A Roscommon County resident has tested positive for Eastern Equine Encephalitis, Michigan's first human case of the disease since 2021.

A Roscommon County resident has tested positive for Eastern Equine Encephalitis, the first human case of the disease reported in Michigan since 2021, the Michigan Department of Health and Human Services confirmed Wednesday.

The department said no EEE activity had been detected in animals anywhere in the state before this human case turned up. Health officials in Roscommon County have started additional mosquito trapping and testing to gauge how widespread the risk is in the area.

EEE spreads to people through the bite of an infected mosquito. Only a handful of human cases show up nationwide each year. Dr. Natasha Bagdasarian, Michigan's chief medical executive, said EEE has a 30% fatality rate among people who become ill.

"It is vital that Michigan residents take precautions against mosquito bites as mosquitoes can carry diseases that can have devastating health effects," Bagdasarian said.

Early symptoms include sudden fever, chills, nausea and body aches. In more severe cases, the virus can inflame the brain, producing disorientation, tremors, seizures and paralysis. Permanent brain damage, coma and death are possible outcomes for people who progress to severe encephalitis. There's no specific antiviral treatment for the disease; doctors can only manage symptoms and provide supportive care while the body fights the infection.

Children under 15 and adults over 50 face the greatest risk of severe illness if infected, according to the state health department. Anyone experiencing the symptoms described above is advised to contact a doctor right away rather than wait to see if symptoms pass.

State and local health departments are watching for further signs of EEE in humans, mosquitoes, pets and wildlife across Michigan. So far this year, the state has tested 5,420 mosquito pools for arboviruses, the broader category of viruses spread by mosquitoes and other biting insects, and 73 of those pools have come back positive. As of this week, no animals in Michigan have tested positive for EEE in 2026.

The last confirmed human case in Michigan was in 2021, during an outbreak that also produced a cluster of animal infections across several counties. This year's case did not follow that pattern. Officials are expanding testing around Roscommon County based on the human case alone, without confirmed animal infections to signal the virus's presence beforehand.

The health department is recommending a standard set of precautions to residents statewide, not just in the area where the case was found. Officials suggest applying insect repellent containing DEET or another EPA-approved ingredient to skin and clothing, following label directions closely. They also recommend wearing long sleeves and pants in light colors when outdoors, keeping window and door screens in good repair, and clearing standing water from buckets, old tires, unused kiddie pools and other containers around the house at least once a week, since those are common spots for mosquitoes to lay eggs.

The department said it will keep publishing weekly updates on human, animal and mosquito pool testing results as the summer mosquito season continues. Roscommon County residents can expect continued trapping and testing in the coming weeks as officials try to determine whether the case reflects broader viral activity in the area or an isolated exposure.