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Vega-Heredia S, Giffard-Mena I, Reverter M. Bacterial and viral co-infections in aquaculture under climate warming: co-evolutionary implications, diagnosis, and treatment. Dis Aquat Organ 2024; 158:1-20. [PMID: 38602294 DOI: 10.3354/dao03778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Climate change and the associated environmental temperature fluctuations are contributing to increases in the frequency and severity of disease outbreaks in both wild and farmed aquatic species. This has a significant impact on biodiversity and also puts global food production systems, such as aquaculture, at risk. Most infections are the result of complex interactions between multiple pathogens, and understanding these interactions and their co-evolutionary mechanisms is crucial for developing effective diagnosis and control strategies. In this review, we discuss current knowledge on bacteria-bacteria, virus-virus, and bacterial and viral co-infections in aquaculture as well as their co-evolution in the context of global warming. We also propose a framework and different novel methods (e.g. advanced molecular tools such as digital PCR and next-generation sequencing) to (1) precisely identify overlooked co-infections, (2) gain an understanding of the co-infection dynamics and mechanisms by knowing species interactions, and (3) facilitate the development multi-pathogen preventive measures such as polyvalent vaccines. As aquaculture disease outbreaks are forecasted to increase both due to the intensification of practices to meet the protein demand of the increasing global population and as a result of global warming, understanding and treating co-infections in aquatic species has important implications for global food security and the economy.
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Affiliation(s)
- Sarahí Vega-Heredia
- Universidad Autónoma de Baja California, Facultad de Ciencias Marinas, Ensenada, México, Egresada del Programa de Ecología Molecular y Biotecnología, carretera transpeninsular Ensenada-Tijuana No. 3917, C.P. 22860, México
| | - Ivone Giffard-Mena
- Universidad Autónoma de Baja California, Facultad de Ciencias Marinas, Ensenada, México
| | - Miriam Reverter
- School of Biological and Marine Sciences, Plymouth University, Drake Circus, Devon PL4 8AA, UK
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Zhu P, Liu C, Liu GF, Liu H, Xie KM, Zhang HS, Xu X, Xiao J, Jiang JZ. Unveiling CRESS DNA Virus Diversity in Oysters by Virome. Viruses 2024; 16:228. [PMID: 38400004 PMCID: PMC10892194 DOI: 10.3390/v16020228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/27/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Oysters that filter feed can accumulate numerous pathogens, including viruses, which can serve as a valuable viral repository. As oyster farming becomes more prevalent, concerns are mounting about diseases that can harm both cultivated and wild oysters. Unfortunately, there is a lack of research on the viruses and other factors that can cause illness in shellfish. This means that it is harder to find ways to prevent these diseases and protect the oysters. This is part of a previously started project, the Dataset of Oyster Virome, in which we further study 30 almost complete genomes of oyster-associated CRESS DNA viruses. The replication-associated proteins and capsid proteins found in CRESS DNA viruses display varying evolutionary rates and frequently undergo recombination. Additionally, some CRESS DNA viruses have the capability for cross-species transmission. A plethora of unclassified CRESS DNA viruses are detectable in transcriptome libraries, exhibiting higher levels of transcriptional activity than those found in metagenome libraries. The study significantly enhances our understanding of the diversity of oyster-associated CRESS DNA viruses, emphasizing the widespread presence of CRESS DNA viruses in the natural environment and the substantial portion of CRESS DNA viruses that remain unidentified. This study's findings provide a basis for further research on the biological and ecological roles of viruses in oysters and their environment.
