counterpart, new variant Creutzfeld-Jacob Disease. That's largely because U.S. farmers are prohibited from feeding cows food that contain ground-up grazing animals, a practice scientists think kicked off the epidemic in Britain. The U.S. also doesn't import cows or cattle feed from Europe, and the federal government tests for the disease. But such precautions haven't convinced Americans it won't happen here. Author Richard Rhodes's book "Deadly Feasts" chronicles research into mad cow disease. Mr. Rhodes, why worry about mad cow disease hitting the U.S. when we have all these safety precautions in place?

RHODES: Well, first of all, because there have been, in humans, cases that appear to emerge spontaneously. It happens in humans to the extent of about one per million population throughout the entire world. If that were so with cattle, then one in every million head of cattle might have the spontaneous form of this disease, which, however, is transmissible. If that animal, then, in the course of normal slaughtering, goes to market, is slaughtered, its waste is cooked up and processed into meat and bone meal and fed back to other cattle, then there's a mechanism inherent in the thing for the disease to emerge here as well as elsewhere. Now, the answer to that, our U.S. Department of Agriculture has felt, has been to ban the feeding of ruminant protein, meaning protein from any animal with hooves, back to ruminants. Thus, they hope, blocking the possibility of this spontaneous form of the disease getting into the cycle of animal feed. The problem is, recently the USDA checked several hundred rendering companies in the United States and found that most of them weren't following the rule.

CURWOOD: What more should the United States government be doing to make sure that an epidemic of mad cow disease doesn't break out here in the United States?

RHODES: I think most of all what the United States meat inspection agencies need to do is to enforce the ban on feeding ruminant protein back to ruminants. And I think it's cheering that the beef cattle industry has finally taken this disease possibility seriously, and has been pressing the USDA to inspect those rendering plants and to convince them that they should indeed enforce the rule. What we need to do is be very aware that there are really insidious ways that this organism gets around. In laboratory experiments it's been shown to be transmissible through blood transfusion in mice, which is why the Red Cross has banned blood donations by people who have lived in England, and has recently banned them by people who lived in Europe for as much as ten years, because now other countries in Europe besides England are starting to see outbreaks of mad cow disease. That, presumably, is the result of the British decision, which I think was criminal. When they realized that their meat and bone meal was infected, they stopped feeding it to British cattle but they shipped it abroad, and it was fed in Germany and France and Italy and other countries, where there is now the beginning of a small-scale, at least, mad cow disease epidemic.

CURWOOD: Richard Rhodes, how worried are you about a breakout of mad cow disease here in this country?

RHODES: Not very.

CURWOOD: Why?

RHODES: There's been no outbreak in our cattle. If there had been, it would be obvious. So it's clear that the disease is lurking in the background, but I don't think it's anything that anybody needs to give up beef for. That's not the case in England, however.

CURWOOD: Where do you think we are in the time course of the epidemic in the European Union?

RHODES: Well, if we assume that the European outbreaks are the result of the kind of tailing off of meat and bone meal from England in the late 80s, then those outbreaks should not be nearly as large as the one was in England, which was where the whole problem began. What's more worrisome, I think, is how many people in England are going to eventually come down with new variant CJD and die, because I don't think there's any question that almost the entire population, at least all those who ate beef, and that's an English tradition, were probably exposed. So, the question now is really, how virulent is the disease agent? The only historical experience we have with an epidemic of TSE in humans is the cannibal tribe in New Guinea, the Fore. At the height of their epidemic, they were losing one percent of their population per year. One percent of the British population would be half a million people. So that's probably the outside limit of a possible epidemic within England. The other insidious thing about this disease organism is that it can incubate silently with no physical symptoms whatsoever, no sign of its presence, for up to 40 years, perhaps even longer. So, the British inadvertently conducted a huge natural experiment on their population, and it remains to be seen how many people will die as a result.

CURWOOD: Richard Rhodes is an investigative reporter whose book about the emergence of mad cow disease is called "Deadly Feasts." Thanks for bringing us up to date, Mr. Rhodes.

RHODES: Thank you.