Infectious Salmon Anemia

Agricultural Disaster Preparedness and Recovery June 06, 2012 Print Friendly and PDF

Infectious Salmon Anemia is a highly contagious viral disease of Atlantic salmon that caused by the causative agent ISA virus. This single stranded RNA, enveloped orthomyxovirus causes internal bleeding and death. The disease is spread through fish-to-fish contact and contaminated water. The mortality rate may be high, causing significant economic loss.


Endemic Areas

Where Atlantic salmon are farmed in the United States, Canada and parts of Europe.


Clinical Signs

  • Lethargy
  • Bulging eyes
  • Distended abdomen
  • Pale gills
  • Skin hemorrhages
  • Darkening of the skin
  • Thin blood



There is no specific treatment for Infectious Salmon Anemia. Any fish suspected of having Infectious Salmon Anemia should be reported to the State Veterinarians or USDA Area Veterinarian in Charge immediately.



The spread of Infectious Salmon Anemia may be prevented by adopting sound biosecurity practices.


Public Health

Infectious Salmon Anemia is not a public health threat.



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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.