Venezuelan equine encephalomyelitis (VEE) is a mosquito-borne single strand, positive-sense, enveloped RNA virus belonging to the Alphavirus genus, family Togaviridae. VEE was the cause of over 150,000 equid and 50,000 human cases between 1935 and 1971. Between 1992 and 1995, VEE IC re-emerged in Venezuela and Colombia, with an estimated 4000 equid deaths and over 100,000 human cases of which 3000 had encephalitis.

Incubation Period
The incubation period is 1–5 days with high fever appearing within a day and neurologic signs manifesting themselves at approximately 5 days.