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Nielsen SS, Alvarez J, Bicout D, Calistri P, Canali E, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Smith CG, Herskin M, Michel V, Miranda Chueca MA, Padalino B, Roberts H, Spoolder H, Ståhl K, Velarde A, Viltrop A, Winckler C, Arzul I, Dharmaveer S, Olesen NJ, Schiøtt M, Sindre H, Stone D, Vendramin N, Antoniou S, Dhollander S, Karagianni AE, Kero LL, Gnocchi M, Aznar I, Barizzone F, Munoz Guajardo IP, Roberts H. Species which may act as vectors or reservoirs of diseases covered by the Animal Health Law: Listed pathogens of molluscs. EFSA J 2023; 21:e08173. [PMID: 37533748 PMCID: PMC10392592 DOI: 10.2903/j.efsa.2023.8173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2023] [Indexed: 08/04/2023] Open
Abstract
Vector or reservoir species of five mollusc diseases listed in the Animal Health Law were identified, based on evidence generated through an extensive literature review, to support a possible updating of Regulation (EU) 2018/1882. Mollusc species on or in which Mikrocytos mackini, Perkinsus marinus, Bonamia exitiosa, Bonamia ostreae and Marteilia refringens were detected, in the field or during experiments, were classified as reservoir species with different levels of certainty depending on the diagnostic tests used. Where experimental evidence indicated transmission of the pathogen from a studied species to another known susceptible species, this studied species was classified as a vector species. Although the quantification of the risk of spread of the pathogens by the vectors or reservoir species was not part of the terms of reference, such risks do exist for the vector species, since transmission from infected vector species to susceptible species was proven. Where evidence for transmission from infected molluscs was not found, these were defined as reservoir. Nonetheless, the risk of the spread of the pathogens from infected reservoir species cannot be excluded. Evidence identifying conditions that may prevent transmission by vectors or reservoir mollusc species during transport was collected from scientific literature. It was concluded that it is very likely to almost certain (90-100%) that M. mackini, P. marinus, B. exitiosa B. ostreae and M. refringens will remain infective at any possible transport condition. Therefore, vector or reservoir species that may have been exposed to these pathogens in an affected area in the wild or at aquaculture establishments or through contaminated water supply can possibly transmit these pathogens. For transmission of M. refringens, the presence of an intermediate host, a copepod, is necessary.
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Mérou N, Lecadet C, Ubertini M, Pouvreau S, Arzul I. Environmental distribution and seasonal dynamics of Marteilia refringens and Bonamia ostreae, two protozoan parasites of the European flat oyster, Ostrea edulis. Front Cell Infect Microbiol 2023; 13:1154484. [PMID: 37384224 PMCID: PMC10293890 DOI: 10.3389/fcimb.2023.1154484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/16/2023] [Indexed: 06/30/2023] Open
Abstract
Introduction Marteilia refringens and Bonamia ostreae are protozoan parasites responsible for mortalities of farmed and wild flat oysters Ostrea edulis in Europe since 1968 and 1979, respectively. Despite almost 40 years of research, the life-cycle of these parasites is still poorly known, especially regarding their environmental distribution. Methods We carried out an integrated field study to investigate the dynamics of M. refringens and B. ostreae in Rade of Brest, where both parasites are known to be present. We used real-time PCR to monitor seasonally over four years the presence of both parasites in flat oysters. In addition, we used previously developed eDNA based-approaches to detect parasites in planktonic and benthic compartments for the last two years of the survey. Results M. refringens was detected in flat oysters over the whole sampling period, sometimes with a prevalence exceeding 90%. It was also detected in all the sampled environmental compartments, suggesting their involvement in parasite transmission and overwintering. In contrast, B. ostreae prevalence in flat oysters was low and the parasite was almost never detected in planktonic and benthic compartments. Finally, the analysis of environmental data allowed describing the seasonal dynamics of both parasites in Rade of Brest: M. refringens was more detected in summer and fall than in winter and spring, contrary to B. ostreae which showed higher prevalence in winter and spring. Discussion The present study emphasizes the difference between M. refringens and B. ostreae ecology, the former presenting a wider environmental distribution than the latter, which seems closely associated to flat oysters. Our findings highlight the key role of planktonic and benthic compartments in M. refringens transmission and storage or potential overwintering, respectively. More generally, we provide here a method that could be useful not only to further investigate non cultivable pathogens life-cycle, but also to support the design of more integrated surveillance programs.
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Affiliation(s)
- Nicolas Mérou
- Adaptation et Santé des Invertébrés Marins (ASIM), Ifremer, La Tremblade, France
- POS3IDON, R&D Department, Saint Malo, France
| | - Cyrielle Lecadet
- Adaptation et Santé des Invertébrés Marins (ASIM), Ifremer, La Tremblade, France
| | | | - Stéphane Pouvreau
- Laboratoire des Sciences de l’Environnement Marin (LEMAR), Unité Mixte de Recherche (UMR) 6539 Ifremer/Université de Bretagne Occidentale (UBO)/Institut de Recherche pour le Développement (IRD)/Centre National de la Recherche Scientifique (CNRS), Ifremer, Argenton-en-Landunvez, France
| | - Isabelle Arzul
- Adaptation et Santé des Invertébrés Marins (ASIM), Ifremer, La Tremblade, France
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Hanea AM, Hilton Z, Knight B, P. Robinson A. Co-designing and building an expert-elicited non-parametric Bayesian network model: demonstrating a methodology using a Bonamia Ostreae spread risk case study. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2022; 42:1235-1254. [PMID: 35187670 PMCID: PMC9303608 DOI: 10.1111/risa.13904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The development and use of probabilistic models, particularly Bayesian networks (BN), to support risk-based decision making is well established. Striking an efficient balance between satisfying model complexity and ease of development requires continuous compromise. Codesign, wherein the structural content of the model is developed hand-in-hand with the experts who will be accountable for the parameter estimates, shows promise, as do so-called nonparametric Bayesian networks (NPBNs), which provide a light-touch approach to capturing complex relationships among nodes. We describe and demonstrate the process of codesigning, building, quantifying, and validating an NPBN model for emerging risks and the consequences of potential management decisions using structured expert judgment (SEJ). We develop a case study of the local spread of a marine pathogen, namely, Bonamia ostreae. The BN was developed through a series of semistructured workshops that incorporated extensive feedback from many experts. The model was then quantified with a combination of field and expert-elicited data. The IDEA protocol for SEJ was used in its hybrid (remote and face-to-face) form to elicit information about more than 100 parameters. This article focuses on the modeling and quantification process, the methodological challenges, and the way these were addressed.
