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Start free with EleplanJapanese encephalitis
ORPHA:79139Disease
What it is
Japanese encephalitis is an arboviral disease (i.e. a disease due to a virus transmitted by an arthropod).
Key facts
- Prevalence
- 1-9 / 1 000 000 (annual incidence, Europe)
- Age of onset
- All ages
- Inheritance
- Not applicable
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Common30–79%
28- Anorexia
- Bilateral tonic-clonic seizure
- Chills
- Cogwheel rigidity
- CSF lymphocytic pleiocytosis
- CSF pleocytosis
- Decreased motor nerve conduction velocity
- Distal lower limb muscle weakness
- EMG: chronic denervation signs
- Facial grimacing
- Fatigue
- Focal T2 hyperintense thalamic lesion
- Functional motor deficit
- Headache
- Hyperintensity of MRI T2 signal of the spinal cord
- Increased circulating IgM level
- Increased circulating immunoglobulin concentration
- Increased CSF protein concentration
- Increased intracranial pressure
- Mask-like facies
- Myalgia
- Neutrophilia
- Paralysis
- Paucity of anterior horn motor neurons
- Reduced consciousness
- Skeletal muscle atrophy
- Vomiting
- Weakness due to upper motor neuron dysfunction
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
ICD-10 codes
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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