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Gherbawy YA, Thabet MA, Sultan S. Genetic and morphological characterization of a new genotype of nervous necrosis virus circulating among Nile tilapia in the south of Egypt. Int Microbiol 2024; 27:559-569. [PMID: 37516696 PMCID: PMC10991031 DOI: 10.1007/s10123-023-00406-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/09/2023] [Accepted: 07/17/2023] [Indexed: 07/31/2023]
Abstract
Nervous necrosis virus (NNV) is the causative agent of viral nervous necrosis in freshwater and marine fishes. In this study, NNV circulating among wild and farmed Nile tilapia (Oreochromis niloticus) was genetically and morphologically characterized using reverse transcription polymerase chain reaction (RT-PCR), sequencing analysis, and transmission electron microscopy (TEM). Brain, eye, and other organ (spleen, kidney, heart, and liver) specimens were collected from 87 wild (66) and farmed (21) Nile tilapia fish during their adult or juvenile stage at different localities in Qena and Sohag governorates in southern Egypt. Among them, 57/87 fish showed suspected NNV clinical signs, and 30/87 were healthy. The results revealed that NNV was detected in 66 out of 87 fish (58.62% in the wild and 17.24% in farmed Nile tilapia by RT-PCR), and the prevalence was higher among diseased (55.17%) than in healthy (20.69%) fish. NNV was detected in the brain, eye, and other organs. Using TEM, virion size variations based on the infected organs were observed. Nucleotide sequence similarity indicated that NNVs had a divergence of 75% from other fish nodaviruses sequenced in Egypt and worldwide. Phylogenetic analysis distinguished them from other NNV genotypes, revealing the emergence of a new NNV genotype in southern Egypt. In conclusion, NNV is circulating among diseased and healthy Nile tilapia, and a new NNV genotype has emerged in southern Egypt.
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Affiliation(s)
- Youssuf Ahmed Gherbawy
- Botany and Microbiology Department, Faculty of Science, South Valley University, Qena, 83523, Egypt
- Applied and Environmental Microbiology Center, South Valley University, Qena, 83523, Egypt
| | - Maha Aboelkassem Thabet
- Botany and Microbiology Department, Faculty of Science, South Valley University, Qena, 83523, Egypt
| | - Serageldeen Sultan
- Department of Microbiology, Virology Division, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt.
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Delpuech E, Vandeputte M, Morvezen R, Bestin A, Besson M, Brunier J, Bajek A, Imarazene B, François Y, Bouchez O, Cousin X, Poncet C, Morin T, Bruant JS, Chatain B, Haffray P, Phocas F, Allal F. Whole-genome sequencing identifies interferon-induced protein IFI6/IFI27-like as a strong candidate gene for VNN resistance in European sea bass. Genet Sel Evol 2023; 55:30. [PMID: 37143017 PMCID: PMC10161657 DOI: 10.1186/s12711-023-00805-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 04/18/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Viral nervous necrosis (VNN) is a major disease that affects European sea bass, and understanding the biological mechanisms that underlie VNN resistance is important for the welfare of farmed fish and sustainability of production systems. The aim of this study was to identify genomic regions and genes that are associated with VNN resistance in sea bass. RESULTS We generated a dataset of 838,451 single nucleotide polymorphisms (SNPs) identified from whole-genome sequencing (WGS) in the parental generation of two commercial populations (A: 2371 individuals and B: 3428 individuals) of European sea bass with phenotypic records for binary survival in a VNN challenge. For each population, three cohorts were submitted to a red-spotted grouper nervous necrosis virus (RGNNV) challenge by immersion and genotyped on a 57K SNP chip. After imputation of WGS SNPs from their parents, quantitative trait loci (QTL) were mapped using a Bayesian sparse linear mixed model (BSLMM). We found several QTL regions that were specific to one of the populations on different linkage groups (LG), and one 127-kb QTL region on LG12 that was shared by both populations and included the genes ZDHHC14, which encodes a palmitoyltransferase, and IFI6/IFI27-like, which encodes an interferon-alpha induced protein. The most significant SNP in this QTL region was only 1.9 kb downstream of the coding sequence of the IFI6/IFI27-like gene. An unrelated population of four large families was used to validate the effect of the QTL. Survival rates of susceptible genotypes were 40.6% and 45.4% in populations A and B, respectively, while that of the resistant genotype was 66.2% in population B and 78% in population A. CONCLUSIONS We have identified a genomic region that carries a major QTL for resistance to VNN and includes the ZDHHC14 and IFI6/IFI27-like genes. The potential involvement of the interferon pathway, a well-known anti-viral defense mechanism in several organisms (chicken, human, or fish), in survival to VNN infection is of particular interest. Our results can lead to major improvements for sea bass breeding programs through marker-assisted genomic selection to obtain more resistant fish.
