127 results on '"Arzul, Isabelle"'
Search Results
102. Haemocytic neoplasia in Mediterranean mussels (Mytilus galloprovincialis) in the Slovene Adriatic Sea
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Gombač, Mitja, primary, Sitar, Rosvita, additional, Pogačnik, Milan, additional, Arzul, Isabelle, additional, and Jenčič, Vlasta, additional
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- 2013
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103. Characterization of the protozoan parasite Marteilia refringens infecting the dwarf oyster Ostrea stentina in Tunisia
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Elgharsalli, Refka, primary, Aloui-Bejaoui, Nejla, additional, salah, Hedi, additional, Chollet, Bruno, additional, Joly, Jean-Pierre, additional, Robert, Maeva, additional, Couraleau, Yann, additional, and Arzul, Isabelle, additional
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- 2013
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104. Evolutionary Origins of Rhizarian Parasites.
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Sierra, Roberto, Cañas-Duarte, Silvia J., Burki, Fabien, Schwelm, Arne, Fogelqvist, Johan, Dixelius, Christina, González-García,, Laura N., Gile, Gillian H., Slamovits, Claudio H., Klopp, Christophe, Restrepo, Silvia, Arzul, Isabelle, and Pawlowski, Jan
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The SAR group (Stramenopila, Alveolata, Rhizaria) is one of the largest clades in the tree of eukaryotes and includes a great number of parasitic lineages. Rhizarian parasites are obligate and have devastating effects on commercially important plants and animals but despite this fact, our knowledge of their biology and evolution is limited. Here, we present rhizarian transcriptomes from all major parasitic lineages in order to elucidate their evolutionary relationships using a phylogenomic approach. Our results suggest that Ascetosporea, parasites of marine invertebrates, are sister to the novel clade Apofilosa. The phytomyxean plant parasites branch sister to the vampyrellid algal ectoparasites in the novel clade Phytorhiza. They also show that Ascetosporea + Apofilosa + Retaria + Filosa + Phytorhiza form a monophyletic clade, although the branching pattern within this clade is difficult to resolve and appears to be model-dependent. Our study does not support the monophyly of the rhizarian parasitic lineages (Endomyxa), suggesting independent origins for rhizarian animal and plant parasites. [ABSTRACT FROM AUTHOR]
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- 2016
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105. Some like it hot: Paracartia grani (Copepoda: Calanoida) arrival in the Thau lagoon (south of France—Mediterranean Sea)
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Boyer, Severine, primary, Arzul, Isabelle, additional, and Bonnet, Delphine, additional
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- 2012
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106. Comparison of haemocytic parameters among flat oyster Ostrea edulis stocks with different susceptibility to bonamiosis and the Pacific oyster Crassostrea gigas
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Comesaña, Pilar, primary, Casas, Sandra M., additional, Cao, Asunción, additional, Abollo, Elvira, additional, Arzul, Isabelle, additional, Morga, Benjamin, additional, and Villalba, Antonio, additional
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- 2012
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107. Bonamia ostreae-induced mortalities in one-year old European flat oystersOstrea edulis: experimental infection by cohabitation challenge
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Lallias, Delphine, primary, Arzul, Isabelle, additional, Heurtebise, Serge, additional, Ferrand, Sylvie, additional, Chollet, Bruno, additional, Robert, Maeva, additional, Beaumont, Andy R., additional, Boudry, Pierre, additional, Morga, Benjamin, additional, and Lapègue, Sylvie, additional
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- 2008
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108. Evidence for interspecies transmission of oyster herpesvirus in marine bivalves
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Arzul, Isabelle, primary, Renault, Tristan, additional, Lipart, Cécile, additional, and Davison, Andrew J., additional
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- 2001
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109. Effects of temperature and salinity on the survival of Bonamia ostreae, a parasite infecting flat oysters Ostrea edulis.
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Arzul, Isabelle, Gagnaire, Béatrice, Bond, Céline, Chollet, Bruno, Morga, Benjamin, Ferrand, Sylvie, Robert, Maeva, and Renault, Tristan
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EUROPEAN oyster ,PARASITES ,AQUATIC animals ,OCEAN temperature ,SALINITY ,FLOW cytometry ,DISEASES - Abstract
The article presents information on a study which investigated the effect of temperature and salinity of different seawater media on the survival of Bonamia ostreae, a parasite that infects flat oysters Ostrea edulis. A brief overview is given on the protistan parasite the belongs to the phylum Haplosporidia. It discusses the incubation of purified parasites in various seawater media at various temperatures and then subjected to a range of salinities. It explores the purification of Bonamia ostreae. It also relates of the findings of the analysis of viability of the parasite using flow cytometry protocols.
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- 2009
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110. Bonamia ostreae-induced mortalities in one-year old European flat oysters Ostrea edulis: experimental infection by cohabitation challenge.
