News Releases

KNOXVILLE, Tenn. — Horse owners are being alerted about a case of Eastern Equine Encephalitis (EEE) in Anderson County. Dr. Frederick Harper says the case is a reason for concern.

The Extension horse specialist for the University of Tennessee Department of Animal Science, Harper noted, “there were no documented cases of EEE, commonly called sleeping sickness, in equine in Tennessee last year, but there have been in other years."

Harper says the infected EEE horse serves as a sentinel that EEE exists in the state. EEE is similar to West Nile Virus (WNV). Both result in an encephalitis, inflammation of the brain. They are spread by mosquitoes that have bitten infected wild birds. There is a vaccine for EEE and WNV but no
treatment for either disease.

Humans can get EEE if bitten by an infected mosquito, but this is a rare concurrence. It is reported that EEE in humans is fatal in 50-75 percent of the cases, which is higher than WNV fatalities in humans.

“Individuals need to know that EEE is not transmitted from horses to people,” says Harper. “As with WNV, EEE is a dead-end host. A mosquito cannot bite an infected horse and transmit either EEE or WNV to a human."

Harper urges horse owners to vaccinate their horses against Eastern Equine Encephalitis as well as West Nile Virus. EEE has a mortality rate of over 90 percent in equine; thus, it is a more deadly disease in equine than WNV that has a mortality rate of about 30 percent.

“Horse owners need to be aware that vaccination for WNV does not protect their horses against EEE. Likewise, a horse vaccinated for EEE is not protected from WNV,” says Harper.

Horses are given two initial EEE injections about 30-days apart followed with an annual booster.

“The high rainfall this spring and standing water in some areas may result in a large mosquito population. In addition to vaccination for EEE and WNV, horse owners are urged to eliminate any standing water that mosquitoes can use as breeding areas,” he says.

Symptoms of EEE include mild to high fever, poor appetite (horses go off feed), stiffness and depression. Hypersensitivity to sound and touch has been observed with periods of excitement, apparent blindness and wandering followed by incoordination. Quiet periods follow nervous activities. Horses may tilt their head and have involuntary twitching of the muscles of the face and limbs. Some of the signs are similar for horses with WNV.

Complete paralysis marks the terminal stages, when the horse is down and unable rise. Death usually occurs within two to four days after the first signs of infection.

At the first indication of any abnormal behavior or signs, owners should contact their veterinarian. Vaccination for EEE and WNV is the major line of prevention.

Horse owners can keep up on the latest EEE and WNV information by checking the University of Tennessee Web site: http://animalscience.ag.utk.edu/horses/horses.htm.

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Contact: Dr. Frederick Harper, 865-974-7295; Patricia McDaniels or Samantha
Hill, 865-974-7141.