Officials at the Michigan Department of Agriculture and Rural Development (MDARD) have confirmed three horses with Eastern equine encephalomyelitis (EEE)—one each in three separate counties. The affected counties are Oakland in the southeast part of the state and Ionia and Montcalm in the west-central part region.

On Aug. 21, an unvaccinated 9-year-old Percheron mare in Oakland County began showing clinical signs that included loss of appetite, circling, and head pressing, progressing to recumbency (down and unable to rise). The horse was confirmed positive on Sept. 11 and was euthanized.

On Aug. 30, an unvaccinated 10-year-old Quarter Horse mare in Ionia County experienced onset of signs that included fever and ataxia (loss of muscle control), progressing to recumbency. She was also confirmed positive on Sept. 11 and was euthanized.

The latest horse to exhibit clinical signs was a yearling Standardbred filly in Montcalm County, on Sept. 4. She had been vaccinated for the first time within a week of showing signs of illness. She was confirmed positive on Sept. 11 and was also euthanized. Another yearling on the premises was also confirmed positive this year