Abstract
The distribution of Vibrio anguillarum serotype J-O-1, a causative agent of vibriosis of ayu Plecoglossus altivelis in Lake Biwa, was investigated by both fluorescence antibody method using specific monoclonal antibody against V. anguillarum J-O-1 (FA-DAPI method) and aconventional cultural method. There were 3.2×104 cells/cm3 of V. anguillarum J-O-1 deposited on the bottom sediment surface (0-0.1cm) under the net cages of an ayu culturing farm in Lake Biwa. In ayu culturing ponds, which are concrete tanks on the lakeshore, we also detected this pathogen(1.6×105 cells/cm3) in the bottom sediments collected from the drains for outflow of pond water intoLake Biwa. In non-culturing areas of the lake, V. anguillarum J-O-1 cells were not found in any water, bottom sediment nor plankton samples. In the same samples from which V. anguillarum J-O-1 cells weredetected by the FA-DAPI method, no cells were recognized by the conventional cultural method. This is the first report for direct detection of V. anguillarum J-O-1 from freshwater environments.
