The North Carolina Department of Agriculture and Consumer Services recently confirmed the fifth and sixth equine cases of Eastern equine encephalitis in that state for 2017.

The cases were discovered in a 6-year-old pony mare in Bladen County and a 5-year-old American Quarter Horse gelding in Camden County. Neither horse had a vaccination history.

“EEE is a mosquito-borne disease that causes inflammation or swelling of the brain and spinal cord in equine and is usually fatal,” North Carolina Agriculture Commissioner Steve Troxler said in a Nov. 1 statement. “The disease is preventable by vaccination. If you haven’t already had your horses, mules and donkeys vaccinated, contact your veterinarian to make sure your animals are protected.”

There were nine recorded cases of EEE in horses in North Carolina in 2016.

“As long as mosquitoes are active, the threat remains,” said State Veterinarian Doug Meckes, DVM.

[brightcove videoid="3127291880001" title="Health Alert: EEE, WEE, VEE"]

A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes. 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. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care; fatality rates reach 75-80% among horses. Horses that survive might have long-lasting impairments and neurologic problems.

Horse owners should also consult their private practicing veterinarian to determine an appropriate disease prevention plan for their horses. Vaccines have proven to be a very effective prevention tool against EEE. Horses that have been vaccinated in past years will need an annual booster shot; in areas with a prolonged mosquito season, veterinarians might recommend two boosters annually—one in the spring and another in the fall. However, if an owner did not vaccinate their animal in previous years, the horse will need the two-shot vaccination series within a three- to six-week period.

In addition to vaccinations, horse owners also need to reduce the mosquito populations and their possible breeding areas. Recommendations include removing stagnant water sources, keeping animals inside during the bugs’ feeding times, which are typically early in the morning and evening, and applying mosquito repellents approved for equine use.

“If your horses or other equine animals exhibit any symptoms of EEE, contact your veterinarian immediately,” Meckes said.