中文摘要：

目的通过分析卫生部全国传染病网络直报系统提供的2005～2010年全国戊型肝炎（戊肝）月发病数据,了解戊肝的发病趋势和季节性特征,为戊肝的防治工作提供参考依据。方法首先利用时间序列分解法分解出戊肝月发病数的季节性变动因素和长期趋势因素,然后利用圆形分布法验证季节性变动因素的季节性聚集趋势,并得到发病高峰时点和高峰期。结果 2005～2010年间全国戊肝发病呈不断上升趋势;戊肝发病呈现季节性,每年为一个周期,呈单峰型,集中趋势有统计学意义（P〈0.01）,发病高峰时点在3月末4月初,发病高峰期在冬春季,尤其是春季相对高发,其他月份低发。结论戊肝发病具有季节性和上升趋势,应于冬季12月份开始开展戊肝的防治工作。

英文摘要：

Objective To determine the long-term trend and seasonal characteristics of hepatitis E and then offer reference for its prevention and control by analyzing the national monthly incidence data of hepatitis E between 2005 and 2010 that provided by China information system for disease control and prevention.Methods Split out the seasonality and long-term trend from the time series by using decomposition methods.Then access the seasonal clustering of seasonality and obtain the peak and peak period by using circular statistical methods.Results From 2005 to 2010,the incidence rate of hepatitis E had been increasingly grown;there was a significant seasonal variation（P0.01） with peak in the end of March or the early April and peak periods in the winter and spring,especially in spring,and troughs in the other seasons.Conclusion There was a seasonal concentration and an increasing trend of hepatitis E,suggesting a start of prevention and control for hepatitis E in December.