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Affiliation(s)
- Emilie Delpuech
- MARBEC, Univ. Montpellier, CNRS, Ifremer, IRD, INRAE, 34250, Palavas-Les-Flots, France.
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France.
| | - Marc Vandeputte
- MARBEC, Univ. Montpellier, CNRS, Ifremer, IRD, INRAE, 34250, Palavas-Les-Flots, France
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Romain Morvezen
- SYSAAF, Station LPGP/INRAE, Campus de Beaulieu, 35042, Rennes, France
| | - Anastasia Bestin
- SYSAAF, Station LPGP/INRAE, Campus de Beaulieu, 35042, Rennes, France
| | - Mathieu Besson
- SYSAAF, Station LPGP/INRAE, Campus de Beaulieu, 35042, Rennes, France
| | - Joseph Brunier
- Ecloserie Marine de Gravelines-Ichtus, Gloria Maris Group, 59273, Gravelines, France
| | - Aline Bajek
- Ecloserie Marine de Gravelines-Ichtus, Gloria Maris Group, 59273, Gravelines, France
| | | | - Yoannah François
- SYSAAF, Station LPGP/INRAE, Campus de Beaulieu, 35042, Rennes, France
- ANSES, Unit Virology, Immunology and Ecotoxicology of Fish, Technopôle Brest-Iroise, 29280, Plouzané, France
| | - Olivier Bouchez
- US 1426, GeT-PlaGe, INRAE, Genotoul, Castanet-Tolosan, France
| | - Xavier Cousin
- MARBEC, Univ. Montpellier, CNRS, Ifremer, IRD, INRAE, 34250, Palavas-Les-Flots, France
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Charles Poncet
- INRAE-UCA, UMR 1095 GDEC, 63000, Clermont-Ferrand, France
| | - Thierry Morin
- ANSES, Unit Virology, Immunology and Ecotoxicology of Fish, Technopôle Brest-Iroise, 29280, Plouzané, France
| | | | - Béatrice Chatain
- MARBEC, Univ. Montpellier, CNRS, Ifremer, IRD, INRAE, 34250, Palavas-Les-Flots, France
| | - Pierrick Haffray
- SYSAAF, Station LPGP/INRAE, Campus de Beaulieu, 35042, Rennes, France
| | - Florence Phocas
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - François Allal
- MARBEC, Univ. Montpellier, CNRS, Ifremer, IRD, INRAE, 34250, Palavas-Les-Flots, France
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Mao M, Jiang J, Xu J, Liu Y, Wang H, Mao Y. Cells and Fugu Response to Capsid of BFNNV Genotype. Viruses 2023; 15:v15040988. [PMID: 37112968 PMCID: PMC10142826 DOI: 10.3390/v15040988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
The nervous necrosis virus (NNV) of the BFNNV genotype is the causative agent of viral encephalopathy and retinopathy (VER) in cold water fishes. Similar to the RGNNV genotype, BFNNV is also considered a highly destructive virus. In the present study, the RNA2 of the BFNNV genotype was modified and expressed in the EPC cell line. The subcellular localization results showed that the capsid and N-terminal (1-414) were located in the nucleus, while the C-terminal (415-1014) of the capsid was located in the cytoplasm. Meanwhile, cell mortality obviously increased after expression of the capsid in EPC. EPC cells were transfected with pEGFP-CP and sampled at 12 h, 24 h and 48 h for transcriptome sequencing. There are 254, 2997 and 229 up-regulated genes and 387, 1611, and 649 down-regulated genes post-transfection, respectively. The ubiquitin-activating enzyme and ubiquitin-conjugating enzyme were up-regulated in the DEGs, indicating that cell death evoked by capsid transfection may be related to ubiquitination. The qPCR results showed that heat stock protein 70 (HSP70) is extremely up-regulated after expression of BFNNV capsid in EPC, and N-terminal is the key region to evoke the high expression. For