[Research in bacterial diseases of salmonid fish.]

The main bacterial diseases in Icelandic aquaculture are furunculosis, bacterial kidney disease (BKD) and vibriosis. Atypical furunculosis caused by A. salmonicida ssp. achromogenes is an endemic disease causing high mortality in salmonids yearly. Classical furunculosis caused by A. salmonicida ssp. salmonicida was first diagnosed in Iceland in 1995. At Keldur the research focus has been on studying the virulence mechanism of A. salmonicida ssp. achromogenes, the immune response evoked in the fish, and vaccine development. Farmed salmonids have been vaccinated with good results against atypical furunculosis with an autogenous bacterin since 1992. Recent results indicate some crossprotection of the autogenous bacterin of A. salmonicida ssp. achromogenes against classical furunculosis. BKD caused by Renibacterium salmoninarum is another endemic disease in Iceland. An intensive program for brood fish screening has been developed. Fertilized eggs from all infected parents are destroyed which has proved to be highly successful for controlling BKD. ELIS A and PCR methods for rapid diagnosis have been developed. BKD in wild stocks of trout is presently being studied. A variety of Vibrio spp. strains have been isolated from skin lesions of infected salmon. Antibiotics and autogeneous vaccines have been used for disease control with good results. Enteric redmouth disease caused by Yersinia ruckeri has once been diagnosed from farmed salmon in 1990.