No, the Koï Herpes Virus (KHV) does not enter the fish it infects through their gills. Alain Vanderplasschen and his colleagues have done irreparable damage to this received idea: the virus penetrates its victims, koï (ornamental) and common carp, through the skin. A discovery which has made the front page of The Journal of Virology.

Life is not good for a virus at the Laboratory of Immunology and Vaccinology, directed by Professor Alain Vanderplasschen. The Koï Herpes Virus (KHV) has already found this out to its cost and it seems that its woes are not yet over. This herpes virus, which affects both koï and common carp, crossed the path of the research carried out by Professor Vanderplasschen’s team a few years ago and has since been subjected to tough ‘interrogations’. The revelations obtained by the researchers are far from being the most insignificant because, in the Spring of 2008, they made the cover of the Journal of Virology; it concerned the cloning of the KHV genome in the form of an infectious artificial bacterial chromosome and its use in the production of a vaccine against this carp executioner (See the article A vaccine against the killer of carp). Today Alain Vanderplasschen, Bérénice Costes, a postdoctoral student at the Laboratory of Immunology and Vaccinology, and their colleagues have been at it once again by making the cover of the April 2009 edition of the Journal of Virology.

The end of a scientific dogma

This time around the researchers have put an end to a scientific dogma concerning the entry portal used by the herpes virus to infect koï carp, and perhaps one which is used by numerous viruses which infect fish. Starting from a simple suggestion in a scientific publication, the idea that KHV infects carp through the gills became, little by little, something that was commonly accepted by the scientific community, without any study having ever confirmed the hypothesis. ‘There was a real cascade effect,’ explains Alain Vanderplasschen. ‘An initial study had suggested that the entry portal for this virus was the carps’ gills, then another study transformed this hypothesis into an affirmation, and over the course of time this suggestion saw itself transformed into a so-called scientifically established fact, when it was no such thing.’ KHV thus fooled the world for many years, until it fell into the hands of the Liège researchers and revealed the path it took to slip into the organisms it infected. ‘It was in wanting to check the effectiveness of the vaccine we had developed a few years ago that we realised that the virus’ entry point was not the gills but instead the fishes skin,’ points out Alain Vanderplasschen.