Population biology of malaria

Four species of the genus Plasmodium cause human malaria. My thesis investigates the population dynamics of P. falciparum in an individual human and in interacting human and mosquito populations, and mixed-species Plasmodium infections in humans and mosquitoes.; The first section develops mathematical models that embody leading empirically-based hypotheses about key parasitological and immunological processes involved in P. falciparum blood-stage infections, and explores their implications for interventions and optimal levels of gametocyte production. Major conclusions are that higher rates of gametocyte production may decrease the severity of individual infections and that gametocyte production may be constrained by interspecific interactions among entities with different rates of gametocyte production.; The second section presents an individual-based approach to modeling parasite transmission, and uses this to outline circumstances in which interventions that increase adult mosquito mortality seem likely to have the greatest and least long-term influence on malaria prevalence in humans. The major conclusion of this section is that in regions with intense perennial transmission the influence of the duration of human infectivity may rival that of vector mortality.; The final section examines the contention that mixed-species infections occur at frequencies lower than those expected from the product of species prevalences, and suggests that mixed-species prevalence patterns in differ in mosquitoes and humans, and that the number of Plasmodium species present may be less important than which species are present in determining mixed-species prevalence patterns.