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Affiliation(s)
- Peng Zhu
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510000, China
- Animal and Plant Inspection and Quarantine Technology Centre, Shenzhen Customs, Shenzhen 518000, China
| | - Chang Liu
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510000, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Marine Sciences, Sun Yat-sen University, Zhuhai 519000, China
| | - Guang-Feng Liu
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510000, China
| | - Hong Liu
- Animal and Plant Inspection and Quarantine Technology Centre, Shenzhen Customs, Shenzhen 518000, China
| | - Ke-Ming Xie
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510000, China
- School of Life Science and Biopharmacy, Guangdong Pharmaceutical University, Guangzhou 510000, China
| | - Hong-Sai Zhang
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510000, China
| | - Xin Xu
- Livestock, Aquaculture and Technology Promotion and Service Center of Conghua District, Guangzhou 510000, China
| | - Jian Xiao
- Livestock, Aquaculture and Technology Promotion and Service Center of Conghua District, Guangzhou 510000, China
| | - Jing-Zhe Jiang
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China
- Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510000, China
- School of Life Science and Biopharmacy, Guangdong Pharmaceutical University, Guangzhou 510000, China
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3
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Trancart S, Tweedie A, Liu O, Paul-Pont I, Hick P, Houssin M, Whittington RJ. Diversity and molecular epidemiology of Ostreid herpesvirus 1 in farmed Crassostrea gigas in Australia: Geographic clusters and implications for "microvariants" in global mortality events. Virus Res 2023; 323:198994. [PMID: 36332723 PMCID: PMC10194400 DOI: 10.1016/j.virusres.2022.198994] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/08/2022]
Abstract
Since 2010, mass mortality events known as Pacific oyster mortality syndrome (POMS) have occurred in Crassostrea gigas in Australia associated with Ostreid herpesvirus 1. The virus was thought to be an OsHV-1 µVar or "microvariant", i.e. one of the dominant variants associated with POMS in Europe, but there are few data to characterize the genotype in Australia. Consequently, the genetic identity and diversity of the virus was determined to understand the epidemiology of the disease in Australia. Samples were analysed from diseased C. gigas over five summer seasons between 2011 and 2016 in POMS-affected estuaries: Georges River in New South Wales (NSW), Hawkesbury River (NSW) and Pitt Water in Tasmania. Sequencing was attempted for six genomic regions. Numerous variants were identified among these regions (n = 100 isolates) while twelve variants were identified from concatenated nucleotide sequences (n = 61 isolates). Nucleotide diversity of the seven genotypes of C region among Australian isolates (Pi 0.99 × 10-3) was the lowest globally. All Australian isolates grouped in a cluster distinct from other OsHV-1 isolates worldwide. This is the first report that Australian outbreaks of POMS were associated with OsHV-1 distinct from OsHV-1 reference genotype, µVar and other microvariants from other countries. The findings illustrate that microvariants are not the only variants of OsHV-1 associated with mass mortality events in C. gigas. In addition, there was mutually exclusive spatial clustering of viral genomic and amino acid sequence variants between estuaries, and a possible association between genotype/amino acid sequence and the prevalence and severity of POMS, as this differed between these estuaries. The sequencing findings supported prior epidemiological evidence for environmental reservoirs of OsHV-1 for POMS outbreaks in Australia.
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Affiliation(s)
- Suzanne Trancart
- LABÉO Research Department, 1 Route de Rosel, Cedex 4, Caen 14053, France
| | - Alison Tweedie
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW 2568, Australia
| | - Olivia Liu
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; Department of Agriculture, Water and the Environment, Canberra, ACT 2601, Australia
| | - Ika Paul-Pont
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; LEMAR, Rue Dumont d'Urville, Plouzané 29280, France
| | - Paul Hick
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW 2568, Australia
| | - Maryline Houssin
- LABÉO Research Department, 1 Route de Rosel, Cedex 4, Caen 14053, France; UMR BOREA Université de Caen Normandie, MNHN, CNRS 8067, SU, IRD 207, UCN, UA, Esplanade de la Paix Caen Cedex 4 14032, France
| | - Richard J Whittington
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia.
