Deer: Wasting disease disaster

1. Sick in the brain
2. Prion eyes
3. Disease on the move
4. Effective eradication?
5.Deer gobble plants




Deer skull with antlers mounted on garage wall.Menacing model
Wisconsin's proposal for confronting the new outbreak of CWD is radical: Since the disease is difficult to diagnose and impossible to treat, the only way to contain the disease is to get rid of all deer around the infected zone. "We really are going to go after every one" of the 15,000 deer, says wildlife ecologist John Cary.

This deer skull, taken from the eradication zone west of Madison, may have carried chronic wasting disease. The numbskull who nailed it to a garage didn't bother to find out...

Landowners are being urged to increase hunting on property in the hot zone. Because overpopulation of deer likely helped cause the epidemic -- by increasing the chances of disease transmission -- hunting restrictions will be eased around the hot zone in an effort to thin the deer herd.

When amateur hunters run out of steam, the state Department of Natural Resources may send in teams of sharpshooters to kill survivors. Although helicopters may be used to drive deer toward shooters, Cary considers that unlikely due to predictable public backlash.

To project the future of the epidemic, Cary built a computer model of population changes in white-tail deer, and then ran it with various assumptions for a period of 25 years.

But will it work?
Kneeling man holds up head of dead deer by antlers. Score's hunters 1, deer 0 after this hunt. Hunters help control a skyrocketing deer population in Wisconsin and many other states. California Department of Fish & Game.

Under many combinations of conditions, CWD would be eliminated in under five years, he says. There are several reasons to think eradication can work, Cary adds.

First, deer are not marathon runners. "We can do a square mile at a time, and they will not spread out automatically. They are stuck onto the landscape more than people think." Females don't stray far from mom, and while males wander, they cluster around females.

Second, while the mechanism of CWD transmission among deer is unknown, the infectious agent is unlikely to survive indefinitely in the environment. Prions, Cary says, are "a protein, and they do degrade after a while. It's not something that can last indefinitely, like anthrax."

The Wisconsin Department of Natural Resources has said it might have to keep killing deer for 5 years, but Cary's computer projections indicate that the grisly job may be done sooner. Other simulations, with inadequate testing and eradication efforts, fail to eliminate CWD even after many years, he adds.

Wiping out entire herds of deer is nobody's idea of "have a nice day," but the results of sitting idly by are grim. The disease seems to be spreading fast, and Cary says the computer projects that "80 percent of deer in the model would become infected in 15 years, and the herd would collapse."

While admitting that this result is based on a sample of only about 500 deer, Cary says it's a disturbing prospect, especially since it considers neither harm to deer outside the hot zone nor the possibility that CWD might even jump to other species.

Reddish-brown deer in green meadow.
A white-tailed deer. Fish & Wildlife Service.

Hunt deer?
Although nobody is known to have caught brain disease from eating chronically wasted deer, government authorities cannot and will not guarantee that deer is safe food. There is, after all, that sobering parallel from across the pond.

For a decade, as thousands of beef cows staggered and slobbered to their deaths, the government of the United Kingdom claimed that British beef was safe. Then, in 1996, in a red-faced about-face, it admitted that tainted beef had probably caused dozens of cases of Creutzfeldt-Jakob disease.

The prospect, however remote, of dying of a gruesome brain disease has apparently cast a shadow on deer hunting. A recent survey found that 36 percent of Wisconsin hunters are reassessing whether to take up arms against Bambi this fall, threatening the hunt's estimated $1 billion economic contribution and undermining its role in controlling the overabundance of white-tails.

A decline of hunting would also have social impacts, says Thomas Heberlein, a long-time hunter and professor emeritus of rural sociology at the University of Wisconsin-Madison. "Deer are hunted for meat and for social purposes. Families come together, fathers and sons, and increasingly daughters. It's a very strong family tradition, it's often tied to place, like a hunting shack or the land of grandfather's farm; it's a big part of what the state is like."

Close-up of spotted White-tailed fawn U.S. Fish & Wildlife Service.

Heberlein worries about the effects of "14 sick deer that changed the world." In particular, he asks, will the cure, eradication, be worse than the disease, CWD? Instead of overplaying the danger, he says, reporters should be looking to Colorado and Wyoming, where, despite the long epidemic of CWD in deer and elk, no human disease has been pinned on venison.

Should the state hunt down the last deer in the eradication zone, he asks, or should it tell hunters, "'There's some additional risk, and what we going to do to reduce that risk'? I am more interested in preserving the deer hunt, and its many social benefits, than in preserving the health of deer at all costs."

If one-third of Wisconsin deer hunters stay home during the hunt, will that change the state's landscape?




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