THE CONDITION
What is Japanese encephalitis?
Japanese encephalitis (JE) is a viral infection of the brain, spread by mosquitoes across parts of Asia and the Western Pacific. The mosquitoes that carry it feed mainly between dusk and dawn, and are most common in rural areas near rice farming or pig farming, though they are increasingly found in some urban locations too.
For most travellers, the individual risk is low: short-term visitors sticking to towns and cities face an estimated risk of less than one case per million travellers. Risk increases for those spending longer periods in rural areas, taking part in outdoor activities, or travelling during an active outbreak.
Where symptoms do develop, they range from mild flu-like illness to, in rare cases, serious neurological complications. There is no specific cure, so treatment focuses on supporting the patient through the illness — which is why prevention through vaccination and bite avoidance matters for higher-risk travellers.