Figure 4From: Piscine orthoreovirus (PRV) in red and melanised foci in white muscle of Atlantic salmon (Salmo salar) Histological investigations of melanised focal changes. (A) Transverse section of necrotic muscle cells (asterisk) and severe fibrosis (arrow) with infiltrates of leukocytes. A cell-rich granuloma with melanin-containing cells is present in the right part of the picture (G), displaying a heterogeneous morphology (HE staining). (B) Severe vacuolisation and adipocytes with surrounding melano-macrophages (black) and clusters of regenerating myocytes with a basophilc cytoplasm (arrow) (HE staining). (C) Multiple vacuoles in an area with severe fibrosis (intense red staining) (van Gieson staining). (D) Several iron-containing macrophage-like cells (blue staining) in association with melano-macrophages (black) (Pearls’ Berlin blue staining). (A, C) scale bar = 100 μm, (B, D) scale bar = 50 μm.Back to article page