Genetic variation and phylogenetic analysis of rabbit haemorrhagic disease virus (RHDV) strains.

Rabbit haemorrhagic disease virus (RHDV) belongs to the family Caliciviridae and is the etiological agent of the haemorrhagic disease, also known as rabbit plague. Its genome is a linear single-stranded (ss) RNA of 7437 nucleotides and the capsid is built from a single structural protein VP60. In connection with the discovery of new RHDV strains, there is a constant need to investigate the genetic variation of this virus and perform phylogenetic analyses which may show the evolutionary relationships among the RHDV strains. Studies on the divergence of RHDV have shown that it is genetically quite stable, although recent observations indicate that some new RHDV strains, significantly different from the original RHDV subtype and the new RHDVa subtype, are appearing. These latest findings suggest that a new group of RHDV strains has evolved. The present review summarizes the current knowledge on the genetic variation and the latest achievements in phylogenetic analyses of RHDV strains isolated in various countries.