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Living with Eastern equine encephalitis

A virus spread by mosquitoes that usually causes no symptoms or a short illness, but can sometimes cause swelling in the brain.

Understanding Eastern equine encephalitis

Eastern equine encephalitis (Triple E) is an illness caused by a virus spread by the bite of an infected mosquito.

Most infected people have no symptoms, but some develop fever, headache, and vomiting. Symptoms begin within 4 to 10 days of infection, and most people recover in 1 to 2 weeks. A small number develop swelling of the brain and severe neurological symptoms that can be permanent. Diagnosis is based on symptoms, blood tests, and sometimes an MRI of the brain.

Signs & symptoms

GARD doesn't list a separate symptom list for this condition, but the summary describes these features:

  • Often no symptoms
  • Fever
  • Headache
  • Vomiting
  • Swelling of the brain in a small number of people
  • Severe neurological symptoms in some people

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Specialists who may be involved include brain and nervous system specialists and seizure and epilepsy specialists.

  3. Ask which tests can help

    Your care team will decide which exams and tests can confirm the diagnosis.

  4. Connect with expert centers

    Epilepsy Foundation may keep lists of experts for this condition.

Care & treatment

Care team
Brain and nervous system specialists (neurologists); Seizure and epilepsy specialists (epileptologist)
Expert care
Expert lists: Epilepsy Foundation
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with Epilepsy Foundation
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
What tests confirm this infection?
What care is recommended while recovering?
How can I lower my risk of mosquito bites?

Quick facts

Symptoms usually startany time in life

The condition is caused by a virus (an arbovirus) spread by mosquitoes that have bitten an infected bird or reptile.

InfectiousNeurological

Also known as: eastern equine encephalitis virus infection; eastern equine encephalitis virus neuroinvasive disease; eastern equine encephalomyelitis; eee - eastern equine encephalitis; encephalitis, eastern equine; neuroinvasive eastern equine encephalitis virus disease

Patient organizations

Broader rare-disease groups

Source: NIH GARD · Eastern equine encephalitisGARD ID 10821 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Eastern equine encephalitis.

Explore the Eastern equine encephalitis blog

Explore research for Eastern equine encephalitis

Explore actively recruiting Eastern equine encephalitis studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Eastern equine encephalitis with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

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