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Lallias, Delphine, Arzul, Isabelle, Heurtebise, Serge, Ferrand, Sylvie, Chollet, Bruno, Robert, Maeva, Beaumont, Andy R., Boudry, Pierre, Morga, Benjamin, and Lapègue, Sylvie
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EUROPEAN oyster , *OYSTERS , *MORTALITY , *OSTREA , *PARASITIC diseases , *AQUACULTURE - Abstract
Bonamiosis is a parasitic disease (causative agent: Bonamia ostreae) affecting the European flat oyster Ostrea edulis, responsible for a drastic decline in its aquaculture production. Selective breeding programs for resistance to bonamiosis have been undertaken to counter this disease. In the present study, a 6-month cohabitation challenge experiment was performed in order to transmit the disease from wild oysters injected with the parasite to two tested families of oysters (20 and 8-month old at the beginning of the experiment, with different genetic backgrounds) originating from a selective breeding program developed by IFREMER in France. Mortalities were checked daily and ventricular heart smears were performed on dying or moribund oysters to detect the level of infection by B. ostreae. Mortality started after 4 months of cohabitation in the tested oysters. The cumulative mortalities after 6 months were 58% for the wild oysters, 9% for Family 1 (20-month old) and 20% for Family 2 (8-month old). In the dying oysters, the parasite could be detected in 67% of the wild oysters, 68% of Family 1 and 89% of Family 2. It was detected in only 11% of the surviving oysters of Family 2. The mortality and the level of infection by the parasite were significantly higher in Family 2 than in Family 1. Our results demonstrate that prespawning oysters as young as 1 year-old can become infected with the parasite and, most importantly, can die from bonamiosis. This result is inconsistent with the commonly accepted critical age of 2 years-old for the disease development. Additionally, no clear relationship between shell length and level of infection was observed. We also review the different methods for infection of the European flat oyster O. edulis with B. ostreae under experimental conditions and their main results. [ABSTRACT FROM AUTHOR]
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- 2008
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111. Inactivation of marine bivalve parasites using UV-C irradiation: Examples of Perkinsus olseniand Bonamia ostreae
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Fernández-Boo, Sergio, Provot, Clément, Lecadet, Cyrielle, Stavrakakis, Christophe, Papin, Mathias, Chollet, Bruno, Auvray, Jean-François, and Arzul, Isabelle
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Diseases represent a major threat for the bivalve production industry. Their control relies on biosecurity measures to prevent their introduction and limit their spread. When maintained in hatcheries, nurseries and depuration centers, bivalves can become infected from the surrounding water and might release pathogens through wastewater effluents. A major effort was done in controlling the safety of bivalves for human consumption, but, on the other hand, information regarding the resistance of mollusc pathogens to water treatment is scarce. The effect of ultraviolet exposure was tested on two protozoan parasites of marine bivalves, the non-culturable parasite Bonamia ostreaeand Perkinsus olseniculturable in DMEM/HAM´s medium. UV exposure experiments were carried out first at the bench scale and then, for P. olseni, at a larger scale mimicking depuration plants, hatcheries and nurseries conditions. At the bench scale, our study indicated that up to 40% of B. ostreaecells and 85% of P. olsenicells died 24 h and 21 days respectively after an exposure to 94 mJ/cm2of UV-C. After 40 mJ/cm2exposure, P. olsenidensity increased between 15 and 21 days of culture suggesting that the parasite is able to recover from low UV intensity exposure. At large scale, no signs of UV recovery were seen in P. olsenicultures, but, at lower intensity (216–244 mJ/cm2), 15% of the parasites remained alive 21 days post exposure. Finally, a minimum dose of 94 mJ/cm2seems required to inhibit proliferation of parasites and 450 mJ/cm2to completely kill all parasites. Taken this into account, a dose higher than 450 mJ/cm2is suggested to properly treat water to avoid dispersion of bivalve protozoan parasites such as P. olseni.
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- 2021
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112. Rapport d'activités 2014 de l'Unité SG2M. Santé, Génétique et Microbiologie des mollusques
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Arzul, Isabelle, Benabdelmouna, Abdellah, Betto, Veronique, Billy, Jean-Christophe, Bodin, Stephane, Brizard, Raphael, Vincent Buchet, Caprais, Marie-Paule, Chollet, Bruno, Cornette, Florence, Cozien, Joelle, Degremont, Lionel, Delsert, Claude, Dubreuil, Christine, Dupuy, Beatrice, Faury, Nicole, Francois, Cyrille, Garcia, Celine, Garry, Pascal, Gourmelon, Michele, Grasset, Martine, Haffner, Philippe, Haure, Joel, Hervio Heath, Dominique, Heurtebise, Serge, Hubert, Francoise, Kaelin, Gaelle, Kergaravat, Cedric, Lamy, Jean-Baptiste, Ledu, Christophe, Le Mennec, Cecile, Le Quintrec, Estelle, Le Saux, Jean-Claude, Loiseau, Veronique, Lozach, Solen, Lupo, Coralie, Maillot, Jessica, Maurouard, Elise, Menanteau, Chantal, Morga, Benjamin, Nourry, Max, Ollivier, Joanna, Palvadeau, Hubert, Papin, Mathias, Parnaudeau, Sylvain, Penisson, Christian, Phelipot, Pascal, Piquet, Jean-Come, Prou, Jean, Quenot, Emmanuelle, Raulin, Pascal, Riou, Karen, Robert, Maeva, Schaeffer, Julien, Schwerdtle, Pascal, Stavrakakis, Christophe, Tourbiez, Delphine, Travers, Marie-Agnes, Vallade, Emilie, and Veron, Antoine
113. Inventaire, diagnostic écologique et restauration des principaux bancs d’huitres plates en Bretagne : le projet FOREVER
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Pouvreau, Stephane, Cochet, Hélène, Fabien, Aurélie, Arzul, Isabelle, Lapegue, Sylvie, Gachelin, Sonia, and Salaun, Benoit
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13. Climate action ,14. Life underwater - Abstract