further study, the immunoregulation of the capsid in fish pcDNA-3.1-CP was constructed and injected into the Takifugu rubripes muscle. pcDNA-3.1-CP can be detected in gills, muscle and head kidney, and lasted for more than 70 d post-injection. The transcripts of IgM and interferon inducible gene Mx were up-regulated after being immunized in different tissues, and immune factors, such as IFN-γ and C3, were also up-regulated in serum, while C4 was down-regulated one week after injection. It was suggested that pcDNA-3.1-CP can be a potential DNA vaccine in stimulating the immune system of T. rubripes; however, NNV challenge needs to be conducted in the following experiments.
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Affiliation(s)
- Mingguang Mao
- Yazhou Bay Innovation Institute, Hainan Tropical Ocean University, Sanya 572022, China
- Key Laboratory of Utilization and Conservation for Tropical Marine Bioresources, Ministry of Education, Hainan Tropical Ocean University, Sanya 572022, China
| | - Jielan Jiang
- Yazhou Bay Innovation Institute, Hainan Tropical Ocean University, Sanya 572022, China
- Key Laboratory of Utilization and Conservation for Tropical Marine Bioresources, Ministry of Education, Hainan Tropical Ocean University, Sanya 572022, China
| | - Jia Xu
- College of Fisheries and Life Sciences, Dalian Ocean University, Dalian 116023, China
| | - Yumeng Liu
- College of Fisheries and Life Sciences, Dalian Ocean University, Dalian 116023, China
| | - Haishan Wang
- Yazhou Bay Innovation Institute, Hainan Tropical Ocean University, Sanya 572022, China
- Key Laboratory of Utilization and Conservation for Tropical Marine Bioresources, Ministry of Education, Hainan Tropical Ocean University, Sanya 572022, China
| | - Yunxiang Mao
- Yazhou Bay Innovation Institute, Hainan Tropical Ocean University, Sanya 572022, China
- Key Laboratory of Utilization and Conservation for Tropical Marine Bioresources, Ministry of Education, Hainan Tropical Ocean University, Sanya 572022, China
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Combe M, Reverter M, Caruso D, Pepey E, Gozlan RE. Impact of Global Warming on the Severity of Viral Diseases: A Potentially Alarming Threat to Sustainable Aquaculture Worldwide. Microorganisms 2023; 11:microorganisms11041049. [PMID: 37110472 PMCID: PMC10146364 DOI: 10.3390/microorganisms11041049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
With an ever-increasing human population, food security remains a central issue for the coming years. The magnitude of the environmental impacts of food production has motivated the assessment of the environmental and health benefits of shifting diets, from meat to fish and seafood. One of the main concerns for the sustainable development of aquaculture is the emergence and spread of infectious animal diseases in a warming climate. We conducted a meta-analysis to investigate the influence of global warming on mortality due to viral infections in farmed aquatic animals. We found a positive trend between increasing temperature and increasing viral virulence, with an increase in water temperature of 1 °C resulting in an increase in mortality of 1.47-8.33% in OsHV-1 infected oysters, 2.55-6.98% in carps infected with CyHV-3 and 2.18-5.37% in fishes infected with NVVs. We suggest that global warming is going to pose a risk of viral disease outbreaks in aquaculture and could compromise global food security.
