Eastern Equine Encephalitis (EEE)

About

Eastern Equine Encephalitis virus (EEE) is a viral illness spread by mosquitoes. EEE virus can cause disease in humans and some mammal and bird species. EEE virus is most commonly found in the eastern half of the United States, including in Maine.

EEE virus spreads through the bite of an infected mosquito. Though rare, EEE is very serious. EEE cases occur sporadically in Maine, usually during the summer and fall when mosquitoes in Maine are most active.

Anyone can get EEE, but certain people are at higher risk, including:

People who spend a lot of time outdoors, whether for work, hobbies, or recreation.
People over 50 years of age.
Children under 15 years of age.
People who have certain conditions, like cancer, diabetes, high blood pressure, or kidney disease.
People who have certain conditions or take medications that weaken the immune system.

Symptoms

Most people infected with EEE virus do not develop any symptoms. However, symptoms may develop. This usually occurs 4 to 10 days after being bitten by an infected mosquito. Symptoms typically last 1-2 weeks. Symptoms include:

Fever and chills
Weakness
Headache
Body and muscle pain

More severe signs and symptoms may develop, though these are rare. While severe illness can occur at any age, people over 60 years of age or people with certain medical conditions are at greater risk. Serious symptoms include:

Inflammation of the brain (encephalitis)
Confusion
Neck stiffness
Coma

About 1 in 3 people who develop severe EEE die. Death usually occurs 2 to 10 days after the onset of symptoms but can occur much later. Many people who recover experience long-term effects. These can range from mild to severe intellectual disability, personality disorders, seizures, paralysis, and cranial nerve dysfunction.

Treatment

Talk to a health care provider if you have any of these symptoms. There is no specific treatment for EEE. Severe EEE illness usually requires supportive treatment in the hospital.

Prevention

Maine Mosquito Meter

Check out the Maine Mosquito Meter! Use this risk meter to understand what steps you should take to prevent mosquito-borne diseases throughout the mosquito season.

Prevent Mosquito Bites

The best way to prevent mosquito-borne diseases is to prevent mosquito bites in the first place. Take these simple steps every day to prevent mosquito bites:

Wear clothes that cover your arms and legs, like long sleeves and pants.
Use an EPA-approved bug spray. This includes products that contain DEET, picaridin, IR3535, and oil of lemon eucalyptus.
Treat clothing with permethrin. Never use this directly on your skin.
Avoid outdoor activities at dusk and dawn, when mosquitoes are most active.

Protect Your Yard from Mosquitoes

You can make your yard a mosquito-safe zone:

Discard man-made containers around your yard that can hold water. If you cannot remove them, consider drilling holes in them to keep them from holding water.
Empty sources of standing water around your home, including in man-made containers.
Put plant pots, yard toys, and other containers that hold water away or store upside-down to keep them from filling with water.
Change the water at least once every week in containers that have to hold water, like birdbaths and pet water bowls. This makes sure that mosquito larvae (baby mosquitoes) cannot grow into adults.
Check window and door screens for holes that mosquitoes can fly through and fix them.

Data and Publications

Arboviral Surveillance

Maine CDC tests for EEE, Jamestown Canyon virus (JCV), and West Nile virus (WNV) in humans, animals, and mosquitoes. Find the Arboviral Surveillance Reports posted weekly from July through September. This data helps Maine CDC understand where mosquito-borne diseases might be in Maine. This helps guide prevention efforts to prevent humans and domestic animals from getting sick.

Maine Center for Disease Control & Prevention