PATHOLOGY ASSOCIATED WITH A VIRAL ERYTHROCYTIC INFECTION IN TURBOT, SCOPHTHALMUS-MAXIMUS (L)

Since 1992, frequent erythrocytic viral infections have occurred in cu ltured turbot, Scophthalmus maximus (L.), on several fish farms in Gal icia, Spain, causing important mortalities. Affected fish showed haemo rrhages in the head, mouth and fins, exophthalmia and abdominal disten sion. The disease was also characterized by the presence of pale blue inclusions in affected erythrocytes. The examination of these erythroc ytes by electronmicroscopy showed virus particles of 50-160 nm in size in the cytoplasm, budding at the cell membrane and extracellularly. T he histopathological study revealed occasional necrosis of kidney haem atopoietic tissue, an increase in the size and number of melanomacroph age centres of the spleen and kidney, and oedematous areas with hepato cytes containing eosinophilic bodies in the liver. Degeneration of mus cle fibres was accompanied by an intense inflammatory oedema. Dermatit is as well as uveitis and corneal oedema were consistent lesions.