Epidemiology

Japanese Encephalitis (JE) is the most important viral encephalitides in Asia (1)

• is the leading cause of childhood encephalitis in Asia
• approximately 20,000 to 50,000 cases per annum are recorded in theses areas (2)
• mainly reported in rural and suburban areas where rice culture and pig farming coexist
• rare and sporadic cases have also been reported in northern Australia and parts of the Western Pacific (1)

The infection is endemic in rural areas (especially where rice growing and pig farming coexist) and epidemics occur in rural and occasionally in urban areas (2)

• in temperate areas of Asia, transmission mainly occurs during the warm season while in tropics and subtropics, year-round transmission is seen with an increase during the rainy season (1)

Reference:

• (1) Campbell GL et al. Estimated global incidence of Japanese encephalitis: a systematic review. Bull World Health Organ. 2011;89(10):766-74
• (2) Immunisation Against Infectious Disease - "The Green Book". Chapter 20 Japanese encephalitis (January 2013)