HERPESVIRAL HEMATOPOIETIC NECROSIS OF GOLDFISH, CARASSIUS-AURATUS (L)

In the spring of 1992 and 1993, an epizootic with severe mortality occurred among cultured goldfish, Carassius auratus (L.),in Aichi and Nara Prefectures in Japan. A herpes virus was isolated from moribund goldfish that induced cytopathic effects in FHM and EPC cells. The isolate was sensitive to IUdR (5-iodo-2-deoxyuridine), acid (pH 3) and ether. Transmission studies confirmed the pathogenicity of the viral isolate for goldfish while it was not pathogenic for fancy carp, Cyprinus carpio L. Diseased fish had no visible external signs except for listlessness, but internally there was softening and discolouration of the spleen and kidney, and necrotic foci in the haematopoietic tissue, splenic pulp, pancreas, and lamina propria and submucosa of the intestine, Electron microscopy revealed enveloped virions ranging from 170 to 220 nm in diameter with hexagonal nucleocapsids (115-117 nm edge-to-edge diameter). The disease has been designated as herpesviral haematopoietic necrosis (HVHN), and to date, is the only herpesvirus infection to be described goldfish.