Encephalitis is a serious inflammation (swelling) of the brain. Arboviral encephalitis is caused by an insect (mosquito)-borne virus. In the United States, these diseases include St. Louis Encephalitis (SLE), Eastern Equine Encephalitis (EEE), Western Equine Encephalitis, LaCrosse Encephalitis, and recently, West Nile Virus Encephalitis (WNV).
SLE is the most common of these diseases in Florida. In an average year, one to 10 cases of SLE are reported. Several large outbreaks involving as many as 200 cases have occurred in the state in recent decades.
Eastern Equine Encephalitis
EEE occurs sporadically in Florida. Eastern Equine Encephalitis is a viral disease that attacks the central nervous system of horses. Transmission of the disease from horse to horse to humans is highly unlikely. The mortality rate for infected horses is 50 to 90%. Vaccinating horses properly will prevent them from contracting the disease. Symptoms of the disease in horses include:
- Impaired vision
- Inability to swallow
- Irregular gait
- Occasional convulsions
- Reduced reflexes
- Sometimes death
In rare cases, humans may contract the disease. The disease is most commonly detected in horses from April through August