Anne Lichtenwalner, DVM, PhD, University of Maine Cooperative Extension and Donald E. Hoenig, VMD, State Veterinarian, Maine Department of Agriculture, Conservation and Forestry, Eastern Equine Encephalitis Eastern Equine Encephalitis (EEE) is a preventable, but fatal, disease in horses. Unfortunately, this disease can also affect humans if they are bitten by mosquitoes that carry the virus.