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

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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.