However, since classical genetic studies previously established that the resistance to T. cruzi is governed by multiple genetic factors, including H-2-linked genes [40, 41], the level of protection given by the TLR4 pathway during the infection of C3H/HeJ mice (whose C3H background is classified as “susceptible”) could not be directly compared to the degree of susceptibility of infected Myd88−/− mice, which are of the resistant C57BL/6 genetic background. The gene discussed is TLR4; the disease is infection.