Abstract: The aim of this research was investigation on infection in reproducing and breeding centers of Rainbow trout in Iran by infectious Necrosis haematpoietic virus. We collected 100 samples from 100 reproducing and breeding centers of Rainbow trout of the Iran that showed clinical sings or were healthy in appearance in larva stage and finger link. Samples were tested by immunohistochemistry and Nested-PCR methods. By immunohistochemistry methods 35 samples and by PCR 43 samples were positive. There were 38 samples with clinical symptoms of Infectious Haematpoietic Necrosis. The results of this study show the dispersion of Infectious hematopoietic necrosis virus in some reproducing and breeding centers of Rainbow trout in the Iran. Also the result of two methods had acceptable overlapping.
