Crassostrea gigas is increasingly being cultured in a great number of countries from animaIs originally introduced from Japan, and is one of the most exploited bivalve species in the EU (FAO, 1989). Although no serious pathogen was detected previously in Japanese oysters in Europe, mortalities have been observed since the introduction of this bivalve species into the EU. Thus, oyster cultivation may be endangered by the occurrence of epizootics, especially virus diseases, which are considered one of the maj or risks to production. Indeed, mortalities have been described among different species of ostreids and are associated with the presence of viruses belonging to various families. The first description of a virus was reported in adult Eastern oyters,... |