Vaccine development for atypical furunculosis in spotted wolffish Anarhichas minor O.: Comparison of efficacy of vaccines containing different strains of atypical Aeromonas salmonicida

The atypical strains of Aeromonas salmonicida isolated from spotted wolffish Anarhichas minor O., show biochemical and molecular variations, but it is not known whether these variations affect bacterial virulence or antigenicity of possible protective antigens. In this study, protection against atypical furunculosis was compared in spotted wolffish vaccinated with monovalent or multivalent vaccines containing different strains of atypical A. salmonicida. In addition, these vaccines were compared to a vaccine containing an atypical A. salmonicida isolate from Atlantic halibut, Hippoglossus hippoglossus L. Vaccinated fish were challenged with three different A. salmonicida strains from spotted wolffish. Significant protection was obtained against both homologous and heterologous challenge. The best protection, regardless of strain used for challenge, was obtained with the multivalent vaccine composed of three different bacterial strains. Also, some of the monovalent vaccines resulted in significant protection, but they seemed to differ in protection against one particular strain of atypical A. salmonicida. In addition, significant cross-protection was observed with a vaccine containing a strain isolated from halibut, while a commercial salmon vaccine against furunculosis based on A. salmonicida subsp. salmonicida, failed to protect against an atypical strain from spotted wolffish. [Copyright &y& Elsevier]