New Jersey Horse Euthanized after Contracting EEE

A 3-year-old horse from Burlington County, N.J., was euthanized on May 27 after testing positive for the mosquito-borne disease Eastern equine encephalitis (EEE).

"It is very early in the season to see Eastern equine encephalitis so horse owners need to be vigilant in vaccinating their animals against diseases spread by mosquitoes," said New Jersey Secretary of Agriculture Douglas H. Fisher. "We hope this incident will raise awareness about the need to protect our official state animal from this and other harmful diseases, especially since June is the Month of the Horse in our state."

The mare had been given the first in a series of two planned EEE vaccinations by a private veterinarian at the beginning of May.

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

Often EEE is preventable by vaccination. Effective equine vaccines for EEE and another mosquito-borne disease, West Nile virus (WNV) are available commercially. Horse owners should contact their veterinarians if their horses are not already up-to-date on their vaccinations against both EEE and WNV.

In 2011, New Jersey had one case of EEE and one case of equine WNV. Both cases came in October after Hurricane Irene and subsequent rains caused flooding that resulted in much higher than normal mosquito populations.

EEE and West Nile virus, like other viral diseases affecting horses' neurologic systems, must be reported to the state veterinarian at 609/671-6400 within 48 hours of diagnosis.

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