DF: A species of Alphavirus causing encephalomyelitisin Equidae and humans. The virus ranges along theAtlantic seaboard of the United States and Canada and as far south as the Caribbean, Mexico, andparts of Central and South America. Infections inhorses show a mortality of up to 90 percent and inhumans as high as 80 percent in epidemics.Culiseta and Aedes mosquitoes are the vectors fordisease transmission.
