In a concerning development for Michigan’s wildlife, the state’s Department of Natural Resources (DNR) has confirmed the presence of a deadly disease affecting deer populations in at least 11 counties this year. The disease in question is Epizootic Hemorrhagic Disease (EHD), which has been detected in the following counties: Barry, Berrien, Branch, Calhoun, Cass, Hillsdale, Kalamazoo, Kent, Ottawa, St. Joseph, and Van Buren.

This year marks a troubling increase in EHD cases compared to 2023, when it was only reported in Washtenaw County. The state witnessed a more widespread outbreak back in 2021, which affected as many as 24 counties.

EHD is an acute, infectious viral disease known to be particularly lethal to wild ruminants such as deer, causing severe hemorrhaging within the animals. This disease has been known to trigger substantial epidemics among deer in parts of the northern United States and southern Canada, posing significant threats to deer not only in Michigan, but across the region.

EHD is distinct yet similar to another viral disease known as Bluetongue, which also affects ruminants and occurs throughout North America. However, the two diseases are antigenically different and exhibit different clinical signs.

The primary mode of transmission for EHD is through bites from a specific type of midge, particularly Culicoides variipennis, which is prevalent in North America. For a deer to be infected, it must be bitten by a midge that carries the virus; therefore, the disease cannot be spread directly from deer to deer. Typically, significant outbreaks happen as single epizootics, and years may pass without recurrence. Notably, smaller die-offs can occur annually, suggesting that areas can become enzootic, harboring the virus in lower numbers.

The peak of EHD outbreaks typically falls between late summer and early fall (August to October), with occurrences sharply ceasing once frost arrives, effectively killing off the midge population. Interestingly, while EHD can also potentially infect domestic hoofed livestock, it rarely results in illness.

Despite the grave implications for deer populations, it is important to note that there are no known health risks for humans consuming venison from infected animals. The disease does not impact the edibility of the meat, and humans cannot contract EHD from either the midge insects or through handling venison. Moreover, pets and other wildlife remain safe from both midges and infected deer carcasses.

As of now, there is no effective treatment or control method to combat EHD in wild deer populations, leaving it up to local wildlife officials and conservationists to monitor the situation closely as they work to understand and manage this alarming outbreak. Wildlife enthusiasts and hunters are encouraged to stay informed and exercise caution, as the ramifications of this disease could profoundly affect deer numbers in Michigan.