EEE Strikes South Carolina; Georgia and Florida Continue to Log Cases

Veterinarians are scrambling to keep up with the number of Eastern equine encephalitis (EEE) cases that continue to emerge in the southeastern United States. South Carolina in the last three weeks had 17 equine cases confirmed, and about 25 pending. Florida’s EEE case count has risen to 113 horses this year, and Georgia has logged 30 cases.

In 2002, South Carolina had five equine cases of EEE, Florida had 25, and Georgia had six.

Venaye P. Reece, DVM, equine programs coordinator and state animal emergency response coordinator with the state veterinarian’s office of South Carolina, said, “We’ve been due a high Eastern (equine encephalitis) year. It tends to be cyclic--it runs in 10-year cycles. Our last big year was 1991, and all the conditions are right (this year for another high EEE year). We’re getting clobbered.”

Reece said that the actual number of EEE cases is always higher than the number of reported and confirmed cases. “It caught everybody a little off guard,” she said, adding that almost all of the horses were never vaccinated, or were not current on their vaccinations.

Reece reports that every confirmed South Carolina equine case has died or has been euthanized, mainly because the cases have been “very acute,” with the horse deteriorating within 12 to 24 hours. “They’re fine one day, then look a little funny that night, and by the next morning they’re down,” she explained. Testing for suspected cases is completed at South Carolina’s Department of Health and Environmental Control and the USDA’s National Veterinary Services Laboratory in Ames, Iowa.

 “The good news is that we have a very good vaccine available for EEE and WNV, but horse owners have to give it early and appropriately,” says Reece. “Our problem now is that we’re in the midst of an outbreak, and some people are just now (vaccinating).” Vaccinating just prior to or immediately following exposure to the virus might not be protective.

“It really hurts to lose a horse to EEE,” said Reece. “The vaccine for it is very inexpensive, so it’s complacency or lack of effort (that lead to these cases), and we sure hate to lose horses for that.” She emphasized the importance of mosquito control via pesticides, larvacides, and by eliminating areas of standing water that encourage mosquito breeding.

Reece explained that EEE, a virus transmitted by the bite of infected mosquitoes, pops up early in years that are unusually hot, as 2003 has been for South Carolina. The state’s EEE season would typically peak in late August or early September, but this year, it will probably peak in July in early August. “All of the conditions are right, and we may have a whole new population of naïve horses that people have missed vaccinations or having vaccinated yet.”
Reece added, “The numbers are going to continue to climb, and at some point this (focus) is going to shift to West Nile virus. We haven’t had a positive West Nile virus horse yet (as of June 27).”

As for WNV in South Carolina this year, she cannot predict its spread. “No one predicted the high number of horses and humans that would be affected, and how seriously. We’re going to have to wait and see what it’s going to do this year.”

 

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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