Increased resistance to CM in CCR5-deficient mice infected with PbA. (A-B) CM incidence occurring between day 7 and day 10 (A) and survival time (B) of WT (n = 13), F₁ (n = 7), and KO (n = 10) mice infected with PbA (10⁶ PEs). Neurologic signs first appear late on days 7 through 10 (B, shaded area), with death occurring in less than 24 hours after their onset. On day 10, as calculated by Fisher exact test, P < .05 between WT (or F₁) and KO mice. This experiment is representative of 3 experiments. (C-D) Parasitemia (C) and hemoglobin levels (D) of PbA-infected WT (n = 5) and KO (n = 5) mice. Mortality is indicated on the first graph at the top (WT mice) and at the bottom (KO mice) as the number of dead mice (d) on that day. F₁ mice have parasitemia and hemoglobin level profiles similar to these observed for the WT mice. Error bars represent mean (SE) of 5 mice.