The interbranchial lymphoid tissue (ILT) was recently described in the gills of salmonids. This study
examined changes in the ILT during a parasitic infection in marine environment, using amoebic gill
disease (AGD) as a model. Atlantic salmon (Salmo salar) experimentally infected with Neoparamoeba
perurans were sampled at 0, 3, 7, 14 and 28 days post challenge. Transversal sections of three areas of the
gills (dorsal, medial and ventral) were histologically assessed for morphological and cellular changes