Epidemiology of Japanese encephalitis in Baoji, Shaanxi, 2004-2013

Objective To understand the epidemiological characteristics of Japanese encephalitis in Baoji, Shaanxi province, from 2004 to 2013 and provide evidence for the prevention and control of Japanese encephalitis. Methods Autoregressive integrated moving average(ARIMA) model was used to analyze the incidence trend of Japanese encephalitis in Baoji from 1995 to 2013. Then descriptive epidemiological analysis and circular distribution analysis were conducted on the incidence data of Japanese encephalitis in Baoji from 2004 to 2013. Results A total of 177 Japanese encephalitis cases, including 5 deaths, were reported during 2004-2013. The average annual incidence was 0.53/lakh, the case fatality rate was 2.82%. More cases were reported in Fengxiang, Qishan and Chencang. The seasonality of the disease was obvious, the annual incidence peak was during July-September, the cases during occurred this period accounted for 97.18%. The male to female ratio of the cases was 0.86:1. Farmers were mostly affected with cases accounting for 66.67%. No cases were reported in age group 15 years during 2011-2013. The cases in people aged 50 years accounted for 90.63%. Conclusion After the slight increase of Japanese encephalitis incidence in recent years,the incidence would decline during 2014-2015, but the incidence pattern would remain, and people aged 50 years would be still mostly affected. It is necessary to conduct the vaccination among the risk population.