Abstract
In Japan, mass mortalities of cultured fish due to infectious diseases have been often reported. Among the pathogens, viruses are the most devastating infectious agents that afflict fish. This paper reviews the major viral diseases of cultured marine fish in Japan. The major diseases caused by DNA viruses include viral epidermal hyperplasia in flounder and herpesviral disease in coho salmon, both caused by a hepesviruses and lymphocystis disease and another iridoviral disease in red sea bream and other marine fishes. The major diseases caused by RNA viruses are viral ascites (VA), viral deformity (VD) in yellowtail, both caused by a birnavirus (YAV or VDV), erythrocytic inclusion body syndrome (EIBS) in coho salmon, a rhabdoviral disease in flounder and viral nervous necrosis (VNN) in striped jack and several other fishes by a nodavirus. The causative virus of Kuchijirosho in tiger puffer has not been classified.
