Chronic wasting disease

June 7, 2002 National Public Radio Talk of the Nation

For the rest of the hour, we're going to be talking about chronic wasting disease. Now maybe you haven't heard about chronic wasting disease, but you have heard about mad cow disease. And now a strikingly similar disease is spreading among deer and elk across the West and the Midwest, and it's called chronic wasting disease. It's a brain disorder that cripples and then kills its victims. And last fall, the US Department of Agriculture called the disease an emergency after the infection spread through a remote wildlife research facility in the Colorado foothills. And now state wildlife officials are gearing up to try to work against that disease that threatens to devastate regional gaming and tourist economies.

And today we're going to ask an expert how much is known about the disease, what the risks to people are and what federal officials are doing about it. Joining me now is Elizabeth Williams, professor of veterinary sciences, University of Wyoming in Laramie. She also works with the Wyoming Game and Fish Department and the Colorado Division of Wildlife. She has been studying chronic wasting disease since 1977, and she joins us today from the campus there.

Welcome to the program.

Professor ELIZABETH WILLIAMS (University of Wyoming): Thank you very much. FLATOW: How come we've never heard of this before, I mean, us city slickers out here?

Prof. WILLIAMS: Well, I can't answer why you haven't heard about it because actually, as you might guess from that introduction, the disease has been known about for about 30 years or so, probably a little bit more than that. So it has been around.

FLATOW: And how similar is this to mad cow disease?

Prof. WILLIAMS: Well, it falls into the same general category of diseases as mad cow disease or Bovine Spongiform Encephalopathy, BSE. So it's in the same group of diseases; it's not the same disease. Another disease that some people might be familiar with that we have here in this country, where we don't have BSE, is a disease called scrapie, that occurs in domestic sheep and goats.

FLATOW: Give us an idea of what is going on with the animals out there. Paint us a little picture, would you?

Prof. WILLIAMS: Well, basically we recognize that there's an area of southeastern Wyoming, north central Colorado over to part of the Nebraska panhandle where chronic wasting disease exists in the wild. And that's what we call the endemic area, the endemic focus of chronic wasting disease. And actually, that's been fairly stable, probably spreading fairly slowly for a number of years. The thing that I think has gotten a lot of attention lately is recognition of the disease being present in free-ranging whitetail deer in one area in Wisconsin and also recognition of the disease in the western part of Colorado, which--it was a little bit distant from the area that we've known about where chronic wasting disease has occurred in our little endemic area here. And then also the disease not only occurs in the wild, but also has been recognized in the elk industry, in the game farming industry. And that also has caused, I think, an increasing amount of attention to this disease.

FLATOW: Now according to an article in The Wall Street Journal, the Center for Food Safety, which is a consumer watchdog group in Washington, called Utah hunter Doug McEwen, who died of Creutzfeld-Jakob disease, the first possible case of what they called 'mad deer disease.' What do you think of that? Is that an accurate way to describe it?

Prof. WILLIAMS: Well, I don't even care for the term 'mad cow disease' personally, so I certainly don't like hearing the disease chronic wasting disease called 'mad deer disease' or 'mad elk disease.' I think that kind of plays off the kind of sensationalism associated with Bovine Spongiform Encephalopathy. So, you know, I don't really care for that so much.

The question about food safety and the issue of whether the disease can be transmitted to people--we rely on the expertise of the people that are in the business of studying these things, and that would be the epidemiologists with the Centers for Disease Control and Prevention out of Atlanta. And they, in fact, did quite an extensive epidemiologic investigation of this case and some other cases and haven't found any link to chronic wasting disease.

FLATOW: So if this is spreading among deer, is there fear that people, deer hunters who go out and shoot the animals for food, might be, you know, spreading this to themselves?

Prof. WILLIAMS: Well, that certainly is a potential issue because we certainly don't know everything there is to know about chronic wasting disease by any means. And so we, again, work with the public health people. They have investigated the information that's available on the potential for humans to be susceptible to it, and at this point in time they don't recognize chronic wasting disease as being a disease that humans are susceptible to. But at the same time, because there certainly are unknowns about it, it makes sense for those people that wish to hunt in the area where chronic wasting disease occurs to take precautions to avoid coming in contact with the agent. And that would be, you know, recommending that people don't consume things like brains or spinal cords, those types of things.