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Affiliation(s)
- Marine Combe
- ISEM, Université de Montpellier, CNRS, IRD, 34095 Montpellier, France
| | - Miriam Reverter
- ISEM, Université de Montpellier, CNRS, IRD, 34095 Montpellier, France
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK
| | - Domenico Caruso
- ISEM, Université de Montpellier, CNRS, IRD, 34095 Montpellier, France
| | - Elodie Pepey
- ISEM, Université de Montpellier, CNRS, IRD, 34095 Montpellier, France
- CIRAD, UMR ISEM, 34398 Montpellier, France
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5
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Krishnan R, Jang YS, Kim JO, Yoon SY, Rajendran R, Oh MJ. Temperature dependent cellular, and epigenetic regulatory mechanisms underlying the antiviral immunity in sevenband grouper to nervous necrosis virus infection. FISH & SHELLFISH IMMUNOLOGY 2022; 131:898-907. [PMID: 36334701 DOI: 10.1016/j.fsi.2022.10.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/25/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Changes in the thermal optima of fish impacts changes in the physiology and immune response associated with infections. The present study showed that at suboptimal temperatures (17 °C), the host tries to evade viral infection by downregulating the inflammatory response through enhanced neuronal protection. There was significantly less abundance of IgM + B cells in the 17 °C group compared to that in the 25 °C group. An increased macrophage population (Iba1+) during the survival phase in fish challenged at 25 °C demonstrated inflammation. Optimal temperature challenge activated virus-induced senescence in brain cells, demonstrated with a heterochromatin-associated H3K9me3 histone mark. There was an abundant expression of anti-inflammatory cytokines in the brain of fish at the suboptimal challenge. Besides the cytokines, the expression of BDNF was significantly higher in the suboptimally challenged group, suggesting that its neuronal protection activity following NNV infection is mediated through TGFβ. The suboptimal challenge resulted in H3k9ac displaying transcriptional competency, activation of trained immunity H3K4me3, and enrichment of H3 histone-lysine-4 monomethylation (H3K4me1), resulting in a robust re-stimulatory immune response. The observations from the H4 modifications showed that besides H4K12ac and H4K20m3, all the assayed modifications were significantly higher in suboptimal convalescent fishes. The suboptimally challenged fish acquired more methylation along cytosine residues than the optimally infected fish. Together, these observations suggest that optimal temperature results in an immune priming effect, whereas the protection enabled in suboptimal convalescent fishes is operated through epigenetically controlled trained immune functions.
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Affiliation(s)
- Rahul Krishnan
- Department of Aqualife Medicine, Chonnam National University, Yeosu, 59629, Republic of Korea.
| | - Yo-Seb Jang
- Department of Aqualife Medicine, Chonnam National University, Yeosu, 59629, Republic of Korea.
| | - Jong-Oh Kim
- Department of Microbiology, Pukyong National University, Busan, Republic of Korea.
| | - Su-Young Yoon
- Department of Aqualife Medicine, Chonnam National University, Yeosu, 59629, Republic of Korea.
| | - Rahul Rajendran
- Department of Aqualife Medicine, Chonnam National University, Yeosu, 59629, Republic of Korea.
| | - Myung-Joo Oh
- Department of Aqualife Medicine, Chonnam National University, Yeosu, 59629, Republic of Korea.
