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Chronic-wasting study bodes ill for elk herds
The New West / By Todd Wilkinson | 0 comments

Part 7 in a series on wildlife diseases in the Greater Yellowstone � Ed.

Chronic wasting disease is notorious for leaving no survivors.

Depending on which member of the deer family it infects and kills by turning victims� brains into sponge-like mush, CWD has been called �mad deer disease� or �mad elk disease.�

Mercilessly lethal, CWD is not only incurable, but the associated rogue proteins, called prions, that cause mortality leach into soils and persist as a disease menace long after dead animals have decomposed on the ground.

Specialists in epizootic diseases say that if an outbreak of CWD occurred in areas where mass numbers of wildlife congregate, the resulting �ecological disaster� would be difficult to contain and clean up.

In 2007, then-Wyoming Game and Fish Department Veterinarian Terry Kreeger made a pronouncement about CWD to the Casper-Star Tribune that caused professional colleagues who make their living thinking about wildlife health issues to gasp.

�Right now,� Kreeger said, �there�s no evidence that a severe reduction of deer and elk will occur [if CWD reaches populations of those animals in Wyoming]. In fact there�s some evidence to show that it will not have any effect on populations, but we expect it does to some degree.�

Kreeger, in essence, was trying to defend artificial feeding at the National Elk Refuge and 22 feedgrounds operated by the state of Wyoming.

Last month, the findings of a new study � peer-reviewed by scientists and published in The Journal of Wildlife Management � cast serious doubts about Kreeger�s assertions.

The study by lead author Ryan J. Monello, a researcher with the National Park Service, and five colleagues in ecology and veterinary medicine examines survival and population dynamics of free-ranging elk in Rocky Mountain National Park of northern Colorado. [Read pdf of study at JHNewsAndGuide.com].

Two hair-raising conclusions: Destroying animals didn�t stop disease progression. And once CWD arrives, mortality is likely to outpace reproduction, resulting in population declines.

Those findings are consistent with those in another study on CWD soon to be released by University of Wyoming doctoral student Malia DeVivo. Her conclusions are expected to paint a dismal outlook for infected mule deer in the southern part of Wyoming, where CWD is decimating some mulie herds.

Critics say these studies are damning illustrations of how Wyoming�s disease management positions are radically out of step with widely held scientific facts. They say it underscores concerns that the CWD danger posed to huge numbers of dispersing elk in Greater Yellowstone is far more problematic than state officials, justifying artificial feeding, are willing to admit.

For comparison�s sake, brucellosis is not �population limiting.� Beyond causing cow elk to abort first pregnancies, it does not typically prevent subsequent successful pregnancies, and it does not kill infected adult animals. CWD, however, is always fatal.

�The Monello journal article indicates that when CWD gets established in an elk population, even after the researchers killed the known infected animals in Rocky Mountain National Park, more elk continued to get the fatal disease,� says Lloyd Dorsey of the Greater Yellowstone Coalition.

He notes the Park Service recognizes that dense concentrations of elk, like those on the elk refuge and Wyoming�s 22 elk feedgrounds, leave animals more susceptible to higher rates of deadly disease.

While Rocky Mountain National Park has densities reaching 115 elk per square kilometer, the densities of elk on the refuge and Wyoming feedgrounds are orders of magnitude greater, literally thousands of elk per square kilometer, Dorsey says.

�This very sobering research in Rocky Mountain National Park should serve as a warning to federal and state wildlife agencies in western Wyoming to do what they can now to avoid such an awful scenario,� he said. CWD is now only miles away from the elk refuge and feedgrounds, he added.

Any day, the Bridger-Teton National Forest is expected to announce whether it will allow Wyoming to keep operating its Alkali Creek elk feedground on national forest land in the Gros Ventre Mountains.

Dorsey, joined by a growing legion of professional wildlife scientists, disease experts and conservationists, cites the expanding body of knowledge about CWD as proof that artificial feedgrounds in Wyoming need to be re-evaluated and targeted for closure.

�Since CWD isn�t here yet, we are positioned well to phase out winter feeding and try to mitigate the effects before it arrives,� Dorsey says.

So CWD has always been around? What happened to the theory it was caused from certain protein blocks being fed to cattle? Does anyone really know? The excuse I keep hearing is it is so expensive to do tests.

CWD has not always been around. It most likely originated in the deer pens at Colorado State University where deer were kept for research purposes. The pens were built on an old sheep experimental area. It is possible that the prions that cause CWD were somehow derived from the prions that cause scrapies in sheep. Scrapies is one of several transmissible spongiform encephalopathies that produce effects similar to CWD. The prions had probably been in the soil for a long time. Unfortunately, the disease was a long time being recognized and it was an even longer time before the causal agent was identified. This explanation has not (and perhaps cannot) be confirmed, but it seems to me to be the most likely explanation for the origin of the disease.

CWD probably spread into wild populations through contact between captive deer and wild deer, either at the deer pens or by the escape and/or release of some of captive animals into the wild. It was transmitted to the west slope of Colorado in captive elk that were transported to a research facility near Maybell. Some of these elk were released into the wild when they were no longer needed. Unfortunately, the genie is out of the bottle. CWD will probably never be completely controlled, but there are management strategies that can minimize the chances for infection in wild deer, elk and moose.

Any idea what those might be and their costs?

