We also identified Rtx-independent mRNAs (found in both challenges) including interleukin 1 receptor II (il1r2) that was significantly more upregulated in the gills from R99-infected eels (Fig 4E) and TNF receptor-associated factor (traf3) that exhibited similar behaviour during both infections (Fig 4E and 4F). Here, IL1R2 is linked to infection.