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Affiliation(s)
- Anca M. Hanea
- Centre of Excellence for Biosecurity Risk AnalysisUniversity of MelbourneParkvilleVictoriaAustralia
| | | | | | - Andrew P. Robinson
- Centre of Excellence for Biosecurity Risk AnalysisUniversity of MelbourneParkvilleVictoriaAustralia
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Egerton S, Lynch SA, Prado-Alvarez M, Flannery G, Brennan E, Hugh-Jones T, Hugh-Jones D, Culloty SC. A Naïve Population of European Oyster Ostrea edulis with Reduced Susceptibility to the Pathogen Bonamia ostreae: Are S-Strategy Life Traits Providing Protection? Integr Comp Biol 2021; 60:249-260. [PMID: 32533837 DOI: 10.1093/icb/icaa071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
European populations of the native flat oyster, Ostrea edulis, have been heavily depleted by two protozoan parasites, Marteila refringens and Bonamia ostreae, with mortalities of up to 90% reported in naïve populations. However, in studies carried out over a 10-year period, researching the parasite-host relationship of B. ostreae and O. edulis in several age cohorts within a naïve O. edulis population from Loch Ryan (LR), Scotland, 1364 specimens were challenged and only 64 (5%), across multiple testing protocols, screened positive for B. ostreae. This article presents a case for the development of S-strategy life traits in the LR population that coincide with enhanced immune function and survival. Oysters are considered typical r-strategists (small in size with fast development and high fecundity) while S-strategists, as outlined in Grime's (1977) competitor-stress tolerant-ruderal (C-S-R) triangle theory, are characterized by slow growth and investment in the durability of individuals. This study hypothesizes that slower growth and reduced reproductive output in LR oysters has resulted in the investment of an enhanced immune function and reduced susceptibility to B. ostreae that is, r-strategists with S-strategy life traits equates to protection from significant pathogens. The findings presented here within provide a strong case study for local adaptation of energy allocation and provides empirical support for the C-S-R triangle theory in a marine organism.
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Affiliation(s)
- Sian Egerton
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
| | - Sharon A Lynch
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
| | - Maria Prado-Alvarez
- Marine Molecular Pathobiology Research Group, Institute of Marine Research, Spanish National Research Council (CSIC), Vigo, Pontevedra, Spain
| | | | - Elaine Brennan
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
| | - Tristan Hugh-Jones
- Atlantic Shellfish Ltd, Rossmore, Carrigtwohill, Co. Cork, Ireland.,Loch Ryan Oysters, Loch Ryan, Scotland, UK
| | - David Hugh-Jones
- Atlantic Shellfish Ltd, Rossmore, Carrigtwohill, Co. Cork, Ireland.,Loch Ryan Oysters, Loch Ryan, Scotland, UK
| | - Sarah C Culloty
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.,MaREI centre, Environmental Research Institute, University College Cork, Cork, Ireland
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5
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Prado-Alvarez M, García-Fernández P, Faury N, Azevedo C, Morga B, Gestal C. First detection of OsHV-1 in the cephalopod Octopus vulgaris. Is the octopus a dead-end for OsHV-1? J Invertebr Pathol 2021; 183:107553. [PMID: 33596434 DOI: 10.1016/j.jip.2021.107553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/28/2021] [Accepted: 02/09/2021] [Indexed: 11/29/2022]
Abstract
The ostreid herpes virus (OsHV-1), associated with massive mortalities in the bivalve Crassostrea gigas, was detected for the first time in the cephalopod Octopus vulgaris. Wild adult animals from a natural breeding area in Spain showed an overall prevalence of detection of 87.5% between 2010 and 2015 suggesting an environmental source of viral material uptake. Overall positive PCR detections were significantly higher in adult animals (p = 0.031) compared to newly hatched paralarvae (62%). Prevalence in embryos reached 65%. Sequencing of positive amplicons revealed a match with the variant OsHV-1 µVar showing the genomic features that distinguish this variant in the ORF4. Gill tissues from adult animals were also processed for in situ hybridization and revealed positive labelling. Experimental exposure trials in octopus paralarvae were carried out by cohabitation with virus injected oysters and by immersion in viral suspension observing a significant decrease in paralarval survival in both experiments. An increase in the number of OsHV-1 positive animals was detected in dead paralarvae after cohabitation with virus injected oysters. No signs of viral replication were observed based on lack of viral gene expression or visualization of viral structures by transmission electron microscopy. The octopus response against OsHV-1 was evaluated by gene expression of previously reported transcripts involved in immune response in C. gigas suggesting that immune defences in octopus are also activated after exposure to OsHV-1.
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Affiliation(s)
- Maria Prado-Alvarez
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain.
| | - Pablo García-Fernández
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain
| | - Nicole Faury
- IFREMER, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390 La Tremblade, France
| | - Carlos Azevedo
- Interdisciplinary Center of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal; Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Benjamin Morga
- IFREMER, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390 La Tremblade, France
| | - Camino Gestal
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain.
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Bookelaar B, Lynch SA, Culloty SC. Host plasticity supports spread of an aquaculture introduced virus to an ecosystem engineer. Parasit Vectors 2020; 13:498. [PMID: 33004060 PMCID: PMC7528252 DOI: 10.1186/s13071-020-04373-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/20/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The common cockle Cerastoderma edule plays an important ecological role in the marine ecosystem both as an infaunal engineer (reef forming and bioturbation) and a food source for protected bird species in its European range. Cockle beds are found in close proximity to aquaculture and fisheries operations, which can be "hot spots" for infectious agents including viruses and bacteria. Ostreid herpesvirus-1 microVar (OsHV-1 μVar) has spread to many Pacific oyster Crassostrea gigas culture sites globally, where it has been associated with significant mortalities in this cultured bivalve. Knowledge on the impact of the virus on the wider ecosystem, is limited. As the likelihood of released virus dispersing into the wider aquatic ecosystem is high, the plasticity of the virus and the susceptibility of C. edule to act as hosts or carriers is unknown. METHODS In this study, wild C. edule were sampled biweekly at two C. gigas culture sites over a four-month period during the summer when OsHV-1 μVar prevalence is at its highest in oysters. C. edule were screened for the virus molecularly (PCR, qPCR and Sanger sequencing) and visually (in situ hybridisation (ISH)). The cockle's ability to act as a carrier and transmit OsHV-1 μVar to the oyster host at a temperature of 14 ℃, when the virus is considered to be dormant until water temperatures exceed 16 ℃, was also assessed in laboratory transmission trials. RESULTS The results demonstrated that OsHV-1 μVar was detected in all C. edule size/age cohorts, at both culture sites. In the laboratory, viral transmission was effected from cockles to naïve oysters for the first time, five days post-exposure. The laboratory study also demonstrated that OsHV-1 μVar was active and was successfully transmitted from the C. edule at lower temperatures. CONCLUSIONS This study demonstrates that OsHV-1 μVar has the plasticity to infect the keystone species C. edule and highlights the possible trophic transmission of the virus from cockles to their mobile top predators. This scenario would have important implications, as a greater geographical range expansion of this significant pathogen via migratory bird species may have an impact on other species that reside in bird habitats most of which are special areas of conservation.
