June 12, 2024

Horse disease found in Michigan

How to reduce risk, prevent infection of EEE

INDIANAPOLIS — Michigan animal health officials announced the first case of eastern equine encephalitis in a 3-year-old horse just across the Michigan-Indiana border.

According to Indiana’s Board of Animal Health, horse owners in Indiana should be aware of the disease.

Indiana had no reported cases of EEE last year. However, the disease can pop any time, any place.

“Horses are not the only ones at risk of eastern equine encephalitis,” according to a BOAH statement. “Like the more common West Nile virus, EEE can infect people and cannot be directly transmitted from infected horses to other horses or humans.”

Signs of EEE include listlessness, high fever, head pressing, seizures and coma. Horses that develop it rarely survive. Contact a veterinarian if any of these signs are noticed.

The virus is maintained in the bird population and is transmitted by mosquitoes that breed in freshwater wetlands.


Preventing EEE infection in horses involves two main steps: vaccinating and minimizing exposure to mosquitoes.

Horse owners should work with their veterinarian to determine a regimen that includes selecting the best vaccine product given in a timely way.

Vaccinations are generally administered in the spring for season-long protection. Combination products will prevent several mosquito-borne viruses in a single dose.

Prevention also accomplished by reducing exposure to mosquito bites.

Prevention tips:

• Eliminate sources of standing water where the pests breed — even small amounts of water in old tires, clogged gutters, puddles, or stagnant water troughs can harbor insects.

• Keep livestock confined indoors with good ventilation during peak flight hours, from dusk to dawn.

• If using an insect repellent, select a product labeled for use on that species.

History Of EEE In Indiana

In 2020, EEE infections were detected in four horses in LaGrange, Kosciusko and LaPorte counties. One human case of EEE occurred in a LaPorte County resident in 2020.

In 2019, EEE infection was detected in 14 horses in Elkhart and LaGrange counties. The infected horses were either not vaccinated or overdue on vaccination.

One fatal human case of EEE occurred in Elkhart County in 2019, and 10 human cases occurred in southern Michigan, six of which were fatal.

Erica Quinlan

Erica Quinlan

Field Editor