Deer disease surges in Southeast Iowa after drought

WASHINGTON — Hundreds of dead deer have been spotted in Southeast Iowa over the last month. While some are found on dry land, most turn up close to streams, ponds, and other bodies of water. One man in Crawfordsville even awoke one morning to find one of the animals deceased in his home swimming pool.

None of the animals have gunshot wounds, or broken bones from a car accident, or goring marks characteristic of a fight with another buck. Those found soon after death are often described as appearing healthy, on the outside.

Experts say the cause is Epizootic Hemorrhagic Disease, or EHD. The disease cannot infect humans, but spreads between deer through culicoides midges: small, mosquito-like flies that bite animals to feed on blood. The mortality rate of the virus in white-tailed deer is as high as 90%, according to one ISU College of Veterinary Medicine report.

“We had it years ago pretty bad, but not this bad, I mean not even close,” said Larry Cuddeback, who owns a stretch of land in Washington County’s Dutch Creek Township which is usually flush with the animals. So far this year he’s found nine dead on his property, but believes there are others unaccounted for based on the smell. “From my place, any evening before this, I could look any direction and see deer … I can do that now and not see a single one.”

While a few cases of EHD are logged in Iowa almost every year since its arrival in 2012, wildlife experts say 2023 is an outlier, with over 1,000 cases reported across 68 counties.

Most of the heavily infected counties are in Southeast Iowa. Henry County is among the worst off, with 111 likely EHD deaths logged by the Iowa Department of Natural Resources as of Oct. 26. Jefferson County hasn’t fared well either, with 49 cases so far, along with 15 in Washington and 40 in Keokuk.

Conventional wisdom holds that the disease gets more prevalent in years with a drought or a flood, according to Washington County Conservation Director Zach Rozmus. He said the bugs laid eggs in muddy areas, like exposed creek beds and poorly drained soil.

The explanation tracks with Southeast Iowa’s summer weather, which was abnormally dry in 2023 with a two-week rainy period in August, months later than usual.

The disease’s symptoms include a fever and swelling of the tongue that makes it difficult for animals to swallow. Rozmus said that drew them to locations with water, where they often die attempting to cool down.

With bow hunting season starting Oct. 1, he said hunters were now starting to find the bodies. The tally will likely rise as more people trek through remote areas during shotgun and muzzleloader seasons, which start in December.

“When you have people actually going out into the timber and walking creek beds, that’s when we’ll get a lot of calls … this is just the tip of the iceberg,” he said. “My phone’s been going off nonstop with individuals reaching out to me about where they’re finding them.”

Iowa DNR Forest Wildlife Biologist Jim Coffey said 2023 was likely the worst year of the decade for EHD in the state, but added that reports might be higher than usual as more people actively look for the animals than in the past.

Still, if anyone finds an unwounded deer deceased on their own stomping grounds, he advises them to call their local conservation officer or the DNR with a heads up.

Part of what makes this year unusual is the geographic spread of reports. The disease tends to show up in one region, even one county, at a time, according to Coffey, rather than the current snapshot of cases spread across most of the state with strong concentrations in Clayton County and Southeast Iowa.

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“It’s not an every-year disease … but when you see it, you tend to see it more in one area than you would statewide,” he said. “We tend not to see it for seven to 10 years after that, because the deer will build up somewhat of an immunity until those populations are then removed, and then the disease can come back.”

Given the high fatality rate, Coffey said the pathogen could be “devastating” on local levels, but likely wouldn’t make a major dent in any countywide herd.

“When you hear people say it can have a huge impact on the deer populations, we’re usually talking about a few sections or a township type of an area,” he said. “You’d probably see an impact in the next year or two on our population surveys … when you start seeing 25% of your herd not being detectable the next year, then you have a significant outbreak.”

EHD deaths are likely close to halting altogether for the season. Midges die each year at the first killing freeze — expected by or before the night of Oct. 30 — according to Coffey, who said the virus would stop killing animals a little under two weeks later, the length of its incubation period.

While the herd thinning may lower some hunting grounds’ success rates, Coffey said the state probably wouldn’t issue any fewer deer licenses in upcoming seasons. He expects the population to rebound soon enough, especially given relative overabundance of the animals in Southeast Iowa compared to the rest of the nation, and its own recent history.

“In many cases, that population will be back to where it is now in two to three years,” he said. “People get worried because they think their deer are devastated and they think we’re going to over-harvest them and they’ll never have deer back again, and that has not been the case in any place where we’ve ever had EHD in the past.”

That makes EHD far less of a concern to officials than Chronic Wasting Disease, which had almost 100 cases reported across Iowa in 2022, and at least two so far in 2023. None of those were in the southeast region, but Coffey said it was still a statewide worry.

“Chronic Wasting Disease is something the department’s very concerned about, about the future of the deer herd and how people use deer in Iowa,” he said. “If people are not educated about CWD, they need to become educated about it.”

The Gazette’s Brittney J. Miller contributed to this report.

Comments: Kalen.McCain@southeastiowaunion.com