Michigan Department of Agriculture (MDA) Director Dan Wyant today announced that the first reported case of Eastern Equine Encephalitis (EEE) this year has occurred in a horse in Barry County. This diagnosis was based on clinical signs and laboratory evaluation of brain tissue conducted by the Animal Health Diagnostic Laboratory at Michigan State University.

This follows the report last week that the EEE virus had been detected in mosquitoes from Gladwin County and from juvenile wild birds in Kalamazoo County. These detections indicate the presence of EEE virus in those areas and possibly other areas of southern Michigan.

Clinical signs of EEE (also known as sleeping sickness) in horses include fever, progressive muscle incoordination, paralysis, blindness, and an inability to rise. The fatality rate for this disease in horses often reaches 95 percent. Human infection with the EEE virus is rare in Michigan and is characterized by a high fever progressing rapidly to coma.

Horses and humans contract EEE from mosquitoes that have fed on birds that carry the virus. Birds are able to harbor the virus without becoming acutely ill and serve as a reservoir for EEE. Horses do not develop a high enough level of the virus in their blood to be contagious to other animals or humans. Horses that contract EEE, however, indicate that the virus is in a particular region and should serve as a warning to residents to avoid being bitten by mosquitoes