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Affiliation(s)
- Babette Bookelaar
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.,Aquaculture and Fisheries Development Centre and Environmental Research Institute, University College Cork, Cork, Ireland
| | - Sharon A Lynch
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland. .,Aquaculture and Fisheries Development Centre and Environmental Research Institute, University College Cork, Cork, Ireland.
| | - Sarah C Culloty
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.,Aquaculture and Fisheries Development Centre and Environmental Research Institute, University College Cork, Cork, Ireland.,MaREI Centre, Environmental Research Institute, University College Cork, Cork, Ireland
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8
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Helmer L, Hauton C, Bean T, Bass D, Hendy I, Harris-Scott E, Preston J. Ephemeral detection of Bonamia exitiosa (Haplosporida) in adult and larval European flat oysters Ostrea edulis in the Solent, United Kingdom. J Invertebr Pathol 2020; 174:107421. [PMID: 32522659 DOI: 10.1016/j.jip.2020.107421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 11/24/2022]
Abstract
The haplosporidian parasite Bonamia exitiosa was detected using PCR in four adult and six larval brood samples of the European flat oyster Ostrea edulis from the Solent, UK. This represents the second reported detection of this parasite along the south coast of England. Adult oysters were collected and preserved from seabed populations or restoration broodstock cages between 2015 and 2018. The larvae within brooding adults sampled during 2017 and 2018 were also preserved. Molecular analysis of all samples was performed in 2019. The DNA of B. exitiosa was confirmed to be present within the gill tissue of one oyster within the Portsmouth wild fishery seabed population (n = 48), sampled in November 2015; the congeneric parasite Bonamia ostreae was not detected in this individual. This is the earliest record of B. exitiosa in the Solent. Concurrent presence of both B. ostreae and B. exitiosa, determined by DNA presence, was confirmed in the gill and heart tissue of three mature individuals from broodstock cages sampled in October 2017 (n = 99), two from a location on the River Hamble and one from the Camber Dock in Portsmouth Harbour. B. exitiosa was not detected in the November 2018 broodstock populations. A total of six larval broods were positive for B. exitiosa, with five also positive for B. ostreae. None of the brooding adults were positive for B. exitiosa suggesting that horizontal transmission from the surrounding environment to the brooding larvae is occurring. Further sampling of broodstock populations conducted by the Fish Health Inspectorate at the Centre for Environment, Fisheries and Aquaculture Science in June 2019 did not detect infection of O. edulis by B. exitiosa. These findings together suggest that the pathogen has not currently established in the area.
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Affiliation(s)
- Luke Helmer
- Institute of Marine Sciences, University of Portsmouth, Portsmouth, UK; Blue Marine Foundation, London, UK.
| | - Chris Hauton
- Ocean and Earth Science, University of Southampton, Southampton, UK.
| | - Tim Bean
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK.
| | - David Bass
- Centre for Environment, Fisheries and Aquaculture Science, Weymouth, UK.
| | - Ian Hendy
- Institute of Marine Sciences, University of Portsmouth, Portsmouth, UK; Blue Marine Foundation, London, UK.
| | - Eric Harris-Scott
- Institute of Marine Sciences, University of Portsmouth, Portsmouth, UK.
| | - Joanne Preston
- Institute of Marine Sciences, University of Portsmouth, Portsmouth, UK.
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9
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Buss JJ, Wiltshire KH, Harris JO, Tanner JE, Deveney MR. Infection dynamics of Bonamia exitiosa on intertidal Ostrea angasi farms. JOURNAL OF FISH DISEASES 2020; 43:359-369. [PMID: 31918456 DOI: 10.1111/jfd.13134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Bonamia spp. cause epizootics in oysters worldwide. In southern Australia, Bonamia exitiosa Hine, Cochennac and Berthe, 2001 threatens aquaculture of Ostrea angasi Sowerby, 1871. Bonamia spp. infections can display strong seasonality, but seasonal dynamics of B. exitiosa-O. angasi are unknown. Ostrea angasi naïve to B. exitiosa infection were stocked onto farms in three growing regions, and B. exitiosa was monitored seasonally for one year. Environmental parameters we measured did not correlate with B. exitiosa prevalence or infection intensities. Extreme temperatures suggest O. angasi culture systems need development. Bonamia exitiosa prevalence increased over time. After three months, O. angasi had B. exitiosa prevalence of 0.08-0.4, and after one year, the prevalence was 0.57-0.88. At some sites, O. angasi had >0.5 B. exitiosa prevalence in >6 months, but at other sites, >9 months passed before prevalence was >0.5. Bonamia exitiosa infection intensities were low with no seasonal pattern but were affected by the interaction of site, season and oyster meat:shell ratio. Understanding infection and initiating a breeding programme for resistance would provide benefits for O. angasi industry expansion.
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Affiliation(s)
- Jessica Jamuna Buss
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
- South Australian Research and Development Institute (SARDI), Aquatic Sciences Centre and Marine Innovation Southern Australia, West Beach, SA, Australia
| | - Kathryn Helen Wiltshire
- South Australian Research and Development Institute (SARDI), Aquatic Sciences Centre and Marine Innovation Southern Australia, West Beach, SA, Australia
| | - James Owen Harris
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
- South Australian Research and Development Institute (SARDI), Aquatic Sciences Centre and Marine Innovation Southern Australia, West Beach, SA, Australia
| | - Jason Elliot Tanner
- South Australian Research and Development Institute (SARDI), Aquatic Sciences Centre and Marine Innovation Southern Australia, West Beach, SA, Australia
| | - Marty Robert Deveney
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
- South Australian Research and Development Institute (SARDI), Aquatic Sciences Centre and Marine Innovation Southern Australia, West Beach, SA, Australia
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10
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Is pallial mucus involved in Ostrea edulis defenses against the parasite Bonamia ostreae? J Invertebr Pathol 2019; 169:107259. [PMID: 31805287 DOI: 10.1016/j.jip.2019.107259] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 10/10/2019] [Accepted: 10/12/2019] [Indexed: 02/04/2023]
Abstract
Bonamia ostreae is an intrahemocytic parasite that has been responsible for severe mortalities in the flat oyster Ostrea edulis since the 1970́s. The Pacific oyster Crassostrea gigas is considered to be resistant to the disease and appears to have mechanisms to avoid infection. Most studies carried out on the invertebrate immune system focus on the role of hemolymph, although mucus, which covers the body surface of molluscs, could also act as a barrier against pathogens. In this study, the in vitro effect of mucus from the oyster species Ostrea edulis and C. gigas on B. ostreae was investigated using flow cytometry. Results showed an increase in esterase activities and mortality rate of parasites exposed to mucus from both oyster species. In order to better understand the potential role of mucus in the defense of the oyster against parasites such as B. ostreae, liquid chromatography and tandem mass spectrometry were used to describe and compare mucus protein composition from both species. In all oyster species, pallial mucus contains a high level of proteins; however, O. edulis mucus produced a variety of proteins that could be involved in the immune response against the parasite, including Cu/Zn extracellular superoxide dismutase, thioxiredoxin, peroxiredon VI, heat shock protein 90 as well as several hydrolases. Conversely, a different set of antioxidant proteins, hydrolases and stress related proteins were identified in mucus from C. gigas. Our results suggest an innate immunity adaptation of oysters to develop a specific response against their respective pathogens. The mucosal protein composition also provides new insights for further investigations into the immune response in oysters.
