title: Can the protozoan parasite Bonamia ostreae infect larvae of flat oysters Ostrea edulis?
abstract: Bonamia ostreae is an intracellular protistan parasite affecting flat oysters Ostrea edulis. It can be detected in juveniles but mortalities mainly affect oysters which are more than 2 years old. The parasite is usually observed inside haemocytes and sometimes free, notably in gill epithelia suggesting a parasite release through this organ. However, the infective form and ways of entry and release remain undetermined. Flat oysters incubate their larvae in their pallial cavity for 8-10 days before releasing them into the water column. Flat oysters in Bay of Quiberon in South Brittany (France) are known to be infected with B. ostreae since 1979 and is the most important area in France for O. edulis spat collection. Flat oysters incubating larvae were sampled in this area during summertime between 2007 and 2009. Both adults and larvae were preserved and assayed by PCR and in situ hybridisation (ISH). PCR tests revealed the presence of parasite DNA in some adults and larvae. Specific labelling could be detected by ISH in gills, digestive system, gonad and mantle in adults and in the epithelium surrounding the visceral cavity of some larvae. Our results demonstrate that larvae can be infected with B. ostreae. Larvae might thus contribute to the spread of the parasite during their planktonic life. In addition, their transfer for aquaculture purpose should be controlled especially when they are exported from infected zones.
authors.affiliation: Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire de Génétique et Pathologie (LGP), Avenue de Mus de Loup, 17390 La Tremblade, France. Isabelle.Arzul@ifremer.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Arzul
authors.forename: Aimé
authors.initials: A
authors.lastname: Langlade
authors.forename: Bruno
authors.initials: B
authors.lastname: Chollet
authors.forename: Maeva
authors.initials: M
authors.lastname: Robert
authors.forename: Sylvie
authors.initials: S
authors.lastname: Ferrand
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Omnes
authors.forename: Sophie
authors.initials: S
authors.lastname: Lerond
authors.forename: Yann
authors.initials: Y
authors.lastname: Couraleau
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Joly
authors.forename: Cyrille
authors.initials: C
authors.lastname: François
authors.forename: Céline
authors.initials: C
authors.lastname: Garcia
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D041602:Haplosporida / Q000502:physiology*; D006790:Host-Parasite Interactions; D017403:In Situ Hybridization; D007814:Larva / Q000469:parasitology; D049895:Ostrea / Q000469:parasitology*; D016133:Polymerase Chain Reaction