TLR5 and infection: Here, only susceptible non-vaccinated Arctic charr overexpressed tlr5 during the proliferative phase of Asal-infection; however, it is possible that due to the nature of our sampling design (i.e., after 8 dpi), we may have missed immediate activation of TLRs (or other immune regulators) in vaccinated fish (or unvaccinated fish), as expression of several TLRs was observed in head kidney of another salmonid species in the first 72 h post-infection with Asal (53).