In order to find out the role of TLR-mediated responses in the control of this pathogen, the course of infection of B. microti was analyzed over 3 weeks in wild-type (WT) and TLR knock out (KO) mice including TLR2−/−, TLR4−/−, TLR9−/−, TLR2×4−/− and TLR2×4×9−/−. The gene discussed is TLR4; the disease is infection.