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目的采用Logistic模型模拟甲型H1N1流感大流行过程。方法使用Logistic模型对长沙市甲型H1N1流感大流行疫情进行拟合,确定模型的参数;推导模型的3个关键点,对大流行疫情进行定量分期。结果长沙市甲型H1N1流感疫情可以分为“输入期”、“本地扩散期”、“大流行期”三个时期。“大流行期”的Logistic模型方程为:n=6878/1+e-(0.1166t-8.3859)。模型模拟结果显示,“大流行期”分为三个阶段:1渐增期(第105~166 d),在该时期,疫情发展缓慢,是采取防控措施的最佳时期;2快增期(第167~188 d),此时期的防控难度较大,付出的防控成本可能收不到预期的效果;3缓增期(第189~244 d),在该时期,免疫屏障已逐步建立,采取防控措施效果将不明显。结论 Logistic模型能较好地模拟城市甲型H1N1流感大流行过程。
Objective To simulate the influenza A (H1N1) pandemic by Logistic model. Methods Logistic model was used to fit the pandemic influenza A (H1N1) in Changsha to determine the parameters of the model. Three key points of the model were deduced to quantitatively stage the pandemic. Results The epidemic situation of influenza A (H1N1) in Changsha can be divided into three periods: “input period”, “local spread period”, “pandemic period”. The Logistic model equation of “pandemic period” is: n = 6878/1 + e- (0.1166t-8.3859). The results of the model simulation show that the “pandemic period” is divided into three stages: a gradual increase period (from 105 to 166 days) during which the epidemic slows down and is the best time to take preventive and control measures; 2 (167th ~ 188th d), the prevention and control of this period is more difficult, and the prevention and control costs paid may not be able to achieve the expected results. 3 The period of moderate increase (the first 189 ~ 244 days), the immune barrier Has been gradually established, the effect of prevention and control measures will not be obvious. Conclusion Logistic model can better simulate the urban pandemic H1N1 influenza.