Infectious hematopoietic necrosis (IHN) is a serious viral disease of salmonid fish. This disease was first reported at fish hatcheries in Oregon and Washington in the 1950s. The causative virus now exists in many wild and farmed salmonid stocks in the Pacific Northwest region of North America. It has also spread to Europe and some Asian countries. Clinical infections are most common in young fish, particularly fry and juveniles. Infectious hematopoietic necrosis can have a major economic impact on farms that rear young rainbow trout or salmon; the cumulative mortality rates on these farms can reach 90-95%. Occasional epizootics have also been reported in wild salmon.
Iowa State University
Iowa State University Center for Food Security and Public Health, "Infectious Hematopoietic Necrosis" (2007). Center for Food Security and Public Health Technical Factsheets. 74.