Thus, massive phagocytosis of trypanosomes (as seen during peak parasitemia) leads to hyper-activation of macrophages and increased production of monokines (IL-1, TNF-α, IL-6, IL-12, monocyte chemotactic protein-1 [MCP-1]) and the T-cell cytokine (IFN-γ). The gene discussed is CCL2; the disease is parasitic infectious disease.