L’huitre plate, la seule huitre native des côtes européennes, est une espèce emblématique de Bretagne. Convoitée depuis l'Antiquité, sur-pêchée au 19ème siècle, fleuron de l'ostréiculture au 20ème, elle est désormais menacée de disparition à l'aube du 21ème. Sous l'impulsion de la commission OSPAR mais aussi dans un contexte grandissant de crise écologique et d'érosion de la biodiversité imposant une nécessaire conservation et/ou restauration de nos patrimoines naturels, une alliance européenne réunissant biologistes et gestionnaires a été créée en novembre 2017 à Berlin sous l'égide de l'Agence Allemande de Conservation de la Nature (BFN) avec un objectif commun: favoriser le retour de l'huitre plate sur les côtes européennes. Cette alliance pour la restauration de l'huitre plate (NORA) regroupe désormais plus d'une centaine de scientifiques et de gestionnaires, tous au chevet de cette espèce. En France, cette démarche est assurée nationalement par le programme FOREVER ("Flat Oyster Recovery"), démarré en 2018 et financé par le FEAMP pour sa première phase (2018-2020) focalisée en Bretagne. Le présent rapport dresse le bilan du projet. En trois ans, ce projet pionnier a permis : (1) de proposer un premier inventaire des dernières populations relictuelles d'huitres plates encore présentes en Bretagne, en fournissant un diagnostic de leur état écologique, parasitaire et génétique et en affinant la description de son habitat actuel. (2) d'étudier plus précisément les mécanismes écologiques impliqués dans la dynamique d'un banc d'huitres plates : abondance et dispersion larvaire, dynamique du recrutement, facteurs environnementaux, effet de la prédation, impact des maladies parasitaires. L'ensemble de ces processus est étudié à la fois en rade de Brest et en baie de Quiberon. (3) d'initier une démarche unique en France et proposer une méthode adaptée permettant la conservation et la restauration écologique des derniers bancs. Cette démarche inclue des opérations de communication et de sensibilisation actives associées à des actions pilotes concrètes et facilement transférables de restauration écologique : enrichissement coquillier, semis de naissain et développement de récifs artificiels adaptés à l'espèce. Ce rapport apporte aussi de nombreux nouveaux éléments de gestion, utiles aux professionnels de l'ostréiculture, de la pêche, mais aussi aux gestionnaires de l'environnement, notamment aux animateurs du réseau des sites Natura 2000, à l'Office Français de la Biodiversité ainsi qu'à différentes associations impliquées. A titre d'exemple, ci-joint quelques résultats marquants : Pour la profession ostréicole, la meilleure compréhension du recrutement de l'espèce ouvre les voies pour assurer un captage "régulier" pour les années à venir. Les cartes de dispersion expliquent la distribution spatiale du recrutement dans les deux seuls sites de captage français. Les tendances temporelles démontrent l'importance de gérer les populations sauvages, seul moyen d'assurer un captage lorsque des étés frais moins favorables à la reproduction. Le seuil des 18°C/19°C constitue une température critique des masses d'eau en deçà de laquelle le recrutement se fait mal, surtout quand les stocks sont faibles. Pour le secteur de la pêche professionnel (mais aussi récréative), les résultats montrent l'extrême fragilité des bancs résiduels bretons et insistent sur le fait qu'aucune exploitation durable de cette espèce ne pourra être menée sans une gestion très précise des populations résiduelles incluant conservation, restauration et suivis scientifiques. Pour les gestionnaires de l'environnement, ce rapport est l'occasion de mettre en lumière cette espèce-ingénieur, qui après trois siècles de surexploitation, est menacée de disparition. Pourtant une huitrière en bonne santé apporte de nombreux services écosystémiques, comme lutter contre l'érosion de la biodiversité et la dégradation de la qualité de l'eau. De nombreux éléments précis sont fournis pour permettre aux services de l'état, aux gestionnaires Natura 2000 et à l'OFB de protéger et restaurer les dernières populations présentes sur leurs périmètres d'intervention. En savoir plus sur le programme FOREVER et les autres projets européens de conservation et restauration de l'huitre plate : https://noraeurope.eu
114. Descriptions of <italic>Mikrocytos veneroïdes</italic> n. sp. and <italic>Mikrocytos donaxi</italic> n. sp. (Ascetosporea: Mikrocytida: Mikrocytiidae), detected during important mortality events of the wedge clam <italic>Donax trunculus</italic> Linnaeus (Veneroida: Donacidae), in France between 2008 and 2011
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Garcia, Céline, Haond, Christophe, Chollet, Bruno, Nerac, Mirella, Omnes, Emmanuelle, Joly, Jean-Pierre, Dubreuil, Christine, Serpin, Delphine, Langlade, Aimé, Le Gal, Dominique, Terre-Terrillon, Aouregan, Courtois, Olivier, Guichard, Benjamin, and Arzul, Isabelle
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DONAX (Bivalves) ,MOLLUSK mortality ,CONFIRMATORY factor analysis ,TRANSMISSION electron microscopy ,MOLLUSK classification - Abstract
Background: Microcell parasites are small intracellular protozoans mostly detected in molluscs and can be associated with mortalities. In 2010 and 2011, strong increases in mortality events were reported in different wild beds of the wedge clam
Donax trunculus Linnaeus, along the Atlantic coast of France and the presence of potential pathogens, including microcells, was investigated. Methods: Clams collected in different beds showing mortality were examined by histology. Based on histological observations, confirmatory analyses were carried out, including transmission electron microscopy (TEM) and molecular characterization. Results: Histological analyses revealed the presence of small protozoans similar to microcell parasites in different tissues ofDonax trunculus , particularly in muscular and connective tissues. TEM examination confirmed the intracellular localization of the protozoans. Moreover, the lack of haplosporosomes and mitochondria suggested that the observed parasites belong to the genusMikrocytos Farley, Wolf & Elston, 1988.Mikrocytos genus-specific PCR and in situ hybridization results supported the microscopic observations. Sequence fragments of the18S rRNA gene shared 75–83% identity with the differentMikrocytos spp. described previously, includingMikrocytos mackini Farley, Wolf & Elston, 1988 andM. boweri Abbott, Meyer, Lowe, Kim & Johnson, 2014. Phylogenetic analyses confirmed that the microcell parasites observed inDonax trunculus in France belong to the genusMikrocytos and suggest the existence of two distinct species. Conclusions: Based on morphological, ultrastructural, molecular data and host information, the two microcell parasites detected inDonax trunculus belong to the genusMikrocytos and are distinct from previously described members of this genus. This is the first report ofMikrocytos spp. found in France and infecting the clamDonax trunculus .Mikrocytos veneroïdes n. sp. was detected in different wild beds andMikrocytos donaxi n. sp. was detected only in Audierne Bay. [ABSTRACT FROM AUTHOR]- Published
- 2018
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115. Recent advances in bivalve-microbiota interactions for disease prevention in aquaculture
