Family: Caliciviridae
Genus: Lagovirus
Distinguishing features
The strains in this genus form a distinct clade within the family Caliciviridae (Figure 4. Caliciviridae).
Virion
See discussion under family description.
Genome organization and replication
See discussion under family description. The genome is organized into two ORFs. ORF1 encodes the non-structural polyprotein, with the major structural protein gene (VP1) in frame with the non-structural polyprotein coding sequence. The translated region of ORF2 overlaps ORF1 by 5 nt in the rabbit hemorrhagic disease virus (RHDV) genome and 5 nt in the European brown hare syndrome virus (EBHSV) genomes. ORF2 encodes a small protein (VP2) of unknown function that has been identified as a minor structural component in the RHDV virion.
Biology
Lagoviruses have characteristically been associated with infection in rabbits and hares (lagomorphs), and can cause epidemics with high mortality in these animals. There is no productive continuous cell culture system for lagoviruses but recently infection of a rabbit kidney cell line (RK-13) with a mutant RHDV has been reported (Zhu et al., 2017).
Species demarcation criteria
Lagoviruses are currently classified into two species, Rabbit hemorrhagic disease virus and European brown hare syndrome virus. However, based on phylogenetic relationships, a single species of lagovirus, tentatively called “Lagovirus europaeus”, has been proposed (Le Pendu et al., 2017). This proposed species is divided into two genogroups that correspond to RHDV- and EBHSV-related viruses (Wirblich et al., 1994). Genogroups were subdivided into genotypes, which could be further subdivided into phylogenetically well-supported variants (Le Pendu et al., 2017).