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Marteilia refringes studies: Molecular systematics and search for the intermediate hosts of the bivalve molluscs parasites.

Objective

I. Development of molecular tools to clarify the systematic of the European Marteilia.
I.1. European Marteilia rDNA sequence
I. l . l. Establishment of the European Marteilia rDNA sequences.
I.1.2. Alignment of sequences and taxonomic implications
I.2. PCR typing of Marteilia species/strains.
I.2.1. Design of Marteilia specific primers for the PCR.
I.2.2. PCR typing of Marteilia species/strains.

II. Searching for potential Marteilia intermediate hosts using immunoassatand specific PCR for the parasite.

II. 1. Marteilia detection in co-habitants using the claire/Ostrea model II.2. Marteilia detection in co-habitants using the raftlMytilus model

Since 1968, Marteilia refringens has caused serious and recurrent mortalities in the European flat oyster (Ostrea edulis) (Alderman, 1979) and continues nowadays to cause high mortalities in the Atlantic coast of France (Grizel, 1985; Anonymous, 1990).

Under the EEC Council directive 91/67 this parasite is included in list II of Annex A. This list includes serious pathogens causing important losses for the European shellfish aquaculture industry, that should be obligatory declared. An area where flat oysters or mussels are infected with any of these parasites will not be allowed to export to another area free of this disease.

The diagnoses of the two species of Marteilia found in Europe (Marteilia refringens and Marteilia maurini) was done using ultrastructural characteristics and host specificity (Grizel 1974 et al., Comps et al., 1982, Figueras and Montes, 1988). However, it is not possible to establish whether one, two, or more species of Marteilia exist in bivalve molluscs in Europe. There is an urgent need to set up more sensitive and accurate methods to allow the detection of low prevalence of Marteilia and to clarify the taxonomy of this parasite.

The existence of a complex life-cycle was early postulated by many authors. Because of the limitations of histology, a sensible and specific tool is needed to screen for
Marteilia presence in intermediate or alternative hosts.

References

Alderman, D.J. 1979. Epizootiology of Marteilia refringens in Europe. Mar. Fish. Rev. 41, 67-69.
Anonymous. 1990. ICES-CM 1990/F:13 Session T. Report of the working group on pathology and diseases of marine organisms. Vigo, 23-27 April, 1990.
Comps, M., Pichot, Y. & Papagianni, P. 1982. Recherche sur Marteilia maurini n. spC parasite de la moule Mytilus galloprovincialis Lmk. Rev. Trav. Inst Peches Marit. 45, 211-214.
Figueras, A. & J. Montes. Marteilia refringens Abers Disease of oysters. 1988. in Disease Processes in Marine Bivalve Molluscs. American Fisheries Society Special Publication Series. 18: 38-46.
Grizel, H. 1985. Etude des recentes epizooties de l'huitre plate (Ostrea edulis) Linne et lieu impact sur l'ostreiculture bretonne. These Sciences et Techniques du Languedoc, mention Sciences. Academie de Montpellier, 145 pp.
Grizel, H., Comps, M., Bonami, J. R., Cousserans, F., Duthoit, J. L. & Le Pennec, M. A. 1974. Recherche sur l'agent de la maladie de la glande digestive de Ostrea edulis Linne. Bull. Institut Peches Marit. 240, 7-30.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Address
6,Eduardo Cabello 6
36208 Vigo
Spain

Participants (3)

Centre National de la Recherche Scientifique
France
Address
Place Du Seminaire
17137 L'houmeau
IFREMER - DRV/RA
France
Address

17390 La Tremblade
Universite Claude Bernard Lyon I
France
Address
43, Boulevard Du 11 Novembre 1918
69622 Villeurbanne