Eastern Equine Encephalitis (EEE)
- What is eastern equine encephalitis?
- Do we have EEE virus in Vermont?
- How is eastern equine encephalitis virus spread?
- What are the symptoms of EEE?
- Who is at risk for getting EEE?
- What is the treatment for EEE?
- Is there a vaccine to protect humans from EEE?
- How do you prevent EEE?
What is eastern equine encephalitis?
Eastern equine encephalitis (EEE) is a rare but serious disease caused by a virus and spread by infected mosquitoes. The disease most commonly affects people and horses, but illness has been reported in other animals including alpacas, llamas, donkeys, pheasants and emus.
Do we have EEE virus in Vermont?
No person or domestic animal has been diagnosed with EEE in Vermont. However, in 2010 blood was collected from deer and moose during hunting season, and evidence of current or prior infection was found in these species. This is the first time evidence of EEE virus has ever been detected in Vermont.
How is eastern equine encephalitis virus spread?
EEE virus is transmitted by the bite of an infected mosquito. EEE virus typically infects birds, and in most years it remains in bird populations, posing minimal danger to humans and horses. Mosquitoes become infected by feeding on infected birds. If an infected mosquito bites a horse, human or other mammal, the animal or person can become sick. The virus that causes EEE is only spread by mosquitoes. People, horses and deer do not spread the disease.
What are the symptoms of EEE?
Symptoms of EEE typically occur 4 to 10 days after a bite from an infected mosquito. The severity of the illness is quite variable, and many people bitten by an infected mosquito will not become ill. Most people who become ill experience a flu-like illness with fever, headache, muscle aches, joint pain and fatigue. This illness can last 1 to 2 weeks.
In rare cases, infection of the brain and spinal cord occurs, causing sudden high fever (103° to 106°F), stiff neck, and a headache that keeps getting worse. Inflammation and swelling of the brain, called encephalitis, is the most dangerous complication. The disease may get worse quickly, and some patients may go into a coma within a week. About 1/3 of people who develop encephalitis will die. Among those who survive, many are left with mild to severe disabilities. People over age 50 or younger than age 15 are at greatest risk for developing severe disease.
Who is at risk for getting EEE?
Anyone who spends time in an area where EEE virus activity has been identified is at risk of infection. Although the risk is thought to be low in Vermont, people should take steps to avoid mosquito bites. People who engage in outdoor work and recreational activities, especially near wetlands and swamps, are at increased risk of infection. The risk of getting EEE is highest from late July through September.
What is the treatment for EEE?
There is no specific treatment for EEE. Treatment focuses on supportive therapy to lower the fever and ease the pressure on the brain and spinal cord.
Is there a vaccine to protect humans from EEE?
No, there is no vaccine because EEE occurs so rarely in people. There is a vaccine for horses, which can also be used in other susceptible animals.
How do you prevent EEE?
The best way to prevent EEE is to prevent mosquito bites. These steps will reduce your chance of being bitten by mosquitoes that carry EEE virus or other viruses, such as the West Nile virus.
- Minimize the time spent outdoors around dusk and dawn when mosquitoes are most active.
- Wear shoes, socks, long pants, and a long-sleeved shirt when outdoors at dawn or dusk. Clothing should be made of tightly woven materials that keep mosquitoes away from the skin
- Consider the use of mosquito repellant when it is necessary to be outdoors. Use insect repellent containing DEET, picaridin, IR3535 or oil of lemon eucalyptus on exposed skin and/or clothing. The repellent/insecticide permethrin can be used on clothing. It remains effective through several washes. When using any insect repellent, always follow the directions on the package
- Make sure all your windows and doors have screens, and that all screens are in good condition
- Mosquitoes can lay eggs even in small amounts of standing water. Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets, barrels, and tires. Change the water in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out. Empty children's wading pools and store on their side after use
- If you own horses, donkeys, llamas or alpacas, ask your veterinarian about the vaccine
Additional Information
Centers for Disease Control and Prevention: http://www.cdc.gov/EasternEquineEncephalitis/index.html
Vermont Department of Health, Insect Repellents: http://www.healthvermont.gov/prevent/wnv/repellents.aspx