UConn Lab Tests Showing Positive Results For EEE in Domestic Animals

STORRS, CT — The state is beginning to experience cases of Eastern Equine Encephalitis in domestic animals, officials from the Connecticut Veterinary Medical Diagnostic Laboratory at the University of Connecticut in Storrs said Wednesday. Also Wednesday, officials from the Connecticut Department of Agriculture announced the first horse testing positive for the mosquito-borne disease this year.

The adult horse, which resided in New London County, began exhibiting neurological signs before being euthanized on Oct. 1, state officials said.

Diagnostic samples collected and sent to the Connecticut Veterinary Medical Diagnostic Laboratoryat the UConn in Storrs confirmed a diagnosis of EEE virus in the unvaccinated animal.

The CVMDL also detected EEE virus the previous week in a 10-year-old male emu in Windham County, which is near several towns that have mosquitos that tested positive for EEE this year.

Like the horse, the emu showed neurological signs when it died, officials said. Diagnostic samples were sent to the CVMDL for West Nile testing. CVMDL determined the animal tested positive for EEE virus.

EEE causes a rare but severe disease in humans and equids, animals in the horse family. In its natural cycle, EEE circulates between birds and mosquitoes. EEE is classified as a select agent in the US due to the potential to pose a severe threat to animal and public health.

The CVMDL detected EEE in both the horse and emu by means of RT-qPCR, and results were communicated to the Connecticut Department of Agriculture and Office of State Veterinarian within hours of detection. This is the third case of EEE detected by the CVMDL since September 2023. The first was a donkey from Rhode Island.

"This detection highlights the importance of vaccinations and continued precautions that owners should undertake to protect their animals from mosquito-borne illnesses," Connecticut State Veterinarian Dr. Jane Lewis said. "Horses are the domestic animals most susceptible to infection with mosquito-borne illnesses such as EEE."

Data collected by the Connecticut Agricultural Experiment Station in 2023 suggests an increased number of mosquitoes carrying EEE. CAES is responsible for trapping, identifying, and testing mosquitoes for encephalitis viruses conducting a statewide surveillance program annually.

EEE is not spread by horse-to-horse or horse-to-human contact. It is a viral disease transmitted through the bites of mosquitoes.