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Isabelle Arzul, Luigi Vezzulli, K. Mathias Wegner, Alberto Pallavicini, Christine Paillard, Yannick Gueguen, David Bass, Paillard, Christine, Gueguen, Yannick, Wegner, K Mathia, Bass, David, Pallavicini, Alberto, Vezzulli, Luigi, Arzul, Isabelle, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Interactions Hôtes-Pathogènes-Environnements (IHPE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Perpignan Via Domitia (UPVD), Alfred Wegener Institute for Polar and Marine Research (AWI), The Natural History Museum [London] (NHM), Centre for Environment, Fisheries and Aquaculture Science [Weymouth] (CEFAS), Department of Life Sciences, Università degli studi di Trieste, National Institute of Oceanography and Applied Geophysics (OGS), Dipartimento di Scienze della Terra dell'Ambiente e della Vita (DISTAV), Universita degli studi di Genova, Laboratoire de Génétique et Pathologie des Mollusques Marins, 17390 La Tremblade, France. (LGPMM), Santé, Génétique et Microbiologie des Mollusques (IFREMER SG2M), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Perpignan Via Domitia (UPVD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Università degli studi di Trieste = University of Trieste, Università degli studi di Genova = University of Genoa (UniGe), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Santé, Génétique et Microbiologie des Mollusques (SGMM), and ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
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Functional role ,Biomedical Engineering ,Bioengineering ,Context (language use) ,[SDV.SA.ZOO]Life Sciences [q-bio]/Agricultural sciences/Zootechny ,Disease ,Aquaculture ,Biology ,Animals ,Host-Pathogen Interactions ,Bivalvia ,Microbiota ,03 medical and health sciences ,14. Life underwater ,ComputingMilieux_MISCELLANEOUS ,030304 developmental biology ,0303 health sciences ,030306 microbiology ,Ecology ,Host (biology) ,business.industry ,Animal ,[SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology ,Host-Pathogen Interaction ,13. Climate action ,[SDE]Environmental Sciences ,Disease prevention ,business ,Biotechnology ,[SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis - Abstract
International audience; In bivalves, no clear-cut functional role of microbiota has yet been identified, although many publications suggest that they could be involved in nutrition or immunity of their host. In the context of climate change, integrative approaches at the crossroads of disciplines have been developed to explore the environment-host-pathogen microbiota system. Here, we attempt to synthesize work on (1) the current methodologies to analyse bivalve microbiota, (2) the comparison of microbiota between species, between host compartments and their surrounding habitat, (3) how the bivalve microbiota are governed by environmental factors and host genetics and (4) how host-associated microorganisms act as a buffer against pathogens and/or promote recovery, and could thereby play a role in the prevention of disease or mortalities.
- Published
- 2022
116. Epizootiology and contribution to the characterization of the infectious agent of the brown muscle disease, an emergent pathology of the Manila clam, Venerupis philippinarum
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Binias, Cindy, STAR, ABES, Montaudouin, Xavier de, Gonzalez, Patrice, Arzul, Isabelle, Garabétian, Frédéric, Bremont-Deletang, Michel, Soudant, Philippe, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux I, Xavier de Montaudouin, and Patrice Gonzalez
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[SDV.SA]Life Sciences [q-bio]/Agricultural sciences ,Perkinsus ,Parasitism ,[SDV.OT] Life Sciences [q-bio]/Other [q-bio.OT] ,Maladie du muscle marron (BMD) ,Brown Muscle Disease (BMD) ,Epizootiology ,Venerupis philippinarum ,Réponse immunitaire ,Immune response ,Epizootiologie ,Parasitisme ,Virus - Abstract
The Manila clam Venerupis philippinarum is the second most exploited mollusk bivalve in the world and represents a major economic interest. At the scale of Arcachon bay, the Brown Muscle Disease or BMD, an emergent pathology discovered in 2005, concerns fishing activity. This pathology affects the posterior adductor muscle of the clam and disrupts the valve opening and closing process. It induces the migration of clams to the surface and their death.This thesis concerns on the one hand the epizootiology of the disease and its impact on host and on the other hand the identification of the causal agent of the disease. A study of the clam distribution in Arcachon bay (French Atlantic coast) shows that prevalence of BMD decreased between 2010 and 2012. However this decrease doesn't affect clams of the legal harvesting size (> 35mm). Furthermore, the disease seems to appear in individuals with increasingly smaller size and thus risks to increase mortality in the youngest stages. The analysis of the environmental factors that are involved in the disease distribution highlights the correlation between prevalence of the BMD and relatively "quiet" hydrodynamism.BMD particularly affects the energy metabolism of the host, the oxidative stress response mechanisms and the immune system.Many functions are up-regulated in the BMD-affected hosts but other ways, as the apoptosis, are down-regulated by the infectious agent.Although viral origin of BMD is now a convincing hypothesis (electronic microscopy, transcriptomic), the nature of the etiological agent (viral family) cannot so far be determined with certainty. Viral particles were observed in tissues of BMD-diseased hosts but not in tissues of healthy host. They have been purified on sucrose gradient. However, the attempt to provoke the disease in healthy individuals failed., Seconde espèce de mollusque bivalve la plus exploitée au monde, la palourde japonaise Venerupis philippinarum représente un intérêt économique majeur. A l’échelle du bassin d’Arcachon, la maladie du muscle marron ou BMD (pour Brown Muscle Disease), pathologie émergente découverte en 2005 inquiète tout particulièrement le secteur de la pêche. Cette pathologie affecte le muscle adducteur postérieur de la palourde et perturbe l’ouverture-fermeture des valves. Cette perturbation entraine la remontée des individus à la surface du sédiment et la mort.Ces travaux de thèse ont porté d’une part sur l’épizootiologie de la maladie et son impact sur l'hôte et d’autre part sur l’identification de l’agent responsable de la maladie.Une étude sur la distribution des palourdes dans le bassin d’Arcachon (littoral Atlantique français) montre que la prévalence de la BMD a diminué entre 2010 et 2012. Toutefois cette baisse ne concerne pas les individus ayant atteint la taille légale de pêche (> 35mm). De plus, la maladie semble apparaitre chez des individus de plus en plus petit et risque donc d’accroitre la mortalité aux plus jeunes stades. L’analyse des facteurs environnementaux impliqués dans la distribution de la maladie souligne la corrélation entre la prévalence de la BMD et un hydrodynamisme relativement « calme ».La BMD affecte tout particulièrement le métabolisme énergétique de l’hôte, les mécanismes de réponse au stress oxydant et également le système immunitaire. De nombreuses fonctions sont surexprimées chez les hôtes malades mais d’autres voies comme celle de l’apoptose sont régulées négativement par l’agent infectieux.Si l’origine virale est maintenant une hypothèse solide (microscopie électronique, transcriptomique), la nature exacte de l’agent étiologique (famille virale) ne peut à ce jour être déterminée avec certitude. Des particules virales ont bien été observées dans les tissus malades mais pas dans les tissus sains, et ont pu être purifiées sur gradient de sucrose. Toutefois, les essais pour provoquer la maladie chez des individus sains ont échoué.
