Illinois ends deer culling as chronic wasting disease spreads southward

Illinois is abandoning the targeted deer culls that once anchored its response to chronic wasting disease, after the fatal prion illness surfaced in Effingham, Scott and Stark counties and spread beyond the northern area officials had spent decades trying to hold in place. The Illinois Department of Natural Resources says the disease has now been detected in 28 counties, and that prevalence in the 21-county endemic area climbed to 9.2% in 2025 after years below 2%.

The shift marks a stark admission after a 23-year campaign that began with the first Boone County detection in 2002 and active management through sharpshooting in 2003. Illinois paired that approach with liberalized hunting opportunities and baiting restrictions, hoping to concentrate removals around known cases and slow transmission. Instead, the latest detections include the first documented cases outside the state’s northern endemic region, a sign that the disease has moved southward faster than managers could contain it.

The numbers show why confidence is fading. Illinois’ 2024-2025 surveillance report found 539 CWD-positive deer among 12,444 usable statewide samples, with the affected area expanding to 20,036 square miles. Through June 30, 2024, the state had collected 185,896 samples and recorded 2,748 positives. A 2022 University of Illinois study of culling from 2003 to 2020 found that 14,661 deer were removed and tested, including 325 positives, and concluded that culling closer to detected cases removed proportionally more infected animals. Even so, the disease kept spreading.

Illinois’ 2025-2029 management plan says there are still no definitive disease-management prescriptions, and the state is moving to a five-year pilot that ends zone-specific removal goals in some areas, keeps sharpshooting only in low-prevalence endemic counties and leans more heavily on hunter harvest and surveillance. Officials also point to fatigue among cooperating landowners and the public, a practical limit on a strategy that demands repeated access, labor and political patience.

The stakes are wider than deer numbers. Illinois says CWD is fatal in every case, has been documented in 36 states and five Canadian provinces, and has no cure or vaccine. The Centers for Disease Control and Prevention has not linked the disease to human transmission, but it still advises against eating meat from CWD-positive deer, a warning that weighs on hunters, state budgets and public confidence in the safety of venison as the map of infected counties keeps expanding.