The detection of Bonamia ostreae (Pichot et al. 1980) in frozen oysters (Ostrea edulis L. ) and the effect of the parasite on condition

Two year classes of frozen flat oysters, Ostrea edulis L., from four different beds in Cork Harbour (southern Ireland) were analysed. Bonamia ostreae, a parasitic protozoan, was detected from frozen heart tissue. Freezing did not appear to affect the ability to diagnose the infection. The detection of Bonamia from oysters frozen in 1986 pre-dates by nine months the initial diagnosis of the disease from fresh oysters in Ireland. The effect of the endoparasite on condition was also examined. Overall, oysters with heavy Bonamia infections were in poorer condition than uninfected oysters.