Kinetics of sleeping disease lesion appearance in the skeletal muscle of experimentally infected rainbow trout through histopathology and immunohistochemistry studies.
A Time course of clinical and histological signs. B Histological and immunohistochemical characterisation of skeletal muscle pathology following SDV infection. a First lesions were observed 18 days post-infection. They were characterized by focal myofiber necrosis (arrows). b The severity of myofiber necrosis increased until day 26; c at this time point, a positive immunolabelling of SDV E2 antigens was detected at the periphery of necrotic myofibers (arrowheads). d At day 54 post-infection, a diffuse regeneration of the skeletal muscle was observed, with infiltration of macrophages and activation/differentiation of satellite cells, e that can fuse to form new myofibers, displaying aligned central nuclei. f Fifty-seven days post-infection, skeletal muscle was regenerated but a high proportion of myofibers was atrophied.