Sequence variation of the glycoprotein gene identifies three distinct lineages within field isolates of viral haemorrhagic septicaemia virus, a fish rhabdovirus.

Abstract

To evaluate the genetic diversity of viral haemorrhagic septicaemia virus (VHSV), the sequence of the glycoprotein genes (G) of 11 North American and European isolates were determined. Comparison with the G protein of representative members of the family Rhabdoviridae suggested that VHSV was a different virus species from infectious haemorrhagic necrosis virus (IHNV) and Hirame rhabdovirus (HIRRV). At a higher taxonomic level, VHSV, IHNV and HIRRV formed a group which was genetically closest to the genus Lyssavirus. Compared with each other, the G genes of VHSV displayed a dissimilar overall genetic diversity which correlated with differences in geographical origin. The multiple sequence alignment of the complete G protein, showed that the divergent positions were not uniformly distributed along the sequence. A central region (amino acid position 245-300) accumulated

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

“…We found that all French continental VHSV isolates belong to the same lineage, described as genotype I (Benmansour et al 1997) or genotype III (Stone et al 1997), grouping isolates from continental Europe. It is suggested that this group be designated 'Genotype I' since it contains the most ancient isolates.As already suggested (Benmansour et al 1997), subgroups could be distinguished within genotype I. The majority of the studied isolates are grouped in subgroups Ia or Ib.…”

“…For instance, a set of 13 isolates obtained between 1990 and 1996 had the same V2 sequence as isolate 3771 (sub-group Ib, Fig. 2).Only 1 isolate (L59X) was affiliated to genotype II, containing isolates from marine fish species such as Atlantic cod Gadus morhua (Stone et al 1997) or turbot Scophthalmus maximus (Benmansour et al 1997, Stone et al 1997. Interestingly, L59X was isolated from wild elvers Anguilla anguilla caught in the river Loire estuary (Castric et al 1992) showing that this migrating fish species can also be naturally infected by a VHSV strain of genotype II.…”

“…More recently, novel genetic studies were conducted within genotype II . They were based upon the analysis of the nucleoprotein gene of 39 VHSV isolates from European marine origin belonging to genotype II and resulted in a sub-grouping of the virus strains according to their respective geographical area of origin.The primary genetic grouping of VHSV was established using only 4 French virus isolates (Benmansour et al 1997). It thus appeared relevant and necessary to extend the genetic studies to representatives of VHSV isolated from French field cases from 1971 to 1999.…”

“…However, detailed comparison of the amino-acid sequences of non-neutralised isolates showed that they were mutated in positions 257, 258 or 259, which is in agreement with the localisation of the MAb 168m4 epitope (Béarzotti et al 1995). Although some of the mutations affecting the reactivity of Mab 168m4 were described previously (Benmansour et al 1997), a new mutation was characterised (T258-A) thus further extending the mutational analysis of the 168m4 epitope.Often, a good correlation was noticed between the geographical origin of the isolates and their position on the phylogenetic tree. However, there was no obvious link between the fish-host species and the VHSV genogroup, as previously reported (Benmansour et al 1997).…”

“…Although some of the mutations affecting the reactivity of Mab 168m4 were described previously (Benmansour et al 1997), a new mutation was characterised (T258-A) thus further extending the mutational analysis of the 168m4 epitope.…”