Throughout most of the U.S., the primary means of spreading CWD to new areas is the commerce of deer and elk bought and sold among game farms. Prohibitions on the interstate movement of captive deer and elk are already on the books in several states. However, there is so much money in canned hunting for selected genetics, supported by enhanced nutrition, that people still choose to ignore these restrictions.

I personally think that prohibiting game farming with cervids (deer, elk and moose) is the single most effective way to inhibit the spread of CWD to areas that are not currently infected. Unfortunately, the industry has become well organized and very adept at quashing attempts to do this in state legislatures. In quite a few states, they have been able to get themselves regulated by the states' departments of agriculture rather than the state game and fish departments and their captive animals are treated as domestic livestock.

Some states have had success simply killing as many animals as they can in infected populations, followed by restrictions on the export of anything but meat and antlers from those areas. Other states (like Colorado) have educational programs that identify GMUs where CWD has been confirmed. They provide hunters and game processors with information on how to properly butcher their animals so as not to export contaminated brain tissues and/or spinal fluids to uninfected areas. Other states have restrictions on the import of meat and trophies by hunters returning for out of state to ensure that they do not bring in contaminated materials.

All of these efforts do cost money and add extra concerns and work for hunters, most of whom are out there to get away from such things. This is the world that we live in today.

Sorry pard; I am a non-believer. The first outbreak of CWD I saw in colorado, had no game ranches for a hundred miles. Lots of cattle, and protien blocks though. When I first reported it to our local warden, he said the elk were mushroomed. I told him mushrooms didn't knock the hair off. For 5 years he complained how expensive it was to do tests; until the population started crashing.
At that time I was outfitting the southern half of CO, and the northern half of NM. 10 months out of the year. The first outbreak I saw were south central CO.

You are certainly welcome to believe what you want. I have never encountered the idea that CWD was introduced in protein blocks being fed to livestock. There may well have been an increase in the use of protein blocks that coincided with outbreaks early on but I can't imagine how the prions would have been incorporated into the blocks in the first place.

The disease was first identified in the deer pens at Fort Collins. The first outbreaks confirmed in free-ranging deer were all within a relatively short distance north and east of Fort Collins. Relatively quickly infected deer started cropping up in southeastern Wyoming, as well.

It was several years before the disease was first confirmed in elk. In the meantime, both deer and elk regarded as excess had been relocated, sold or donated to a number of different locations. As you noted, diagnosis in live animals is difficult and expensive. Until morbidity sets in, animals seem healthy. Patterns of infection in whitetails have been mapped in several states and the results strongly suggest that initial infections originated in captive populations of animals.

This was the first theory I had heard about. Cow bones were ground up and fed back to cattle as protein supplement in blocks. These blocks were imported from brittain. Such blocks were banned; but after the ranchers unknowingly put em out, mother nature dissolved parts of em, and these "prions", or whatever you call em, leached into the ground.

http://www.cwd-info.org/pdf/WYcwdarticle.pdf

https://www.google.com/#q=protien+blocks+containing+mad+cow+disease




Also interesting as the first elk I remember fish and game testing was sent to ft collins.



It was easy enough to spot a sick elk. These elk would lose whole patches of hair down their backs and sides. Weight loss big time. Wouldn't go into the timber, as it must have looked like a wall to em. The worst ones, if they could stand, would spin circles and fall on their asses.

For better than 5 years I heard how expensive it was to test an elk to find out whats going on.
CWD is a cover up by fish and game, blm, and forest service. The truth is out there. Thier fingers are crossed and are hoping it goes dormant or just goes away.

Far be it from me to mess with a good conspiracy theory.

So, you think that the Forest Service and DOW were/are trying to conceal the fact that the disease was originally transmitted to wild cervids through protein blocks containing prions from cows infected with bovine spongiform encephalopathy (BSE)? Why would they have an interest in doing this?

Who's to blame? Anyone? Would a clean-up even be possible? At what cost? Pretty sure tag moneys go into the general fund. Can't use that.

I ain't been all colleged up. Just telling you what I saw out in the field. We'll let those more edumacated handle this one


Heck; I'll bet one day, they'll be able to look at an elk and tell if its sick, just by its appearance.

Well, I spent a lot of time over the last ten years or so, researching the literature on CWD and talking to biologists and veterinarians who have had to deal with it. The scenario I described above summarizes my conclusions. YMMV.

Probably why you never heard about the blocks. That was buried rather quickly 25 or so years ago. I've read about it a little, but was there to watch it start.

This doesn't copy and paste too well, but it is the best thumbnail history of the disease that I have found:

http://www.cwd-info.org/index.php/fuseaction/about.timeline

Thanks, very interesting.

Gleaned this






Again; almost appears to have been man made.

I believe bone was crushed, added to these nutrient blocks. For calcium I guess??

They started to figure out you can't feed meat to vegetarians, is what I heard.

I wonder if carcasses have to be burnt after death, or just buried?



Any idea what this means?

It means that infected animals are already distributing the infectious agent in their schit before they show clinical signs of being infected.

OK, and thanks again for an interesting subject.

Bear, you're more than welcome. Be nice to meet you someday. Haven't been to Wasilla for almost 20 years.

You'll have to come fishing; just wipe them prions off your boots before you get on the plane.

Another tid bit about them prions you might find interesting

http://scienceblogs.com/neurophilosophy/2008/08/11/the-shaking-death-cjd-epidemic/

Any practice that encourages crowding can certainly elevate the potential. It's not overbearing, but it's a pain in the ass to remove brains and spinal tissue before coming home to Oregon with out of state game.