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Pathogenicity of Different Betanodavirus RGNNV/SJNNV Reassortant Strains in European Sea Bass. Pathogens 2022; 11:pathogens11040458. [PMID: 35456134 PMCID: PMC9026442 DOI: 10.3390/pathogens11040458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/22/2022] [Accepted: 04/06/2022] [Indexed: 11/21/2022] Open
Abstract
European sea bass (Dicentrarchus labrax) is an important farmed marine species for Mediterranean aquaculture. Outbreaks of betanodavirus represent one of the main infectious threats for this species. The red-spotted grouper nervous necrosis virus genotype (RGNNV) is the most widely spread in Southern Europe, while the striped jack nervous necrosis virus genotype (SJNNV) has been rarely detected. The existence of natural reassortants between these genotypes has been demonstrated, the RGNNV/SJNNV strain being the most common. This study aimed to evaluate the pathogenicity of different RGNNV/SJNNV strains in European sea bass. A selection of nine European reassortants together with parental RGNNV and SJNNV strains were used to perform in vivo experimental challenges via intramuscular injection. Additional in vivo experimental challenges were performed by bath immersion in order to mimic the natural infection route of the virus. Overall, results on survival rates confirmed the susceptibility of European sea bass to reassortants and showed different levels of induced mortalities. Results obtained by RT-qPCR also highlighted high viral loads in asymptomatic survivors, suggesting a possible reservoir role of this species. Our findings on the comparison of complete genomic segments of all reassortants have shed light on different amino acid residues likely involved in the variable pathogenicity of RGNNV/SJNNV strains in European sea bass.
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Zrnčić S, Brnić D, Panzarin V, Abbadi M, Lojkić I, Zupičić IG, Oraić D. Transmission Pathways of the VNN Introduced in Croatian Marine Aquaculture. Pathogens 2022; 11:pathogens11040418. [PMID: 35456093 PMCID: PMC9026106 DOI: 10.3390/pathogens11040418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/22/2022] [Accepted: 03/29/2022] [Indexed: 02/05/2023] Open
Abstract
Due to the insufficient capacity of Croatian hatcheries, marine aquaculture depends on the importation of fry from different countries in the Mediterranean basin. Importation enables a risk of spreading pathogenic agents. Viral nervous necrosis (VNN), caused by betanodavirus is devastating for the farming of European sea bass. We described a VNN outbreak that occurred in Croatia in 2014. After the diagnosis of VNN in sea bass fry introduced from the same hatchery to five unconnected marine farms at the Adriatic Coast, we performed surveillance within one of the affected farms. It resulted in proven horizontal spreading of the virus within the farm and to feral fish around farm cages. Real-time RT-PCR tested samples showed the dependence of the virus’ proliferation to the water temperature and the fish age. The highest mortality rates were noted during higher sea temperatures. Phylogenetic analysis of partial sequences of RNA1 and RNA2 supported the hypothesis that the virus was introduced to all studied farms from the same hatchery. Moreover, phylogenetic analysis of the whole genome sequences of infected farmed sea bass and thicklip mullet showed high similarity and it is unlikely that infection in Croatian sea bass farms has originated from wild reservoirs, as the first positive record in wild mullet was recorded after the disease outbreak.
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Affiliation(s)
- Snježana Zrnčić
- Department of Pathology, Croatian Veterinary Institute, Savska cesta 143, 10000 Zagreb, Croatia; (I.G.Z.); (D.O.)
- Correspondence:
| | - Dragan Brnić
- Department of Virology, Croatian Veterinary Institute, Savska cesta 143, 10000 Zagreb, Croatia; (D.B.); (I.L.)
| | - Valentina Panzarin
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell’Università 10, 35020 Legnaro, PD, Italy; (V.P.); (M.A.)
| | - Miriam Abbadi
- Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell’Università 10, 35020 Legnaro, PD, Italy; (V.P.); (M.A.)
| | - Ivana Lojkić
- Department of Virology, Croatian Veterinary Institute, Savska cesta 143, 10000 Zagreb, Croatia; (D.B.); (I.L.)
| | - Ivana Giovanna Zupičić
- Department of Pathology, Croatian Veterinary Institute, Savska cesta 143, 10000 Zagreb, Croatia; (I.G.Z.); (D.O.)
| | - Dražen Oraić
- Department of Pathology, Croatian Veterinary Institute, Savska cesta 143, 10000 Zagreb, Croatia; (I.G.Z.); (D.O.)
