A new rhabdovirus isolated in Japan from cultured hirame (Japanese flounder) Paralichthys olivaceus and ayu Plecoglossus altivelis

摘要

In March 1984, a new rhabdovirus was isolated from moribund cultured hirame (Japanese flounder) Paralichthys olivaceus and from ayu Plecoglossus altivelis fry In Hyogo Prefecture, Japan. From February through May 1985, the virus was again isolated from hirame in seawater tanks in Hyogo and Kagawa Prefecture, and in Hokkaido, Japan. At temperatures between 5 and 20℃ the virus replicated and induced cytopathic effects (CPE), which progressed to eventual cytolysis, in susceptible cell lines, including FHM, EPC, BF-2, RTG-2, STE-137, HF-1, BB, YNK, CCO, and EK-1. The CHSE-214, KO-6 and CHH-1 cell lines were refractory. Maximum virus titers of about 10^9.3 to 10^9.8 TCID50ml^[-1] were obtained in FHM or EPC cell lines, and virus replicated optimally at 15 to 20℃. Virus particles were bullet-shaped and measured 80 nm × 180 to 200 nm. The isolate was sensitive to pH 3, to diethyl ether, and to heat (50℃, 2 min). Virus did not hemagglutinate human O type erythrocytes. Viral replication was not inhibited by 10^[-4] M 5-iododeoxyuridine. Infectivity was not reduced by antisera aginst infectious hematopoietic necrosis virus (IHNV), viral hemorrhagic septicemia virus (VHSV), spring viremia of carp virus (SVCV), pike fry rhabdovirus (PFRV), eel virus-America (EVA), and eel virus-European (EVX). The viral isolate was pathogenic for rainbow trout Salmo gairdneri by injection but not for chum salmon Oncorhynchus keta, coho salmon O. kisutch, masu salmon O. masou, or ayu fry by water-borne exposure. The new virus has been named Rhabdovirus olivaceus (hirame rhabdovirus, HRV).