Figure 1: Plasmodium transmission dynamics. (a) Illustration of the natural history of infection with the P. vivax parasite. The variables represent a classification of the population at any given age and time into six states: completely susceptible ( 𝑆 ); clinical malaria resulting from an infection in a completely susceptible individual ( 𝐼 1 ); recovered with clinical immunity without any hypnozoites ( 𝑅 ); mild or asymptomatic infection resulting from exposure of recovered individuals ( 𝐼 2 ); recovered with a certain degree of clinical immunity, carrying hypnozoites ( 𝐿 1 ); recovered with clinical immunity, carrying hypnozoites ( 𝐿 2 ). Description and values for the parameters can be found in Table 1. (b) P. falciparum transmission dynamics. This is a subset of the previous system which is retrieved by making 𝑝 1 = 1 .