Michigan's first 2025 case of Eastern Equine Encephalitis found in domestic horse
Michigan's first case of Eastern Equine Encephalitis (EEE) in 2025 has been found in a domestic horse in Benzie County.
State health officials said the mosquito-borne illness was found in an unvaccinated horse.
"While this is the first case of EEE detected this season, other mosquito-borne diseases have been discovered throughout Michigan, including six human cases of West Nile virus," said State Veterinarian Dr. Nora Wineland, in a statement. "These detections clearly indicate disease is circulating in the state's mosquito population, making it crucial to protect animals and people against these insects. Preventing mosquito bites will prevent mosquito-borne diseases."
Like other mosquito-borne illnesses, Michigan health officials say EEE cannot be passed by horse-to-horse or horse-to-human contact. Cases are typically seen in the late summer and early fall each year in the state.
"It only takes one bite from an infected mosquito to cause a severe illness," said Dr. Natasha Bagdasarian, Michigan Department of Health and Human Services chief medical executive. "We urge Michiganders to take precautions such as using an EPA-registered insect repellent when outdoors, avoiding areas where mosquitoes are present if possible, and wearing clothing to cover arms and legs to prevent bites. EEE is one of the most dangerous mosquito-borne diseases in the United States, with a 33% fatality rate in people who become ill."
While there have not been any additional cases of EEE in animals or humans in 2025, the West Nile virus has been detected in 126 mosquito pools, 16 wild birds and six humans. Earlier in August, a Kent County resident died as a result of complications of West Nile virus.
How you can protect animals from mosquito-borne illnesses
- Talk to a veterinarian about vaccinating horses against EEE, WNV, and other mosquito-borne diseases.
- Eliminate standing water—i.e., fill in puddles, repair eaves, and change the water in buckets and bowls at least once a day.
- Place livestock in a barn under fans (as mosquitoes are not strong flyers) and pets inside the home during peak mosquito activity from dusk to dawn.
- Use an insect repellant on animals that is approved for the species.
- Contact a veterinarian if an animal shows signs of illness. If a Michigan animal is suspected of having EEE or WNV, funding is available under an arbovirus grant to cover these testing costs.
How you can protect yourself against mosquito-borne diseases
MDARD recommends the following tips to protect you and your family from mosquito-borne illnesses like EEE.
- Apply insect repellents that contain the active ingredient DEET or other EPA-approved products to exposed skin or clothing. Always follow the manufacturer's directions for use.
- Wear light-colored, long-sleeved shirts and long pants when outdoors. Apply insect repellent to clothing to help prevent bites.
- Maintain window and door screening to help keep mosquitoes outside.
- Empty water from mosquito breeding sites around the home, such as buckets, unused kiddie pools, old tires, and other water-holding containers where mosquitoes can lay eggs.
The above video first aired on Aug. 18, 2025.