A challenge model for pancreas disease in A tlantic salmon, S almo salar L . fry, was developed comparing two salmonid alphavirus ( SAV ) subtypes: SAV 1 and SAV 5. Viral doses of 3 × 10 5 TCID 50 mL −1 for SAV 1 and 3 × 10 4 for SAV 5 were tested in triplicate tanks, each containing 450 salmon fry. Cumulative mortalities of 1.2% were recorded. Titres of virus recovered from the mortalities ranged from 10 2 to 10 7 TCID 50 mL...