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

Abstract

In March 1984, a new rhabdovlrus was isolated from moribund cultured hlrame (Japanese flounder) Parahchthys ohvaceus and from ayu Plecoglossus alhvelis 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 Hokkaldo, Japan. At temperatures between 5 and 20 "C the vlrus replicated and induced cytopathic effects (CPE), which progressed to eventual cytolysis, in susceptible cell lines, ~ncludmg FHM, EPC, BF-2, RTG-2, STE-137, HF-l, BB, YNK, CCO, and EK-l. The CHSE-214, KO-6 and CHH-l cell lines were refractory. Maximum virus titers of about log to 10g8 TCID,, rill-l were obtained In FHM or EPC cell hnes, and virus replicated optimally at 15 to 20 "C. Virus part~cles were bullet-shaped and measured 80 nm X 180 to 200 nm. The isolate was sensitive to pH 3, to dlethyl ether, and to heat (50 "C, 2 mm). Virus did not hemagglutinate human 0 type erythrocytes. Viral rephcabon was not inhib~ted by 104 M 5-~ododeoxyundlne. Infect~vity was not reduced by antisera aginst infectious hematopoletic necrosis v ~r u s (IHNV), v ~r a l hemorrhagic septicemia virus (VHSV), spring viremia of carp virus (SVCV), pike fry rhabdovirus (PFRV), eel vlrus-America (EVA), and eel wus-European (EVX). The viral isolate was pathogen~c for rainbow trout Salmo gairdnen by injection but not for chum salmon Oncorhynchus keta, coho salmon 0 . krsutch, masu salmon 0. masou, or ayu fry by water-borne exposure. The new virus has been named Rhabdovirus olivaceus (hirame rhabdovirus, HRV).