Missouri's CWD Doesn't Creep — It Jumps
The intuitive picture of a wildlife disease is a stain spreading outward from a center. Missouri's CWD record (933 positive deer mapped to the section of ground where each was killed, 2011 through 2025) does not look like that. For three years it stayed within a half-mile of one spot in Macon County. Then it stopped spreading and started jumping: most of the counties it now occupies first appeared as isolated foci a hundred to two hundred and forty miles from the origin. That pattern has a cause, and it changes where a hunter should expect it next.
- Missouri's first CWD cluster (2011–2013) stayed inside a half-mile of its Macon County origin — textbook local spread, one county, a few sections.
- From 2014 on the pattern broke: of the 56 counties now carrying positives, 39 of the 55 that map first appeared more than 75 miles from that origin: as far as 240 miles, in disconnected pockets.
- Newly detected positive locations climbed from single digits a year (2011–2016) to 100-plus a year by 2023–2024: the disease is being found faster every season.
- Long-distance, disconnected foci are the fingerprint of human-assisted movement — hauled carcasses and the captive-deer industry — not deer walking. The next infected county is not necessarily the next county over.
IThe half-mile years
Missouri confirmed CWD in free-ranging deer in the early 2010s, in Macon County in the state's north. For the first three sampling years the positives behaved exactly as a contagious disease of a walking animal should: every one of them fell within roughly a half-mile of the others. If that had continued, Missouri's CWD map today would be a single widening blot centered on Macon, and management would be a matter of drawing rings. It did not continue.
IIThe jumps
Beginning in 2014 the positives stopped respecting distance. New foci opened in Franklin County (143 miles from the origin), then Jefferson (184 miles), then a cascade down the state's southern half: Ste. Genevieve and Perry in the southeast, Taney, Barry, and Christian near the Arkansas line in the southwest. These were not the leading edge of a spreading blot; they were separate ignitions, each surrounded by clean ground. Of the 55 positive counties that map to a location, 39 first appeared more than 75 miles from Macon.
| County | First positive | Miles from origin |
|---|---|---|
| Macon (origin) | 2011 | 0 |
| Adair | 2014 | 24 |
| Cole | 2014 | 98 |
| Franklin | 2014 | 143 |
| St. Clair | 2016 | 152 |
| Jefferson | 2016 | 184 |
| Ste. Genevieve | 2017 | 207 |
| Perry | 2017 | 215 |
| Taney | 2018 | 236 |
| Howell | 2021 | 231 |
| Barry | 2021 | 241 |
| Jasper | 2023 | 216 |
Selected county first-detections and their great-circle distance from the 2011 Macon origin. 39 of 55 mapped counties debuted beyond 75 miles — the geography of introductions, not diffusion.
IIIWhat jumps mean
A prion cannot fly and a deer cannot walk 200 miles in a season through country with no infected deer between here and there. When a disease appears far from every known case, surrounded by clean ground, something carried it. For CWD the two established long-distance vectors are hauled carcasses (a deer shot in an infected county, its spinal column and lymph nodes dumped in a clean one) and the movement of live animals through the captive deer-farming industry. Missouri's foci pattern, disconnected and far-flung, is what that looks like on a map.
A prion cannot fly. When CWD appears two hundred miles from the nearest case, surrounded by clean ground, something carried it there, and the something is usually us.
IVReading the map
The practical lesson is that “my county is clean and so are the counties around it” is a false comfort in a jump-driven epidemic. A clean county's real exposure is its connections (the deer processors it shares, the carcass-transport habits of its hunters, any captive facility inside or upstream of it) more than its infected neighbors. A hunter who wants to know where CWD is headed in Missouri should watch the plumbing of deer movement, not the distance to the nearest dot.
- Each positive is mapped to the Public Land Survey section centroid where the deer was taken; source Missouri Department of Conservation CWD services (gisblue.mdc.mo.gov). Distances are great-circle from the 2011 Macon centroid.
- 933 CWD-positive deer across 56 counties, sample years 2011–2025. 107 records carry a 2022–2023 range rather than a single year and are included in totals but excluded from the annual-cadence figure so as not to overstate 2022.
- First-detection year partly reflects when and where MDC sampled; a later first-detection does not by itself prove later arrival. The disconnected geography of the foci, however, is not an artifact of where sampling happened.
- “Miles from origin” is measured to the earliest positive location within each county.
- This paper describes spread geography, not prevalence; Missouri's per-county positive counts are lower than Wisconsin's because its sampling and disease history differ.
Fully Drawn Research is an independent data analysis desk, not affiliated with the Illinois Department of Natural Resources, the Illinois Department of Transportation, or any mapping or outfitting provider. Figures trace to Missouri Department of Conservation public CWD data, retrieved June 2026.