Most infected persons only develop mild symptoms or experience none at all. Those who do have symptoms usually experience flu-like symptoms 6–8 days after the bite of an infected mosquito, such as:
• Fever and chills
• Headache
• Abdominal pain
• Nausea and vomiting
• Tiredness

Neurologic symptoms (related to the nervous system) may develop later, which include:
• Feeling markedly tired
• Agitation
• Unsteadiness
• Convulsions (especially in children)
• Reduced consciousness
• Abnormal muscle movements like tremors and spasms
• Inability to blink or move other muscles

Japanese encephalitis (JE) should be suspected if a patient has neurologic symptoms and has recently traveled to or resided in an endemic country in Asia or the western Pacific. To confirm the diagnosis, doctors can test the blood or the cerebrospinal fluid (CSF) to detect antibodies to the virus.

Currently, there is no specific treatment for Japanese Encephalitis. Management is focused on relieving severe clinical signs and providing supportive care to help the patient overcome the infection.

There are two main strategies to prevent the Japanese Encephalitis virus from spreading:

a. Getting vaccinated against the virus, especially if moving to or spending a long time in an area with Japanese Encephalitis.

b. Avoiding mosquito bites, by:
• Minimizing outdoor activities during the cooler hours at dusk and dawn when mosquitoes are active.
• Wearing long-sleeved shirts and long pants.
• Applying mosquito repellent on exposed skin.
• Staying in air-conditioned rooms or rooms with window and door screens.
• Sleeping under a mosquito net.