西尼罗病毒（WNV）传播动力学模型及防制措施评价的研究

美国1999年首次在纽约检测到西尼罗病毒(WNV)后,病毒快速在西半球传播,导致WNV大范围的流行,仅2005年,截止到12月20日美国共发生近2799例人类感染病例。WNV如此快速的大面积扩散提醒我们要提高对WNV传入的警惕,提高对WNV传播过程的认识。本研究根据WNV生态学特点,构建WNV在媒介(蚊虫)与宿主(鸟类与人群)间感染传播的数学模型。模型建立3个种群(蚊虫、鸟、人)相互间的联系过程。通过WNV感染过程及模型推导出基本传染数R0的计算公式,通过R0的阈值确定WNV传播动力学,如果R0≤1则说明疾病处于稳定状态,不会在局部范围内发生流行;如果R0>1则说明疾病可在一定范围内发生流行。分析通过改变模型中参数提出应采取相应的控制措施,为进一步研究预防和控制WNV提供有力依据。

MODELING THE DYNAMICS OF WEST NILE VIRUS AND EVALUATION OF CONTROL MEASURE

After the surprising detection of West Nile virus(WNV)in New York City in 1999,the virus has spread dramatically in the Western Hemisphere,resulting in the largest epidemics since reported.In a total,just one year of 2005,2799 human cases were reported in U.S till Dec.20.The epidemic through all the world warn us the introduction of WNV and increase the information about WNV transmission.In this work we formulate and analyze a mathematics model for the transmission of WNV infect between vector(mosquito)and host(avian population and human population),according to the ecology of WNV.The model concludes three populations(mosquito,avian and human)and provides the relationship between the populations.We build the formula of the Basic Reproductive Number(R_0)in terms of WN epidemiology.R_0 is the threshold condition that determines the dynamics of WNV infection.We can take the relevant control measure according to the changed parameters and provide a new platform for further research in preventing and controlling WNV disease.