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Japanese encephalitis vaccination

Japanese encephalitis vaccination

Japanese encephalitis is caused by a Flavivirus.

Japanese encephalitis is found in almost all Asian countries and parts of the Western Pacific. It poses a threat mainly in rural agricultural regions, particularly in areas where irrigation (artificial watering of crops) is widespread, including rice paddies. It can take from 5 to 15 days for symptoms to appear. Most cases are asymptomatic.

Less than 1% of those infected develop encephalitis (swelling of the brain), which is fatal in 20-30% of cases.

Severe cases are usually characterized by a sudden onset of :

  • fever
  • headaches
  • vomiting

Other symptoms include:

  • a stiff neck
  • mental confusion
  • mental or behavioural changes
  • general weakness
  • motor disorders
  • paralysis (inability to move)
  • a coma
  • convulsions
  • nerve and brain damage that may be permanent

Source: Health Canada