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Delisle L, Laroche O, Hilton Z, Burguin JF, Rolton A, Berry J, Pochon X, Boudry P, Vignier J. Understanding the Dynamic of POMS Infection and the Role of Microbiota Composition in the Survival of Pacific Oysters, Crassostrea gigas. Microbiol Spectr 2022; 10:e0195922. [PMID: 36314927 PMCID: PMC9769987 DOI: 10.1128/spectrum.01959-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/16/2022] [Indexed: 11/07/2022] Open
Abstract
For over a decade, Pacific oyster mortality syndrome (POMS), a polymicrobial disease, induced recurring episodes of massive mortality affecting Crassostrea gigas oysters worldwide. Recent studies evidenced a combined infection of the ostreid herpesvirus (OsHV-1 μVar) and opportunistic bacteria in affected oysters. However, the role of the oyster microbiota in POMS is not fully understood. While some bacteria can protect hosts from infection, even minor changes to the microbial communities may also facilitate infection and worsen disease severity. Using a laboratory-based experimental infection model, we challenged juveniles from 10 biparental oyster families with previously established contrasted genetically based ability to survive POMS in the field. Combining molecular analyses and 16S rRNA gene sequencing with histopathological observations, we described the temporal kinetics of POMS and characterized the changes in microbiota during infection. By associating the microbiota composition with oyster mortality rate, viral load, and viral gene expression, we were able to identify both potentially harmful and beneficial bacterial amplicon sequence variants (ASVs). We also observed a delay in viral infection resulting in a later onset of mortality in oysters compared to previous observations and a lack of evidence of fatal dysbiosis in infected oysters. Overall, these results provide new insights into how the oyster microbiome may influence POMS disease outcomes and open new perspectives on the use of microbiome composition as a complementary screening tool to determine shellfish health and potentially predict oyster vulnerability to POMS. IMPORTANCE For more than a decade, Pacific oyster mortality syndrome (POMS) has severely impacted the Crassostrea gigas aquaculture industry, at times killing up to 100% of young farmed Pacific oysters, a key commercial species that is cultivated globally. These disease outbreaks have caused major financial losses for the oyster aquaculture industry. Selective breeding has improved disease resistance in oysters, but some levels of mortality persist, and additional knowledge of the disease progression and pathogenicity is needed to develop complementary mitigation strategies. In this holistic study, we identified some potentially harmful and beneficial bacteria that can influence the outcome of the disease. These results will contribute to advance disease management and aquaculture practices by improving our understanding of the mechanisms behind genetic resistance to POMS and assisting in predicting oyster vulnerability to POMS.
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Affiliation(s)
| | | | | | | | | | | | - Xavier Pochon
- Cawthron Institute, Nelson, New Zealand
- Institute of Marine Science, University of Auckland, Warkworth, New Zealand
| | - Pierre Boudry
- Département Ressources Biologiques et Environnement, Ifremer, ZI de la pointe du diable, Plouzané, France
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Delmotte J, Pelletier C, Morga B, Galinier R, Petton B, Lamy JB, Kaltz O, Avarre JC, Jacquot M, Montagnani C, Escoubas JM. Genetic diversity and connectivity of the Ostreid herpesvirus 1 populations in France: A first attempt to phylogeographic inference for a marine mollusc disease. Virus Evol 2022; 8:veac039. [PMID: 35600094 PMCID: PMC9119428 DOI: 10.1093/ve/veac039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022] Open
Abstract
The genetic diversity of viral populations is a key driver of the spatial and temporal diffusion of viruses; yet, studying the diversity of whole genomes from natural populations still remains a challenge. Phylodynamic approaches are commonly used for RNA viruses harboring small genomes but have only rarely been applied to DNA viruses with larger genomes. Here, we used the Pacific oyster mortality syndrome (a disease that affects oyster farms around the world) as a model to study the genetic diversity of its causative agent, the Ostreid herpesvirus 1 (OsHV-1) in the three main French oyster-farming areas. Using ultra-deep sequencing on individual moribund oysters and an innovative combination of bioinformatics tools, we de novo assembled twenty-one OsHV-1 new genomes. Combining quantification of major and minor genetic variations, phylogenetic analysis, and ancestral state reconstruction of discrete traits approaches, we assessed the connectivity of OsHV-1 viral populations between the three oyster-farming areas. Our results suggest that the Marennes-Oléron Bay represents the main source of OsHV-1 diversity, from where the virus has dispersed to other farming areas, a scenario consistent with current practices of oyster transfers in France. We demonstrate that phylodynamic approaches can be applied to aquatic DNA viruses to determine how epidemiological, immunological, and evolutionary processes act and potentially interact to shape their diversity patterns.
