Increase in chronic wasting disease ‘definitely a concern’ in Aspen region

Chronic wasting disease prevalence is rising in multiple deer herds in the northwest region of Colorado, which includes Aspen, amid a lack of understanding about how the disease spreads. 

CWD is a neurological disease among deer, elk, moose, and other hoofed species, according to the Centers for Disease Control and Prevention. Colorado Parks and Wildlife’s website states that CWD is fatal in every animal infected, with no treatment or vaccine. 

Roughly half of Colorado’s deer herds and one-third of its elk herds have animals within the herd infected with the disease. 

In Pitkin County, Epidemiology Program Administrator Carly Senst confirmed there are no known CWD cases locally. The disease, however, is spreading into new regions across the country where it hasn’t been before.

“It is moving up in elevation and moving into areas we haven’t seen in the past,” Senst said. “Disease dynamics are changing with climate change. Locally, we’re paying attention.”

CPW Northwest Region Senior Wildlife Biologist Brad Banulis emphasized there is reason to be worried.

“Increasing prevalence and distribution are definitely a concern,” Banulis said. “CWD left unchecked can increase quickly in prevalence and affect buck survival and doe survival.”

CWD always leads to death after infection, decreasing the survival trends of herds and populations over time.

“Once well established in a herd, it is usually impossible to eradicate,” the CPW website states. “No immunity develops, and infected animals do not recover. Without management, the presence of the disease will increase and may cause a population to decline over time.​​”

Banulis confirmed the region around Aspen has experienced an uptick in cases.

“We are seeing some herds with increasing CWD prevalence across the (northwest) region,” he said, but “there isn’t anything really consistent.”

The good news is that there are also some herds in northwest Colorado that are stable and even decreasing in prevalence and one last herd where CPW hasn’t detected CWD at all. 

The problem is, it’s still uncertain how CWD spreads.

Recent studies out of Wyoming suggest CWD prevalence remains low among populations where there are high harvest rates of bucks. Banulis said CPW is looking into how harsh winters that “severely concentrate” deer on their winter ranges cause an increase in the disease’s prevalence via nose-to-nose contact.

It’s not out of the question, though, that CWD can potentially be transmitted through soil and vegetation.

He confirmed that CWD in humans resulting from exposure has not been reported to date, but public health officials cannot guarantee there is no risk from eating meat of infected animals. Senst said Pitkin County is tracking the disease in relation to public health.

A statewide CWD Response Plan outlines alternatives to managing CWD if prevalence in herds exceeds 5%, which is determined through Colorado’s mandatory testing process for deer harvested in specific areas. In areas with above 5% prevalence, license numbers are increased, according to Banulis. 

Currently, CPW considers hunting “the single most effective tool to monitor and manage the spread of the disease.” 

Hunters who see a deer that appears to be sick are asked not to shoot the animal; instead, note its specific location and call the closest CPW office. Symptoms include dramatic weight loss, stumbling, drooling, listlessness, excessive thirst and urination, drooping ears, and a lack of fear of people.

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