The population dynamics of Plasmodium within the mosquito
Image from Wellcome CollectionProject Information
People:
- Emma Dawes
- María-Gloria Basáñez
Funders: Medical Research Council
Disease: P.berghei malaria
Collaborators:
Classical mathematical models of malaria typically describe infection prevalence in humans and vectors, ignoring the influence of infection intensity. This work aims to characterize the role played by density dependence in the sporogony of Plasmodium within the mosquito with the ultimate aim of contributing to the design and evaluation of transmission blocking strategies.
The approach is multi-pronged, encompassing statistical and mathematical modelling as well as experimental work and the analysis of laboratory- and field-derived datasets. Fitting statistical models to data allow relevant parameters of adequate functional forms to be estimated, and the results derived are used to inform mathematical models of the dynamics of Plasmodium within Anopheles. Analysis of results generated by establishing mosquito infections using defined numbers of Plasmodium berghei indicates that every developmental transition within Anopheles stephensi exhibits strong density dependence. Experimental work, conducted to determine the effect of parasite density on vector survival, followed An. stephensi cohorts fed on blood containing increasing P. berghei ookinete densities, indicates that mosquito mortality is both age- and parasite density-dependent under lab conditions. This work focuses mainly on the laboratory model systems with the objective of generating hypotheses testable using data from other Plasmodium–Anopheles combinations, either in laboratory or natural transmission systems. It will be important to determine whether the phenomena identified are combination-specific or truly represent underlying biological processes that can be generalised.
