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

University Of Alabama In Huntsville, Huntsville AL

Investigators

Abstract

Li The investigator develops and analyzes mathematical models of mosquito populations in which genetically altered mosquitoes have been introduced into wild mosquito populations. The genetically altered mosquitos are resistant to infection by mosquito-borne diseases, so their introduction into wild populations could be an effective measure in controlling mosquito-borne diseases such as malaria, dengue fever, and West Nile virus. He aims to understand the complexity of the dynamics of interacting genetically-altered and wild mosquitoes and to predict gene distributions in future generations of the population. The population models are structured, that is, they account for both gender and genetic structure. Within this structure, homogeneous models, where all transgenic (genetically-altered) mosquitoes are considered as a single group without distinction, heterogeneous models, where homozygous and heterozygous transgenic mosquitoes are distinguished, and multiple-transgenic models, where genetically-altered mosquitoes have different transgenes, are examined. Within each model category, formulas for the birth functions and contact rates are established. To account for data deviations and environmental noise, the investigator formulates versions of these models that include demographic and environmental stochasticities. Transmission dynamics of the diseases are incorporated with various epidemiological models for both human and mosquito populations. The investigator combines analysis and numerical simulation to study qualitative and quantitative features of the models, including existence and stability of equilibria, existence of periodic and aperiodic oscillations through bifurcations, and chaotic behavior and transient dynamics. Model parameters are estimated or derived from real biological data and the mathematical analysis of the models covers all parameter regions. Biologists recently have been able to genetically alter mosquitoes so that they are resistant to malaria infection or other mosquito-borne diseases, such as dengue fever and West Nile virus. These diseases are transmitted between humans by blood-feeding mosquitoes. Their spread and control have been major concerns for public health. The introduction of transgenic (genetically altered) mosquitoes into wild mosquito populations could be an effective measure in controlling mosquito-borne diseases. To explore this possibility, the investigator in collaboration with biologists develops and analyzes mathematical models that represent the population dynamics of wild and transgenic mosquitoes. The models account for the spread of transgenes through the mosquito population over multiple generations. They help answer such questions as how effectively transgenic mosquitoes would be able to compete for partners with their wild counterparts, how long it would take for a new resistance gene to penetrate the mosquito population, and how effective it would be in mosquitoes that carry it. In this way, the results of the project can provide useful guidance for public health measures.