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Falco A, Bello-Perez M, Díaz-Puertas R, Mold M, Adamek M. Update on the Inactivation Procedures for the Vaccine Development Prospects of a New Highly Virulent RGNNV Isolate. Vaccines (Basel) 2021; 9:vaccines9121441. [PMID: 34960187 PMCID: PMC8705346 DOI: 10.3390/vaccines9121441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 01/01/2023] Open
Abstract
Viral nervous necrosis (VNN) caused by the nervous necrosis virus (NNV) affects a broad range of primarily marine fish species, with mass mortality rates often seen among larvae and juveniles. Its genetic diversification may hinder the effective implementation of preventive measures such as vaccines. The present study describes different inactivation procedures for developing an inactivated vaccine against a new NNV isolate confirmed to possess deadly effects upon the European seabass (Dicentrarchus labrax), an important Mediterranean farmed fish species that is highly susceptible to this disease. First, an NNV isolate from seabass adults diagnosed with VNN was rescued and the sequences of its two genome segments (RNA1 and RNA2) were classified into the red-spotted grouper NNV (RGNNV) genotype, closely clustering to the highly pathogenic 283.2009 isolate. The testing of different inactivation procedures revealed that the virus particles of this isolate showed a marked resistance to heat (for at least 60 °C for 120 min with and without 1% BSA) but that they were fully inactivated by 3 mJ/cm2 UV-C irradiation and 24 h 0.2% formalin treatment, which stood out as promising NNV-inactivation procedures for potential vaccine candidates. Therefore, these procedures are feasible, effective, and rapid response strategies for VNN control in aquaculture.
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Affiliation(s)
- Alberto Falco
- Institute of Research, Development and Innovation in Healthcare Biotechnology in Elche (IDiBE), Miguel Hernández University, 03202 Elche, Spain; (M.B.-P.); (R.D.-P.)
- Correspondence:
| | - Melissa Bello-Perez
- Institute of Research, Development and Innovation in Healthcare Biotechnology in Elche (IDiBE), Miguel Hernández University, 03202 Elche, Spain; (M.B.-P.); (R.D.-P.)
| | - Rocío Díaz-Puertas
- Institute of Research, Development and Innovation in Healthcare Biotechnology in Elche (IDiBE), Miguel Hernández University, 03202 Elche, Spain; (M.B.-P.); (R.D.-P.)
| | - Matthew Mold
- The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG, UK;
| | - Mikolaj Adamek
- Fish Disease Research Unit, Institute for Parasitology, University of Veterinary Medicine, 30559 Hannover, Germany;
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Nervous Necrosis Virus-like Particle (VLP) Vaccine Stimulates European Sea Bass Innate and Adaptive Immune Responses and Induces Long-Term Protection against Disease. Pathogens 2021; 10:pathogens10111477. [PMID: 34832632 PMCID: PMC8623669 DOI: 10.3390/pathogens10111477] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 12/29/2022] Open
Abstract
The rapidly increasing Mediterranean aquaculture production of European sea bass is compromised by outbreaks of viral nervous necrosis, which can be recurrent and detrimental. In this study, we evaluated the duration of protection and immune response in sea bass given a single dose of a virus-like particle (VLP)-based vaccine. Examinations included experimental challenge with nervous necrosis virus (NNV), serological assays for NNV-specific antibody reactivity, and immune gene expression analysis. VLP-vaccinated fish showed high and superior survival in challenge both 3 and 7.5 months (1800 and 4500 dd) post-vaccination (RPS 87 and 88, OR (surviving) = 16.5 and 31.5, respectively, p < 0.01). Although not providing sterile immunity, VLP vaccination seemed to control the viral infection, as indicated by low prevalence of virus in the VLP-vaccinated survivors. High titers of neutralizing and specific antibodies were produced in VLP-vaccinated fish and persisted for at least ~9 months post-vaccination as well as after challenge. However, failure of immune sera to protect recipient fish in a passive immunization trial suggested that other immune mechanisms were important for protection. Accordingly, gene expression analysis revealed that VLP-vaccination induced a mechanistically broad immune response including upregulation of both innate and adaptive humoral and cellular components (mx, isg12, mhc I, mhc II, igm, and igt). No clinical side effects of the VLP vaccination at either tissue or performance levels were observed. The results altogether suggested the VLP-based vaccine to be suitable for clinical testing under farming conditions.
