Eastern Equine Encephalomyelitis (EEE) Diagnosed in Maine Horse

A case of Eastern Equine Encephalomyelitis (EEE) was diagnosed in a Standardbred horse in Lebanon, Maine.

The recumbent horse presented to Myhre Equine Clinic in Rochester, NH on Sept. 16 after an acute onset of neurologic signs of 24 hour duration. The horse was euthanized that day and returned to the farm for burial. There are six other horses on the farm and they were boosted with EEE/WEE vaccine and are currently under quarantine until Sept. 26.

I have been in contact with Dr. Dora Anne Mills of the Maine CDC and a joint press release will be issued in the next couple days. Horse owners are encouraged to contact their practicing veterinarian for advice on this serious disease. There are approved annual vaccines for EEE as well as Western Equine Encephalomyelitis and West Nile Virus.

EEE is a virus that is transmitted through the bite of an infected mosquito and can be contracted by horses and people by this mode of transmission. Wild birds serve as the reservoir for this virus. The disease is not transmitted by direct contact from horses to people or from horse to horse- only through the bite of an infected mosquito.

The disease causes an infection in the central nervous system of affected horses resulting in neurologic signs- lethargy, aimless wandering, impaired vision, head pressing, circling, inability to swallow, irregular gait, paralysis, convulsions and often death. Most deaths occur within 2-3 days after the onset of clinical signs.

The last case of EEE in a horse in Maine was in September 2005, when a horse died of EEE in the town of Lebanon as well as another horse in the town of York.

Source: Maine Department of Agriculture, Food and Rural Resources Press Release