A method was designed for rapid and reliable demonstration of the presence of infectious pancreatic necrosis virus retrieved from 5 l water samples. Viruses together with an added carrier protein were adsorbed to a resin of an added anion exchanger. Then the resin was collected rapidly and quantitatively through a specific device which we designed. The resin was transferred to a column from which the viruses were eluted, and subsequently further concentrated by acid precipitation, followed by SDS-polyacrylamide gel electrophoresis and Western blot analysis. Serological results were obtained within 24 h after the water sample was introduced into the laboratory. Proteins were recovered at an efficiency between 70 and 80% and the total concentration factor ranged between 150000 and 250000 times, depending on the requirements and the methods of choice.