{"id":262334,"date":"2026-02-25T16:23:09","date_gmt":"2026-02-25T23:23:09","guid":{"rendered":"https:\/\/montanafreepress.org\/?p=262334"},"modified":"2026-02-25T16:25:05","modified_gmt":"2026-02-25T23:25:05","slug":"cwd-is-spreading-in-montana-will-deer-and-elk-populations-decline-as-a-result","status":"publish","type":"post","link":"https:\/\/montanafreepress.org\/2026\/02\/25\/cwd-is-spreading-in-montana-will-deer-and-elk-populations-decline-as-a-result\/","title":{"rendered":"CWD is spreading in Montana. Will deer and elk populations decline as a result?"},"content":{"rendered":"\n

For decades, wildlife managers in Wyoming, Colorado and Utah have been grappling with the spread of chronic wasting disease, a neurodegenerative disorder that sickens and ultimately kills ungulates such as deer, elk and moose over a period of months or years. <\/p>\n\n\n\n

The disease is now well established in Montana, according to wildlife managers. Montana Fish, Wildlife and Parks told state lawmakers last month that the infection curve is climbing, particularly among white-tailed and mule deer. According to FWP\u2019s analysis, the disorder, first detected in 2017, is spreading in the Treasure State. <\/p>\n\n\n\n

\u201cWe now know that chronic wasting disease is found in 33% of hunt districts in Montana, it\u2019s found in all susceptible species, and as of the end of our last hunting season, the data showed that our highest three-year prevalence was 39% in white-tailed deer and 23% in mule deer,\u201d <\/strong>FWP wildlife biologist <\/strong>Bevin McCormick told lawmakers. <\/p>\n\n\n\n

So, will we see a decline in Montana\u2019s deer and elk populations?<\/p>\n\n\n\n

McCormick said there isn\u2019t enough data to conclude with certainty if CWD is contributing to the decline in eastern Montana mule deer populations<\/a>, but that the state is doing its best to manage the disease by increasing monitoring efforts, expanding hunting opportunities where it has been found, and educating hunters on proper carcass disposal.<\/p>\n\n\n\n

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Even if it\u2019s too early to tell if Montana hunters and other wildlife stakeholders should prepare for a sustained deer population decline, neighboring Wyoming\u2019s experience with the disease offers a cautionary tale about what happens when the disorder becomes endemic, or consistently present, in a given region.<\/p>\n\n\n\n

CWD is believed to have originated in the 1960s or 1970s<\/a> from a U.S. Department of Agriculture facility in northern Colorado where scientists were researching a related disease called Scrapie that infects sheep and goats, according to the National Institutes of Health.<\/p>\n\n\n\n

In a recent conversation with Montana Free Press, leading CWD researcher Peter Larsen described Wyoming and Colorado as the \u201cepicenter\u201d of CWD in the United States. That\u2019s because the disease, which is caused by a highly transmissible misfolded protein called a prion, has been present there for decades. <\/p>\n\n\n\t\n\t\t

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FAQ: Chronic wasting disease in Montana<\/a><\/h3>\t\t\t\t\t\t

Though Chronic Wasting Disease infection rates statewide have stayed in the single digits, in some units up to 20% of deer tested are carrying the fatal neurodegenerative disease. Here\u2019s how hunters can help slow CWD\u2019s spread.<\/p>\n\t\t\t\t

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A sick and doomed elk infected with chronic wasting disease. While CWD is well established in Montana, leading CWD researcher Peter Larsen described Wyoming and Colorado as the \u201cepicenter\u201d of CWD in the United States. Credit: Wyoming Game and Fish Department
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CWD is highly infectious, in part because the prions that cause it can continue to sicken animals long after the carrier has died. A study in Wisconsin has demonstrated that the prions that cause CWD, which an infected animal sheds in its bodily fluids and tissues, can persist in the environment for 16 years, Larsen said.<\/p>\n\n\n\n

\u201cIn a late-stage white-tailed deer with CWD, there are enough prions in that brain to kill all deer in North America,\u201d he added. \u201cWe\u2019re starting to get worried about accumulation in the environment and other species coming into contact with it.\u201d<\/p>\n\n\n\n

\u201cCWD is spreading fast throughout the U.S., but we\u2019re really only at the very beginning. \u2026The way this disease spreads and how those infections spread make it really difficult to manage.\u201d <\/p>Peter Larsen, co-director of the Minnesota Center for Prion Research and Outreach<\/cite><\/blockquote><\/figure>\n<\/span>\n\n\n

As the disease becomes more widespread, the risk that it will jump the species barrier and infect other animals, such as mountain lions or coyotes, increases, Larsen said. While humans can\u2019t contract CWD, the disease poses a \u201cnon-zero\u201d risk to them, he said. \u201cSome studies show there\u2019s a really strong species barrier. Other studies show it\u2019s not 100%, and there may actually be potential [for] crossover.\u201d<\/p>\n\n\n\n

Researchers trying to learn more about whether the prions become more or less infectious as they move through the food chain, according to Larson, are grappling with a \u201cdynamic\u201d situation. It\u2019s possible, he said, that movement through an animal\u2019s GI tract can change the prions\u2019 shape in a way that increases the infection risk for other species.<\/p>\n\n\n\n

\u201cIt\u2019s really difficult to know whether or not predators are going to be an effective way to manage it,\u201d Larsen continued. \u201cI don\u2019t think it hurts anything \u2026 but it\u2019s still going to be spreading during that long incubation time.\u201d<\/p>\n\n\n\n

Asked about the most effective tools to limit the spread of CWD, Larsen responded, \u201chunting, hunting, hunting.\u201d Culling is another management approach, though Missouri\u2019s experience with that strategy<\/a> has demonstrated that taking such an aggressive approach to CWD can invite controversy.<\/p>\n\n\n\n

FWP spokesperson Greg Lemon said Montana\u2019s approach centers on enlisting hunters to help with monitoring and hunting efforts.<\/p>\n\n\n\n

\u201cIf we can keep prevalence low where it exists, we can hopefully limit the disease\u2019s ability to spread to other herds that might not have CWD yet,\u201d Lemon said. \u201cAnd if we can do that with the help of hunters \u2026 then we can protect the herds and the hunting heritage that we value in Montana.\u201d<\/p>\n\n\n\n

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