Physicochemical and Serological Characterization of Two Rhabdoviruses Isolated from Eels
Summary Two bullet-shaped viruses, isolated from eels, have been characterized physico-chemically, and their serological relationship to the other fish rhabdoviruses has been determined. Preparations of each virus contain truncated as well as bullet-shaped particles and the RNAs from these sediment at 18S and 4IS, respectively. As determined by PAGE, the virion polypeptide patterns for both viruses were indistinguishable, but were found to differ from those of the other fish rhabdoviruses. Using vesicular stomatitis virus polypeptides as internal markers, the molecular weights of the eel virus polypeptides were calculated to be > 150,000, 64,000, 49,000, 47,000 and 26,000. The two viruses are closely related to each other antigenically, but show no relationship to the other fish rhabdoviruses in neutralization tests.Copyright © 1980 S. Karger AG, Basel
- "The first one, designated eel virus American (EVA), was imported from Cuba within a shipment of A. rostrata elvers, while the second one originated from France through European eel culture-ponds and was named EVEX (Sano, 1976; Sano et al., 1976, 1977). Their physico-chemical, morphological, serological and infectivity properties are strongly similar, suggesting they are two strains of a single virus (Hill et al., 1980; Nishimura et al., 1981). Since then, EVEX isolates have been detected in wild and farmed eel from various geographical regions: France (Castric & Chastel, 1980; Castric et al., 1984), The Netherlands (van Beurden et al., 2011; van Ginneken et al., 2005), Italy (van Ginneken et al., 2004), UK, Denmark and Sweden (Jørgensen et al., 1994), and Germany and Russia (Ahne et al., 1987; Shchelkunov et al., 1989). "
[Show abstract] [Hide abstract]
- "A related rhabdovirus, EVEX, was isolated later from European elvers (Sano et al., 1977). EVA and EVEX are highly similar in morphological (Nishimura et al., 1981), serological (Hill et al., 1980; Nishimura et al., 1981) and physicochemical characteristics (Hill et al., 1980), and were proposed to be two strains of a single virus species (Hill et al., 1980). Preliminary molecular comparison of partial sequences from the RNA polymerase or L gene from EVEX and EVA reference isolates confirms the existence of two lineages with 91.5% sequence identity over a 2040 bp fragment (M.Y. "
ABSTRACT: Eel virus European X (EVEX) is one of the most common pathogenic viruses in farmed and wild European eel (Anguilla anguilla) in the Netherlands. The virus causes a hemorrhagic disease resulting in increased mortality rates. Cell culture and antibody-based detection of EVEX are laborious and time consuming. Therefore, a two-step real-time reverse transcriptase (RT-)PCR assay was developed for rapid detection of EVEX. Primers and probe for the assay were designed based on a sequence of the RNA polymerase or L gene of EVEX. The real-time RT-PCR assay was validated both for use with SYBR Green chemistry and for use with a TaqMan probe. The assay is sensitive, specific, repeatable, efficient and has a high r²-value. The real-time RT-PCR assay was further evaluated by testing field samples of European eels from the Netherlands, which were positive or negative for EVEX by virus isolation followed by an indirect fluorescent antibody test. The real-time RT-PCR assay allows rapid, sensitive and specific laboratory detection of EVEX in RNA extracts from 10% eel organ suspensions and cell cultures with cytopathic effects, and is a valuable contribution to the diagnosis of viral diseases of eel.
[Show abstract] [Hide abstract]
- "EVEX is a RNA-virus, and has a bullet-like form and a size of 170–175 × 90–95 nm (Sano et al. 1977). Hill et al. (1980) showed that EVA and EVEX were closely related. Infected elvers in Japan showed vascular congestion of the abdominal surfaces and pectoral and anal fins, and histology revealed extensive haemorrhaging and necrosis of kidney, muscle, pancreas and liver (Sano 1976). "
ABSTRACT: Eels have an uncommon catadromic life cycle with exceptional migratory patterns to their spawning grounds several thousand kilometres away: the European eel (Anguilla anguilla) travels over 5,500 km to the Sargasso Sea (Schmidt 1923; McCleave and Kleckner 1987; Tesch 1982; Tesch and Wegner 1990); the American eel (A. rostrata) migrates over 4,000 km also to the Sargasso Sea (Castonguay and McCleave 1987; McCleave and Kleckner 1987; Tesch and Wegner 1990); the Australian eel (A. aus-tralis) travels over 5,000 km into the Pacific Ocean to spawn (Jellyman 1987); and the Japanese eel (A. japonica) travels over 4,000 km to an area near the Marianna Islands in the Philippines to spawn (Tsukamoto 1992). Evidently such long distance swimming will place those fishes under extra stress caused by the long starvation period, the high energy cost of the journey, and the many changes in the environment such as salt water, darkness, high pressure, and low temperatures, among other stress factors. Stress is often a basis for disease in eel, especially in intensive eel culture (Haenen and Engelsma, 2005 unpublished finding). Nowadays, global transport of live fishes for aquaculture has facilitated the global spread of pathogens from diseased to healthy stocks. Within the last few decades, aquaculture has become an important production branch in our society. Its global production has more than doubled between 1986 and 1996 in tonnage and value, and over one quarter of human fish consumption at world scale is now produced in aquaculture (Naylor et al. 2000). The Netherlands is one of the leading eel producing & trading countries (Heinsbroek and Kamstra 1995). Blanc (1997) showed that nearly 100 pathogens have been introduced into European water bodies since the introduction of aquaculture. Worldwide many diseases are known in both wild and cultured eel. Parasites, for example trematodes, Anguillicola crassus(nematode), and Myxidium giardi (myxosporean)occur naturally in wild eel populations, mostly in low numbers, without causing mortality (Køie 1988; Van Banning and Haenen 1990; Borgsteede et al. 1999). However, under culture conditions, with eels kept in high densities, they may be harmful. Eel pathogenic bacteria like Vibrio vulnificus, Vibrio anguillarum, Pseudomonas anguillisepticaand Edwardsiella tardamay also cause disease, especially when a stress factor is involved or when the eel is injured (Veenstra et al. 1993; Austin and Austin 1999; Haenen and Davidse 2001). As far as we know, the clinical signs are often more severe under culture conditions compared to in the wild.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.