TLR9 and infection: Such a phenomenon appears to be the case in infection with a related intracellular protozoan parasite, T. cruzi, where mice deficient in both TLR2 and TLR9 were found to be more susceptible than mice deficient in either one receptor, and the TLR2−/−TLR9−/− dual deficient mice had levels of susceptibility comparable to that of mice deficient in MyD88 [44].