A fatal neurological disease has been cropping up in area deer populations and is driving potential new management plans that will be discussed Monday in Montrose.
Chronic wasting disease afflicts deer and related species; it is caused by a prion, or non-living protein, and there is no cure. The disease is similar to mad cow disease and to scrapie disease in domestic sheep.
Although present in the state for sometime, its appearance in the Montrose area is relatively recent.
“We just found it around Montrose for the first time in March 2016. We’ve been doing testing, checking suspect animals that look sick, but never found it until 2016,” Brad Banulis, a terrestrial biologist with Colorado Parks and Wildlife, based in Montrose.
Prior to that time, the closest known incidents of chronic wasting disease, or CWD, had occurred on the Grand Mesa.
In 2016, about seven deer between Montrose and Delta were found to have CWD.
In 2017, a buck in the Nucla area succumbed to the disease and CPW launched mandatory testing of deer taken by randomly selected rifle hunters in specific game management units to help the agency determine how prevalent the disease might be here.
“Essentially, for the Uncompahgre deer herd (units 61 and 62), our estimated prevalence is about 3.5 percent. Our Cimarron deer herd (units 64 and 65) is 1.5 percent,” Banulis said.
“The vast majority of positives came from the valley, really kind of a ‘hot spot’ from Delta to Montrose. Fortunately, we’ve only detected it on migratory, public land (deer) up on the mountains, in a couple of cases. Everywhere else has come from the valley.”
CPW issued its Colorado Chronic Wasting Disease Response Plan in December of last year. The document notes that eradication is not possible with existing management tools, so the focus is to keep disease prevalence at low levels.
Potential management actions and recommendations include reduction of population and reduction of male-female ratio, as CWD appears to be more prevalent in male deer than in does.
Banulis said bucks tend to move around more than does, as well as interact more with other deer, particularly as they seek mates.
“The idea is to try to manage the buck population more — not to get rid of bucks, but to keep the number of bucks down. We can add some more buck licenses,” he said.
CPW is also considering adding an earlier rifle season to increase harvesting bucks in the valley “hot spots” and is seeking input, he said.
The response plan also lists tactics to change the age structure of herds, because the age classes of deer most likely to be infected with CWD are 4 - 6-year-old males. Without changing the population or sex ratio, wildlife managers could change the age structure to reduce the number of male deer that age and increase the number of younger male deer. Such tactics might include shifting hunting season dates for bucks and possibly creating new, special hunts for young and new hunters.
The plan also details steps by which CPW could remove diseased animals within hot spots.
Presently, hunters are required to report the locations of their take, which are matched with wasting disease test results to map all positive animals and establish where the disease may be concentrated. By targeting management actions there, CPW could better control the spread of the disease.
However, hunting is often prohibited in exurban development areas and city and county open space; CPW would need to work with such governments to address chronic wasting disease in deer and elk herds, but, the report says, reducing CWD prevalence to 5 percent or below on such open spaces will be difficult.
The response plan also details ways that might make areas less attractive for deer, elk and moose to congregate and means of minimizing prion point sources. For the latter, taxidermists and meat processors may be encouraged to dispose of carcasses in ways that do not leave the carcasses exposed.
CPW may launch an educational campaign in that regard and also create carcass disposal sites at landfills, in cooperation with local, state and federal agencies.
The response plan also makes provisions to incorporate CWD management actions into overall herd management plans. Local herd management plans are being updated.
“It’s fatal disease and there’s nothing really to do to vaccinate for it, or anything,” Banulis said.
CPW wants to avoid the fate of states like Wyoming, where prevalence rates of almost 50 percent have been detected.
“We’ve seen places in Colorado where prevalence has been growing. That gets to be a concern of it spreading through the deer herd. Part of our intent is to try to manage the deer more in the valley so we don’t spread it more to our migratory, mountain deer,” Banulis said.
CPW will hold a local informational meeting about CWD and its effects on deer management; this is from 6 - 8 p.m. Monday, at Friendship Hall’s Pioneer Room, Montrose County Fairgrounds, 1001 N. Second St.
The meeting includes general information about the disease and the possible management actions, as well as updates on deer herd management plans and the opportunity to ask questions.
“There’s enough of a prevalence that we are concerned. CPW would like to encourage anyone interested in chronic wasting disease and its effect on local herds to attend this meeting,” CPW area wildlife manager Renzo DelPiccolo said.
“We will also be talking about our path forward as we begin our herd management plan process and discuss how we may be managing herds differently in the face of CWD.”
The herd management plans entail many more elements than CWD, including overall objective for deer populations, what might be limiting the herds and the history of the herds.
The management plan updates must ultimately be approved by the Colorado Wildlife Commission.
For more about chronic wasting disease, visit https://tinyurl.com/chronicdeer1
Katharhynn Heidelberg is the Montrose Daily Press assistant editor and senior writer.