Infectious Salmon Anemia(ISA)

What is Infectious Salmon Anemia?

Infectious Salmon Anemia (ISA) is a severe, notifiable, infectious viral disease caused by the infectious salmon anemia virus (ISAV). The condition causes severe anemia, poor health and high mortality.

Two major epidemics in the Faroe Islands (2003) and Chile (2008), devastated the salmon farming industry in these regions and reduced the production to only a fraction of its potentials. No successful treatment is currently available, and vaccination has not been successful in offering complete protection from the disease. The disease can cause severe losses to infected farms as all fish have to be culled, and zone restrictions enforced to prevent the spread of the virus.

As of 2016, Benchmark Genetics offers ISA robust fish using GS. Prior to the implementation of GS, the company has been selecting for ISA resistance based on family levels. In 2018, Benchmark Genetics added additional measures when selecting for ISA robust fish. This was to ensure that the more tolerant animals have higher resistance by carrying low to undetectable levels of the virus while at the same time retaining higher growth and lower rates of shedding pathogen (Figure 1).

Figure 1: Scatterplot showing that the fish with lower levels of ISAV pathogen also tend to shed less virus in the environment and as a result, are less likely to infect other animals.

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