Infectious salmon anemia (ISA) has been confirmed at a site operated by Norwegian salmon producer Refsnes Laks in Afjord municipality in central Norway, according to the Norwegian Food Safety Authority.
The Norwegian Food Safety Authority was alerted to a potential outbreak on 25 August when the facility’s veterinary service suspected the presence of ISA.
The Veterinary Institute officially diagnosed the disease on 6 September. This diagnosis followed tests conducted on samples taken from the facility on 30 August.
Upon further inspection of the affected fish and assessment of the signs of the disease, the Norwegian Food Safety Authority verified the ISA diagnosis on 7 September. The confirmation was further backed by analysis results from the Veterinary Institute.
In a bid to curb the spread of the disease, stringent restrictions have been put in place at the facility. This includes a stringent ban on transferring fish without obtaining specific permission.
ISA is a viral disease that can result in serious economic losses in the salmon farming industry.
The virus can cause severe anemia in salmon due to the bursting of red blood cells. Clinical signs in infected fish can include lethargy, swimming close to the water surface or the sides of cages, pale gills, swollen abdomen, and sometimes, internal and external hemorrhaging.
The disease is a concern for aquaculture operations because of its potential to cause high mortality rates and its impact on fish health and farm productivity.