Deadly chronic wasting disease spreading in Ohio deer population

The outbreak that wiped out tens of thousands of deer in southeastern Ohio over the summer and fall served as a spectacular reminder of what pathogens can do in the wild.

The outbreak of epizootic hemorrhagic disease (EHD) has deservedly attracted considerable attention and disrupted whitetail hunting in a significant portion of the state.

Moreover, closer to central Ohio, another deadly disease with nowhere near the kill count of EHD is glacially advancing through the deer population. Chronic wasting disease, or CWD, is not only spreading, it is also unlikely to go away.

The differences between the two deer disasters are important in terms of both causes and consequences.

Although the death toll from EHD remains high, outbreaks continue, but it is several months before cold autumn weather eliminates the sandflies that spread the virus. Because conditions such as temperature and precipitation vary from year to year, a rapid recurrence of an outbreak in one region is unlikely. Moreover, surviving deer usually acquire some immunity.

Sometimes, as was likely the case after this year’s Ohio outbreak, mortality numbers can be high enough to deplete deer numbers in an area for several years.

While CWD is not as deadly as EHD at this point in terms of numbers, it appears to be more concerning.

One reason for this is that, as far as is known, deer do not develop immunity. Moreover, the infection is always fatal. Another is that CWD is triggered by a type of rogue protein known as a prion, which can survive in soil for long periods of time even after an infected animal has left.

The possibility of further infection among later arriving deer remains possible. Infected whitetails do not sit still, so it is almost inevitable that the infection will spread to more and more deer.

Most hunters are aware that CWD-infected deer can appear normal for years. Considering the late onset of symptoms of brain and nervous system disorders, it is certain that infected deer succumbed.

Fortunately, there is little to no evidence that people who eat venison from infected deer can contract a brain-wasting disease, but such a possibility has not been ruled out. Common sense dictates that deer that show any signs of disease should not be eaten; carcasses require special handling.

In 2020, a Wyandot County deer became Ohio’s first confirmed case of CWD in a free-ranging whitetail.

CWD has since been confirmed by laboratory testing in other animals in Wyandot, Marion, Hardin, Allen, Crawford and Hancock counties. Meanwhile, parts of Delaware, Union and Morrow counties have been included in a designated area where hunters must comply with enhanced regulations.

Ohio entered the September start of its final deer season with 73 confirmed cases of CWD in wild whitetails. During the 2025-26 hunt, the number of confirmed cases increased by 36 to 109, an increase of almost 50%.

Results from additional deer, many of which came from well outside the infection zone, were pending.

Finding animals far from the area may seem unlikely, but positive results are possible given that some fawns have been known to travel long distances. It is also possible for a hunter to accidentally or otherwise discard an infected carcass away from where the animal was taken.

All of this, along with increased harvest, will impact how much deer regulations change (if at all) 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, usually among the top-producing counties among the 88 counties, led central Ohio with 5,754 deer, 16 fewer than a year ago.

Trailing Licking was Fairfield with 2,351, Delaware with 1,877, Union with 1,401, Pickaway with 1,153, Madison with 767 and Franklin with 709.

outdoors@dispatch.com

This article first appeared on The Columbus Dispatch: Ohio elk face long-term threat as chronic wasting disease persists