FLATOW: Our number, 1 (800) 989-8255 if you'd like to ask a question about chronic wasting disease. Are cattle--you said you're not sure. Are cattle susceptible to this if they come in contact?

Prof. WILLIAMS: There is--and that's certainly an important issue as to whether or not cattle might be susceptible. And to that end, a number of us--and there actually are quite a number of researchers in this country and in Canada, as well as in other parts of the world that have been studying chronic wasting disease for some time. And one of the things that has been of considerable interest is whether or not cattle might be susceptible. And we've had studies going on now for about five years looking at that. And at this point in time, there's no evidence that cattle are susceptible by natural means to chronic wasting disease. Those studies are set to go for, oh, probably another five years because this disease does have a long incubation period. We don't want to miss it because we cut our experiments short too soon. But at this point in time, again, no evidence that cattle can get it, but we are obviously continuing to do surveillance and continuing to do our studies.

FLATOW: I'm Ira Flatow, and you're listening to TALK OF THE NATION/SCIENCE FRIDAY from NPR News.

What are the symptoms of this? If people are out there and they're wondering whether, you know, the deer they're looking at are coming down with this...

Prof. WILLIAMS: Sure. Well, as you might guess from the name of the disease, chronic wasting disease, these animals show two primary signs. One is wasting; that is, they go through a long period of time when they continue to lose weight even though they continue to eat. But they just don't eat enough to actually maintain their body condition. So they do lose weight. And in the terminal stages of a natural case, these animals would be quite emaciated. One of the earliest signs of chronic wasting disease, though, is behavioral changes. The animals don't act like normal deer or elk. You know, deer and elk are pretty wary creatures,and they are pretty well aware of their environment. And an animal that is coming down with chronic wasting disease or actually has various stages of the disease just has lost that wariness, interacts with people in a different way, interacts with other deer and elk in different ways than they normally would. So they don't act quite right.

FLATOW: We used to say that about watching rabies in raccoons, the same thing, they would do things that are not characteristic of the animal.

Prof. WILLIAMS: Right. And, in fact, though, of course, this disease is not anything like rabies itself.

FLATOW: Right.

Prof. WILLIAMS: But in terms of the animals showing abnormal behaviors, it's true that because both of those diseases cause disease in the brain or cause damage to the brain, that affects how the animals behave.

FLATOW: Let me see if I can get a quick phone call in.

Prof. WILLIAMS: Sure.

FLATOW: John in Madison, Wisconsin. Hi, Josh.

JOSH (Caller): Hi. Down here in Wisconsin near the disease, and we're all kind of wondering if this has been known about for 30-some years, then why don't we know more about how it's spread and, you know, if it can be spread to other animals, other than the deer?

Prof. WILLIAMS: Sure. Sure, that's a good question, and one of the primary reasons why we don't know more about it is that, for the vast majority of those 30 years, no one was very interested in chronic wasting disease except for kind of a few of us out here in the West where it occurs. It wasn't until basically the new variant, Creutzfeld-Jakob disease's, association with Bovine Spongiform Encephalopathy came along that the interest in these transmissible spongiform encephalopathies, this group of diseases, kind of increased the amount of funding available to do the kinds of studies that are needed. And so, unfortunately, because of that, we're kind of wishing we had some answers.

FLATOW: Do you feel this is just the same disease in a different form? I hate to call it mad cow since you don't want to, but just for deer?

Prof. WILLIAMS: No, it's actually quite different in a number of different ways. The epidemiology of the disease is very different than Bovine Spongiform Encephalopathy, and the way it behaves in the animal itself, the different places that the agent is present, is quite different. And so while they fall under the same category of diseases, they actually are very different.

FLATOW: Is it a prion disease like mad cow?

Prof. WILLIAMS: That's correct.

FLATOW: So it's one of these weird new kinds of things.

Prof. WILLIAMS: It's unusual, yes.

FLATOW: It's unusual. And is there something in that now that it's got attention, it's going to be given more attention?

Prof. WILLIAMS: Oh, I think it definitely will be, not only because of the public interest; the media's certainly been more interested in it lately, and certainly the funding agencies that, you know, have all these questions because they need to understand how to manage the disease are certainly interested in getting some answers to the questions that they have.

FLATOW: Dr. Williams, thank you very much for joining us. And good luck to you.

Prof. WILLIAMS: Thank you very much.

FLATOW: Dr. Elizabeth Williams is a professor of veterinary sciences at the University of Wyoming.

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