Anti-viral activity in four species of salmonids following exposure to poly inosinic:cytidylic acid

Pink, chum, and sockeye salmon and steelhead trout produced an anti-viral interferon-like response following intraperitoneal injections of the dsRNA synthetic polymer poly inosinic:cytidylic acid (Poly 1:C). In all cases, maximum anti-viral titers were reached between 3 and 7 d post-injection with Poly 1:C. Following mjection with Poly I:C, chum and sockeye salmon were challenged with Infectious Hematopoietic Necros~s Virus (IHNV) and chum salmon with Erythrocytic Necrosis Virus (ENV). Fish pretreated with Poly 1:C and then challenged with IHNV developed an anti-viral response which resulted in a decreased IHNV titer, lower cumulative mortalities, and a delay in virus replication when compared to untreated fish. The ENV could not be transmitted to chum salmon that had been pretreated with Poly I:C, but was successfully transmitted to untreated fish.