Basic Sciences Bldg. 2001 S. Lincoln Ave. By Joseph Hahn Information Specialist University of Illinois College of Veterinary Medicine Equine encephalitis, also called sleeping sickness, is a viral disease which affects parts of a horse's central nervous system. This virus is attracted to nervous tissue which leads to inflammation in and damage to the brain.
Mosquitoes pick up the disease from birds, principally pheasants.
Mosquitoes can then transmit the virus to horses and humans. He stressed that while humans can develop viral encephalitis, the disease is transmitted from mosquitos that have bitten birds, not from mosquitoes that have bitten horses. There are three main types of equine encephalitis. Primarily in the eastern states. The southern tier of states is at the greatest risk.