JACKSON — The Wyoming Game and Fish Department on Tuesday announced that chronic wasting disease was detected in an elk carcass at the Black Butte Feedground in the Pinedale region, making it the third feedground to have a confirmed case this year.

This is the first year ever that the disease has been detected on a feedground. For the highly transmissible, slow-killing, always-lethal disease, even single-digit detections could mean that there is widespread infection in the population, biologists say.

Western Wyoming herds that are adjacent to one another mix during the summer, meaning that elk from infected feedgrounds could find their way into the Jackson Elk Herd and spread the infection, which was first detected in the population in 2020.

“One of the hardest things about managing these herds in western Wyoming is that they’re very interconnected,” said Ben Wise, a Jackson-based disease biologist with Wyoming Game and Fish.

CWD was found in an elk carcass on the Scab Creek Feedground east of Pinedale in January and in three carcasses on the Dell Creek Feedground near Bondurant in February.

Elk on the Black Butte and Dell Creek feedgrounds are part of the Upper Green River Herd, which borders and shares summer range with the Jackson Herd.

At the end of last fall, CWD also was detected in the Fall Creek Herd, which similarly borders and shares summer range with the Jackson Herd.

Wildlife managers were spooked by the first feedground detection, declaring that the CWD cat was out of the bag.

The detection on a third feedground “is making it very loud and clear that CWD is here,” said John Lund, the Pinedale supervisor for Game and Fish.

“Just the two at Dell Creek is incredibly alarming,” said Hank Edwards, a retired Game and Fish wildlife health supervisor. “This disease is really slow. This is a disease that percolates along for many years, basically undetected.”

Because elk carry the disease for around two years before they succumb to it, it could still take another decade to see a population crash, said Tom Roffe, a retired chief of wildlife health for the U.S. Fish and Wildlife Service.

“I’m going to give [Wyoming] 20 years,” he said. “Ten years if they do nothing.”

For decades, biologists have warned that continued feeding eventually would decimate herds, but stockgrowers and outfitters support the practice. The best available science indicates that the Jackson Elk Herd will begin to decline if prevalence reaches 7% herdwide.

Elk typically migrate out of feedgrounds in March and April, depending on each feedground’s particular weather and snow conditions. The dispersal of the elk means that transmission will be lower, as elk no longer will be congregating.

During the summer, elk from various herds and feedgrounds hang out in the high country, where the days are cool, the grass is tall and bugs are less prevalent.

Summer transmission isn’t as much of a concern to Wise because the elk are more spread out. But elk from infected feedgrounds may mingle with elk from other herds and end up following them back to a different feedground the following winter. Marked elk from Dell Creek in the past have ended up on the National Elk Refuge.

Dell Creek flows out of the Gros Ventre Range, and the high country above it also is the head of the Flat Creek, Twin Creek and Cache Creek drainages, all of which run toward the 24,700-acre wildlife refuge.

“There’s so much movement and interchange amongst those adjacent herds,” Wise said.

Elk have strong fidelity to their calving range and summer range; their connection to their winter range is less strong. There isn’t mass movement between feedgrounds, but a handful of marked elk each year will end up on different feedgrounds than they left from.

“It’s amazing to be here because we have such intact long-range migrations, but it’s a double-edged sword,” Wise said. “When you’re migrating you’re also taking your baggage with you. That magnificent 100-plus-mile migration could also be a 100-plus-mile transmission.”

Infected elk will leave CWD on the landscape in their feces, urine and saliva, which also could infect mule deer, whitetail deer and moose.

“When summer comes, they’re taking their disease with them,” Edwards said. “These feedgrounds are going to serve as a source of this disease.”

Game and Fish officials are focused on limiting transmission on feedgrounds by ending feeding each season as soon as possible and implementing low-density feeding.

“There’s not a whole lot we can do to stop transmission off of feedgrounds,” Wise said. “Our goal is to limit transmission on feedgrounds.”

Elk are “going to leave the feedgrounds, and they’re going to go do elk things and be elk,” he said. “We don’t really have any other option.”

A lot of the feedgrounds in the region are conducive to early end dates, meaning mid-March. Elk usually stay later at the Upper Green River feedgrounds, including Dell Creek and Black Butte, due to persistent snowpack and active cattle production. Those elk likely won’t disperse until mid to late April.

The shorter feedground seasons and lower-density feeding won’t worsen the spread of CWD, but it may not significantly help either, Roffe said.

“Will it slow it down? It might,” he said. “No one knows. There’s no good data on that. They’re just grasping at straws. It’s like closing the barn doors on horses that have already escaped.”