SYSTEMIC, GRANULOMATOUS-HEXAMITOSIS OF FARMED ATLANTIC SALMON - INTERACTION WITH WILD FISH

The occurrence and pathology of a new manifestation of hexamitosis in Atlantic salmon is described. Since 1989, a hexamitid protozoan has caused severe granulomatous disease in adult Atlantic salmon raised in seawater cages in northern Norway. Most of the affected fish farms have a common link to one particular hatchery, while the fish in one of the farms have acquired the infection via infected processing water from a slaughter facility nearby, where Hexamita-infected fish from other farms have been slaughtered and processed.