title: Bonamia exitiosa (Haplosporidia) observed infecting the European flat oyster Ostrea edulis cultured on the Spanish Mediterranean coast.
abstract: Bonamia exitiosa and Bonamia ostreae are parasites that reproduce within the haemocytes of several oyster species. In Europe, the host species is the flat oyster Ostrea edulis. The parasite B. ostreae has been responsible for mortalities since the late 1970s throughout the European Atlantic coast. B. exitiosa was first detected, in 2007, on this continent in flat oysters cultured in Galicia (NW Spain). Since then, the parasite has also been detected in France, Italy and the United Kingdom. The bays of the Ebro Delta in the south of Catalonia represent the main bivalve culture area in the Mediterranean coast of Spain. Previous information from the area includes reports of several flat oyster pathogens, including the notifiable parasite Marteilia refringens. However, the status with regard to Bonamia parasites was uncertain. In the present study, a Bonamia parasite was observed in flat oysters cultured in the Alfacs Bay of the Ebro Delta by histology and real-time PCR. PCR-RFLP and sequencing suggested the presence of B. exitiosa. Finally, phylogenetic analyses of the studied Bonamia isolates corroborated B. exitiosa infection. M. refringens was also observed in the same oyster batch, and co-infection with both parasites was also detected. This is the first detection of B. exitiosa, in Catalonia and the Spanish Mediterranean coast. The impact of the parasite on the Mediterranean flat oyster activity needs to be urgently addressed.
authors.affiliation: IRTA-Sant Carles de la Ràpita and Catalonia's Aquaculture R&D and innovation Reference Network (XRAq), Ctra. Poblenou Km 5, 43540 St. Carles de la Ràpita, Spain. noelia.carrasco@irta.es
authors.forename: N
authors.initials: N
authors.lastname: Carrasco
authors.forename: A
authors.initials: A
authors.lastname: Villalba
authors.forename: K B
authors.initials: KB
authors.lastname: Andree
authors.forename: M Y
authors.initials: MY
authors.lastname: Engelsma
authors.forename: B
authors.initials: B
authors.lastname: Lacuesta
authors.forename: A
authors.initials: A
authors.lastname: Ramilo
authors.forename: I
authors.initials: I
authors.lastname: Gairín
authors.forename: M D
authors.initials: MD
authors.lastname: Furones
mesh_terms: D000818:Animals; D016054:DNA, Protozoan / Q000235:genetics; D004784:Environmental Monitoring; D005506:Food Contamination; D041602:Haplosporida / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D006434:Hemocytes / Q000469:parasitology; D017403:In Situ Hybridization; D008522:Mediterranean Sea; D049895:Ostrea / Q000469:parasitology*; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D011529:Protozoan Infections, Animal / Q000235:genetics / Q000473:pathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013030:Spain
chemical_list: D016054:DNA, Protozoan