South Carolina Foal Confirmed EEE-Positive

South Carolina Foal Confirmed EEE-Positive

A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes.


A South Carolina foal tested positive for Eastern equine encephalitis (EEE) last week, marking that state's first case of 2013.

In a June 28 statement, Boyd Parr, DVM, South Carolina state veterinarian and director of the Clemson University Livestock Poultry Health, announced that a foal from Sumter County (located in central South Carolina) that died recently tested positive for the disease. Two adult horses that died at the same farm around the same time are suspected of also having EEE, the statement indicated.

“This diagnosis is a vivid reminder of the threat that mosquito-borne diseases represent to horses in our state,” Parr said in the statement. “Maintaining protection by vaccinating horses is important again this year.”

During 2012 there were 14 confirmed EEE cases and seven WNV cases in South Carolina.

A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes. The fatality rate for EEE-affected 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 for 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.

The American Association of Equine Practitioners recommends all horses be vaccinated against EEE at least annually.

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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