IL1B and pyelonephritis: This included significant induction of antiviral (Mx) and inflammatory (IL-1β) associated genes as assessed by qPCR, which is consistent with previous observations of IHNV infections of rainbow trout (Oncorhynchus mykiss) [49], and is suggestive that both type-I interferon and NF-κB cellular response pathways are initiated during early IHNV kidney infection.