DAO prepress abstract  -  DOI: https://doi.org/10.3354/dao03177

Molecular investigations of outbreaks of Perch perhabdovirus infections in pike-perch

Laurent Bigarré, Georges Plassiart, Claire de Boisséson, Laurane Pallandre, Françoise Pozet, Yannick Ledoré, Pascal Fontaine, François Lieffrig

*Email: laurent.bigarre@anses.fr

ABSTRACT: In 2016, a total of 5 massive mortality episodes each affecting hundreds of thousands of pike-perch larvae occurred in 2 sites in 2 Western European countries. For each episode, perhabdoviruses related to the perch rhabdovirus (PRV) were detected in samples, using either PCR or cell culture combined with PCR. The sequences of the glycoprotein (g), phosphoprotein (p) and nucleoprotein (n) genes of these samples demonstrated that 2 different genotypes were present at 1 site, each associated with 1 of the 3 episodes. At the other site, a single genotype was associated with the 2 outbreaks. Furthermore, this genotype was strictly identical to 1 genotype involved in the outbreaks of the first site, strongly suggesting a common origin for these 2 viruses. The common origin was confirmed a posteriori because some larvae introduced to both sites had exactly the same geographic origin, i.e. in Eastern Europe. Taken together, the molecular and epidemiological data suggest that both horizontal and vertical transmission of 2 distinct strains of perhabdoviruses were involved in the various outbreaks affecting pike-perch.