Modeling the Impact of Releasing Genetically Altered Mosquitoes in Preventing the Transmission of Mosquito-Borne Diseases

研究者开发并分析了蚊子种群的数学模型，其中转基因蚊子被引入到野生蚊子种群中。 转基因蚊子对蚊子传播的疾病有抵抗力，因此将它们引入野生种群可能是控制蚊子传播的疾病如疟疾、登革热和西尼罗河病毒的有效措施。 他的目标是了解基因改变蚊子和野生蚊子相互作用的复杂性，并预测种群后代的基因分布。 种群模型是结构化的，即它们同时考虑了性别和遗传结构。 在这种结构中，对所有转基因（基因改变的）蚊子被视为一个单一的组而没有区别的异质性模型，其中纯合和杂合转基因蚊子被区分开的异质性模型，以及其中基因改变的蚊子具有不同转基因的多重转基因模型进行了检查。 在每个模型类别中，建立了出生函数和接触率的公式。 为了解释数据偏差和环境噪音，研究者制定了这些模型的版本，包括人口统计学和心理随机性。 疾病的传播动力学与人类和蚊子种群的各种流行病学模型相结合。 研究者结合分析和数值模拟来研究模型的定性和定量特征，包括平衡点的存在性和稳定性，通过分叉的周期和非周期振荡的存在性，以及混沌行为和瞬态动力学。 模型参数是从真实的生物数据中估计或导出的，模型的数学分析覆盖了所有的参数区域。生物学家最近已经能够对蚊子进行基因改造，使它们对疟疾感染或其他蚊子传播的疾病（如登革热和西尼罗河病毒）具有抵抗力。 这些疾病是通过吸血蚊子在人类之间传播的。 它们的传播和控制已成为公共卫生的主要问题。 将转基因蚊子引入野生蚊子种群是控制蚊媒疾病的有效措施。 为了探索这种可能性，研究人员与生物学家合作开发并分析了代表野生和转基因蚊子种群动态的昆虫模型。 这些模型解释了转基因在蚊子种群中的多代传播。 它们有助于回答诸如转基因蚊子如何有效地与野生蚊子竞争伴侣，新的抗性基因需要多长时间才能渗透到蚊子种群中，以及它在携带这种基因的蚊子中的效果如何等问题。通过这种方式，该项目的结果可以为公共卫生措施提供有用的指导。

LiThe investigator develops and analyzes mathematical models ofmosquito populations in which genetically altered mosquitoes havebeen introduced into wild mosquito populations. The geneticallyaltered mosquitos are resistant to infection by mosquito-bornediseases, so their introduction into wild populations could be aneffective measure in controlling mosquito-borne diseases such asmalaria, dengue fever, and West Nile virus. He aims tounderstand the complexity of the dynamics of interactinggenetically-altered and wild mosquitoes and to predict genedistributions in future generations of the population. Thepopulation models are structured, that is, they account for bothgender and genetic structure. Within this structure, homogeneousmodels, where all transgenic (genetically-altered) mosquitoes areconsidered as a single group without distinction, heterogeneousmodels, where homozygous and heterozygous transgenic mosquitoesare distinguished, and multiple-transgenic models, wheregenetically-altered mosquitoes have different transgenes, areexamined. Within each model category, formulas for the birthfunctions and contact rates are established. To account for datadeviations and environmental noise, the investigator formulatesversions of these models that include demographic andenvironmental stochasticities. Transmission dynamics of thediseases are incorporated with various epidemiological models forboth human and mosquito populations. The investigator combinesanalysis and numerical simulation to study qualitative andquantitative features of the models, including existence andstability of equilibria, existence of periodic and aperiodicoscillations through bifurcations, and chaotic behavior andtransient dynamics. Model parameters are estimated or derivedfrom real biological data and the mathematical analysis of themodels covers all parameter regions. Biologists recently have been able to genetically altermosquitoes so that they are resistant to malaria infection orother mosquito-borne diseases, such as dengue fever and West Nilevirus. These diseases are transmitted between humans byblood-feeding mosquitoes. Their spread and control have beenmajor concerns for public health. The introduction of transgenic(genetically altered) mosquitoes into wild mosquito populationscould be an effective measure in controlling mosquito-bornediseases. To explore this possibility, the investigator incollaboration with biologists develops and analyzes mathematicalmodels that represent the population dynamics of wild andtransgenic mosquitoes. The models account for the spread oftransgenes through the mosquito population over multiplegenerations. They help answer such questions as how effectivelytransgenic mosquitoes would be able to compete for partners withtheir wild counterparts, how long it would take for a newresistance gene to penetrate the mosquito population, and howeffective it would be in mosquitoes that carry it. In this way,the results of the project can provide useful guidance for publichealth measures.