Japanese encephalitis: what is it, how dangerous is it, how do you get it, and should you vaccinate?

What is Japanese encephalitis?

• Japanese encephalitis is a form of encephalitis caused by a virus.
• The disease is transmitted by mosquitoes. This specific mosquito species generally bites at dusk and at night.

Where does Japanese encephalitis occur?

• Japanese encephalitis occurs primarily in Southeast Asia and the western Pacific region.
• In addition, there are a few small areas where cases are still being reported, such as eastern China, northern Japan, Russia, and also in Australia around Torres State.
• Infections occur in rural areas and on the outskirts of cities.
• This is especially true in areas where pigs are kept in the fields. Pigs often serve as hosts for infected mosquitoes.
• Another very typical location for infection is in rural areas near rice paddies.
• Most travelers to Asia have little chance of infection. Those most at risk are those who spend extended periods in rural areas during a season when the disease occurs. The disease occurs predominantly in children under the age of ten.

What are the symptoms of Japanese encephalitis?

• The vast majority of infected individuals ultimately develop no symptoms.
• If symptoms do develop, they usually begin five to fifteen days after the mosquito bite.
• Symptoms often include fever, headache, behavioral changes, and significant loss of strength.
• In severe cases, symptoms of encephalitis and meningitis develop, with headache, vomiting, and eventually drowsiness, coma, and seizures.
• Paralysis and respiratory problems can lead to death.

Can Japanese encephalitis be treated?

• There is no known official treatment.
• However, supportive therapy can lead to a milder course of the disease.

What to do to prevent Japanese encephalitis abroad?

• Vaccination: The travel vaccine available in the Netherlands prevents outbreaks of Japanese encephalitis in 80 to 90 percent of cases. The vaccine's duration of action has not yet been definitively determined.
• Prevent mosquito bites: Japanese encephalitis can be prevented by wearing long-sleeved clothing, using DEET or another effective mosquito repellent, and using a mosquito net. This is because mosquitoes are most active at dusk and at night.