Effect of water temperature on pathological states of Japanese flounder experimentally infected with viral hemorrhagic septicemia virus, an flounder isolate KRRV-9601

Abstract

The effect of water temperature on virus propagation, mortality and histopathological changes of Japanese flounder Paralichthys olivaceus intraperitoneally injected with an isolate (KRRV-9601) of VHSV from flounder were examined. Mortalities for 15 days at 10, 15 and 20°C were 100, 60 and 0%, respectively. At 10°C, all of the infected fish showed high virus titers in both the heart and kidney, and histopathologically displayed necrotizing myocarditis and necrotic lesions in the spleen, hematopoietic tissue and liver. At 15°C, all fish showed higher virus titers in the heart than in the kidney, and myocardial necrosis. No histopathological changes were observed and no VHSV was recovered from fish at 20°C.