Development of injection and cohabitation challenge models for Vibrio anguilarum serotype 01 in farmed ballan wrasse (Labrus bergylta)

The FHF funded project 900818 – Cleaner fish: Causes of loss and preventive measures aims to facilitate development of vaccines for cleaner fish by developing infection (challenge) models for some important bacterial pathogens.

This report describes 4 trials involving intraperitoneal, bath and cohabitant based exposure in ballan wrasse (Labrus bergylta). Two strains of Vibrio anguillarum serotype O1, one originally isolated from farmed Atlantic salmon and one from captive, wild-caught ballan wrasse were utilised. Only one strain (the Atlantic salmon isolate) induced mortality levels suitable for vaccine testing when given by intraperitoneal (i.p.) injection. Bath or cohabitation exposure did not lead to satisfactory levels of mortality for use in vaccine efficacy testing. Vibrio anguillarum was re-isolated from all (exposed) dead fish examined. We conclude that the intraperitoneal model is promising for testing of vaccines against Vibrio anguillarum in ballan wrasse, although pre-challenges will be necessary to establish virulence levels in different combinations of bacterial strain and fish stocks.

Duncan Colquhoun

Senior Forsker/ adjunct Professor
Mobilnr: +47 91179686
E-post: duncan.colquhoun@vetinst.no

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