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11
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Buss JJ, Wiltshire KH, Prowse TAA, Harris JO, Deveney MR. Bonamia in Ostrea angasi: Diagnostic performance, field prevalence and intensity. JOURNAL OF FISH DISEASES 2019; 42:63-74. [PMID: 30324720 DOI: 10.1111/jfd.12906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/07/2018] [Accepted: 09/07/2018] [Indexed: 06/08/2023]
Abstract
Bonamia spp. parasites threaten flat oyster (Ostrea spp.) farming worldwide. Understanding test performance is important for designing surveillance and interpreting diagnostic results. Following a pilot survey which found low Bonamia sp. intensity in farmed Ostrea angasi, we tested further oysters (n = 100-150) from each of three farms for Bonamia sp. using heart smear, histology and qPCR. We used a Bayesian Latent Class Model to assess diagnostic sensitivity (DSe) and specificity (DSp) of these tests individually or in combination, and to assess prevalence. Histology was the best individual test (DSe 0.76, DSp 0.93) compared to quantitative polymerase chain reaction (qPCR) (DSe 0.69, DSp 0.93) and heart smear (DSe 0.61, DSp 0.60). Histology combined with qPCR and defining a positive from either test as an infected case maximized test performance (DSe 0.91, DSp 0.88). Prevalence was higher at two farms in a high-density oyster growing region than at a farm cultivating oysters at lower density. Parasite intensities were lower than in New Zealand and European studies, and this is probably contributed to differences in the performance of test when compared to other studies. Understanding diagnostic test performance in different populations can support the development of improved Bonamia surveillance programs.
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Affiliation(s)
- Jessica J Buss
- College of Science and Engineering, Flinders University, Adelaide, SA, 5042, Australia
- South Australian Research and Development Institute (SARDI) Aquatic Sciences and Marine Innovation Southern Australia, Adelaide, SA, 5024, Australia
| | - Kathryn H Wiltshire
- South Australian Research and Development Institute (SARDI) Aquatic Sciences and Marine Innovation Southern Australia, Adelaide, SA, 5024, Australia
| | - Thomas A A Prowse
- School of Mathematical Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - James O Harris
- College of Science and Engineering, Flinders University, Adelaide, SA, 5042, Australia
| | - Marty R Deveney
- South Australian Research and Development Institute (SARDI) Aquatic Sciences and Marine Innovation Southern Australia, Adelaide, SA, 5024, Australia
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12
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Bookelaar BE, O'Reilly AJ, Lynch SA, Culloty SC. Role of the intertidal predatory shore crab Carcinus maenas in transmission dynamics of ostreid herpesvirus-1 microvariant. DISEASES OF AQUATIC ORGANISMS 2018; 130:221-233. [PMID: 30259874 DOI: 10.3354/dao03264] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ostreid herpesvirus-1 microVar (OsHV-1 µVar) has been responsible for significant mortalities globally in the Pacific oyster Crassostrea gigas. While the impact of this virus on the Pacific oyster has been significant, this pathogen may have wider ecosystem consequences. It has not been definitively determined how the virus is sustaining itself in the marine environment and whether other species are susceptible. The shore crab Carcinus maenas is a mobile predator and scavenger of C. gigas, commonly found at Pacific oyster culture sites. The aim of this study was to investigate the role of the crab in viral maintenance and transmission to the Pacific oyster. A field trial took place over 1 summer at different shore heights at 2 Irish Pacific oyster culture sites that are endemic for OsHV-1 µVar. Infection of OsHV-1 µVar in tissues of C. maenas at both shore heights of both sites was detected by polymerase chain reaction (PCR), quantitative PCR (qPCR), in situ hybridization and direct Sanger sequencing. In addition, a laboratory trial demonstrated that transmission of the virus could occur to naïve C. gigas within 4 d, from C. maenas previously exposed to the virus in the wild. These findings provide some insight into the possibility that the virus can be transmitted through marine food webs. The results also suggest viral plasticity in the hosts required by the virus and potential impacts on a range of crustacean species with wider ecosystem impacts if transmission to other species occurs.
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Affiliation(s)
- B E Bookelaar
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences & Environmental Research Institute, University College Cork, Cork, Ireland
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13
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The role of the mussel Mytilus spp. in the transmission of ostreid herpesvirus-1 microVar. Parasitology 2017; 145:1095-1104. [PMID: 29262879 DOI: 10.1017/s0031182017002244] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The Pacific oyster Crassostrea gigas contributes significantly to global aquaculture; however, C. gigas culture has been affected by ostreid herpesvirus-1 (OsHV-1) and variants. The dynamics of how the virus maintains itself at culture sites is unclear and the role of carriers, reservoirs or hosts is unknown. Both wild and cultured mussels Mytilus spp. (Mytilus edulis, Mytilus galloprovincialis and hybrids) are commonly found at C. gigas culture sites. The objective of this study was to investigate if Mytilus spp. can harbour the virus and if viral transmission can occur between mussels and oysters. Mytilus spp. living at oyster trestles, 400-500 m higher up the shore from the trestles and up to 26 km at non-culture sites were screened for OsHV-1 and variants by all the World Organization for Animal Health (OIE) recommended diagnostic methods including polymerase chain reaction (PCR), quantitative PCR (qPCR), histology, in situ hybridization and confirmation using direct sequencing. The particular primers that target OsHV-1 and variants, including OsHV-1 microVar (μVar), were used in the PCR and qPCR. OsHV-1 μVar was detected in wild Mytilus spp. at C. gigas culture sites and more significantly the virus was detected in mussels at non-culture sites. Cohabitation of exposed wild mussels and naïve C. gigas resulted in viral transmission after 14 days, under an elevated temperature regime. These results indicate that mussels can harbour OsHV-1 μVar; however, the impact of OsHV-1 μVar on Mytilus spp. requires further investigation.
