Overview
Japanese encephalitis (JE) is a serious viral infection that affects the brain. It is caused by the Japanese encephalitis virus (JEV), which belongs to a family of viruses called flaviviruses — the same family that includes West Nile virus and dengue virus. The virus is spread to humans through the bites of infected Culex mosquitoes, mainly in rural and agricultural areas of Asia and the western Pacific. You cannot catch it directly from another person. Once the virus enters the body, it can travel to the brain and cause dangerous swelling (encephalitis). Most people who are infected — about 99 out of 100 — never develop serious symptoms. But in those who do, the illness can be life-threatening. Symptoms usually start with fever, headache, and vomiting, and can quickly progress to confusion, seizures, and loss of consciousness. Children are especially vulnerable to severe disease. There is no specific antiviral drug to treat Japanese encephalitis. Care focuses on managing symptoms in a hospital setting, such as controlling seizures and reducing brain swelling. Vaccination is the most effective way to prevent the disease. A safe and effective vaccine is available and is recommended for travelers to high-risk areas and for people living in regions where the virus is common.
Key symptoms:
High feverSevere headacheNausea and vomitingStiff neckConfusion or disorientationSeizures or convulsionsWeakness or paralysis on one side of the bodyTremors or shakingLoss of consciousness or comaDifficulty speaking or understanding speechSensitivity to lightBehavioral changes or agitationMuscle stiffness or rigidity
Clinical phenotype terms (50)— hover any for plain English
Sporadic
Usually appears on its own, not inherited from a parent
Variable
Can begin at different ages, from infancy through adulthood
FDA & Trial Timeline
1 eventIXIARO: FDA approved
IXIARO is a vaccine indicated for the prevention of disease caused by Japanese encephalitis virus (JEV). IXIARO is approved for use in individuals 2 months of age and older.
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
1 availableIXIARO
IXIARO is a vaccine indicated for the prevention of disease caused by Japanese encephalitis virus (JEV). IXIARO is approved for use in individuals 2 months of age and older.
Clinical Trials
View all trials with filters →No actively recruiting trials found for Japanese encephalitis at this time.
New trials open frequently. Follow this disease to get notified.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Japanese encephalitis.
Community
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Start the conversation →Latest news about Japanese encephalitis
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What tests will confirm whether this is Japanese encephalitis, and how long will results take?,What are the most important warning signs that mean I or my child needs emergency care right away?,What long-term effects should we watch for, and how soon will we know if there is lasting brain damage?,What rehabilitation services are available to help with recovery, such as speech therapy or physical therapy?,Should other family members or close contacts be vaccinated, and is it too late for vaccination to help?,Are there any clinical trials or new treatments we should know about?,How long will recovery take, and when is it safe to return to school or work?
Common questions about Japanese encephalitis
What is Japanese encephalitis?
Japanese encephalitis (JE) is a serious viral infection that affects the brain. It is caused by the Japanese encephalitis virus (JEV), which belongs to a family of viruses called flaviviruses — the same family that includes West Nile virus and dengue virus. The virus is spread to humans through the bites of infected Culex mosquitoes, mainly in rural and agricultural areas of Asia and the western Pacific. You cannot catch it directly from another person. Once the virus enters the body, it can travel to the brain and cause dangerous swelling (encephalitis). Most people who are infected — about
How is Japanese encephalitis inherited?
Japanese encephalitis follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
Which specialists treat Japanese encephalitis?
25 specialists and care centers treating Japanese encephalitis are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.
What treatment and support options exist for Japanese encephalitis?
1 patient support program are currently tracked on UniteRare for Japanese encephalitis. See the treatments and support programs sections for copay assistance, eligibility, and contact details.