On October 18, a new Eastern Equine Encephalitis (EEE) case was confirmed in Osceola County, Florida. The 4 year old grade male’s vaccination history is unknown and he had no recent travel history. Clinical signs began on October 9 and the horse was euthanized for humane reasons one day later.


This is the fifth confirmed EEE case in Osceola County and case 21 in Florida for 2016.

EEE is a mosquito-transmitted disease that is much more severe than West Nile Virus (WNV).  The mortality rate in horses from WNV is reported at around 30%, while the rate for EEE is almost 90%.  Infected mosquitoes are the primary source for EEE.

The virus causes inflammation or swelling of the brain and spinal cord.  General symptoms include central nervous system signs such as: head pressing, convulsions, lack of response to facial stimulation, fever above 103 degrees, ataxia, paralysis, anorexia, depression and stupor.  Other symptoms may include irregular gait, teeth grinding, in-coordination, circling, and staggering.  All symptoms may not be exhibited by an infected horse.