Transmission is more marked in rural areas, in flooded rice paddies, and during wet seasons.
The risk to the average traveler is less than 1 per million per year. Etiology Japanese encephalitis is caused by a virus from the Flaviviridae family. Presenting symptoms are compatible with encephalitis and include fever, lethargy, and altered mental status. Preparing the international traveler The vaccine is made of inactivated virus and is given as a three-shot primary series. Serious allergic reactions including urticaria, angioedema, and anaphylaxis occur at the rate of about 15 to 62 per 10,000 doses.