Epidemiology of Japanese encephalitis in Inner Mongolia, 1950 - 2007

Objective To understand the epidemiological characteristics of Japanese encephalitis (JE) in Inner Mongolia and provide scientific evidence for the effective control and prevention of JE. Methods Descriptive epidemiological analysis was conducted on reported JE cases in Inner Mongolia from 1950 to 2007. Results During 1950 - 2007, a total of 4850 cases of JE were reported to occur in Inner Mongolia with the average annual incidence rate of 0.49/lakh. Most cases (4297 cases) were reported during 1969-1984, and the average annual incidence rate was 1.55/lakh. However the average annual incidence rate from 1985 to 2007 was 0.08/lakh (412 cases), which was lower than national level. Only 26 cases had been reported since 2000 with the average annual incidence rate of 0.01/lakh. The JE cases occurred in Chifeng and Tongliao (4117 cases) accounted for 84.89% of the total cases. Conclusion The JE incidence declined in Inner Mongolia in recent 20 years. Chifeng and Tongliao were the areas with high incidence of JE.