Determination of the etiological agent of brown ring disease in southwestern Spain.
Manila clams (Tapes philippinarum) with and without signs of brown ring disease (BRD) were collected in the Bay of Cadiz and at Huelva (Andalusia, Spain). An immunodetection test, based on the indirect immunofluorescence technique, was developed, using polyclonal antisera to Vibrio tapetis whole cells and against outer membrane. This method provided evidence for the presence of the bacterium in all the BRD-affected clams analysed. V. tapetis was also detected by the same method in healthy clams, which indicates its opportunistic character.