EHD in Illinois– Summer 2024

Each year between August and October, especially during hot and dry summers, landowners, deer hunters and wildlife enthusiasts are encouraged to keep an eye open for signs of an outbreak of Epizootic Hemorrhagic Disease (EHD) in the local white-tailed deer herd.

In 2023, EHD activity was lower than previous years with a drop in both the number of suspected deer and counties with an observed infected deer. The highest number of reports came from Pike and Tazewell counties. A limited number of reports also came from west central and southern Illinois, resulting in a total of 18 counties, a significant drop from 22 counties in 2022.

EHD is an acute, infectious, and often fatal viral disease of some wild ruminants, including white-tailed deer. Characterized by extensive hemorrhages, this disease has been responsible for significant outbreaks in deer in the northern United States and southern Canada. Signs of EHD appear about seven days after the deer has been bitten and include sluggishness, difficulty breathing, loss of appetite, salivation, and swelling of the head, neck, tongue or eyelids. Affected animals develop a fever, and typically many are found in, or adjacent to, water where they try to reduce their body temperature. Death can come quickly, from 8 to 36 hours after the onset of observable signs, to some infected deer. Other deer may die days or weeks later, and some will completely recover.

EHD is observed somewhere in Illinois every year, typically where receding water levels provide the muddy shoreline breeding habitat necessary for the EHD vector, a Culicoides biting gnat. EHD is transmitted when a gnat carrying the virus bites a deer. Outbreaks tend to be localized because environmental and habitat conditions play an important role in producing the right mix of virus, high gnat populations, and susceptible deer. An insect-killing frost typically ends an EHD outbreak.

EHD cannot be transmitted directly from deer to deer and is not considered to be hazardous to humans or pets.

The patchy annual distribution of EHD means that Illinois residents are key to tracking annual outbreaks. Illinois residents and hunters serve as the Illinois Department of Natural Resources’ eyes and ears in monitoring the annual distribution of this disease, as well as the health of the local deer herd.

To learn more about EHD, or report incidences of sick and dead deer, access the online Report Sick or Dead Deer reporting form at White-tailed Deer Illinois. You will be asked to report facts including the county, number, age, sex and specific location of the deer.