To investigate whether the resistance of Ship1-chimeric mice to N67 infection is dependent on the increased production of IFN-I, we infected WT and Ifnar−/− mice with N67 after the tail vein injection (IOCV) of scramble small interfering RNA (siRNA) and Ship1 siRNA, respectively; then, we detected lower parasitemia and longer survived in WT mice which handled with Ship1 siRNA (Fig. 1J and K), and higher production of IFN-α/β in the serum and higher Ifn-a/b expression in the spleen than the infected WT mice which handled with scramble siRNA (Fig. 1L and M). This evidence concerns the gene IFNAR1 and infection.