1,000 miles,
more or less, separate Wisconsin from the epidemic of chronic wasting disease (CWD), in the Rocky Mountains. Mule deer, white-tail deer, and elk in Wyoming and Colorado have been getting CWD for several decades. In some parts of Colorado, 10 to 15 percent of deer are infected, according to Jeff VerSteeg of the Colorado Division of Wildlife (see "Antlers..." in the bibliography).

State authorities want to kill 15,000 deer in this 328-square-mile zone. Lower portion of map from DNR.

One of the first tasks of a medical detective is to pin down the origin of a new disease. Although the question of how CWD reached Wisconsin is still open, deer probably did not do the kind of long-distance migration characteristic of caribou.

They did not eat their way across Nebraska and Iowa, in other words.

Instead, human action and diesel fuel likely deserve the credit. In Wisconsin, some fingers are being pointed at game farms, which serve people whose idea of hunting is "ducks in a barrel," rather than "wild game on the hoof." The Wisconsin Department of Agriculture has known since 1998 that elk were shipped to Wisconsin game farms from western farms infected with chronic wasting disease (see "Ag Department Criticized..." in the bibliography).

A successful deer hunt in California. California Department of Fish & Game.

Such movement is now barred by state regulation.

Another possible source is groups of landowners that jointly "manage" deer, often with the goal of producing big antlers. "It would provide an impetus to bring in deer that they think are superior," says John Cary, an expert in computer simulations at the department of wildlife biology at University of Wisconsin-Madison who has tried to project the course of the CWD epidemic.

These "Quality Deer Management" groups need no license. Although they are bound by the new prohibition on moving deer, Cary says they probably do not follow them.

Cary speculates that somebody near the present-day epicenter of the Wisconsin outbreak imported sick deer two to 10 years ago. Not knowingly, of course, but since wasting disease incubates for more than a year, healthy-seeming animals may have carried the disease anyway.

Will eradication work?

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