Symptoms & Treatment

Symptoms

Less than 1% of people infected with Japanese encephalitis (JE) virus develop neurologic illness. In persons who develop symptoms, the time from infection until illness onset (incubation period) is typically 5-15 days.

• Initial symptoms often include fever, headache, and vomiting.
• Mental status changes, neurologic symptoms, weakness, and movement disorders might develop over the next few days.
• Seizures are common, especially among children.
• Among patients who develop encephalitis (infection of the brain), 20% – 30% die.
• Although some symptoms improve after the acute illness, 30%-50% of survivors continue to have neurologic, cognitive, or psychiatric symptoms.

Diagnosis

See your healthcare provider if you have traveled to an area where JE is present and develop the symptoms described above.

• Tell your healthcare provider when and where you traveled.
• Your healthcare provider can order tests to look for JE virus infection.

To learn more about testing, visit our Healthcare Providers page.

Treatment

• No specific treatments have been found to benefit patients with JE. Treatment is symptomatic. However, a vaccine is available to prevent disease.
• Rest, fluids, and over-the-counter pain medications may relieve some symptoms.
• Hospitalization for supportive care and close observation is generally required.

To learn more about treatment, visit our Healthcare Providers page.