Active and Passive Immunization of Certain Salmonid Fishes Against Aeromonas Salmonicida

Passive protection against Aeromonas salmonicida, the causative agent of furunculosis in fishes, was produced in juvenile coho salmon by administration of serum from adult rainbow trout containing antibodies actively produced by intra-abdominal vaccination.The levels of natural (or residual) agglutinins against A. salmonicida and those produced by vaccination are shown for two age-groups of rainbow trout.Oral vaccine administered in the diet of juvenile coho salmon failed to produce either agglutinating antibody or protection against experimental infection under the conditions employed.