The efficacy of amantadine and other antiviral compounds against two salmonid viruses in vitro.

Various compounds, with known clinical efficacy against human viruses, were evaluated for their ability to inhibit the growth of infectious hematopoietic necrosis virus (IHNV, a rhabdovirus), and infectious pancreatic necrosis virus (IPNV, a birnavirus), in rainbow trout cell cultures. Amantadine inhibited the plaque forming ability of IHNV, at concentrations which did not affect cell growth or morphology, although it was not active against IPNV. Metisazone and bis-benzimidazole were also effective against IHNV; but they were slightly cytotoxic. Ribavirin, as expected, was active against IPNV, but was also equally effective against IHNV, although it was cytotoxic. Several other compounds were also tested but they were not inhibitory to either virus. The attraction of amantadine is the fact that relatively easy administration should be feasible.