Definition

Eastern equine encephalitis (EEE) is a virus spread by a bite from an infected mosquito. While EEE is rare, an infected person can become seriously ill and even die from the virus.

Effect on Encephalitis on the Brain

Swollen brain

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Causes

EEE is caused by a virus.

Risk Factors

The greatest risk factors for EEE are spending time in areas where mosquitoes are present, such as wetlands and swamps. Another risk factors is failing to use insect repellent.

Risk factors for developing serious symptoms from EEE include:

    
  • Being over 50 years old or younger than 15 years old
  • Having a condition that affects your immune system

    • Symptoms

    Most people with EEE do not have any symptoms.

    If symptoms do occur, they may appear in 4-10 days and include:

        
  • Headache
  • Neck stiffness
  • Fever
  • Chills
  • Fatigue
  • Joint and muscle pain
  • Vomiting

    • EEE can lead to more serious, life-threatening symptoms of inflammation of the brain, like altered mental status, weakness, numbness, paralysis, seizures, and coma .

    Diagnosis

    In addition to taking your medical history and doing a physical exam, your doctor will ask you:

        
  • What kind of symptoms you are experiencing
  • Where you have been living or traveling
  • Whether you have been exposed to mosquitoes

    • A blood test or a test of your spinal fluid is commonly used to confirm the diagnosis of EEE.

    Your doctor may need pictures of structures inside your head. This can be done with:

        
  • MRI scan
  • CT scan

    • Treatment

    Treatment for EEE focuses on supportive care. Severe symptoms require hospitalization, which may include:

        
  • Mechanical ventilation (breathing support)
  • IV fluids
  • Medicine to control seizures
  • Medicine to decrease brain swelling

    • Prevention

    To help reduce your chances of getting EEE, take the following steps:

        
  • Stay inside when mosquitoes are most active (at dawn and at dusk).
  • Repair screens on your windows and doors to prevent mosquitoes from getting into your house.
  • When outside, wear insect repellent, long pants and long-sleeved shirts to limit exposure to bites.
  • Eliminate insect breeding areas. These may include areas of standing water, like pet water bowls, rain barrels, and other containers.