The South Carolina state veterinarian received laboratory confirmation of another new equine case of Eastern Equine Encephalitis (EEE) on Friday. A five-year-old Mustang mare located in Berkley County was confirmed.


This horse was unvaccinated and did not survive. This is the first confirmed case in Berkley County this year. The total number of confirmed cases in SC in 2016 is now 9.

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.