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Ma X, Li X, Sun G, Sharawy ZZ, Qiu T, Du Y, Liu Y. The biofilteration ability of oysters (Crassostrea gigas) to reduce Aeromonas salmonicida in salmon culture. Appl Microbiol Biotechnol 2017; 101:5869-5880. [DOI: 10.1007/s00253-017-8296-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/09/2017] [Accepted: 04/11/2017] [Indexed: 11/24/2022]
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Prado-Alvarez M, Darmody G, Hutton S, O'Reilly A, Lynch SA, Culloty SC. Occurrence of OsHV-1 in Crassostrea gigas Cultured in Ireland during an Exceptionally Warm Summer. Selection of Less Susceptible Oysters. Front Physiol 2016; 7:492. [PMID: 27877131 PMCID: PMC5099240 DOI: 10.3389/fphys.2016.00492] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
The occurrence of OsHV-1, a herpes virus causing mass mortality in the Pacific oyster Crassostrea gigas was investigated with the aim to select individuals with different susceptibility to the infection. Naïve spat transferred to infected areas and juveniles currently being grown at those sites were analyzed using molecular and histology approaches. The survey period distinguishes itself by very warm temperatures reaching up to 3.5°C above the average. The virus was not detected in the virus free area although a spread of the disease could be expected due to high temperatures. Overall mortality, prevalence of infection and viral load was higher in spat confirming the higher susceptibility in early life stages. OsHV-1 and oyster mortality were detected in naïve spat after 15 days of cohabitation with infected animals. Although, infection was associated with mortality in spat, the high seawater temperatures could also be the direct cause of mortality at the warmest site. One stock of juveniles suffered an event of abnormal mortality that was significantly associated with OsHV-1 infection. Those animals were infected with a previously undescribed microvariant whereas the other stocks were infected with OsHV-1 μVar. Cell lesions due to the infection were observed by histology and true infections were corroborated by in situ hybridization. Survivors from the natural outbreak were exposed to OsHV-1 μVar by intramuscular injection and were compared to naïve animals. The survival rate in previously exposed animals was significantly higher than in naïve oysters. Results derived from this study allowed the selection of animals that might possess interesting characteristics for future analysis on OsHV-1 resistance.
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Affiliation(s)
- Maria Prado-Alvarez
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Grainne Darmody
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Stephen Hutton
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Amy O'Reilly
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Sharon A Lynch
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Sarah C Culloty
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
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Gervais O, Chollet B, Renault T, Arzul I. Flat oyster follows the apoptosis pathway to defend against the protozoan parasite Bonamia ostreae. FISH & SHELLFISH IMMUNOLOGY 2016; 56:322-329. [PMID: 27431587 DOI: 10.1016/j.fsi.2016.07.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/12/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
The in vitro model Ostrea edulis hemocyte - Bonamia ostreae is interesting to investigate host-parasite interactions at the cellular level. Indeed, this unicellular parasite infects the flat oyster Ostrea edulis and multiplies within hemocytes, the central effectors of oyster defenses. Apoptosis is a mechanism used by many organisms to eliminate infected cells. In order to study the potential involvement of this mechanism in the oyster response to B. ostreae, in vitro experiments were carried out by exposing hemocytes from the naturally susceptible oyster O. edulis and a resistant oyster species Crassostrea gigas to live and heat-inactivated parasites. Hemocyte apoptotic response was measured using a combination of flow cytometry and microscopy analyses. Whatever the host species was, the parasite was engulfed in hemocytes and induced an increase of apoptotic parameters including intracytoplasmic calcium concentration, mitochondrial membrane potential or phosphatidyl-serine externalization as well as ultrastructural modifications. However, the parasite appears more able to infect flat oyster than cupped oyster hemocytes and the apoptotic response was more important against live than dead parasites in the natural host than in C. gigas. Our results suggest that O. edulis specifically responds to B. ostreae by inducing apoptosis of hemocytes.
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Affiliation(s)
- Ophélie Gervais
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390, La Tremblade, France
| | - Bruno Chollet
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390, La Tremblade, France
| | - Tristan Renault
- Ifremer, RBE, Centre de Nantes, Rue de l'Ile d'Yeu, F-44311, Nantes, France
| | - Isabelle Arzul
- Ifremer, RBE-SG2M-LGPMM, Station de La Tremblade, Avenue de Mus de Loup, F-17390, La Tremblade, France.
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Batista FM, López-Sanmartín M, Grade A, Navas JI, Ruano F. Detection of Bonamia exitiosa in the European flat oyster Ostrea edulis in southern Portugal. JOURNAL OF FISH DISEASES 2016; 39:607-611. [PMID: 26096446 DOI: 10.1111/jfd.12396] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/05/2015] [Accepted: 05/05/2015] [Indexed: 06/04/2023]
Affiliation(s)
- F M Batista
- Divisão de Aquicultura e Valorização, Instituto Português do Mar e da Atmosfera (IPMA), Lisboa, Portugal
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Faro, Portugal
| | - M López-Sanmartín
- Instituto de Investigación y Formación Agraria y Pesquera (IFAPA), Centro "Agua del Pino", Junta de Andalucía, Cartaya, Spain
| | - A Grade
- Divisão de Aquicultura e Valorização, Instituto Português do Mar e da Atmosfera (IPMA), Lisboa, Portugal
| | - J I Navas
- Instituto de Investigación y Formación Agraria y Pesquera (IFAPA), Centro "Agua del Pino", Junta de Andalucía, Cartaya, Spain
| | - F Ruano
- Divisão de Aquicultura e Valorização, Instituto Português do Mar e da Atmosfera (IPMA), Lisboa, Portugal
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Flannery G, Lynch SA, Culloty SC. Investigating the significance of the role of Ostrea edulis larvae in the transmission and transfer of Bonamia ostreae. J Invertebr Pathol 2016; 136:7-9. [PMID: 26880159 DOI: 10.1016/j.jip.2016.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 01/29/2016] [Accepted: 02/01/2016] [Indexed: 10/22/2022]
Abstract
In this study, the ability of oyster larvae, brooded in the pallial cavity of the parent oyster, to become infected in the pallial fluid, which is influenced by the brooding oyster and surrounding environment, was investigated. Larvae were collected over three summers from three areas around Ireland. Samples were screened for the presence of Bonamia ostreae DNA using PCR analysis. Four samples of larvae were found to be positive for B. ostreae DNA, though the parent oysters were negative for infection. Larvae may be able to acquire the pathogen from the water column during filter feeding or elimination of pseudo-faeces by the brooding adult.
