Dead deer reports surge in southeastern Wisconsin amid EHD outbreak

Wisconsin wildlife regulators have logged almost 900 reports of dead deer in the state’s southeastern region, primarily in Washington County, where about 700 cases were reported, along with more than 150 in Waukesha County and over 30 in Ozaukee County. The deaths are associated with an outbreak of Epizootic Hemorrhagic Disease (EHD), a viral illness transmitted by biting flies or midges that is often fatal to deer but does not pose a risk to humans.

The Wisconsin Department of Natural Resources confirmed two wild deer in Washington County tested positive for EHD last month. DNR wildlife health supervisor Jasmine Batten said the current numbers are “significantly higher” than in previous Wisconsin outbreaks, noting that the state’s highest prior county total was 226 dead deer in Crawford County.

"Certainly, an EHD outbreak of this magnitude locally for this season appears devastating to landowners and hunters in terms of the number of deer in a small area they’re seeing dead," Batten said.

"We can really appreciate why people are so concerned. There probably will be hunting properties that have far fewer deer this fall going into the season," she added.

Batten cautioned that some reports may be duplicates and that the disease was first noted in the region in late July, earlier than typical outbreaks that usually peak from August to October. She explained that drought conditions can concentrate deer near waterways, which serve as breeding sites for the insect vectors, increasing transmission risk.

"You have to have the right conditions where these fly populations are really coming into contact with the deer," Batten said.

Deer infected with EHD may exhibit foaming at the mouth, weakness, or seek water to cool down due to fever. Mortality can reach up to 50% of a local herd, though survivors often develop immunity that reduces the likelihood of future outbreaks in the same population for several years.

"Those deer that are exposed, and do not die, will have immunity next year," Batten explained.

Despite the current surge, Wisconsin’s overall deer population continues to grow, reaching a record 1.89 million statewide, with Washington County estimated at about 16,200 deer. Batten emphasized that the robust deer numbers provide capacity for recovery.

"As disturbing as it is when there’s a big outbreak here, it’s really good to keep in mind that it’s not typically something to panic about. Our deer populations in those areas are very robust," she said.