Eastern Equine Encephalitis (EEE) has been confirmed in the United Counties of Leeds and Grenville, Ontario. On August 6, 2024, a 25 year old mare was found acutely down. Supportive treatment was provided but the mare was euthanized two days later. EEE was confirmed on August 19, 2024. The horse was not vaccinated against EEE. There is one additional suspected case, the mare's pasture-mate was euthanized on August 3, 2024 after being found down in the field. This horse was not tested.