Replication of the infectious salmon anaemia virus (ISAV) in rainbow trout, Oncorhynchus mykiss (Walbaum)

• Published in: Journal of Fish Diseases
• Main Authors: Nylund, A., Kvenseth, A.M., Krossøy, B., Hodneland, K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1997
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1046/j.1365-2761.1997.00300.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2761.1997.00300.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2761.1997.00300.x

Infectious salmon anaemia (ISA) is a viral disease of farmed Atlantic salmon, Salmo salar L., in Norway. However, in laboratory experiments, the virus has also been found to propagate in trout, Salmo trutta L., where it is a persistent infection. It is crucial for the management of ISA in Norway, and for the prevention of spread to fish in other countries, that possible carriers of the virus are found. Another possible salmonid reservoir species is the rainbow trout, Oncorhynchus mykiss (Walbaum). After experimental infection, the ISA virus was found to be present in O. mykiss as late 28 days after infection, with a peak around day 20. The infection resulted in a significant drop in the haematocrit and haemorrhages on the liver in some specimens. The ISA virus was seen budding from endothelial cells lining blood vessels in the heart ventricle of challenged rainbow trout. It is concluded that the ISA virus is able to propagate in O. mykiss and that this species may function as a reservoir when cultured in areas where the virus is found. The virus does not seem to cause any significant mortalities of infected rainbow trout.