although one isolate from Israel had two additional polypeptides (Gilad et al., 2003). Aoki et al., 2007 compared the complete genome sequences of three KHV strains isolated from Japan, Israel and the United States of America (USA). The genomes were found to be highly similar to each other at the sequence level (>99%), with the Israel and USA strains more closely related to each other than either is to the Japan strain. The three isolates were interpreted as having arisen as two lineages (J and U/I) from a wild-type parent. However, further studies in Japan suggest that the lineages were independently brought to those regions and caused KHV epidemics (Ilouze et al., 2011). A more recent study in France has identified a third intermediate between the J and U/I lineages and suggested that the three lineages of CyHV-3 have been introduced into Europe since 2001 via imported koi carp (Bigarré et al., 2009). More recently, a further intermediate lineage has been discovered that may have emerged in Indonesia (Sunarto et al., 2011).