Medycyna Wet. 63 (5), 519-521, 2007
Pękala A.
Infection of flat oysters (Ostrea edulis) with Bonamia ostreae
Infection with Bonamia ostreae has significantly decreased the production of the European flat oyster (Ostrea edulis) in Europe. This pathogen came from North America and rapidly spread to almost the entire oyster farming areas in Europe. The etiological agent is a parasite, Bonamia ostreae, with an unclear taxonomy at present. This parasite is located intrahaemocytic but can be observed extracellularly between epithelial or interstitial cells in gills and stomach. Two cells types of the parasite are apparent: 2, 3 µm to 6 µm in diameter. Bonamiosis is a lethal infection. Dead or gaping oysters are the most common clinical signs. Most of the infected oysters appear normal, but sometimes lesions in the connective tissue of the gills, mantle, and digestive glands can be observed. Yellow discoloration appears when advanced infections become systemic. Direct transmission from host to host is the most possible. Life cycle outside the host is unknown. The disease is seasonal. Prevalence and intensity of infection tends to increase during the warm season. There is no chemotherapy and vaccination. An effective program to prevent the transfer of infected stocks is the sole method of controlling this disease, which should be connected with appropriate diagnostic methods to detect the etiological agent.
Keywords: Bonamia ostreae, molluscs