Similar peak parasitemia was observed on day 7 post-infection in both groups of mice [Single parasites (32.2% ± 9.3 vs. 29.4% ± 5.4., C57BL/6 vs. CCR2-/-, n.s.), Multiple parasites (3.7% ± 1.9 vs. 2.9% ± 1.6., C57BL/6 vs. CCR2-/-, n.s.)]. The gene discussed is CCR2; the disease is parasitic infectious disease.