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Affiliation(s)
| | - Camille Pelletier
- Ifremer, RBE-ASIM, Station La Tremblade, La Tremblade F-17390, France
| | - Benjamin Morga
- Ifremer, RBE-ASIM, Station La Tremblade, La Tremblade F-17390, France
| | - Richard Galinier
- IHPE, CNRS, Ifremer, UPVD, University of Montpellier, Perpignan F-66000, France
| | - Bruno Petton
- Ifremer, CNRS, IRD, Ifremer, LEMAR UMR 6539 Université de Bretagne Occidentale, Argenton-en-Landunvez F-29840, France
| | | | - Oliver Kaltz
- ISEM, IRD, CNRS, University of Montpellier, Montpellier F-34095, France
| | | | - Maude Jacquot
- Ifremer, RBE-ASIM, Station La Tremblade, La Tremblade F-17390, France
- IHPE, CNRS, Ifremer, UPVD, University of Montpellier, Montpellier F-34095, France
| | - Caroline Montagnani
- IHPE, CNRS, Ifremer, UPVD, University of Montpellier, Montpellier F-34095, France
| | - Jean-Michel Escoubas
- IHPE, CNRS, Ifremer, UPVD, University of Montpellier, Montpellier F-34095, France
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Yu J, Liu Y, Huang B, Li C, Wang D, Yao M, Xin L, Bai C, Wang C. Characterization of Host Cell Potential Proteins Interacting with OsHV-1 Membrane Proteins. Viruses 2021; 13:2518. [PMID: 34960787 DOI: 10.3390/v13122518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022] Open
Abstract
The interaction between viral membrane associate proteins and host cellular surface molecules should facilitate the attachment and entry of OsHV-1 into host cells. Thus, blocking the putative membrane proteins ORF25 and ORF72 of OsHV-1 with antibodies that have previously been reported to subdue OsHV-1 replication in host cells, especially ORF25. In this study, prey proteins in host hemocytes were screened by pull-down assay with recombinant baits ORF25 and ORF72, respectively. Gene Ontology (GO) analysis of these prey proteins revealed that most of them were mainly associated with binding, structural molecule activity and transport activity in the molecular function category. The protein–protein interaction (PPI) network of the prey proteins was constructed by STRING and clustered via K-means. For both ORF25 and ORF72, three clusters of these prey proteins were distinguished that were mainly associated with cytoskeleton assembly, energy metabolism and nucleic acid processing. ORF25 tended to function in synergy with actins, while ORF72 functioned mainly with tubulins. The above results suggest that these two putative membrane proteins, ORF25 and ORF72, might serve a role in the transport of viral particles with the aid of a cytoskeleton inside cells.
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Fuhrmann M, Georgiades E, Cattell G, Brosnahan C, Lane HS, Hick PM. Aquatic pathogens and biofouling: pilot study of ostreid herpesvirus 1 translocation by bivalves. Biofouling 2021; 37:949-963. [PMID: 34628999 DOI: 10.1080/08927014.2021.1985474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 09/16/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
Ostreid herpesvirus 1 (OsHV-1) has caused mass mortalities in Pacific oysters (Crassostrea gigas) in Europe, Australia, and New Zealand. While aquaculture-associated movements of infected Pacific oysters are a well-known cause of OsHV-1 spread once established in a region, translocation via biofouling of aquaculture equipment or vessels needs further investigation to explain the more distant spread of OsHV-1. Laboratory experiments were designed to test for transmission of OsHV-1 between infected and naïve Pacific oysters via a simulated biofouling translocation scenario. Three common biofouling species [Sydney rock oysters (Saccostrea glomerata), Mediterranean mussels (Mytilus galloprovincialis) and Pacific oysters] were tested as intermediaries using a cohabitation challenge with Pacific oysters infected by injection. Transmission occurred, albeit for one of eight replicates when Pacific oysters were the intermediary species. This demonstrated a possible pathway for pathogen spread via biofouling containing Pacific oysters while highlighting the complexity of OsHV-1 transmission. Such complexities require further investigation to inform future risk assessments and management of fouled aquaculture equipment and vessels.
