Chronic Wasting Disease Threatening Montana Deer

I was lucky to get this nice whitetail buck last fall. CWD threatens our future deer hunts.

It might be fishing season, but the 2019 big game hunting seasons are just two and a half months away, when the archery season for deer and elk start the first Saturday in September, which this year is September 1.

Last year, deer infected with chronic wasting disease (CWD) were found in two areas, south central Montana, and north central Montana. You may recall that Montana Fish, Wildlife & Parks opened late hunting seasons in those areas to get more samples of deer tissue to better determine the extent of CWD in Montana.

A couple weeks ago, at the annual conference of the Outdoor Writers Association of America, held this year in Fort Wayne, Indiana, a panel of wildlife biologists presented the latest research on CWD.

Chronic Wasting Disease was first found in a mule deer in a Colorado research facility 50 years ago. Since then, CWD has spread to both wild and captive cervid (elk, deer and moose) populations in 23 states and two Canadian provinces. That includes Wyoming, just to the south of the south central Montana hunting district, and Alberta, to the north of the north central district.

Wyoming mule deer numbers are declining at a rate of 21 percent per year, and the decline is attributed to CWD. In Wisconsin, which has a number of captive deer operations, offering “canned hunts,” CWD rates are increasing dramatically.

While there has been a lot of CWD research, it is clear that there are still unknowns about how the disease gets transmitted. The disease is carried by prions, a form of protein. If CWD gets in a deer population, those prions become part of the environment, and can transmit CWD even after no deer have been in the area for several years or more.

It is proven that captive deer populations are CWD incubators, yet some states, such as Wisconsin, still allow captive herds. Bryan Richards, with the USGS National Wildlife Health Center in Madison WI, noted that transportation of animals from one facility to another is a factor in spread of CWD. Feeding deer also tends to concentrate deer numbers, making them vulnerable to CWD.

We might recall that a captive elk herd in the Philipsburg area had a CWD problem, and the entire herd was destroyed and the carcasses were incinerated. In 2000, a sportsmen-backed constitutional initiative, I-143, banned new elk farms, transportation of captive wildlife, and canned hunts. Since then, many of the captive elk farms have gone out of business.

As far as wild populations, the panel agreed that reducing deer numbers, especially bucks, is important. There is belief that predators, such as wolves, can have a beneficial effect in controlling deer numbers and taking diseased animals out of the population.

Currently, there is no known impact of CWD on humans. On the other hand, Richards advocated that hunters who harvest animals in an area known to have CWD should have them tested. He emphatically added, “If it tests positive for CWD, do not eat it.”

The CWD information pages on the FWP website also advises that consumption of infected animals should be avoided.

The issue of reducing buck numbers might be thorny for some, especially people who want bucks to live longer in order to grow big antlers, something espoused by Quality Deer Management (QDM) advocates. I asked an old college classmate, a retired midwestern deer biologist, for his thoughts. He confirmed that bucks pick up CWD at least three times the rate for females, adding, “Historically, we always focused on shooting females to reduce herds. But, it seems to me that we need to shoot both males and females…and impose a harvest mortality rate that exceeds the force rate of infection.”

Obviously, the CWD issue will not go away in Montana. If we have found some infected animals in the state, it is likely that there are more infected deer running around, spreading disease.

Deer hunters like to see lots of deer, but what we need is fewer numbers, widely dispersed. It may make hunting more difficult but that’s better than the alternative.

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