EEE and WNV Confirmed in Connecticut Horses

Officials announce the state’s first cases of Eastern equine encephalitis and West Nile virus for 2019.

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EEE and WNV Confirmed in Connecticut Horses
Mosquitoes that feed on birds infected with EEE can transmit the disease to humans, horses, and other birds. | Photo: iStock

On Aug. 14, the Connecticut Department of Agriculture (CDA) announced the state’s first confirmed cases of Eastern equine encephalitis (EEE) and West Nile virus (WNV) for the year, followed by a third case (EEE) on Aug. 16.

On Aug. 3, a 12-year-old draft-cross in Easton (Fairfield County) began showing owner-reported signs of poor appetite and lethargy without fever. Despite veterinary care, the horse’s condition subsequently progressed to sweating, showing signs of colic and possibly requiring surgical intervention. At the local referral hospital, the horse presented with a rapid heart rate, muscle fasciculations (twitching), and profuse sweating. Veterinarians noticed additional neurologic signs while treating the horse and submitted diagnostic serum samples for West Nile virus testing, which indicated recent infection with WNV. The horse was relocated to a referral center for specialized medical treatment and, according to a CDA statement, is recovering well. The horse was up to date on its WNV vaccination.

On Aug. 5, an 18-month-old Quarter Horse filly from Colchester, in New London County, began showing signs of difficulty breathing, anxiety, fever, circling continuously, and stumbling into stall walls, according to its owner. Despite veterinary treatment, the horse deteriorated rapidly and died. Diagnostic samples collected at the University of Connecticut’s Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL) and submitted to the United States Department of Agriculture (USDA) National Veterinary Services Laboratories (NSVL) tested positive for EEE virus. The filly had no documented history of EEE or WNV vaccination

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