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Affiliation(s)
- M Fuhrmann
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, Australia
| | - E Georgiades
- Ministry for Primary Industries, Wellington, New Zealand
| | - G Cattell
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, Australia
| | - C Brosnahan
- Ministry for Primary Industries, Wellington, New Zealand
| | - H S Lane
- Ministry for Primary Industries, Wellington, New Zealand
| | - P M Hick
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, Australia
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Morga B, Jacquot M, Pelletier C, Chevignon G, Dégremont L, Biétry A, Pepin JF, Heurtebise S, Escoubas JM, Bean TP, Rosani U, Bai CM, Renault T, Lamy JB. Genomic Diversity of the Ostreid Herpesvirus Type 1 Across Time and Location and Among Host Species. Front Microbiol 2021; 12:711377. [PMID: 34326830 PMCID: PMC8313985 DOI: 10.3389/fmicb.2021.711377] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/21/2021] [Indexed: 11/15/2022] Open
Abstract
The mechanisms underlying virus emergence are rarely well understood, making the appearance of outbreaks largely unpredictable. This is particularly true for pathogens with low per-site mutation rates, such as DNA viruses, that do not exhibit a large amount of evolutionary change among genetic sequences sampled at different time points. However, whole-genome sequencing can reveal the accumulation of novel genetic variation between samples, promising to render most, if not all, microbial pathogens measurably evolving and suitable for analytical techniques derived from population genetic theory. Here, we aim to assess the measurability of evolution on epidemiological time scales of the Ostreid herpesvirus 1 (OsHV-1), a double stranded DNA virus of which a new variant, OsHV-1 μVar, emerged in France in 2008, spreading across Europe and causing dramatic economic and ecological damage. We performed phylogenetic analyses of heterochronous (n = 21) OsHV-1 genomes sampled worldwide. Results show sufficient temporal signal in the viral sequences to proceed with phylogenetic molecular clock analyses and they indicate that the genetic diversity seen in these OsHV-1 isolates has arisen within the past three decades. OsHV-1 samples from France and New Zealand did not cluster together suggesting a spatial structuration of the viral populations. The genome-wide study of simple and complex polymorphisms shows that specific genomic regions are deleted in several isolates or accumulate a high number of substitutions. These contrasting and non-random patterns of polymorphism suggest that some genomic regions are affected by strong selective pressures. Interestingly, we also found variant genotypes within all infected individuals. Altogether, these results provide baseline evidence that whole genome sequencing could be used to study population dynamic processes of OsHV-1, and more broadly herpesviruses.
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Affiliation(s)
| | | | | | | | | | | | - Jean-François Pepin
- Ifremer, ODE-Littoral-Laboratoire Environnement Ressources des Pertuis Charentais (LER-PC), La Tremblade, France
| | | | - Jean-Michel Escoubas
- IHPE, CNRS, Ifremer, Université de Montpellier - Université de Perpignan Via Domitia, Montpellier, France
| | - Tim P Bean
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom.,Centre for Environment, Fisheries and Aquaculture Science, Weymouth, United Kingdom
| | - Umberto Rosani
- Department of Biology, University of Padua, Padua, Italy
| | - Chang-Ming Bai
- Yellow Sea Fisheries Research Institute, CAFS, Qingdao, China
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Burge CA, Friedman CS, Kachmar ML, Humphrey KL, Moore JD, Elston RA. The first detection of a novel OsHV-1 microvariant in San Diego, California, USA. J Invertebr Pathol 2021; 184:107636. [PMID: 34116033 DOI: 10.1016/j.jip.2021.107636] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 01/25/2021] [Accepted: 06/04/2021] [Indexed: 11/15/2022]
Abstract
The spread, emergence, and adaptation of pathogens causing marine disease has been problematic to fisheries and aquaculture industries for the last several decades creating the need for strategic management and biosecurity practices. The Pacific oyster (Crassostrea gigas), a highly productive species globally, has been a target of disease and mortality caused by a viral pathogen, the Ostreid herpesvirus 1 (OsHV-1) and its microvariants (OsHV-1 µvars). During routine surveillance to establish health history at a shellfish aquaculture nursery system in San Diego, California, the presence of OsHV-1 in Pacific oyster juveniles was detected. Quantification of OsHV-1 in tissues of oysters revealed OsHV-1 viral loads > 106 copies/mg. We characterized and identified the OsHV-1 variant by sequencing of ORFs 4 (C2/C6) and 43 (IA1/IA2), which demonstrated that this variant is a novel OsHV-1 microvariant: OsHV-1 µvar SD. A pilot transmission study indicates that OsHV-1 µvar SD is infectious with high viral loads ~ 7.57 × 106 copies/mg detected in dead individuals. The detection of OsHV-1 µvar SD in a large port mirrors previous studies conducted in Australia where aquaculture farms and feral populations near port locations may be at a higher risk of OsHV-1 emergence. Further research is needed to understand the impacts of OsHV-1 µvar SD, such as transmission studies focusing on potential vectors and characterization of virulence as compared to other OsHV-1 µvars. To increase biosecurity of the global aquaculture industry, active and passive surveillance may be necessary to reduce spread of pathogens and make appropriate management decisions.
