To further understand the contribution of murine TLR4 in the pathogenesis of leptospirosis, adult (10 weeks) WT and TLR4−/− mice were infected via the ip route with 2 × 108 cells of L. interrogans strain 56606v, and the pathological lesions were examined at 8 h, 1, 2, 3, 5, 7, 14 and 28 dpi. Here, TLR4 is linked to leptospirosis.