Development of injection and cohabitation challenge models for atypical Aeromonas salmonicida 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 2 trials where ballan wrasse (Labrus bergylta) were infected by 2 strains of the bacterium atypical Aeromonas salmonicida. Both strains induced mortality levels suitable for vaccine testing when given by intra peritoneal (i.p.) injection, but only one strain induced this level of mortality by cohabitation. Atypical A. salmonicida was reisolated from dead fish and found in tissue lesions by immunohistochemistry. We conclude that the described models are promising for testing of vaccines against atypical A. salmonicida inballan wrasse.