MDARD Confirms First Case of Eastern Equine Encephalitis for 2025 in a Benzie County Horse

By Lynsey Mukomel

The Michigan Department of Agriculture and Rural Development (MDARD) is reporting Michigan's first case of eastern equine encephalitis (EEE) in a domestic animal in 2025.

The disease was detected in a horse from Benzie County that was unvaccinated against EEE. This case is the first detection of EEE in Benzie County, and it highlights the importance for all Michiganders to take precautions to protect their animals and themselves from mosquito bites. 

"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, DVM, MS, DACVPM. "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."

EEE is a zoonotic, viral disease transmitted through the bites of mosquitoes to both animals and people. Cases of the disease are typically seen in late summer to early fall each year in Michigan. EEE and other mosquito-borne diseases are not spread by horse-to-horse or horse-to-human contact.

"It only takes one bite from an infected mosquito to cause a severe illness," said Dr. Natasha Bagdasarian, MDHHS 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."

EEE is not the only mosquito-borne disease regularly detected in Michigan. As of August 22, 2025, West Nile virus (WNV) has been detected in 126 mosquito pools, 16 wild birds, and six humans. For the latest information on cases of mosquito-borne diseases in Michigan, please visit michigan.gov/emergingdiseases for weekly summaries.