
An entomologist identifies mosquito species at Dragon Mosquito Control in Northampton, N.H., on June 9, 2005. Darren McCollester/Getty Images
A Roscommon County resident has contracted a verified case of eastern equine encephalitis (EEE) inside the state, the Michigan Department of Health and Human Services reported Wednesday. It marks the state’s first such human infection of the deadly disease since 2021.
Health units at the state and local levels, along with the Michigan Department of Agriculture and Rural Development plus the Department of Natural Resources, continue to test mosquitoes and monitor individuals and household and wild animals for any symptoms of the virus. Fresh trapping and lab work are ongoing in Roscommon County as crews attempt to quickly determine the scale of the local threat.
“It is vital that Michigan residents take precautions against mosquito bites as mosquitoes can carry diseases that can have devastating health effects,” said Dr. Natasha Bagdasarian, the state’s chief medical executive. “EEE is one of the most dangerous mosquito-borne diseases in the U.S., with a 30% fatality rate among people who become ill.”
There are no vaccines against EEE infection in people and no treatments for the disease, the state government noted on its website reporting on emerging diseases in Michigan.
The pathogen infects people through the bite of a mosquito already carrying the disease. The illness is uncommon, with only a few human cases nationwide most years, with most infections occurring in eastern or Gulf Coast states.
Symptoms include fever, headache, chills, and nausea. The infection can also result in brain swelling, which causes confusion, seizures, and even coma.
To stop the virus from spreading, officials are working to shrink mosquito numbers near houses. Environmental Protection Agency-registered sprays that list DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone among the active ingredients can deter mosquitoes, though repellent should not be used on babies younger than two months.
Instead, officials advise dressing babies in long sleeves and pants, and draping netting over cribs, strollers and carriers. Adults should dress in lace-up shoes, socks, pale long pants and a long-sleeved shirt, as well as check that door and window screens fit tight, and repair or replace any that are ripped.
Dump any water that sits still and can grow larvae, including birdbaths, unused pools, kiddie pools, discarded tires, and every other item that collects water.
Recent cases of EEE have resulted in death, including the first EEE-related death in South Carolina in 20 years in September 2025, according to the state’s health department, as well as an elderly man in New York that same month, according to the University of Minnesota’s Center for Infectious Disease Research and Policy. Another individual in Maine contracted the disease in August 2025 and was hospitalized.









