Production of salmonid amoebic gill disease by exposure to Paramoeba sp harvested from the gills of infected fish

Atlantic salmon, Salmo salar L., were exposed to different concentrations o f Paramoeba sp. The lowest concentration which induced amoebic gill disease (AGD) was 230 Paramoeba sp. L-1 and the severity of infection increased wi th increasing concentration. The concentration of Paramoeba sp, positively correlated with the number of gill lesions (R-2 > 0.7). This study provides evidence that Paramoeba sp. is the causative agent of AGD and describes an experimental model that enables the severity of the induced disease to be controlled.