A field study on intraperitoneal vaccination of Atlantic salmon (Salmo salarL.) against furunculosis

Protection and side-effects after intraperitoneal (i.p.) vaccination of Atlantic salmon (Salmo salarL.) against furunculosis were studied in a field trial. Pre-smolts held in fresh water and salmon growers held in sea water were immunised with different monovalent furunculosis vaccines. In both cohorts, disease attack rates and cumulative mortalities after field challenge were significantly lower in populations given a mineral oil adjuvanted vaccine compared to other vaccination groups included in the study, demonstrating that tentatively pathogen-free as well as furunculosis carrier populations can be protected by vaccination. Injection-site lesions of significance for the commercial quality of harvested salmon were observed, being more severe in fish given the mineral oil adjuvanted vaccine. In spite of the side-effects, i.p. vaccination with mineral oil adjuvanted vaccine is strongly recommended for effective furunculosis prophylaxis in commercial farming of Atlantic salmon.