CWD Surveillance

2020 CWD management zones
CWD Management Zones

Each year, MDC tests a sample of the state’s deer population for CWD, as part of its disease surveillance program. CWD testing has two main goals: detect the disease as early as possible in new locations and monitor changes in disease occurrence over time.

MDC partners with taxidermists throughout the entire state, who collect CWD samples on MDC’s behalf. Focusing testing on adult males increases the likelihood of finding CWD in new areas.

Within CWD Management Zone counties (counties within 10-miles of CWD detections), a greater number of samples are collected, due mostly to “mandatory sampling” on opening weekend of fall firearms season.

This important effort allows MDC scientists to better understand where the disease is on the landscape so that management actions can be applied (especially post-season targeted culling), learn about how the disease is spreading, and keep the public informed.


2020-2021 Sampling Results to Date

The table below shows MDC sampling efforts and test results so far for the current sampling season (July 1, 2020 - June 30, 2021). These numbers are subject to frequent change.


CWD in Free-Ranging Deer

This map shows cases of CWD found so far in free-ranging deer.
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CWD Cases Found in Free-Ranging Deer Through June 30, 2020

This table shows the total number of CWD cases found in Missouri free-ranging deer by county through June 30, 2020. Positives for the current surveillance season are not included in this table.

Total CWD-positives (free-ranging deer) by County (through 6/30/2020)
County Total Positives Year of 1st CWD Detection
Macon 42 2011-12
Adair 19 2014-15
Cole 1 2014-15
Franklin 19 2015-16
Linn 19 2015-16
Jefferson 4 2016-17
St Clair 8 2016-17
Cedar 1 2017-18
Perry 3 2017-18
Polk 7 2017-18
Ste Genevieve 23 2017-18
Crawford 1 2018-19
Mercer 1 2018-19
Oregon 7 2018-19
Stone 3 2018-19
Taney 4 2018-19