Kentucky Reports Second Equine EEE Case of 2013

Kentucky Reports Second Equine EEE Case of 2013

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


The Kentucky State Veterinarian's office announced Saturday (Oct. 19) that a horse residing in Carlisle County tested positive for Eastern equine encephalitis (EEE) late on Oct. 18. This is the second EEE case reported in Kentucky this year.

A statement from Kentucky Equine Programs manager E.S. "Rusty" Ford relayed that on Oct. 10, the unvaccinated 17-year-old Quarter Horse mare presented in an acute recumbent state and was unable to rise, eat, or drink. The mare survived for 24 hours before she died naturally, Ford's statement said.

In August, an unvaccinated Tennessee Walking Horse gelding from Hart County died after contracting EEE.

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.

Commercial vaccinations are available to help prevent horses from contracting EEE. In the northern regions of the United States, most veterinarians recommend vaccinating horses in the spring prior to peak mosquito levels. In the south, where mosquito populations are present year-round, veterinarians might recommend more frequent vaccination. The EEE vaccine is on the American Association of Equine Practitioners' list of core vaccines, which are those considered important for every horse to have annually, regardless of geographic location or athletic use. 

The United States Department of Agriculture Animal and Plant Health Inspection Service reported 209 cases of EEE in U.S. horses in 2012; prior to 2013, the last case of equine EEE reported in Kentucky was confirmed in 2008 when one horse tested positive for the disease.

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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