Heart and skeletal muscle inflammation (HSMI) is an emerging disease of marine-farmed Atlantic salmon (Salmo salar L), first recognized in 1999 in Norway, and later also reported in Scotland, Chile and Canada.
HSMI is transmissible and, the weight of recent evidence supports the contention that the cause is an Orthoreovirus with the proposed name Piscine orthoreovirus (PRV).
This virus has not yet been cultured in vitro, thereby hampering traditional experimental reproduction of the disease.
As the name of the disease suggests, major changes in HSMI involve the heart and red skeletal muscle where extensive inflammation and multifocal degeneration of myocytes are evident.
Liver is also frequently involved, a consequence of hypoxia due to failing cardiovascular output.
Histological findings include epicarditis, myocarditis and myositis (red muscle). In the liver, zonal coagulative hepatic necrosis can be observed.
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- Yousaf, M. N., & Powell, M. D. (2012). The effects of heart and skeletal muscle inflammation and cardiomyopathy syndrome on creatine kinase and lactate dehydrogenase levels in Atlantic salmon (Salmo salar L.). The Scientific World Journal, 2012.