Raised levels of IL-8 have been reported in several infections caused by intracellular microbes (e.g., infection caused by mycobacteria, rickettsial infection and malaria) [23]–[25], and notably, IL-8 seems to be induced not only by stimulation of membrane-bound toll-like receptors (TLRs), but also by activating intracellular TLRs such as TLR9 and TLR5 [26]–[28]. Here, TLR5 is linked to infection.