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Emergence of Reassortment between a New and Reported Types of Betanodavirus in Shellfish. Pathogens 2021; 10:pathogens10101232. [PMID: 34684181 PMCID: PMC8540928 DOI: 10.3390/pathogens10101232] [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] [Received: 08/20/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022] Open
Abstract
Recently, three types of betanodavirus including red spotted grouper nervous necrosis virus (RGNNV), barfin flounder nervous necrosis virus (BFNNV), and Korean shellfish nervous necrosis virus (KSNNV) (proposed as a new fifth type) have been detected in shellfish in the marine environment around Korea. To investigate the presence of reassortment between betanodavirus types, the type based on the RNA2 segment of betanodaviruses carried in 420 domestic shellfish (n = 306) and finfish (n = 35), as well as imported shellfish (n = 79), was compared with the type identified by reverse-transcriptase polymerase chain reaction (RT-PCR) for RNA1 segment. Only five samples carrying reassortant betanodaviruses were found, appearing as RG/KSNNV (n = 2), KS/RGNNV (n = 1), and SJ/RGNNV (n = 2) types. From these samples, we successfully isolated two reassortant strains from Korean and Chinese shellfish in E-11 cells and called them KG1-reKS/RG and CM1-reRG/KS, respectively. In the full genome sequences, each RNA segment of the reassortant strains exhibited the same gene length and high sequence homology (≥98%) with the reference strains corresponding to the type of each segment. Both these reassortant strains induced high mortality to sevenband grouper (Epinephelus septemfasciatus) larvae with high viral concentrations in the body (109 viral particles/mg) and severe vacuolation in the retina and brain. These are the first results showing the involvement of the KSNNV type in the reassortment of RNA segments in the reported types of betanodavirus, which could represent a new potential risk in fish.
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Zrnčić S, Vendramin N, Boutrup TS, Boye M, Madsen L, Nonneman B, Brnić D, Oraić D. First description and diagnostics of disease caused by Piscirickettsia salmonis in farmed European sea bass (Dicentrarchus labrax Linnaeus) from Croatia. JOURNAL OF FISH DISEASES 2021; 44:1033-1042. [PMID: 33754342 DOI: 10.1111/jfd.13366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
During the winter of 2013 and 2016, several Croatian fish farms experienced mortalities in the fry of European sea bass, Dicentrarchus labrax. Affected fish showed abnormal swimming behaviour and reduced appetite, and death ensued several days after the onset of clinical signs of disease. Necropsy revealed pale liver, empty digestive tract, distended gall bladder, and hyperaemia and congestion of the meninges. Routine bacteriological examination tested negative, and virological examination ruled out nodavirus infection. Histological examination revealed multifocal necrosis and extensive inflammation in the brain with abundant cellular debris in the ventricles. Inflammatory cells displayed intra-cytoplasmic basophilic vacuoles leading to suspicion of Piscirickettsia salmonis infection. Fluorescent in situ hybridization using an oligonucleotide probe targeting Domain Bacterium applied to tissue sections tested positive. The pathogen was identified by 16S rRNA gene sequencing of brain material, and the sequence showed 99% similarity with P. salmonis. This result enabled the design of an oligonucleotide probe specifically targeting P. salmonis. In 2016, P. salmonis was successfully isolated on CHAB from the brain of an affected specimen and identified using 16S rRNA gene sequencing and MALDI-TOF. This study describes the first outbreak of disease caused by P. salmonis in sea bass in Croatia, while new diagnostic tools will enable further research on its epidemiology and pathogenicity.
