Biochemical Characterization of Eel Virus European

Abstract

SUMMARYThe polypeptide and RNA compositions of purified virions of eel virus European were compared to those of three strains (VR-299, SP and AB) of infectious pancreatic necrosis virus (IPNV) isolated from trout. All three IPNV strains could be distinguished by the relative mobilities of either the virion polypeptides or the doublestranded RNA genome segments. The eel virus had a similar polypeptide profile to strain AB IPNV but differences between the two viruses in the migration of genome segments indicated each was unique. Annual epizootics among pond-cultured Japanese eels (Anguilla japonica) in Shizuoka prefecture, Japan have been reported since 1969 (Egusa, 1970). Environmental and physiological factors alone or in combination with a bacterium of the genus Cytophaga were believed to be the major causes of the observed epizootics (Egusa et al., 1971 ;Egusa, 1976). Virological examinations of diseased eels, however, revealed the presence of a previously undescribed virus (Sano, 1976). Examinations of eels from farms in 10 different locations indicated that this same virus was present in several populations of cultured eels in Japan (Sano et al., 1981). This disease outbreak followed the importation of European eels (Anguilla anguilla) to Shizuoka prefecture. The virus was also isolated from these imported eels. Because the virus showed an antigenic relationship to a European strain of infectious pancreatic necrosis virus (IPNV), it was designated eel virus European (EVE).Infectious pancreatic necrosis virus is a known pathogen of hatchery reared brook (Salvelinus fontinalis) and rainbow (Salmo gairdneri) trout and is found in many countries where these fish are cultured (Wolf, 1966). Three major serological groups or serotypes of IPNV have been identified (Okamoto et al., 1983;Macdonald & Gower, 1981). Two of these serotypes, AB and SP (Jorgensen & Kehlet, 1971), are found only in Europe. Both the AB and SP serotypes have been detected in trout, in several nonsalmonid species and in elvers in Europe (Hudson et al., 1981 ;Adair & Ferguson, 1981 ;Castric & Chastel, 1980; Munro et al., 1976; Ahne, 1980). The third serotype of IPNV is prevalent in North America and is represented by reference strain VR-299 (Wolf & Quimby, 1971).Eel virus European (EVE) is similar to IPNV in particle size and morphology, cytopathogenic effect in cell culture and buoyant density in caesium chloride (Nishimura et al., 1981). Unlike the VR-299 and SP strains, EVE was not pathogenic for rainbow trout even though the virus was found to replicate to high concentrations in several internal organs (Sano et aL, 1981). Similar results were obtained with the AB strain of IPNV which was less virulent for rainbow trout (Jorgensen & Kehlet, 1971) than SP or VR-299 IPNV. Cross-neutralization studies have shown EVE to be closely related to the AB strain of IPNV (Okamoto et al., 1983). The results presented here provide the first comparisons of the RNA and polypeptides of VR-299, SP and AB IPNV with EVE. From this study, we have confirmed that E...

Use of monoclonal antibodies for detection of infectious pancreatic necrosis virus by the enzyme-linked immunosorbent assay (ELISA)

“…Virus purification was similar to that previously described for IPNV (Hedrick et al 1983). Briefly, virus isolates were propagated using the Chinook salmon Oncorhynchus tshawytscha embryo cell line (CHSE-214) (ATCC CRL 1691).…”

Viral diseases of wild and farmed European eel Anguilla anguilla with particular reference to the Netherlands

“…EVE and IPNV type Ab were also found to be similar in polypeptide and RNA composition, and clearly distinguishable from IPNV strains VR-299 and Sp (T. Sano et al 1981, Hedrick et al 1983a. Using cross-neutralisation assays with almost 200 IPNV isolates, Hill & Way (1995) later proposed a new serological classification, consisting of serogroup A containing serotypes A1 to A9, and serogroup B containing the single serotype B1.…”

“…Electron microscopy (EM) revealed that EVE virions were non-enveloped polyhedrons with a diameter of 68 to 77 nm, only present in the cytoplasm of infected cells. EVE also resembled IPNV in terms of biological properties, such as polypeptide composition and the bisegmented double-stranded RNA genome (Nishimura et al 1981a, T. Sano et al 1981, Hedrick et al 1983a Lee et al 1999aLee et al , 2001.…”

“…It was therefore suggested -and allegedly proven -that EVE entered Japan with the import of A. anguilla elvers (T. Sano et al 1981, Hedrick et al 1983a. EVE/IPNV type Ab and IPNV type VR-299 were later also isolated from various A. japonica farms in Taiwan (Chen et al 1985, Hsu et al 1989, 1993.…”

“…Electron microscopy (EM) revealed that EVE virions were non-enveloped polyhedrons with a diameter of 68 to 77 nm, only present in the cytoplasm of infected cells. EVE also resembled IPNV in terms of biological properties, such as polypeptide composition and the bisegmented double-stranded RNA genome (Nishimura et al 1981a, T. Sano et al 1981, Hedrick et al 1983a Lee et al 1999aLee et al , 2001.Aquabirnaviruses form an antigenically diverse group of viruses, with the type species IPNV being the aetiological agent of an acute contagious systemic disease of several species of freshwater and marine fish, molluscs and crustaceans (Rodriguez Saint-Jean et al 2003). Mortality caused by IPNV in salmonids is high in fry and fingerlings, but rare in older fish.…”