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- 2013
117. Epidemiological surveillance in animal health
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Dufour, Barbara, Hendrikx, Pascal, Thonnat, Jérôme, Chillaud, Thierry, Roger, François, Calavas, Didier, Moutou, François, Lazard, Charlotte, Squarzoni, Cécile, Chazel, Myriam, Ouagal, Mahamat, Moussu, Claire, Thebault, Anne, Arzul, Isabelle, Bendali, Fatah, and Chardonnet, Bertrand
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C10 - Enseignement ,Méthodologie ,Formation ,L73 - Maladies des animaux ,technique de prévision ,Maladie des animaux ,Maladie infectieuse ,Système d'information ,Évaluation ,Surveillance épidémiologique ,Danger pour la santé - Abstract
This book is the result of collaboration among epidemiological surveillance specialists at all the operational echelons of an epidemiological surveillance network: organisation, training, data management and evaluation. The coordinators of various networks contributed their valuable experience to this practical guide. Part one provides readers with all the methodological elements they need to help create, operate and evaluate an epidemiological surveillance networks in operation. It shows that all networks use the same methodological procedure even though their surveillance subjects and methods vary so widely. This practical guide is aimed at all those responsible for epidemiological surveillance network design, organisation and operation in both the northern and southern hemispheres. It will also be of interest to students and teachers of animal epidemiology.
- Published
- 2009
118. Surveillance épidémiologique en santé animale
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Dufour, Barbara, Hendrikx, Pascal, Thonnat, Jérôme, Chillaud, Thierry, Roger, François, Calavas, Didier, Moutou, François, Lazard, Charlotte, Squarzoni, Cécile, Chazel, Myriam, Ouagal, Mahamat, Moussu, Claire, Thebault, Anne, Arzul, Isabelle, Bendali, Fatah, Chardonnet, Bertrand, Toma, Bernard, Lefrançois, Thierry, Chaisemartin, Daniel, Bouchot, Alexandre, Guix, Estevan, and François, Cyrille
- Subjects
Santé animale ,Évaluation du risque ,Formation ,Réseau ,L73 - Maladies des animaux ,méthode ,Organisation ,Maladie infectieuse ,Évaluation ,Surveillance épidémiologique ,C20 - Vulgarisation ,Danger pour la santé - Abstract
Cet ouvrage est le fruit d'une large collaboration entre des spécialistes de la surveillance épidémiologique à tous les échelons du fonctionnement d'un réseau: organisation, formation, gestion des données et évaluation. Il est enrichi par l'expérience d'animateurs de réseaux dans des contextes géographiques et techniques très variés. La première partie est un véritable guide pratique à l'attention de tous les acteurs des réseaux de surveillance épidémiologique, et plus particulièrement des animateurs et acteurs impliqués dans leur conception, leur organisation et leur fonctionnement. Il est conçu de manière à faire mieux comprendre ce qu'est la surveillance épidémiologique, ses objectifs et ce qu'elle peut apporter; mais surtout, il fournit au lecteur tous les éléments de méthode lui permettant de participer à la création, au fonctionnement et à l'évaluation d'un réseau de surveillance épidémiologique sur le terrain. Chaque sujet est abordé d'un point de vue méthodologique et pratique afin de faciliter l'appropriation des concepts. Les méthodes et exemples s'adressent aussi bien aux pays du Nord qu'à ceux du Sud. Dans une deuxième partie, des exemples concrets de réseaux de surveillance épidémiologique en fonctionnement sont présentés de manière à illustrer la grande diversité des réseaux existant sur le terrain. Sont ainsi exposés d'une part les réseaux de surveillance nationaux; avec d'abord ceux "ciblés" sur une maladie particulière puis les réseaux dits "globaux" qui surveillent plusieurs maladies ou syndromes, et, d'autre part, les systèmes supranationaux. On découvre ainsi que, derrière la diversité des sujets traités et des moyens de surveillance utilisés, une démarche méthodologique identique est appliquée. Sommaire : Remerciements. Préface. Introduction. Partie I - Modalités de fonctionnement des réseaux de surveillance épidémiologique - Principes de la surveillance épidémiologique : Définitions; Surveillance, prophylaxie et recherche en épidémiologie; Objectifs; Fonctionnement général des réseaux de surveillance épidémiologique. Protocoles de surveillance : Définition de l'objet de la surveillance; Standardisation; Définition de la stratégie de surveillance; Gestion des données; Diffusion de l'information. Organisation institutionnelle des réseaux : Comité de pilotage; Comité technique; Unité centrale; Laboratoire; Equipe mobile; Unotés régionales; Intervenants de terrain; Relations entre les acteurs des réseaux. Formation : Rôle de la formation; Construction des besoins en formation; Elaboration du plan de formation; Cahier des charges et analyse d'une offre; Évaluation de la formation. Evaluation des réseaux : Présentation générale; Évaluation interne : indicateurs de performance et de diagnostic; Audit. Partie II - Réseaux de surveillance épidémiologique - Classification des réseaux : Principes d'une classification; Critères de classement; Exemples de réseaux illustrant la classification. Réseaux nationaux et locaux : Réseaux ciblés; Réseaux globaux. Systèmes de surveillance épidémiologique supranationaux : Enjeux; Objectifs et fonctionnement; Intérêt et limites; Exemples de systèmes supranationaux. Annexes : Annexe 1 - Questionnaire destiné à évaluer la qualité d'un réseau de surveillance épidémiologique d'une maladie présente. Annexe 2 - Questionnaire destiné à évaluer la qualité d'un réseau de surveillance épidémiologique d'une maladie rare ou exotique. Annexe 3 - Guide pour l'exploitation du questionnaire de recueil de données sur la qualité d'un réseau de surveillance épidémiologique d'une maladie présente. Annexe 4 - Guide pour l'exploitation du questionnaire de recueil de données sur la qualité d'un réseau de surveillance épidémiologique d'une maladie rare ou exotique. Annexe 5 - Utilisation des questions récapitulatives pour l'animation participative des séances de formation des intervenants d'un réseau de surveillance épidémiologique. Annexe 6 - Fiche de synthèse d'un programme de formation; Bibliographie
