Parasites performed better when injected via intravenous, at ring-stage, and matched to host rhythms, resulting in greater virulence. Total parasite densities of infections (a) on day 1 post-infection, (b) on day 2 post infection, and (c) summed from day 1 to day 7 pi (cumulative density); (d) overall loss of RBCs during the pre-peak phase. Bars show mean (±se) densities of parasites or RBC with (a) n = 39 infections per group (b-d) n = 40 per group. The top row compares the route of infection either by IP (intraperitoneal injection, black bars) or IV (intravenous injection, grey bars). The middle row compares the parasite stage used to initiate the infections, with rings (black bars) or trophozoites (grey bars). The bottom row compares parasites on the same (matched, black bars) or perturbed (mismatched, grey bars) schedule as the host.