IL18 and viral load: The interplay between the gastrointestinal microbiota, invasive viruses, and host immunology is complex and not fully characterized; however, recent evidence shows that the microbiota plays an important role in the pathogenesis of viral diseases [46]. The gut microbiota provides necessary signals for the expression of cytokines, such as pro-IL-1β and pro-IL-18, and following influenza virus infection, the inflammasome activation leads to homing of immune cells from the lung to the draining lymph nodes for activating cell-mediated immune responses [11].