- Published
- 2007
119. Emergence and clonal expansion of Vibrio aestuarianus lineages pathogenic for oysters in Europe.
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Mesnil A, Jacquot M, Garcia C, Tourbiez D, Canier L, Bidois A, Dégremont L, Cheslett D, Geary M, Vetri A, Roque A, Furones D, Garden A, Orozova P, Arzul I, Sicard M, Charrière GM, Destoumieux-Garzón D, and Travers MA
- Subjects
- Animals, Europe, Vibrio genetics, Crassostrea genetics, Crassostrea microbiology
- Abstract
Crassostrea gigas oysters represent a significant global food source with 4.7 million tons harvested per year. In 2001, the bacterium Vibrio aestuarianus subsp. francensis emerged as a pathogen that causes adult oyster mortality in France and Ireland. Its impact on oyster aquaculture has increased in Europe since its re-emergence in 2012. To better understand the evolutionary mechanisms leading to the emergence and persistence over time of this pathogen, we conducted a survey of mollusc diseases through national reference laboratories across Europe. We analysed 54 new genomes of Vibrio aestuarianus (Va) isolated from multiple environmental compartments since 2001, in areas with and without bivalve mortalities. We used a combination of comparative genomics and population genetics approaches and show that Va has a classical epidemic population structure from which the pathogenic Va francensis subspecies emerged and clonally expanded. Furthermore, we identified a specific cus-cop-containing island conferring copper resistance to Va francensis whose acquisition may have favoured the emergence of pathogenic lineages adapted and specialized to oysters., (© 2023 Crown copyright. Molecular Ecology © 2023 John Wiley & Sons Ltd. This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland.)
- Published
- 2023
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120. Optimizing surveillance for early disease detection: Expert guidance for Ostreid herpesvirus surveillance design and system sensitivity calculation.
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Gustafson LL, Arzul I, Burge CA, Carnegie RB, Caceres-Martinez J, Creekmore L, Dewey W, Elston R, Friedman CS, Hick P, Hudson K, Lupo C, Rheault R, Spiegel K, and Vásquez-Yeomans R
- Subjects
- Animals, Aquaculture, Herpesviridae Infections diagnosis, Crassostrea virology, Herpesviridae, Herpesviridae Infections veterinary
- Abstract
To keep pace with rising opportunities for disease emergence and spread, surveillance in aquaculture must enable the early detection of both known and new pathogens. Conventional surveillance systems (designed to provide proof of disease freedom) may not support detection outside of periodic sampling windows, leaving substantial blind spots to pathogens that emerge in other times and places. To address this problem, we organized an expert panel to envision optimal systems for early disease detection, focusing on Ostreid herpesvirus 1 (OsHV-1), a pathogen of panzootic consequence to oyster industries. The panel followed an integrative group process to identify and weight surveillance system traits perceived as critical to the early detection of OsHV-1. Results offer a road map with fourteen factors to consider when building surveillance systems geared to early detection; factor weights can be used by planners and analysts to compare the relative value of different designs or enhancements. The results were also used to build a simple, but replicable, model estimating the system sensitivity (SSe) of observational surveillance and, in turn, the confidence in disease freedom that negative reporting can provide. Findings suggest that optimally designed observational systems can contribute substantially to both early detection and disease freedom confidence. In contrast, active surveillance as a singular system is likely insufficient for early detection. The strongest systems combined active with observational surveillance and engaged joint industry and government involvement: results suggest that effective partnerships can generate highly sensitive systems, whereas ineffective partnerships may seriously erode early detection capability. Given the costs of routine testing, and the value (via averted losses) of early detection, we conclude that observational surveillance is an important and potentially very effective tool for health management and disease prevention on oyster farms, but one that demands careful planning and participation. This evaluation centered on OsHV-1 detection in farmed oyster populations. However, many of the features likely generalize to other pathogens and settings, with the important caveat that the pathogens need to manifest via morbidity or mortality events in the species, life stages and environments under observation., (Published by Elsevier B.V.)
