Progress in understanding the fish pathogen Aeromonas salmonicida

Aeromonas salmonicida is the causal agent of furunculosis in various fish species. Detection methods include culturing, serology and molecular biology techniques. Controversy surrounds its possible independent existence in water; enzyme-linked immunosorbent assay and the polymerase chain reaction have detected A. salmonicida in the absence of colony-forming units, but cells that are nonculturable may be significant to fish pathology. Furunculosis is probably transmitted by the pathogen's entry into gills, mouth, anus and/or surface injury of fish through contact with infected fish or contaminated water. Disease-control is possible by good husbandry practices, disease-resistant stock, improved diets, nonspecific immunostimulants, antimicrobial compounds and vaccines.