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.
Horse with symptoms of Eastern Equine Encephalitis
Officials in Polk County Florida reported its first confirmed case of Eastern Equine Encephalitis in 2016 this past week, saying the eighteen month old unvaccinated Quarter Horse had not been off the property in at least 6 months.
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.
Prevention
Annual vaccination of all horses and other equines is recommended. Horses vaccinated for the first time must receive an injection of EEE-WEE combined vaccine, followed by a second dose three to four weeks later.
The two-dose series is necessary to establish an effective immune response. If an outbreak occurs in the area, a second booster is advised.
Foals should be vaccinated at 4, 5, and 6 months of age for a total of three doses. Another booster should be given in six months and annually from then on.
In addition to making sure that all equines are vaccinated, horses should be taken in at times when the mosquito population is highest. This usually includes the hours around dawn and dusk. In some cases, horses can be blanketed or covered with protective gear to prevent bites. Insect repellant can be used on horses to prevent bites from mosquitoes.
In all cases, the population of mosquitoes should be controlled as much as possible by following the recommendations of mosquito-control personnel and the agencies in the area where horses are kept.
Any bodies of stagnant water should be drained and water-holding containers such as buckets, tires and other receptacles where water might accumulate should be emptied. Horse troughs and waterers should be flushed often to reduce mosquitoes near paddock areas.
Insecticides for treating mosquito nesting areas around homes and livestock premises should be used on a regular basis.