Abstract
Plasmodium species exhibit differential preferences for red blood cells (RBCs) of different ages. From a fundamental standpoint, we develop an original approach to show that such a differential ecological characteristic of Plasmodium species within their human host is fundamental to capture species diversity within the same host. This is based on a within-host malaria infection model coupled with a discrete maturity stage of RBCs production. The parasitized RBCs stage is an age-structured model with a continuous variable representing the time since the concerned RBC is parasitized. We show that with such difference in the RBCs preferences, the long-term coexistence of different species is possible under a certain condition, basically based on a suitable order on the basic reproduction numbers of each species. In particular, we show that the dynamical behavior of the model is not trivial and can range from the extinction of all species, the persistence of a single species, to the coexistence of more than one species. We also describe how our general analysis can be applied in some co-infection configurations including three malaria species: P. Falciparum, P. Vivax, and/or P. Malariae. This improved understanding of the within-host parasite multiplication in a context of mixed Plasmodium species interactions.