BIG RAPIDS -- A horse in Mecosta County has tested positive for a virus that can be deadly.

The Michigan Department of Agriculture and Rural Development (MDARD) confirmed Equine Infectious Anemia (EIA) in the 17-year-old mare.

State Veterinarian Dr. Steven Halstead says the virus is spread by deer and horse flies. It also affects other members of the horse family such as mules, donkeys, burros and ponies. It can cause severe illnesses including fever, anemia and swelling, and it can be deadly.

"This is the first case of EIA in Michigan since 2008," said Dr. Halstead. "MDARD is investigating the case to identify other horses that may have been exposed to the positive horse or may have caused the exposure.  Any such horses will be quarantined on their farms and tested for EIA by a regulatory veterinarian."

To stop the spread of the virus, the MDARD requires a negative test for EIA before horses travel to public events such as fairs and auctions or ship to a new owner.