This is a mosquito-borne viral disease that affects South, Central and North America.
Merck Animal Health Solutions
For Venezuelan Encephalomyelitis
It is impossible to differentiate among EEE, WEE and VEE solely by clinical signs. Early clinical signs of encephalitis include marked depression and high fever. The disease may result in prostration and death usually within 1-5 days. Other signs of acute disease are impaired vision, uncoordination, inappetence, circling, restless excitement, dyspnea and frequently paralysis. With EEE and WEE usually only one horse in a herd is affected; in VEE the morbidity rate in herds may be 50% or more because it can be spread directly from horse to horse.