Mise en évidence d'Haplosporidium sp. (Haplosporida - Haplosporidiidae) parasite de l'huître plate Ostrea edulis L.

A new Haplosporidie has been observed in the flat oyster Ostrea edulis from the Mediterranean Sea. Different development stages have been described in light and electron microscopy. The characteristics of the spores and especially the presence of at least four sporal filaments enable us to distinguish this Haplosporidie from those already described in the Atlantic flat oysters. Different haplosporidies have been described in the oyster. Some are known as being pathogenic, Minchinia costalis (Andrews et al., 1962 and 1978; Couch 1967) and Minchinia nelsoni (Haskin et al., 1966; Farley 1968 and 1975), others, identified only recently, are considered as occasional parasites (Van Banning, 1977). During the research conducted on Bonamia ostreae (Pichot et al., 1980), a haplosporidie has been characterized in flat oysters coming from the Mediterranean Sea and used as hosts in experimental infestation trials.