Effects of pyrimethamine treatment on parasite dynamics of virulent and avirulent P. chabaudi. Number of asexual parasites/ml of blood over time ± s.e. for increasing pyrimethamine doses. PYR0 = no drug, PYR1, 3, 4, 5, 8, 12 and 20 indicate daily doses of pyrimethamine in mg/kg. 4A. 4-day pyrimethamine treatment, combined for experiments 1 and 2 with 9 mice in all treatment groups, except CWvir dose 5 (n = 8). Death of mice during the experiment is indicated by the table below the CWvir graph. 4B. Experiment 3, 1-day treatment with 4 mice in each treatment group.