CPW seeks ways to control Chronic Wasting Disease

Mule deer, elk and moose are affected by Chronic Wasting Disease (CWD). Colorado Parks and Wildlife is concerned that the prevalence of the disease is on the rise. Fifty-six percent of deer herds, 33 percent of elk herds and 33 percent of moose herds have CWD present. PIXABAY STOCK PHOTO

RBC | Maintaining wildlife health is a fundamental component of sound wildlife management and is a high priority in Colorado. That’s the framework of a series of Colorado Parks and Wildlife (CPW) public information meetings about chronic wasting disease (CWD) in Meeker and Craig on Jun 26 and July 2. CPW is dedicated to delivering a coordinated and systematic approach for monitoring, investigating, reporting and—where feasible—controlling CWD.

The CPW Commission has established a CWD advisory group to begin developing a Chronic Wasting Disease Response Plan. Their goal is to have a draft plan in place by November with approval consideration by the Commission in December.

As of January 2018, 31 of 55 deer herds in the state (56 percent), 14 of 43 elk herds (33 percent), and two of the nine moose herds (22 percent) have CWD present. This prion (deformed protein)-caused, neurologic disease is also known to exist in 27 other states and provinces, South Korea, and most recently Norway.

Former Meeker-based area wildlife manager for CPW, Dan Prenzlow, who attended the Craig meeting, told the Herald Times, “When I was the area manager back in 2002 and we discovered the surprise presence of chronic wasting disease at the Motherwell Ranch east of Hamilton—the first such discovery on the western slope—we opted to take the one in a hundred chance of eradicating it. That didn’t work ,as we discovered the disease was more widespread than just a few animals.

“The scenario is much different now. We know the disease is here, we have it, and now we need to manage its presence the best way we can. We must reduce its prevalence and protect the herds that aren’t yet infected.” Prenzlow is now the southeast regional manager for CPW.

It’s the prevalence of CWD within the infected herds, especially mule deer, that has renewed CPW concern. The rate of infection appears to be rising. Trends have been difficult to track in the last 10 years because too few hunters voluntarily submit samples for testing. This has admittedly been at least partially attributable to decreased emphasis on testing by CPW.

In 2017, CPW resumed mandatory harvest sample submissions in select herd areas. Sample numbers in the targeted herd units increased 10-fold, yielding better data to inform herd management planning. A growing body of data suggests that unchecked CWD epidemics impair the long-term performance of affected populations. The percentage of deer samples testing positive for CWD have stayed at about two percent in game management unit 22 of the White River mule deer herd, but have jumped from 11 to almost 27 percent in most of the other White River herd GMUs.

According to CPW, on average, animals become infected at younger ages as epidemics increase. If infection rates become too high, CWD can affect a herd’s ability to sustain itself. Observed patterns in Colorado suggest cause for both hope and concern. Prevalence in the Red Feather/Poudre Canyon deer herd above Fort Collins has declined in the decade since CPW applied focused culling and increased harvest in the early 2000s. Relatively aggressive buck and doe harvest may be helping suppress prevalence in the Middle Park deer herd. In contrast, prevalence in the White River deer herd, where there has been no active change in management, appears to have markedly risen since 2002.

The options now before the advisory group, using licensed public hunters, include: reducing herd population density, reducing the male/female ratio, changing herd age structure, maximizing removal of animals on the smallest (targeted “hot spots”) scale possible, removing factors that lead to herd congregations, minimizing point sources of prions and incorporating prevalence threshold limits into herd management plans.

Feedback from many of the assembled attendees at the Craig meeting was “to keep scratching their heads and come up with options that don’t amount to just killing more deer.” Concern was expressed about reduced deer numbers and the impact that would have on hunting season participation and local economies.

The next advisory group meeting will be held in Rifle, July 25, from 9 a.m. until 5 p.m., at the Rifle Library. The public is urged to attend, especially to share any insights on how to deal with CWD.