Days: duration of pyrimethamine treatment in days, starting from day 5 after infection. Dose: mg/kg/day. Nr mice: sample sizes for each group, with sample sizes for each experiment. * Each symbol indicates a mouse excluded from analysis, euthanized early in the experiment because of severe anaemia. § 1 mouse excluded, no parasites detected at time of treatment. # 4 mice euthanized on d11 and d12 after infection, data have been used where possible.