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Affiliation(s)
- Grace Flannery
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork, Ireland.
| | - Sharon A Lynch
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork, Ireland
| | - Sarah C Culloty
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork, Ireland
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Lane HS, Webb SC, Duncan J. Bonamia ostreae in the New Zealand oyster Ostrea chilensis: a new host and geographic record for this haplosporidian parasite. DISEASES OF AQUATIC ORGANISMS 2016; 118:55-63. [PMID: 26865235 DOI: 10.3354/dao02960] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Previous reports of the haplosporidian parasite Bonamia ostreae have been restricted to the Northern Hemisphere, including Europe, and both eastern and western North America. This species is reported for the first time in New Zealand infecting the flat oyster Ostrea chilensis. Histological examination of 149 adult oysters identified 119 (79.9%) infected with Bonamia microcells. Bonamia generic PCR of several oysters followed by DNA sequencing of a 300 bp portion of the 18S rDNA gene produced a 100% match with that of B. ostreae. All DNA-sequenced products also produced a B. ostreae PCR-restriction fragment length polymorphism (PCR-RFLP) profile. Bonamia species-specific PCRs further detected single infections of B. exitiosa (2.7%), B. ostreae (40.3%), and concurrent infections (53.7%) with these 2 Bonamia species identifying overall a Bonamia prevalence of 96.6%. Detailed histological inspection revealed 2 microcell types. An infection identified by PCR as B. ostreae histologically presented small microcells (mean ± SE diameter = 1.28 ± 0.16 µm, range = 0.9-2 µm, n = 60) commonly with eccentric nuclei. A B. exitiosa infection exhibited larger microcells (mean ± SE diameter = 2.12 ± 0.27 µm, range = 1.5-4 µm, n = 60) with more concentric nuclei. Concurrent infections of both Bonamia species, as identified by PCR, exhibited both types of microcells. DNA barcoding of the B. ostreae-infected oyster host confirmed the identification as O. chilensis. A suite of other parasites that accompany O. chilensis are reported here for the first time in mixed infection with B. ostreae including apicomplexan X (76.5%), Microsporidium rapuae (0.7%) and Bucephalus longicornutus (30.2%).
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Affiliation(s)
- Henry S Lane
- Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
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The ecology, evolution, impacts and management of host-parasite interactions of marine molluscs. J Invertebr Pathol 2015; 131:177-211. [PMID: 26341124 DOI: 10.1016/j.jip.2015.08.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/10/2015] [Accepted: 08/12/2015] [Indexed: 11/22/2022]
Abstract
Molluscs are economically and ecologically important components of aquatic ecosystems. In addition to supporting valuable aquaculture and wild-harvest industries, their populations determine the structure of benthic communities, cycling of nutrients, serve as prey resources for higher trophic levels and, in some instances, stabilize shorelines and maintain water quality. This paper reviews existing knowledge of the ecology of host-parasite interactions involving marine molluscs, with a focus on gastropods and bivalves. It considers the ecological and evolutionary impacts of molluscan parasites on their hosts and vice versa, and on the communities and ecosystems in which they are a part, as well as disease management and its ecological impacts. An increasing number of case studies show that disease can have important effects on marine molluscs, their ecological interactions and ecosystem services, at spatial scales from centimeters to thousands of kilometers and timescales ranging from hours to years. In some instances the cascading indirect effects arising from parasitic infection of molluscs extend well beyond the temporal and spatial scales at which molluscs are affected by disease. In addition to the direct effects of molluscan disease, there can be large indirect impacts on marine environments resulting from strategies, such as introduction of non-native species and selective breeding for disease resistance, put in place to manage disease. Much of our understanding of impacts of molluscan diseases on the marine environment has been derived from just a handful of intensively studied marine parasite-host systems, namely gastropod-trematode, cockle-trematode, and oyster-protistan interactions. Understanding molluscan host-parasite dynamics is of growing importance because: (1) expanding aquaculture; (2) current and future climate change; (3) movement of non-native species; and (4) coastal development are modifying molluscan disease dynamics, ultimately leading to complex relationships between diseases and cultivated and natural molluscan populations. Further, in some instances the enhancement or restoration of valued ecosystem services may be contingent on management of molluscan disease. The application of newly emerging molecular tools and remote sensing techniques to the study of molluscan disease will be important in identifying how changes at varying spatial and temporal scales with global change are modifying host-parasite systems.
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Prado-Alvarez M, Lynch SA, Kane A, Darmody G, Pardo BG, Martínez P, Cotterill J, Wontner-Smith T, Culloty SC. Oral immunostimulation of the oyster Ostrea edulis: Impacts on the parasite Bonamia ostreae. FISH & SHELLFISH IMMUNOLOGY 2015; 45:43-51. [PMID: 25652290 DOI: 10.1016/j.fsi.2015.01.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 01/22/2015] [Accepted: 01/23/2015] [Indexed: 05/27/2023]
Abstract
Bioactive compounds were orally administered to the native European oyster Ostrea edulis to evaluate the immune response and the progression of infection of the protozoan parasite Bonamia ostreae. The immunostimulants lipopolysaccharide and zymosan directly administrated to the water column induced an increase in lysozyme activity and the percentage of granulocytes in naïve oysters over a period of 7 days. In another set of experiments, zymosan and curdlan were microencapsulated in alginate and also administered to the water column to naïve and B. ostreae infected O. edulis. Oyster mortality, prevalence and intensity of infection and several immune parameters were evaluated up to 28 days post-administration. Lysozyme activity, nitric oxide production and the expression of galectin, lysozyme and superoxide dismutase increased after 24 h in both infected and uninfected oysters. Zymosan immunostimulated oysters displayed a decrease in the prevalence of B. ostreae infection not attributed to mortalities but which could be associated to the enhanced ability of immunostimulants to evoke an enhanced immune response in the oysters and reduce infection.
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Affiliation(s)
- M Prado-Alvarez
- Aquaculture & Fisheries Development Centre, School of Biological, Earth & Environmental Science, University College Cork, The Cooperage, Distillery Fields, North Mall, Cork, Ireland.
| | - S A Lynch
- Aquaculture & Fisheries Development Centre, School of Biological, Earth & Environmental Science, University College Cork, The Cooperage, Distillery Fields, North Mall, Cork, Ireland
| | - A Kane
- Aquaculture & Fisheries Development Centre, School of Biological, Earth & Environmental Science, University College Cork, The Cooperage, Distillery Fields, North Mall, Cork, Ireland
| | - G Darmody
- Aquaculture & Fisheries Development Centre, School of Biological, Earth & Environmental Science, University College Cork, The Cooperage, Distillery Fields, North Mall, Cork, Ireland
| | - B G Pardo
- Departamento de Genética, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo, Spain
| | - P Martínez
- Departamento de Genética, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo, Spain
| | - J Cotterill
- The Food & Environment Research Agency, Sand Hutton, York YO41 1LZ, United Kingdom
| | - T Wontner-Smith
- The Food & Environment Research Agency, Sand Hutton, York YO41 1LZ, United Kingdom
| | - S C Culloty
- Aquaculture & Fisheries Development Centre, School of Biological, Earth & Environmental Science, University College Cork, The Cooperage, Distillery Fields, North Mall, Cork, Ireland
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22
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Lynch SA, Flannery G, Hugh-Jones T, Hugh-Jones D, Culloty SC. Thirty-year history of Irish (Rossmore) Ostrea edulis selectively bred for disease resistance to Bonamia ostreae. DISEASES OF AQUATIC ORGANISMS 2014; 110:113-121. [PMID: 25060503 DOI: 10.3354/dao02734] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The protistan pathogen Bonamia ostreae was first detected in Ostrea edulis at Rossmore, Cork Harbour, on the south coast of Ireland in 1987. A selective breeding programme commenced in 1988 by Atlantic Shellfish Ltd. to produce B. ostreae-resistant oysters using 3 to 4 yr old survivors as broodstock for controlled spawning in land-based spatting ponds. On-growing of oyster spat settled on mussel cultch was carried out on designated beds within Cork Harbour. Oyster production subsequently increased successfully, resulting in 3 yr old Rossmore O. edulis being marketed from 1993 onwards and a record tonnage of 4 yr old oysters being produced in 1995 and 1996. O. edulis production, B. ostreae prevalence and oyster mortalities have been monitored and recorded at Rossmore for over 30 yr. The collation and analysis of this data from 52 samples and 3190 oysters demonstrate the introduction and progression of bonamiosis and subsequent interventions to ameliorate disease effects during this period at Rossmore. Results suggest that O. edulis mortalities are now negligible during the first 4 yr of growth, prevalence of B. ostreae infection is low, and no correlation exists between prevalence of infection and oyster mortalities. This study, when compared to other studies of bonamiosis-infected oyster populations, suggests that an intervention in the form of a selective breeding programme is required to reduce the impact of the disease.
