Japanese B encephalitis is a viral infection transmitted by the Culex species of mosquito. This mosquito is a night time feeder with a large number of possible food sources, e.g. dogs, cats, birds and man, and occurs in rural agricultural areas throughout Asia, primarily from June through September. For years, before the vaccine was available, the incidence of this disease among U.S. travelers was so infintesimal that it was not of great concern. The average traveler is not at risk for contracting this disease unless spending more than three to four months during the transmission season in a rural agricultural (rice-growing, pig-farming) endemic area.

Vaccination

In persons at risk, preventative measures include vaccination, and protection against mosquito bites (particularly at night). Refer to Insect Protection Measures for more information.