- Published
- 2021
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121. A new multiplex real-time PCR assay to improve the diagnosis of shellfish regulated parasites of the genus Marteilia and Bonamia.
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Canier L, Dubreuil C, Noyer M, Serpin D, Chollet B, Garcia C, and Arzul I
- Subjects
- Animals, France, Host-Parasite Interactions, Reproducibility of Results, Aquaculture methods, Multiplex Polymerase Chain Reaction methods, Ostrea parasitology, Real-Time Polymerase Chain Reaction methods, Rhizaria isolation & purification
- Abstract
Aquaculture including shellfish production is an important food resource worldwide which is particularly vulnerable to infectious diseases. Marteilia refringens, Bonamia ostreae and Bonamia exitiosa are regulated protozoan parasites infecting flat oysters Ostrea edulis that are endemic in Europe. Although some PCR assays have been already developed for their detection, a formal validation to assess the performances of those tools is often lacking. In order to facilitate the diagnosis of flat oyster regulated diseases, we have developed and evaluated a new multiplex Taqman® PCR allowing the detection of both M. refringens and Bonamia sp. parasites in one step. First part of this work consisted in assessing analytical sensitivity and specificity of the new PCR assay. Then, diagnostic performances were assessed by testing a panel of field samples with the new real-time PCR and currently recommended conventional PCR methods for the detection of M. refringens and Bonamia sp. Samples were collected from the main flat oyster production sites in France (N = 386 for M. refringens and N = 349 for B. ostreae). In the absence of gold standard, diagnostic sensitivity and specificity of the new PCR were estimated through Bayesian latent class analysis (DSe 87,2% and DSp 98,4% for the detection M. refringens, DSe 77,5% and DSp 98,4% for the detection of Bonamia sp.). Those results suggest equivalent performances for the detection of Bonamia sp. and an improved sensitivity for the detection of M. refringens compared to commonly used conventional protocols. Finally, the new PCR was evaluated in the context of an inter-laboratory comparison study including 17 European laboratories. Results revealed a very good reproducibility with a global accordance (intra-laboratory precision) >96% and a global concordance (inter-laboratory precision) >93% for both targets, demonstrating that this new tool is easily transferable to different laboratory settings. This is the first assay designed to detect both Marteilia refringens and Bonamia sp. in a single step and it should allow reducing the number of analysis to monitor both diseases, and where relevant to demonstrate freedom from infection., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2020
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122. Global invasion genetics of two parasitic copepods infecting marine bivalves.
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Feis ME, Goedknegt MA, Arzul I, Chenuil A, Boon OD, Gottschalck L, Kondo Y, Ohtsuka S, Shama LNS, Thieltges DW, Wegner KM, and Luttikhuizen PC
- Subjects
- Animals, Copepoda classification, Copepoda physiology, Europe, North America, Phylogeny, Phylogeography, Bivalvia parasitology, Copepoda genetics, Introduced Species
- Abstract
Invasive species, and especially invasive parasites, represent excellent models to study ecological and evolutionary mechanisms in the wild. To understand these processes, it is crucial to obtain more knowledge on the native range, invasion routes and invasion history of invasive parasites. We investigated the consecutive invasions of two parasitic copepods (Mytilicola intestinalis and Mytilicola orientalis) by combining an extensive literature survey covering the reported putative native regions and the present-day invaded regions with a global phylogeography of both species. The population genetic analyses based on partial COI sequences revealed significant population differentiation for M. orientalis within the native region in Japan, while introduced populations in North America and Europe could not be distinguished from the native ones. Thus, M. orientalis' invasion history resembles the genetic structure and recent spread of its principal host, the Pacific oyster, Crassostrea gigas, while M. intestinalis lacks population genetic structure and has an overall low genetic diversity. Therefore, the native origin of M. intestinalis remains unclear. With this study, we demonstrate that even highly related and biologically similar invasive species can differ in their invasion genetics. From this, we conclude that extrapolating invasion genetics dynamics from related invasive taxa may not always be possible.
- Published
- 2019
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- View/download PDF
123. Recommended reporting standards for test accuracy studies of infectious diseases of finfish, amphibians, molluscs and crustaceans: the STRADAS-aquatic checklist.
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Gardner IA, Whittington RJ, Caraguel CG, Hick P, Moody NJ, Corbeil S, Garver KA, Warg JV, Arzul I, Purcell MK, Crane MS, Waltzek TB, Olesen NJ, and Gallardo Lagno A
- Subjects
- Animals, Diagnostic Tests, Routine standards, Guidelines as Topic, Host-Pathogen Interactions, Publishing standards, Amphibians microbiology, Communicable Diseases veterinary, Crustacea microbiology, Diagnostic Tests, Routine veterinary, Fish Diseases microbiology, Fishes, Mollusca microbiology
- Abstract
Complete and transparent reporting of key elements of diagnostic accuracy studies for infectious diseases in cultured and wild aquatic animals benefits end-users of these tests, enabling the rational design of surveillance programs, the assessment of test results from clinical cases and comparisons of diagnostic test performance. Based on deficiencies in the Standards for Reporting of Diagnostic Accuracy (STARD) guidelines identified in a prior finfish study (Gardner et al. 2014), we adapted the Standards for Reporting of Animal Diagnostic Accuracy Studies-paratuberculosis (STRADAS-paraTB) checklist of 25 reporting items to increase their relevance to finfish, amphibians, molluscs, and crustaceans and provided examples and explanations for each item. The checklist, known as STRADAS-aquatic, was developed and refined by an expert group of 14 transdisciplinary scientists with experience in test evaluation studies using field and experimental samples, in operation of reference laboratories for aquatic animal pathogens, and in development of international aquatic animal health policy. The main changes to the STRADAS-paraTB checklist were to nomenclature related to the species, the addition of guidelines for experimental challenge studies, and the designation of some items as relevant only to experimental studies and ante-mortem tests. We believe that adoption of these guidelines will improve reporting of primary studies of test accuracy for aquatic animal diseases and facilitate assessment of their fitness-for-purpose. Given the importance of diagnostic tests to underpin the Sanitary and Phytosanitary agreement of the World Trade Organization, the principles outlined in this paper should be applied to other World Organisation for Animal Health (OIE)-relevant species.
