The evolution of malaria incubation time
Malaria is one of the most dangerous infectious diseases, responsible for a significant fraction of human deaths in a large part of the world. Yet, past eradication efforts have failed. To design effective eradication campaigns, the infection cycle must be well understood. Malaria’s infectious agents (parasites of one of several species of the genus Plasmodium) are transmitted between mosquitos and humans through mosquito bites: after transmission, symptoms occur only after a certain incubation period. In particular, Plasmodium vivax - the malaria-inducing parasite species most prevalent in temperate zones - remains dormant in the human liver for longer periods than other species, which makes its combatting especially difficult. While incubation periods of P. vivax malaria in Korea show a clearly bimodal distribution, with short-term and long-term incubation periods, the reasons for this bimodality are not known. Using adaptive dynamics theory, we study the evolution of incubation times and investigate the evolutionary constraints guiding the emergence of bimodality. Based on the evolutionary insights gained in this first step, we identify and investigate the simplest suitable transmission model for P.vivax malaria that is in agreement with observed data.