Japanese encephalitis

Japanese encephalitis (JE) is a viral brain infection caused by the
Japanese encephalitis virus (JEV).

Areas of risk

JE is most common in rural areas
in Southeast Asia, the Pacific
Islands, and the Far East

However, the risk for transmission may shift as boundaries between rural and urban areas are blurred.

Recent JE outbreaks have been
reported in Australia

Since January 1, 2021, 45 people have been infected with JE in Australia, with 7 deaths recorded during this period. The outbreak has officially been declared a Communicable Disease Incident of National Significance (CDINS) by the Australian government.

Key facts

JEV is the main cause of viral encephalitis in many countries of Asia with an estimated 68,000 clinical cases every year.

Up to 20,400 people die from JE every year.

prevention guidance

More than one-third of people

who travelled to Asia and developed JE were on short-term trips (<30 days).

The consequences of symptomatic JE are serious

Up to 50% of JE survivors suffer from neurological, cognitive, and/or physical disabilities

Up to 30% of those who experience symptoms die

~35% of patients fully recover from JE

JE at a glance

Primary vector

Culex, particularly Culex tritaeniorhynchus

Biting habits:

  • Evening to morning


The majority of infections in humans are asymptomatic, and overt encephalitis occurs in 1:50 to 1,000 infected individuals.

Most common:

  • Fever
  • Headache
  • Vomiting


  • Mental status changes
  • Neurologic symptoms
  • Weakness
  • Movement disorders
  • Seizures

Help reduce the risk of mosquito-borne diseases dampening your travel experience. Learn more by speaking to your healthcare professional, such as a doctor or pharmacist, or visiting a travel clinic, before your next trip.