应用集中度及圆分布法分析甘肃省1962-2010年流行性乙型脑炎发病季节性特征

目的 分析甘肃省乙型脑炎(JE)的季节性规律,为制定防控措施提供依据。方法 利用甘肃省疾病预防控制中心1962-2010年疫情资料和法定传染病报告资料,用集中度和圆分布法,分析乙脑季节性特征。结果 甘肃省1962-2010 年JE季节性分布的集中度M值为0.825 9。经圆分布样本平均角的Rayleigh 检验,Z=3 506.092 5,P＜0.01。平均角α所对应的日期即JE的集中发病高峰日为8月30日,发病高峰期的95%可信区间为7月22日至10月7日。结论 使用集中度和圆分布有助于我们更准确地掌握乙脑流行的高峰季节。甘肃省JE发病有很强的季节性, 7月底至10月初为流行高峰期。

Analysis on the seasonal characteristics of acute Japanese encephalitis in GansuProvince in 1962-2010 by concentration ratio and circular distribution

The seasonal characteristics of Japanese encephalitis (JE) in Gansu Province in 1962-2010 were analyzed in order to provide reference for making strategies of disease control and prevention. The JE data is the Epidemic Data between 1962 and 2003 from Gansu CDC, and National Notifiable Diseases Registry System (NNDRS, 2004-2010). Concentration ratio and circular distribution method were used in this study. Results showed that the M-value of the seasonal distribution of JE in 1962-2010 was 0.825 9. The corresponding peak date of JE was the 30th August (95％ CI: 22 July to 7 October). The Z value of Rayleigh test was 3 506.092 5 (P<0.01). In conclusion, the concentration and circular distribution method helps us to grasp the JE epidemic peak season more accurately. There were significant seasona1 characteristics for JE in Gansu Province and the epidemic peak was from late July to early October.