Mosquitos Positive for Eastern Equine Encephalitis found in Barry County

 July 6, 2023

Michigan residents are urged to take precautions against mosquito bites as mosquitos collected in Barry County on June 30th, 2023 have tested positive for Eastern Equine Encephalitis (EEE) at the Michigan Department of Health and Human Services (MDHHS) Bureau of Laboratories.

Although no cases have been diagnosed in people or animals, it is important to know they can be infected with EEE from one bite of a mosquito carrying the virus. Anyone can become ill with EEE. People under age 15 and over age 50 are at greatest risk of severe disease following an EEE infection

EEE is one of the most dangerous mosquito-borne diseases in the United States, with a 33% fatality rate in people who become ill.” said Dr. Natasha Bagdasarian, MDHHS chief medical executive, in a press release earlier this week.

Signs of EEE infection include sudden onset of fever, chills and body and joint aches that can progress to severe encephalitis, resulting in headache, disorientation, tremors, seizures and paralysis. Anyone who thinks they may be experiencing these symptoms should contact a medical provider. Permanent brain damage, coma and death may occur in some cases.

Residents can stay healthy by using simple, effective strategies to protect themselves and their families from mosquito bites. The following steps are recommended to avoid mosquito-borne diseases:

  • 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 keep mosquitos outside.
  • At least once a week, empty water from mosquito breeding sites around the home, such as buckets, unused children’s pools, old tires and other water-holding containers where mosquitos can lay eggs.

Horses are also vulnerable to EEE, with a 90% fatality rate in horses that become ill. The disease is not spread by horse-to-horse or horse-to-human contact. The Michigan Department of Agriculture and Rural Development recommends that owners protect their horses by:

  • Talking to their veterinarian about vaccinating horses against EEE and other mosquito-borne diseases.
  • Placing horses and other livestock in a barn under fans during peak mosquito activity (from dusk to dawn).
  • Using an insect repellant on animals that is approved for the species.
  • Contacting a veterinarian if an animal shows signs of illness.

As of June 30, more than 600 mosquito pools had been tested in Michigan during 2023. In addition to the recent discovery in Barry County, a mosquito pool in Bay County also tested positive for EEE, and a mosquito pool in Saginaw County tested positive for Jamestown Canyon virus.

In 2022, there were no human cases of EEE, however, EEE caused the death of three horses from Eaton, Roscommon and St. Joseph counties and one bird from Houghton County. In 2021, there was one human case of EEE. In 2020, there were four human cases of EEE, two of which were fatal. In 2019, Michigan had 10 cases of EEE, six of which were fatal.

For more information about EEE, visit