Print PagePlasmodium parasites, the causative agent of malaria, are completely dependent on Anopheles mosquitoes for transmission between human hosts. Ambient temperature speeds or slows various parts of the mosquito life history and also affects the parasites’ external incubation period in the mosquito. As a result temperature is a critical, but complicated, determinant of malaria transmission intensity and prevalence. It is vital, therefore, to understand how temperature impacts the dynamics of mosquito populations in the field and their capacity to effectively vector Plasmodium parasites. We present a new temperature-dependent delayed differential equation model of Anopheles population dynamics. The model is stage structured with temperature-dependence incorporated throughout the mosquito life cycle. We use sensitivity analyses across plausible ranges of future temperature scenarios to explore which geographic/climatic regions are likely to experience enhanced or diminished malarial attack rates.
Results/Conclusions
Our new model allows for quantitative and analytic exploration of temperature effects on mosquito population dynamics. The model formalism is robust to constant or fluctuating temperatures. Model simulations give more biologically reasonable predictions about the potential for malaria transmission, predicting a peak transmission occurs when temperatures are in the upper 20 to lower 30 C range. The model further highlights the importance of incorporating all juvenile life stages into vector population models because these are critical determinants of adult abundance and stage composition. Our analysis shows that temperature is important in the dynamics of all life stages. Moreover, the interaction between non-linear temperature relationships and within-stage density-dependent competition lead to non-intuitive patterns that will be helpful in understanding how the capacity of mosquito populations to vector Plasmodium may change with changing climatic conditions.