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Affiliation(s)
- Sharon A Lynch
- Aquaculture & Fisheries Development Centre, School of Biological, Earth & Environmental Science, University College Cork, The Cooperage, Distillery Fields, North Mall, Cork, Ireland
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23
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Hine PM, Carnegie RB, Kroeck MA, Villalba A, Engelsma MY, Burreson EM. Ultrastructural comparison of Bonamia spp. (Haplosporidia) infecting ostreid oysters. DISEASES OF AQUATIC ORGANISMS 2014; 110:55-63. [PMID: 25060497 DOI: 10.3354/dao02747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The ultrastructure of Bonamia from Ostrea angasi from Australia, Crassostrea ariakensis from the USA, O. puelchana from Argentina and O. edulis from Spain was compared with described Bonamia spp. All appear conspecific with B. exitiosa. The Bonamia sp. from Chile had similarities to the type B. exitiosa from New Zealand (NZ), but less so than the other forms recognized as B. exitiosa. Two groups of ultrastructural features were identified; those associated with metabolism (mitochondrial profiles, lipid droplets and endoplasmic reticulum), and those associated with haplosporogenesis (Golgi, indentations in the nuclear surface, the putative trans-Golgi network, perinuclear granular material and haplosporosome-like bodies). Metabolic features were regarded as having little taxonomic value, and as the process of haplosporogenesis is not understood, only haplosporosome shape and size may be of taxonomic value. However, the uni-nucleate stages of spore-forming haplosporidians are poorly known and may be confused with Bonamia spp. uni-nucleate stages. The many forms of NZ B. exitiosa have not been observed in other hosts, which may indicate that it has a plastic life cycle. Although there are similarities between NZ B. exitiosa and Chilean Bonamia in the development of a larger uni-nucleate stage and the occurrence of cylindrical confronting cisternae, the clarification of the identity of Chilean Bonamia must await molecular studies.
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Affiliation(s)
- P M Hine
- Investigation and Diagnostic Centre, Biosecurity New Zealand, PO Box 40-742, Upper Hutt 6007, New Zealand
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Engelsma MY, Culloty SC, Lynch SA, Arzul I, Carnegie RB. Bonamia parasites: a rapidly changing perspective on a genus of important mollusc pathogens. DISEASES OF AQUATIC ORGANISMS 2014; 110:5-23. [PMID: 25060494 DOI: 10.3354/dao02741] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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.
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Affiliation(s)
- Marc Y Engelsma
- Central Veterinary Institute of Wageningen UR (CVI), PO Box 65, 8200 AB, Lelystad, The Netherlands
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Spiers ZB, Gabor M, Fell SA, Carnegie RB, Dove M, O'Connor W, Frances J, Go J, Marsh IB, Jenkins C. Longitudinal study of winter mortality disease in Sydney rock oysters Saccostrea glomerata. DISEASES OF AQUATIC ORGANISMS 2014; 110:151-164. [PMID: 25060507 DOI: 10.3354/dao02629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Winter mortality (WM) is a poorly studied disease affecting Sydney rock oysters Saccostrea glomerata in estuaries in New South Wales, Australia, where it can cause significant losses. WM is more severe in oysters cultured deeper in the water column and appears linked to higher salinities. Current dogma is that WM is caused by the microcell parasite Bonamia roughleyi, but evidence linking clinical signs and histopathology to molecular data identifying bonamiasis is lacking. We conducted a longitudinal study between February and November 2010 in 2 estuaries where WM has occurred (Georges and Shoalhaven Rivers). Results from molecular testing of experimental oysters for Bonamia spp. were compared to clinical disease signs and histopathology. Available environmental data from the study sites were also collated and compared. Oyster condition declined over the study period, coinciding with decreasing water temperatures, and was inversely correlated with the presence of histological lesions. While mortalities occurred in both estuaries, only oysters from the Georges River study site showed gross clinical signs and histological changes characteristic of WM (lesions were prevalent and intralesional microcell-like structures were sometimes noted). PCR testing for Bonamia spp. revealed the presence of an organism belonging to the B. exitiosa-B. roughleyi clade in some samples; however, the very low prevalence of this organism relative to histological changes and the lack of reactivity of affected oysters in subsequent in situ hybridisation experiments led us to conclude that this Bonamia sp. is not responsible for WM. Another aetiological agent and a confluence of environmental factors are a more likely explanation for the disease.
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Affiliation(s)
- Zoe B Spiers
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales 2568, Australia
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Flannery G, Lynch SA, Longshaw M, Stone D, Martin P, Ramilo A, Villalba A, Culloty SC. Interlaboratory variability in screening for Bonamia ostreae, a protistan parasite of the European flat oyster Ostrea edulis. DISEASES OF AQUATIC ORGANISMS 2014; 110:93-99. [PMID: 25060501 DOI: 10.3354/dao02717] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The spread of the protozoan parasite Bonamia ostreae is of major concern to the European flat oyster Ostrea edulis industry. Many studies have looked at the sensitivity of individual methods available to screen for B. ostreae, but in this study, 3 separate laboratories examined 4 methods of diagnosis currently used routinely in laboratories: heart imprints, histology, polymerase chain reaction (PCR) and in situ hybridisation (ISH). The results were compared to estimate interlaboratory variability. Heart imprints and histology had the highest reproducibility amongst the 3 laboratories, with greatest agreement between detection of infected and uninfected individuals. PCR had the highest detection level in every laboratory. These positives were related to the presence of confirmed infections but also in unconfirmed infections, possibly due to the presence of traces of B. ostreae DNA in oysters where clinical infections were not observed. PCR, in combination with histology or ISH, provided the most reliable detection levels in every laboratory. Variation in results for PCR and ISH observed between laboratories may be due to the different protocols used by each laboratory for both methods. Overall, the findings from the 3 laboratories indicated that at least 2 methods, with fixed protocols, should be used for the accurate detection and determination of infection prevalence within a sample. This combination of methods would allow for a clearer and more precise diagnosis of B. ostreae, preventing further spread of the disease and providing more accurate detection levels and epidemiological information.
