Equine viral encephalomyelitis (EVE) is an infectious mosquito-borne disease, characterized clinically by paralysis and other signs of nervous derangement. It is caused by Eastern, Western and Venezuelan equine encephalitis (EEE, WEE and VEE, respectively) viruses, are arthropod-borne infections of horses and humans. EEE and WEE viruses are maintained in nature by alternating cycles of infection in birds and mosquitoes. EEE virus is transmitted by mosquitoes belonging to Culiseta spp. and WEE virus by Culex spp. Deaths can occur soon after the onset of neurological signs or after prolonged illness. Recovered animals can exhibit permanent neurological deficits (CFSPH 2008).