KHV gets new formal name in study


Editor's Picks

Koi Herpes Virus, or KHV, now has a new formal name after scientists published the details on its taxonomy following a recent study.

The international team of virologists, which included scientists from Japan, the USA and the UK, concluded that the virus is a member of the family Herpesviridae and should now go under the formal name of Cyprinid herpesvirus 3 (or CyHV-3 for short).

In order to assess how the KHV virus was related to existing fish viruses the team of experts sequenced four complete genes found in the virus's genome. Their findings have just been published in the Journal of General Virology.

It was assumed that the virus was closely related to the carp pox virus, formally known as Cyprinid herpesvirus-1 (CyHV-1) and to the haematopoietic necrosis herpesvirus which affects goldfish (known as Cyprinid herpesvirus-2 or CyHV-2), but it was almost postulated that KHV could be a relative of the Channel catfish virus IcHV-1, too.

The study showed that the KHV virus was closely related to both CyHV-1 and CyHV-2, and that all three of the cyprinid viruses are related, albeit distantly, to the Channel catfish virus, also known as Ictalurid herpesvirus-1.

By analysing 12 different samples of the virus collected from four widely separated outbreaks around the world, the team were able to find a match with identical sequences occurring in part of the DNA polymerase gene.

The study concludes: "These findings, with previously published morphological and biological data, indicate that KHV should join the group of lower-vertebrate viruses in the family Herpesviridae, under the formal designation Cyprinid herpesvirus 3 (CyHV-3)."

KHV has been responsible for a number of mass mortalities of fish around the world, most notably including Israel, Japan and South Africa, but the UK has also seen a number of cases reported.

For more details see the paper: Waltzek TB, Kelley GO, Stone DM, Way K, Hanson L, Fukuda H, Hirono I, Aoki T, Davison AJ, Hedrick RP (2005) - Koi herpesvirus represents a third cyprinid herpesvirus (CyHV-3) in the family Herpesviridae. Journal of General Virology, 2005 Jun ; 86(Pt 6): 1659-67.