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Affiliation(s)
- Grace Flannery
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Sciences, University College Cork (UCC), Ireland
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Longshaw M, Stone DM, Wood G, Green MJ, White P. Detection of Bonamia exitiosa (Haplosporidia) in European flat oysters Ostrea edulis cultivated in mainland Britain. DISEASES OF AQUATIC ORGANISMS 2013; 106:173-179. [PMID: 24113250 DOI: 10.3354/dao02643] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Following a reported mortality event of European flat oysters Ostrea edulis in southwestern England in December 2010, a sample of 30 oysters was examined using histology and molecular techniques. Histological examination of the oysters revealed the presence of microcell stages in the haemocytes and connective tissues of 3 out of the 30 animals examined. One animal showing marked haemocyte infiltration of the connective tissues was considered to be infected with Bonamia ostreae based on the presence of small uninucleate microcells measuring approximately 1 to 1.5 µm in diameter. Two other oysters were considered by histology to be infected with B. exitiosa. Infected haemocytes contained up to 5 microcells, measuring approximately 2 to 3 µm in diameter with a central or subcentral nucleus. Rarely, larger plasmodia-like multinucleated stages were noted in the haemocyte cytoplasm characterised by its irregular shape and increased eosinophilic cytoplasm. Haemocyte infiltration of the connective tissues surrounding the digestive gland and the mantle was noted along with necrosis of the tissues associated with the infection. Molecular analysis of the infected animals confirmed the presence of B. exitiosa in the sample. This study describes the parasite from flat oysters cultured in the UK; subsequent targeted sampling has not detected the parasite in flat oyster populations at this or other sites within the UK.
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Affiliation(s)
- Matt Longshaw
- Cefas Weymouth Laboratory, Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK
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Feng C, Lin X, Wang F, Zhang Y, Lv J, Wang C, Deng J, Mei L, Wu S, Li H. Detection and characterization of Bonamia ostreae in Ostrea edulis imported to China. DISEASES OF AQUATIC ORGANISMS 2013; 106:85-91. [PMID: 24062556 DOI: 10.3354/dao02631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The protozoan parasite Bonamia ostreae is a destructive pathogen of flat oysters and has been reported to be widespread in Europe and North America. The biological characteristics of this unicellular parasite are still not fully understood. In this study, 104 Ostrea edulis imported from the USA to the Guangdong province of China for consumption were examined for Bonamia infection. PCR assay, combined with restriction fragment length polymorphism, sequencing and BLAST analysis, showed that B. ostreae DNA could be detected in 1 of the 104 oyster samples. Light microscopy revealed Bonamia-like organisms in the oyster. PCR assay and fluorescent in situ hybridization showed that B. ostreae organisms were present and retained their integrity after 4 wk in culture. Acridine orange-ethidium bromide staining indicated that the B. ostreae were still alive. In conclusion, B. ostreae was present in oysters imported to China. More importantly, the parasite was able to survive for at least 4 wk of in vitro culture at 4°C, which further implied a long-term transmission risk of B. ostreae. Considering the wide culture beds of Crassostrea ariakensis and C. gigas in China, and that C. ariakensis and C. gigas are susceptible hosts or reservoirs of B. ostreae, our study highlights the potential risk of introducing B. ostreae by importing O. edulis from a Bonamia endemic area.
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Affiliation(s)
- Chunyan Feng
- Institute of Animal Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100029, PR China
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Thrupp TJ, Lynch SA, Wootton EC, Malham SK, Vogan CL, Culloty SC, Rowley AF. Infection of juvenile edible crabs, Cancer pagurus by a haplosporidian-like parasite. J Invertebr Pathol 2013; 114:92-9. [PMID: 23796496 DOI: 10.1016/j.jip.2013.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 06/11/2013] [Accepted: 06/12/2013] [Indexed: 11/28/2022]
Abstract
This study aimed to examine the pathobiology of a haplosporidian-like infection in juvenile (pre-recruit) edible crabs (Cancer pagurus) from two locations in South West Wales, UK. Infected crabs showed no external symptoms of the disease but dissection revealed an infected and hypertrophic antennal gland. Histological examination showed extensive parasitisation of the antennal gland overlying the hepatopancreas. Heavily infected crabs also showed the presence of parasites with morphological similarities to Haplosporidia in the labyrinth of the antennal gland and in the gills. The spread of the infection from the antennal gland to the gills suggests that these parasites are released into the haemolymph. Attempts to characterise the haplosporidian-like organism using several primers previously shown to amplify members of the phylum Haplosporidia failed. The prevalence of infection in juvenile edible crabs varied throughout the sampling period of November 2011 to July 2012 with the lowest level of ca. 15% in November peaking at 70% in March. This parasite may represent a threat to the sustainability of edible crab fisheries in this region if the damage observed in the antennal gland and gills results in host mortality. The identification of these parasites as members of the phylum Haplosporidia based on morphology alone must be seen as tentative in the absence of sequence data.
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Affiliation(s)
- Tara J Thrupp
- Department of Biosciences, Swansea University, Swansea SA2 8PP, Wales, UK
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A previously undescribed ostreid herpes virus 1 (OsHV-1) genotype detected in the pacific oyster, Crassostrea gigas, in Ireland. Parasitology 2012; 139:1526-32. [DOI: 10.1017/s0031182012000881] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Carrasco N, Villalba A, Andree KB, Engelsma MY, Lacuesta B, Ramilo A, Gairín I, Furones MD. Bonamia exitiosa (Haplosporidia) observed infecting the European flat oyster Ostrea edulis cultured on the Spanish Mediterranean coast. J Invertebr Pathol 2012; 110:307-13. [PMID: 22465568 DOI: 10.1016/j.jip.2012.03.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/09/2012] [Accepted: 03/13/2012] [Indexed: 11/26/2022]
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.
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Affiliation(s)
- N Carrasco
- 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.
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Comesaña P, Casas SM, Cao A, Abollo E, Arzul I, Morga B, Villalba A. Comparison of haemocytic parameters among flat oyster Ostrea edulis stocks with different susceptibility to bonamiosis and the Pacific oyster Crassostrea gigas. J Invertebr Pathol 2012; 109:274-86. [DOI: 10.1016/j.jip.2011.12.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 12/22/2011] [Accepted: 12/29/2011] [Indexed: 01/09/2023]
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Identification and expression of immune genes in the flat oyster Ostrea edulis in response to bonamiosis. Gene 2012; 492:81-93. [DOI: 10.1016/j.gene.2011.11.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 10/25/2011] [Accepted: 11/01/2011] [Indexed: 12/26/2022]
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