The State Board of Animal Health has recorded probable cases of Eastern equine encephalopathy in two horses in LaGrange County and one horse in Kosciusko County.
The Indiana State Department of Health confirmed one case in a human resident of LaPorte County as well as one horse in LaPorte County.
Three suspected cases have been identified in horses in LaGrange County.
The serious illness, while rare, can be fatal, and is spread through infected mosquitos which have a range of up to five miles, according to the Indiana Department of Health.
That means that the affected areas include 375,000 acres in portions of Elkhart, Kosciusko, LaGrange, LaPorte, Marshall and Noble counties.
Health officials plan targeted mosquito control to help protect residents from EEE beginning Tuesday evening and continuing Wednesday if needed, as weather permits.
Those wishing to minimize exposure may stay indoors for several hours beginning at dusk on the treatment dates. Animals may be brought indoors, and ornamental fish ponds may be covered.
The pesticide is not expected to be harmful to bees, but beekeepers may choose to cover their hives overnight, and prevent bees from exiting during the application, according to a release from the state health department.
