ACQUIRED PROTECTION IN ATLANTIC SALMON SALMO-SALAR PARR AND POST-SMOLTS AGAINST PANCREAS DISEASE

Experimental infection of Atlantic salmon Salmo salar parr and post-sm olts with pancreas disease infective kidney homogenate induced a highl y significant protection against the disease following exposure to cha llenge infections at either 3, 4, 7 or 9 mo after the initial infectio n. Protection was maintained in fish infected as parr and exposed to a challenge infection following smolting and sea water transfer. A carr ier status was not demonstrated in immune fish since homogenates of ki dneys taken 1 and 2 wk post-challenge were not infective, unlike homog enates of kidneys from non-immune fish.