Comparison of atypical furunculosis vaccines in spotted wolffish (Anarhicas minor O.) and Atlantic halibut (Hippoglossus hippoglossus L.)

Atypical furunculosis caused by atypical Aeromonas salmonicida is a problem in farming of Atlantic halibut (Hippoglossus hippoglossus) and spotted wolffish (Anarhicas minor) in Norway, and vaccines for marine fish species are not available. Susceptibility to atypical A. salmonicida infection and efficacy of furunculosis vaccines in various fish species indicate that the host responses differ. Here, spotted wolffish was shown to be highly susceptible to intraperitoneal challenge with atypical A. salmonicida compared to halibut, and the two species appeared to respond differently to identical vaccines. Grouping of the atypical A. salmonicida isolates used as vaccines was based on a variable region in the surface A-layer protein, but no clear correlation between vaccine efficacy and A-protein group was found.