On August 3, two new Eastern Equine Encephalitis (EEE) case were confirmed, one each in Jackson and Jefferson County, Florida. The Jackson County case, a 10 year old Quarter Horse, became clinical on July 16 and was last vaccinated against EEE in February 2016 per submitting veterinarian. The horse was euthanized for humane reasons the same day.


The Jefferson County case has no previous vaccine history and no recent travel history. Clinical signs began on July 24 and the horse was euthanized for humane reasons three days later.

This is the second confirmed EEE case in Jackson County, the third case in Jefferson County and cases 17 and 18 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.