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Affiliation(s)
- Colleen A Burge
- Institute of Marine & Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA.
| | - Carolyn S Friedman
- School of Aquatic & Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98105, USA
| | - Mariah L Kachmar
- Institute of Marine & Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA
| | | | - James D Moore
- California Department of Fish & Wildlife, UC Davis Bodega Marine Laboratory, 2099 Westside Road, Bodega Bay, CA 94923, USA
| | - Ralph A Elston
- AquaTechnics Inc, 455 West Bell Street, Sequim, WA 98382, USA
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Cain G, Liu O, Whittington RJ, Hick PM. Reduction in Virulence over Time in Ostreid herpesvirus 1 (OsHV-1) Microvariants between 2011 and 2015 in Australia. Viruses 2021; 13:946. [PMID: 34065570 DOI: 10.3390/v13050946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/06/2021] [Accepted: 05/17/2021] [Indexed: 01/05/2023] Open
Abstract
Microvariant genotypes of Ostreid herpesvirus 1 (OsHV-1) are associated with mass mortality events of Pacific oysters in many countries. The OsHV-1 microvariant (µVar) emerged in France 2008 and caused significant economic losses as it became endemic and displaced the previously dominant OsHV-1 reference genotype. Recently, considerable genotypic variation has been described for OsHV-1 microvariants, however, less is known about variation in viral phenotype. This study used an in vivo laboratory infection model to assess differences in total cumulative mortality, peak viral load, transmissibility, and dose-response for three OsHV-1 isolates obtained between 2011 and 2015 from endemic waterways in Australia. This followed field observations of apparent reductions in the severity of mass mortalities over this time. Significantly higher hazard of death and cumulative mortality were observed for an isolate obtained in 2011 compared to isolates from 2014–2015. In keeping with other studies, the hazard of death was higher in oysters challenged by injection compared to challenge by cohabitation and the mortality was higher when the initial dose was 1 × 104 OsHV-1 DNA copies per oyster injection compared to 1 × 102 DNA copies. There was no difference in the quantity of OsHV-1 DNA at time of death that could be related to isolate or dose, suggesting similar pathogenetic processes in the individual oysters that succumbed to end-stage disease. While the isolates examined in this study were biased towards pathogenic types of OsHV-1, as they were collected during disease outbreaks, the variation in virulence that was observed, when combined with prior data on subclinical infections, suggests that surveillance for low virulence genotypes of OsHV-1 would be rewarding. This may lead to new approaches to disease management which utilize controlled exposure to attenuated strains of OsHV-1.
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Petton B, Destoumieux-Garzón D, Pernet F, Toulza E, de Lorgeril J, Degremont L, Mitta G. The Pacific Oyster Mortality Syndrome, a Polymicrobial and Multifactorial Disease: State of Knowledge and Future Directions. Front Immunol 2021; 12:630343. [PMID: 33679773 PMCID: PMC7930376 DOI: 10.3389/fimmu.2021.630343] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/06/2021] [Indexed: 01/22/2023] Open
Abstract
The Pacific oyster (Crassostreae gigas) has been introduced from Asia to numerous countries around the world during the 20th century. C. gigas is the main oyster species farmed worldwide and represents more than 98% of oyster production. The severity of disease outbreaks that affect C. gigas, which primarily impact juvenile oysters, has increased dramatically since 2008. The most prevalent disease, Pacific oyster mortality syndrome (POMS), has become panzootic and represents a threat to the oyster industry. Recently, major steps towards understanding POMS have been achieved through integrative molecular approaches. These studies demonstrated that infection by Ostreid herpesvirus type 1 µVar (OsHV-1 µvar) is the first critical step in the infectious process and leads to an immunocompromised state by altering hemocyte physiology. This is followed by dysbiosis of the microbiota, which leads to a secondary colonization by opportunistic bacterial pathogens, which in turn results in oyster death. Host and environmental factors (e.g. oyster genetics and age, temperature, food availability, and microbiota) have been shown to influence POMS permissiveness. However, we still do not understand the mechanisms by which these different factors control disease expression. The present review discusses current knowledge of this polymicrobial and multifactorial disease process and explores the research avenues that must be investigated to fully elucidate the complexity of POMS. These discoveries will help in decision-making and will facilitate the development of tools and applied innovations for the sustainable and integrated management of oyster aquaculture.
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Affiliation(s)
- Bruno Petton
- Ifremer, LEMAR UMR 6539, UBO/CNRS/IRD/Ifremer, Argenton-en-Landunvez, France
| | | | - Fabrice Pernet
- Ifremer, LEMAR UMR 6539, UBO/CNRS/IRD/Ifremer, Argenton-en-Landunvez, France
| | - Eve Toulza
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Julien de Lorgeril
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | | | - Guillaume Mitta
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
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