Heart and skeletal muscle inflammation (HSMI) of farmed Atlantic salmon (Salmo salar L.) and the associated Piscine reovirus (PRV)

Heart and skeletal muscle inflammation (HSMI) has only been recorded in farmed Atlantic salmon (Salmo salar L.) after sea transfer and in freshwater hatcheries that use seawater in their production (Johansen et al., 2008).Piscine reovirus (PRV) seems to be ubiquitous in Norwegian salmon farms, but viral loads and tissue distribution support a causal relationship between the virus and disease (Løvoll et al., 2012). PRV has also been found in wild Atlantic salmon and in anadromous brown trout (sea-trout; Salmo trutta L.) without clinical signs (Garseth et al., 2012). PCR-screening of marine fish caught along the Norwegian coast revealed PRV in great silver smelt (Argentina silus Ascanius), capelin (Mallotus villosus Muller), Atlantic horse mackerel (Trachurus trachurus L.), and Atlantic herring (Clupea harengus L.; Wiik-Nielsen et al.,2012). The significance of these findings is unknown.