It seems everyone has a lot of questions about Chronic Wasting Disease - even the scientists who study it. There's no cure. There's no vaccine. There's no way to test a living animal for the disease.

Byron Caughey does research on CWD and some related diseases at a National Institutes of Health lab in Montana. He says CWD is one of the biggest puzzles in microbiology in the past 30 years.

The disease isn't caused by a virus or a bacterium. Researchers believe it's passed on through microscopic bits of protein called prions. That's the same theory behind BSE commonly called "mad cow disease." But Byron Caughey says scientists don't know how Chronic Wasting Disease gets from one animal to another. There's one theory that deer and elk pass the disease by touching noses, but Caughey says no one's sure.

"It could be shed in the urine or in the feces," Caughey says. "We don't know whether that really happens or not. Or it could be shed into the environment from carcasses of animals that die of CWD."

BSE is a relative of CWD, and Caughey says a few people have picked up BSE by eating parts of infected cattle. As for CWD, he says laboratory tests show it's unlikely people could get the disease from eating deer or elk - but it's possible.

"There's also the potential that people could pick it up by butchering infected deer," he says. "There's the potential for many different routes of exposure. We have to consider the possibility that CWD could pose a problem for people without assuming that it is a threat, necessarily, until we have direct evidence."

Caughey says it's also unlikely that CWD will infect cattle or other livestock - but that, too, is possible.

The disease moves slowly, and it has a long incubation period. Caughey says it probably can't wipe out the wild deer in Wisconsin. But considering all the questions about the disease, Caughey says it's best to try to control it.

In Minnesota, the biggest question is: has chronic wasting disease gotten here yet?

"That's an impossible question to answer," says Mike DonCarlos, the head of wildlife research at the Minnesota Department of Natural Resources.

DonCarlos says there isn't enough evidence yet. If biologists find an animal that has the disease, it will be obvious that CWD is here.

"It's harder to prove that you're CWD-free," says DonCarlos. "That requires an accumulation of negative samples over time. It'll be several years before we can say that Minnesota - with confidence - doesn't have the disease."

In Wisconsin, the disease has showed up in wild deer. In several western states, CWD has attacked deer and elk in the wild, as well as those raised on farms. Elk and deer raised on farms are a special worry because people sell the animals from state to state. And Minnesota has about 11,000 captive elk. That's more than any other state.

Minnesota's Board of Animal Health won't allow certified elk and deer farms to import animals from areas where chronic wasting disease has been detected. But elk and deer breeders volunteer to get certified. They can choose to operate as game farms instead, under different rules. Most of the state's elk breeders have chosen to be certified.

The DNR and other groups are pushing for a state law that will require all elk and deer farms to monitor their herds for chronic wasting disease.

The DNR also plans more testing of wild deer. Mike DonCarlos of the DNR says he hopes the department will test thousands of wild deer for the disease next fall during hunting season.

If the DNR discovers CWD in Minnesota's wild deer, DonCarlos says the action plan is much like what's happening in Wisconsin. The DNR will kill and test dozens of deer in the area the disease is detected. If some of those animals are infected, the state will begin a mass killing of deer in the area, with hopes of thinning the deer population to the point that CWD can't spread.

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