Connecticut Confirms First Equine EEE Case of 2013

Connecticut Confirms First Equine EEE Case of 2013

Animal health officials encouraged owners to review vaccination records with their veterinarians to ensure that horses' EEE and WNV vaccinations are current.

Photo: Stephanie L. Church, Editor-in-Chief

Connecticut Agriculture Commissioner Steven K. Reviczky announced Sept. 17 that the state had confirmed its first case of Eastern equine encephalitis (EEE) infection in a horse for 2013.

“I am sad to report that a 2-year-old Miniature Horse from Griswold tested positive for the disease,” said Reviczky. “This case underscores the importance of vaccinating horses to protect them from mosquito-transmitted diseases.”

According to agency officials, the horse’s owner noticed the animal was sick on Sept. 8; the horse appeared dull and had a poor appetite. Despite treatment, the Miniature Horse developed a fever, became progressively more depressed and uncoordinated, and continued to deteriorate. The attending veterinarian euthanized the animal.

Diagnostic samples were collected at the Connecticut Veterinary Medical Diagnostic Laboratory at the University of Connecticut and were submitted to the United States Department of Agriculture National Veterinary Services Laboratories, where they tested positive for EEE.

The horse had no documented history of EEE or West Nile virus (WNV) vaccinations and had not traveled recently.

“Horse owners should review vaccination records with their veterinarians to ensure that EEE and WNV vaccinations are current and to take precautions against mosquito bites, especially when residing in areas with known infected mosquitoes” said Mary Jane Lis, DVM, MS, PhD, state veterinarian for the Connecticut Department of Agriculture.

As of Sept. 10, officials in 16 states have reported 123 EEE cases involving horses. Connecticut reported just one equine EEE case in 2012.

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.

In Connecticut neurologic diseases of domestic animals—such as EEE and WNV—are reportable to the state veterinarian.

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