- Published
- 2016
- Full Text
- View/download PDF
124. Bonamia parasites: a rapidly changing perspective on a genus of important mollusc pathogens.
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Engelsma MY, Culloty SC, Lynch SA, Arzul I, and Carnegie RB
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- Animals, Haplosporida genetics, Host-Parasite Interactions, Phylogeny, Haplosporida physiology, Ostreidae parasitology
- Abstract
Organisms of the genus Bonamia are intracellular protistan parasites of oysters. To date, 4 species have been described (B. ostreae, B. exitiosa, B. perspora and B. roughleyi), although the status of B. roughleyi is controversial. Introduction especially of B. ostreae and B. exitiosa to naïve host populations has been shown to cause mass mortalities in the past and has had a dramatic impact on oyster production. Both B. ostreae and B. exitiosa are pathogens notifiable to the World Organisation for Animal Health (OIE) and the European Union. Effective management of the disease caused by these pathogens is complicated by the extensive nature of the oyster production process and limited options for disease control of the cultured stocks in open water. This review focuses on the recent advances in research on genetic relationships between Bonamia isolates, geographical distribution, susceptible host species, diagnostics, epizootiology, host-parasite interactions, and disease resistance and control of this globally important genus of oyster pathogens.
- Published
- 2014
- Full Text
- View/download PDF
125. Molecular characterisation of an Australian isolate of Bonamia exitiosa.
- Author
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Corbeil S, Arzul I, Robert M, Berthe FC, Besnard-Cochennec N, and Crane MS
- Subjects
- Animals, Base Sequence, DNA Primers chemistry, DNA, Protozoan chemistry, DNA, Protozoan isolation & purification, Haplosporida isolation & purification, Molecular Sequence Data, New South Wales, Sequence Alignment, DNA, Ribosomal Spacer genetics, Haplosporida genetics, Ostrea parasitology, RNA, Ribosomal, 18S genetics
- Abstract
An Australian (New South Wales) isolate of Bonamia was characterised at the molecular level by sequencing the 18S-ITS-1 region of the small subunit rRNA operon obtained from flat oysters Ostrea angasi shown to be infected by histological examination. Sequence data alignment with homologous genes from 2 other isolates of Bonamia (New Zealand and France) revealed high levels of nucleotide identity with both isolates. However, the Australian Bonamia is shown to be more closely related to the New Zealand isolate, suggesting the existence of an oceanic subgroup of Bonamia.
- Published
- 2006
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126. Development of a TaqMan PCR assay for the detection of Bonamia species.
- Author
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Corbeil S, Arzul I, Diggles B, Heasman M, Chollet B, Berthe FC, and Crane MS
- Subjects
- Animals, DNA Primers chemistry, DNA, Protozoan isolation & purification, Haplosporida genetics, RNA, Ribosomal, 18S genetics, Reproducibility of Results, Sensitivity and Specificity, DNA, Protozoan analysis, Haplosporida isolation & purification, Ostrea parasitology, Polymerase Chain Reaction methods
- Abstract
The development of molecular diagnostic assays with increased sensitivity compared with conventional histological techniques is highly desirable for effective management of bonamiosis in cultured oyster stocks and wild populations. A real-time TaqMan PCR assay was developed for the specific detection of Bonamia species in infected oyster tissues. The TaqMan assay was shown to be significantly more sensitive than histopathology. Although a real-time TaqMan PCR assay is comparable with conventional PCR in terms of sensitivity, it offers the advantages that it is a rapid test and has a very low risk of sample cross-contamination. Furthermore, it can be optimised to quantify the parasite load in samples. The assay detected Bonamia isolates from Australia, New Zealand, Europe, Canada, Chile and the USA and therefore demonstrated genus specificity as tested in this study.
- Published
- 2006
- Full Text
- View/download PDF
127. Viral gametocytic hypertrophy of Crassostrea gigas in France: from occasional records to disease emergence?
- Author
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Garcia C, Robert M, Arzul I, Chollet B, Joly JP, Miossec L, Comtet T, and Berthe F
- Subjects
- Animals, Female, France, Germ Cells pathology, Germ Cells virology, Male, Oocytes virology, Spermatozoa pathology, Spermatozoa virology, Viruses ultrastructure, Crassostrea virology, Viruses isolation & purification, Viruses pathogenicity
- Abstract
Viral gametocytic hypertrophy was reported for the first time in 2001 in Pacific oyster Crassostrea gigas in France. Since this date, the number of reported cases and the distribution area have increased every year; however, the cases are not associated with macroscopic signs or increased mortality rates. Both male and female gametes were hypertrophied and basophilic inclusions were observed in gamete nuclei. Transmission electron microscopy revealed the presence of viral particles in these intranuclear basophilic inclusions. These particles had characteristics similar to those of the Papillomaviridae and Polyoma viridae families: they were small, non-enveloped, icosahedral, and 44 to 56 nm in diameter. The viral particles were found in male, female and hermaphrodite oysters and no significant difference in viral infection was observed between those groups. The frequency of detection and the intensity of infection were low and no host defence reaction was recognised, suggesting that the viral particles had a weak impact on C. gigas. The viral particles described in the present study seem to be similar to these described in C. virginica in the USA and Canada and in C. gigas in Korea, but further studies are required to confirm their identity. The issue of a possible emergence of this infection is discussed.
- Published
- 2006
- Full Text
- View/download PDF
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