The epidemic that wiped out tens of thousands of deer in southeastern Ohio over the summer and fall offered a spectacular reminder of what pathogens can do in the wild.
The outbreak of epizootic hemorrhagic disease (EHD) has drawn much, all-deserved attention, and disrupted whitetail hunting across a significant swath of the state.
Closer to central Ohio, moreover, another lethal disease that has nowhere near the kill count of EHD is making a glacial move through the deer population. Chronic wasting disease, also known as CWD, is not only spreading but unlikely to go away.
The differences between the two deer banes are substantial in both causes and effects.
While the death toll from EHD can be high, outbreaks persist but a few months before the cold weather of autumn eliminates the midges that spread the virus. A rapid recurrence of an outbreak in an area is unlikely because conditions including temperature and rainfall vary from year to year. In addition, surviving deer usually retain some immunity.
Sometimes, as will likely be the case after this year’s Ohio outbreak, the death toll can be high enough to reduce deer numbers in a location for a few years.
CWD, although not as deadly at this point as EHD in terms of numbers, seems more ominous.
Chronic wasting disease was confirmed by laboratory testing in additional animals from Wyandot, Marion, Hardin, Allen, Crawford and Hancock counties.
One reason is that, as far as is known, deer do not develop immunity. In addition, infection is always fatal. Another is that CWD is triggered by a type of rogue protein known as a prion that can survive in the soil long after an infected animal has left.
The chance for further infections among deer that arrive later persists. Infected whitetails do not remain stationary, so the spread of infection involving more and more deer is almost inevitable.
Most hunters are aware that deer infected with CWD can appear normal for years. Infected deer must be eaten, as symptoms of brain and nervous system damage develop late.
Fortunately, evidence is scant or non-existent that humans who eat venison from infected deer can develop a brain-wasting disease, but such a possibility has not been ruled out. Prudence dictates that deer showing any symptoms of disease should not be eaten; carcasses require special treatment.
A Wyandot County deer in 2020 became Ohio’s first confirmed case of CWD in a free-range whitetail.
Since then, CWD has been confirmed through laboratory testing in additional animals from Wyandot, Marion, Hardin, Allen, Crawford and Hancock counties. Meanwhile, parts of Delaware, Union and Morrow counties have been included in a designated area in which hunters must comply with enhanced regulations.
Ohio entered the early September of the recent deer season with 73 confirmed cases of CWD in wild whitetails. During the 2025-26 hunt, the number of authenticated cases increased to 109, a jump of 36, or almost 50%.
Results were pending on additional deer, many from outside the infection zone.
Finding animals far from the area may seem unlikely, but positives are possible because some small bucks have been known to travel long distances. It is also possible that a hunter, inadvertently or otherwise, may dispose of an infected carcass far from where the animal was taken.
All of this combined with the growing harvest will affect how much, if at all, deer regulations change in 2026-27. The proposals will be made public soon.
Loose ends
At the close of another exceptional season for Ohio deer hunters it should come as no surprise that Licking, typically among the highest producing counties among the 88, led central Ohio with 5,754 deer, 16 fewer than a year ago.
Trailing Licking were Fairfield with 2,351, Delaware 1,877, Union 1,401, Pickaway 1,153, Madison 767 and Franklin 709.
outdoors@dispatch.com
This article originally appeared on The Columbus Dispatch: Ohio’s deer face long-term threat as chronic wasting disease persists