Although similar numbers of CD45hi infiltrating leukocytes, comprised of CD4+ and CD8+ (lymphocytes) and CD11b+ (macrophages) were present between WT and CCR5−/− mice in the cerebellar tissues on day 8 following WNV infection (Fig. 5b), the total number of CD45hi CD4+ and CD8+ lymphocytes was significantly decreased in the cortices of CCR5-deficient, WNV-infected mice on day 8 post-infection (Fig. 5d). The gene discussed is CCR5; the disease is infection.