| Summer mortality has been observed on oyster spat Crassostrea gigas since 1991 on french coasts. In our study, we deseribed symptoms observed during the mortality, especially adductor muscle weakness and we isolated strains on Zobell medium and TCBS from moribund spat. Strains isolated during a high mortality (60 %) were selected by experimental pathology on spat. Inoculation by bath led us to select a pathogenic strain (TNEMF6) for oyster spat. Phenotypic identification, phylogenetic study on 16S rDNA and quantitative DNA/DNA hybridisation showed that this strain belongs to Vibrio splendidus biovar II. Phenotyping and ribotyping with strains isolated during the study showed that only TNNIII7 and TNMB5 are similar to the pathogenic strain TNEMF6.... |
