Abstract
A histopathological examination was made on red sea bream with a symptom of cloudiness on the body surface found in fish farms in Kyushyu in 1986. The examination revealed that the cloudiness was induced by the proliferation of prickle cells, the intra-and inter-cellular edema and over-secretion of mucus of the epidermis. The epidermis showed spongiosis caused by a severe inter-cellular edema. A highly inflammatory response was noted in the dermis. No virus-like particles were observed under an electron microscope either in the nucleus or in the cytoplasm of proliferating prickle cells. An enlargement of the respiratory epithelial cells of the gill as well as the fusion of gill lamellae and an increase of mucus cells were detected. From these histopathological findings on the skin and gills it was suspected that stimulative substances in the environmental water were part of the causes of the described disease.
