A startling increase in the prevalence of chronic wasting disease (CWD) in southeastern Minnesota’s deer population has triggered a new management response from the Department of Natural Resources that might surprise hunters.
Starting immediately, the agency will end its deployment of sharpshooters in all Driftless Area disease management zones. In previous winters, the shooters were sent to the area to curtail the spread of CWD by thinning whitetail herds in disease hot spots.
But now that CWD prevalence in the southeast part of the state has doubled in one year, to 5% or more, the benefit of offseason culling is considered too meager to justify the expense. The DNR is expected to formally announce the policy after the start of the new year.
“The positives have spiked,” DNR Wildlife Health Program Supervisor Michelle Carstensen said in an interview. “We are past the point where culling in the area will do any good. The gates are open and the horses are out.”
As a result, she said, computer modeling predicts CWD prevalence in wild deer in the area will climb to around 15% in 2028. Continued offseason culling at an expense of more than $800,000 a year would slow the spread, but only minimally, she said.
“Once disease is greater than 5% prevalence, and widespread, culling is not effective to curb the disease in that area,” Carstensen said.
CWD, a neurological disease that is always fatal in deer, is dreaded because of its proven potential to infect high percentages of deer, elk and moose. According to the U.S. Centers for Disease Control and Prevention, there is no direct evidence that CWD infects people. However, some experiments have raised the concern that CWD may pose a risk to people, and the agency has advised people not to eat CWD-infected deer.
Carstensen said the state’s program was hampered by a shortage of landowners willing to grant access for culling operations. She said she doesn’t blame landowners for their reluctance. But in a disease zone dominated by private land ownership, access to only 10% of the target area wasn’t enough to disrupt the transmission cycle of the disease, she said. Infected deer shed the disease in ways that put closely related deer at higher risk of getting it. The culling was always targeted in pockets of about 2 square miles where the disease was detected and where deer grouped together. But limited access left too many pockets of disease untouched and ripe for transmission.