Phylogenetic analysis of viral haemorrhagic septicaemia virus (VHSV) isolates from France (1971-1999)

Abstract

The nucleotide sequences of a specific region of the glycoprotein gene were compared among 63 strains of viral haemorrhagic septicaemia virus (VHSV) isolated from fish in France between 1971 and 1999. The analysis was performed on a region corresponding to amino acids 238 to 331 of the glycoprotein gene, also designated the V2 region and previously shown to accumulate most of the mutations. The sequences of many VHSV isolates were found to be identical or very conserved. An isolate, designated L59X, obtained from elver in the Loire estuary, depicted a higher degree of divergence compared to the other French isolates. The deduced amino-acid sequences were analysed together with the results of neutralisation tests performed using monoclonal antibody 168m4 specific to serotype 1. Non-neutralised VHSV strains had mutations in the region corresponding to the previously described 168m4 epitope. Phylogenetic analysis showed that all the VHSV isolates studied, except L59X, belong to genotype I, previously described as containing VHSV strains isolated from continental Europe. Most of the VHSV isolates studied were found to be genetically related to one of the previously described VHSV strains representative of the major serotypes. Isolate L59X, which was the only French marine strain studied, was found to belong to genotype II, previously shown to encompass the VHSV strains isolated from the British Isles coastal waters. Overall there was a good correlation between the geographical origin of the studied isolates and their genetic characteristics. KEY WORDS: Viral haemorragic septicaemia virus · Novirhabdoviruses · Phylogeny · Glycoprotein Resale or republication not permitted without written consent of the publisherDis Aquat Org 52: [29][30][31][32][33][34][35][36][37] 2002 cases in sea water-reared rainbow trout had been reported (Castric & de Kinkelin 1980, Horlyck et al. 1984. However, in both these outbreaks, infected fish originated from inland VHS-infected areas. Similarly, VHSV of freshwater origin (isolate 07-71) has also been experimentally demonstrated to infect 2 marine fish species, sea bass Dicentrarchus labrax and turbot Scophthalmus maximus, following water-borne infection (Castric & de Kinkelin 1984).The accepted epidemiology of VHS changed in 1987, after it was established (Jørgensen & Olesen 1987) that a rhabdovirus isolated from cod Gadus morhua in the Baltic Sea, 8 yr before (Jensen et al. 1979), was indistinguishable from VHSV. Since then, VHSV has been recovered from several fish species caught in Pacific North Western coastal areas of the United States of America, and the North Atlantic and related sea areas (Castric et al. 1992, Ross et al. 1994, Meyers & Winton 1995, Mortensen et al. 1999.Studies of the sequence variations of the glycoprotein (G) gene of VHSV made it possible to delineate 3 different lineages designated genotypes I, II and III for continental European virus, turbot virus (North Atlantic) and Pacific virus respectively (Benmansour et al. 1997). Another study, complete...

Genotyping of marine viral haemorrhagic septicaemia virus isolated from the Flemish Cap by nucleotide sequence analysis and restriction fragment length polymorphism patterns

“…To date, Genotype 3 included marine isolates from the North Sea/coastal waters of the British Isles together with 2 isolates recovered from outbreaks of VHS in Irish and Scottish turbot farms , Einer-Jensen et al 2004 as well as 1 isolate originating from eel caught in northern France (Thiéry et al 2002, Einer-Jensen et al 2004. Results obtained in the present study based on sequencing of a 335 nt region of the N gene indicated that the Flemish Cap isolates must also be grouped in Genotype 3, extending the geographic area in which this genotype is found to the eastern rim of the North Atlantic Ocean.…”

“…It has a genome consisting of approximately 11 200 nucleotides and containing 6 genes (3' N-P-M-G-NV-L 5'). Initial nucleotide sequence analyses based on different regions of the glycoprotein (G) gene demonstrated the existence of 3 geographically distinct genotypes (Benmansour et al 1997, Stone et al 1997, Thiéry et al 2002. Sequence analysis of the nucleoprotein (N) gene has supported the existence of these 3 established genetic groups and, in addition, identified a new genotype (Snow et al 2004).…”

Comparative susceptibility of turbot Scophthalmus maximus to different genotypes of viral haemorrhagic septicaemia virus

“…Resale or republication not permitted without written consent of the publisher (Genotype Ia) along with a group of naturally occurring isolates originating from wild marine fish species residing predominantly within the Baltic Sea (Genotype Ib) (Benmansour et al 1997, Nishizawa et al 2002, Thiery et al 2002, Einer-Jensen et al 2004. Evidence suggests that an ancestor of marine Genotype Ib was the original source of introduction of VHSV into the rainbow trout industry (for review see Snow et al 2004).…”

Genetically similar VHSV isolates are differentially virulent in olive flounder Paralichthys olivaceus

“…These genotypes reflect a largely geographic rather than a species-specific distribution. Genotype I includes a wide range of viruses originating from freshwater rainbow trout farms in continental Europe (Thiéry et al 2002, Einer-Jensen et al 2004) and a large number of isolates originating from marine species in the Baltic Sea, Skagerrak, Kattegat, and English Channel (Dixon et al 1997, Einer-Jensen et al 2004, Snow et al 2004. Genotype II includes a limited number of VHSV isolates recovered from the Baltic Sea (Snow et al 2004).…”