Japanese Encephalitis (JE) is a serious mosquito-borne viral infection caused by a flavivirus. It primarily affects children and can lead to severe brain inflammation (encephalitis). JE is most common in rural parts of Southeast Asia and the Western Pacific region.
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Japanese Encephalitis was first clinically described in Japan in 1871, leading to its name. The causative virus was isolated in 1935, clarifying its viral nature. It has since been recognized as a major public health concern across Asia, prompting the development of effective vaccines.
JE is transmitted to humans through the bite of infected mosquitoes, primarily *Culex tritaeniorhynchus*. Mosquitoes become infected by feeding on amplifying hosts like wading birds and pigs. Humans are accidental 'dead-end' hosts, meaning the virus does not spread directly from person to person.
Contagious Period: Varies by disease
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Data sources: BEACON, ProMED, WHO, CDC, and 50+ national health agencies
Our AI-powered surveillance hasn't detected significant JE activity in the past 30 days.
Real-time monitoring continues 24/7 across BEACON, ProMED, WHO, CDC, and 50+ global health agencies
Currently, JE case counts are within baseline expectations globally. However, diseases can emerge rapidly, which is why continuous monitoring is critical.
Download the Virus Watcher app to get instant alerts if JE activity increases in your region or travel destinations.
Even without active outbreaks, understanding JE prevention helps protect you and your community:
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Trusted information from leading health organizations
Official guidance from the U.S. Centers for Disease Control and Prevention
View CDC Resources →Global disease surveillance and guidelines from the World Health Organization
View WHO Resources →Disease information on Virus Watcher is reviewed by our Chief Epidemiologist, a former CDC lead analyst for FluSight forecasting. Outbreak data is aggregated from verified sources including BEACON, ProMED, WHO, CDC, and 50+ national health agencies. This information is for educational purposes and should not replace professional medical advice.
Last reviewed: 2026-07-18
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