Detection of Aeromonas salmonicida in wild Atlantic salmon using a specific DNA probe test

The presence of Aeromonas salrnonicida, the etiological agent of furunculosis, was examined using polymerase chain reaction (PCR) and DNA probe methodology in wild Atlantic salmon Salmo salar taken from 3 Irish river systems Blood samples from 61 individual fish were examined and the presence of pathogen was determined in 87% of the fish examined. However, the level of pathogen was extremely low, calculated at less than 100 A. salmonicida genome equivalents per fish. These data imply a widespread low level infection of A. salmonicida amongst wild salmon in Irish rivers.