NFκB is activated by both MyD88- and TRIF-dependent pathways.48 The activation of RIP1 is essential for the induction of NFκB via the TLR4–TRIF axis.49,50 We observed significant expression of RIP1 at later stages of infection overlapping the expression of TRIF and NFκB, suggesting the importance of TRIF-induced NFκB activation in A. hydrophila pathogenesis in zebrafish. This evidence concerns the gene TLR4 and infection.