EEE Detected in Alabama Horses

The Alabama Department of Public Health has confirmed four positive cases of Eastern equine encephalitis (EEE) in horses located in Dallas County. There have been additional reports of cases in horses in Elmore and Montgomery counties, however, laboratory confirmation has not been performed.

According to Dee W. Jones, DVM, Alabama public health veterinarian, EEE, West Nile virus (WNV), and other mosquito-borne viruses are transmitted by mosquitoes after they feed on infected birds. The same mosquitoes can then infect mammals, particularly humans and horses. Both humans and horses can sometimes become seriously ill from the infection.

Transmission to humans and horses can be decreased by individuals taking steps to avoid mosquitoes and by the use of WNV and EEE vaccine in horses. According to Jones, although there is no vaccine available for humans, vaccination for horses is very important in preventing infection in these animals.

A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes. Its fatality rate in horses is 75-95%. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care. Horses that survive might have long-lasting impairments and neurologic problems. Clinical signs of EEE include moderate to high fever, depression, lack of appetite, cranial nerve deficits (facial paralysis, tongue weakness, difficulty swallowing), behavioral changes (aggression, self-mutilation, or drowsiness), gait abnormalities, or severe central nervous system signs, such as head-pressing, circling, blindness, and seizures. Sixty equine EEE cases were confirmed in the United States in 2011, according to USDA Animal and Plant Health Inspection Service equine disease surveillance; no cases were reported in Alabama last year.

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