Chronic wasting disease found at the National Elk Refuge

Winter feeding of elk

During my 22 years working at the National Elk Refuge (NER) in Wyoming, I and others dreaded the day that chronic wasting disease (CWD ) would reach the NER where 7,000 to 8,000 elk congregate each winter. The herd is supplementally fed alfalfa hay to support this number of elk which exceeds the habitat's carrrying capacity (available natural food resources).

The crowding of elk at feedsites facilitates the transmission and maintenance of several diseases. But none have the capacity to infect and kill hundreds of animals, as CWD may well do. See my January 27, 2025 post for more about the disease and the eipidemiology of CWD.

Now the nightmare has arrived. During April 2026, an animal exhibiting the clinical signs of CWD was euthanized by refuge staff (see the news release). Tissues were collected and analyzed. The animal was found to be sick with CWD. Out of a herd of thousands of elk, one case may seem inconsequential. But following infection, CWD slowly develops over 12-36 months, attacking the central nervous system before killing its host. It's highly likely that other -- possibly many other -- elk are infected but not yet clinically symptomatic or detected.

Originally identified in mule deer and elk in a small area of northeast Colorado and southeast Wyoming in the 1980s, CWD has spread to 36 states and 5 Canadian provinces. Nowhere that it has spread has the disease gone away. Prevalence tends to increase over time. And in a herd of animals fed and crowded in winter on the NER, the opportunity -- and potentially the rapidity -- of the disease amplifying is certainly enhanced. This does not bode well for the largest wintering herd of elk in North America that roams a broad swathe of the 20 million-acre Greater Yellowstone Ecosystem.

To learn more about CWD and the biological, ecological, and economic consequences of the coming disaster, I suggest reading Where Elk Roam: Conservation and Biopolitics of Our National Elk Herd, my assessment of the situation.