Time-series (×10-2 per μl) of parasites (A) and RBCs (B) for mice treated with IL-10-R (grey, n=4) and controls (blue, n=4), and the corresponding estimate of the effective reproductive ratio, RE on days 4-7 (C) that would be observed in the absence of immune killing of infected cells obtained by combining RBC age-specific estimates of PE obtained from CD4+ T cell-depleted mice with the RBC dynamics and age-structure indicated by these time-series. Dotted regions in A and B show the time period plotted in C. In IL-10R treated mice, this predicted RE drops precipitously simply due to RBC depletion (B); and this anemia is not due to parasite levels, which remain comparable in controls and treated mice (A). This indicates that immune-mediated killing of uninfected RBCs is a key mechanism of control.