TWENTY-FIFTH ANNUAL EASTERN FISH HEALTH WORKSHOP MARCH 10-13, 2000    Development Of A Vaccine Against Infectious Salmon Anaemia Virus       Laura L. Brown1, Sandra A. Sperker1, Sharon Clouthier2, Julian C.Thornton2, W. Kelleher3, and D. Bouchard3   1National Research Council Canada, Institute for Marine Biosciences, 1411 Oxford Street, Halifax, NS, B3H 3Z1, Canada; 2Microtek/Bayotek International Limited, 6761 Kirkpatrick Crescent, Saanichton, BC, V8M 1Z8, Canada: 3Micro Technologies Inc., 41 Main Street, Richmond ME 04357, U.S.A.     Development of a vaccine against Infectious Salmon Anaemia Virus (ISAV) would provide salmon farmers with a method for protecting their fish stocks against this devastating pathogen.  The ISA virus used to develop the vaccine for this study was isolated from a moribund ISA-infected farmed Atlantic salmon from New Brunswick.  The virus was then cultured, inactivated and formulated as an oil-based vaccine with a titre of 1x107 TCID50/ml.  The formulation also contained antigens for Aeromonas salmonicida, Vibrio anguillarum serotypes 01 and 02, and V. salmonicida.  Atlantic salmon in duplicate tanks were each given 200 µl intra-peritoneal (i.p.) injections of the vaccine formulation.  Control fish were injected with 200 µl of the vaccine formulation without the inactivated virus.  The fish were held in freshwater at 4-8ºC.  Five weeks after vaccination, each fish was challenged by i.p. injection with 5 x 103.5 TCID50 live ISAV.  Mortalities were monitored daily until 99 days post-infection.  All mortalities were confirmed to be due to ISAV by indirect fluorescent antibody test on tissue imprints, virus culture from tissue, and RT-PCR.  The vaccinates had a relative percent survival (RPS) of 54% compared to controls (p<0.01).  In addition, neutralizing activity in convalescent  sera  was demonstrated by incubating ISAV with sera from fish that had survived, and then inoculating the ISAV onto Salmon Head Kidney (SHK-1) cells in tissue culture.  Sera from vaccinated and non-vaccinated fish neutralized the virus when diluted 1/20 whereas sera from vaccinated fish maintained neutralizing activity when diluted further to 1/40.  The data from this study indicate that the vaccine formulation provides significant protection against ISA.     Return to 25th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page