Histopathology of the New Virus Infection with Abnormal Swimming in Coho Salmon (Oncorhynchus kisutch)

Abstract

Histopathological studies were made on a virus-infected coho salmon (Oncorhynchus kisutch) characterized by an abnormal swimming. Both naturally and artificially infected coho salmon showed necrosis in the kidney, including the hematopoietic elements and renal tubular epithelial cells, and also degenerative changes of melanomacrophage centers. In the brain, vacuolar degeneration with necrosis of nerve cells, congestion of blood vessels and degenerated nerve fibers were observed. By the EM, viral particles were seen in the cytoplasm of tubular cells and the macrophages in the kidney and in the axons of necrosed nerve cells in the brain.