Comparative susceptibility of Arctic char ( Salvelinus alpinus), rainbow trout ( Oncorhynchus mykiss) and brown trout ( Salmo trutta) to the Scottish isolate of infectious salmon anaemia virus

Experimental infection studies were conducted to determine the susceptibility of pathogen-free Arctic char ( Salvelinus alpinus), rainbow trout ( Oncorhynchus mykiss) and brown trout ( Salmo trutta) to the Scottish isolate of infectious salmon anaemia virus (ISAV). No mortalities were recorded in any of these species following infection by intra-peritoneal injection, although transient drops in haematocrit were recorded. Sub-samples of all species were screened for the presence of ISAV using RT-PCR and virus culture. While virus was unculturable from all samples at 40 days post-infection, virus was detectable using RT-PCR in all species. Clearance of virus following experimental infection did however progress at a greater rate in Arctic char than in rainbow trout and brown trout. The potential for this species to act as a long-term carrier of ISAV, and thus exert a role in the epizootiology of ISAV in Scotland may be less than in other salmonid species. The increasing commercial production of Arctic char render these findings significant to the future management of ISAV in Scotland.