Officials from the Michigan Department of Health and Human Services have notified Branch-Hillsdale-St. Joseph Community Health Agency that a fawn in Hillsdale County tested positive for Eastern equine encephalitis.
It is the first deer in the state found with the virus, which is transmitted by mosquitoes.
Mammals, specifically horses, humans and deer, can become infected when bitten by a mosquito that has fed on an infected bird.
A deer or horse infected with EEE may exhibit unusual behavior, such as loss of awareness of its surroundings, walking in circles, muscle paralysis, stupor and lethargy.
Lauren Vogel, medical director at the tri-county health department, also warned residents about chronic wasting disease, a prion disease of deer and elk that has been identified in both captive and free-ranging deer in Michigan.