EEE Detected in Minnesota

Minnesota recently had its first encounter with Eastern equine encephalitis (EEE) when the disease was confirmed in two horses in separate areas of the state. One horse was from Blue Earth County in southern Minnesota, and the other was from Kanabec County in the eastern part of the state. Strong evidence suggests that two horses in Wright County died of EEE.

According to Paul Anderson, DVM, director of the equine division of the Minnesota Board of Animal Health, the two confirmed cases were horses which had not been vaccinated for EEE, although Minnesota horse owners generally have their horses vaccinated against the disease. Anderson said officials are encouraging horse owners to vaccinate all horses, but are leaving the decision to booster vaccinated horses up to owners and their veterinarians. The vaccine should be protective for one year.

The first case (Blue Earth County) was confirmed in late August, and the Kanabec case was confirmed Sept. 18. "Both deaths were very quick--less than 24 hours from onset of clinical signs," said Anderson. He explained that the two Wright County horses died on the same farm, showing symptoms consistent with EEE.

Eastern equine encephalitis can be incubated (carried without symptoms) from one to three weeks. Infected horses can then show lethargy, ataxia, droopy eyes and lips, fever, inappetence, depression, elevated heart rate, and white blood cell count abnormalities. The disease is spread by the bite of an infected mosquito, and the disease cannot be transmitted from horse to horse.

Neighboring Wisconsin had outbreaks of EEE this year, but the disease had never before been detected in Minnesota. "There's a specific mosquito that is required to amplify (EEE), and they've demonstrated this year that the particular insect (Culiseta melanura) is here," said Anderson.

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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