Officials in Polk County have reported a case of Eastern Equine Encephalitis (EEE) in a horse this week. The eighteen month old, unvaccinated Quarter Horse had not been off the property in at least 6 months.

Image/Dusan Bicanski
Image/Dusan Bicanski

Clinical signs began April 4th and the horse passed on the same day. The case was confirmed positive on April 14th. This is the first confirmed case in Polk County and the first positive in Florida since the beginning of the year.

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.