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Affiliation(s)
| | - Niccolò Vendramin
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, DTU AQUA, Kgs Lyngby, Denmark
| | | | - Mette Boye
- Norwegian Veterinary Institute, Oslo, Norway
| | - Lone Madsen
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, DTU AQUA, Kgs Lyngby, Denmark
| | - Bettina Nonneman
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, DTU AQUA, Kgs Lyngby, Denmark
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12
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Geoghegan JL, Di Giallonardo F, Wille M, Ortiz-Baez AS, Costa VA, Ghaly T, Mifsud JCO, Turnbull OMH, Bellwood DR, Williamson JE, Holmes EC. Virome composition in marine fish revealed by meta-transcriptomics. Virus Evol 2021; 7:veab005. [PMID: 33623709 PMCID: PMC7887440 DOI: 10.1093/ve/veab005] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Revealing the determinants of virome composition is central to placing disease emergence in a broader evolutionary context. Fish are the most species-rich group of vertebrates and so provide an ideal model system to study the factors that shape virome compositions and their evolution. We characterized the viromes of nineteen wild-caught species of marine fish using total RNA sequencing (meta-transcriptomics) combined with analyses of sequence and protein structural homology to identify divergent viruses that often evade characterization. From this, we identified twenty-five new vertebrate-associated viruses and a further twenty-two viruses likely associated with fish diet or their microbiomes. The vertebrate-associated viruses identified here included the first fish virus in the Matonaviridae (single-strand, negative-sense RNA virus). Other viruses fell within the Astroviridae, Picornaviridae, Arenaviridae, Reoviridae, Hepadnaviridae, Paramyxoviridae, Rhabdoviridae, Hantaviridae, Filoviridae, and Flaviviridae, and were sometimes phylogenetically distinct from known fish viruses. We also show how key metrics of virome composition-viral richness, abundance, and diversity-can be analysed along with host ecological and biological factors as a means to understand virus ecology. Accordingly, these data suggest that that the vertebrate-associated viromes of the fish sampled here are predominantly shaped by the phylogenetic history (i.e. taxonomic order) of their hosts, along with several biological factors including water temperature, habitat depth, community diversity and swimming behaviour. No such correlations were found for viruses associated with porifera, molluscs, arthropods, fungi, and algae, that are unlikely to replicate in fish hosts. Overall, these data indicate that fish harbour particularly large and complex viromes and the vast majority of fish viromes are undescribed.
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Affiliation(s)
- Jemma L Geoghegan
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.,Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.,Institute of Environmental Science and Research, Wellington 5018, New Zealand
| | | | - Michelle Wille
- WHO Collaborating Centre for Reference and Research on Influenza, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Ayda Susana Ortiz-Baez
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Vincenzo A Costa
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Timothy Ghaly
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Jonathon C O Mifsud
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Olivia M H Turnbull
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - David R Bellwood
- ARC Centre of Excellence for Coral Reef Studies and College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Jane E Williamson
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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13
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Moreno P, Gemez-Mata J, Garcia-Rosado E, Bejar J, Labella AM, Souto S, Alonso MC. Differential immunogene expression profile of European sea bass (Dicentrarchus labrax, L.) in response to highly and low virulent NNV. FISH & SHELLFISH IMMUNOLOGY 2020; 106:56-70. [PMID: 32702480 DOI: 10.1016/j.fsi.2020.06.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
European sea bass is highly susceptible to the nervous necrosis virus, RGNNV genotype, whereas natural outbreaks caused by the SJNNV genotype have not been recorded. The onset and severity of an infectious disease depend on pathogen virulence factors and the host immune response. The importance of RGNNV capsid protein amino acids 247 and 270 as virulence factors has been previously demonstrated in European sea bass; however, sea bass immune response against nodaviruses with different levels of virulence has been poorly characterized. Knowing the differences between the immune response against both kinds of isolates may be key to get more insight into the host mechanisms responsible for NNV virulence. For this reason, this study analyses the transcription of immunogenes differentially expressed in European sea bass inoculated with nodaviruses with different virulence: a RGNNV virus obtained by reverse genetics (rDl956), highly virulent to sea bass, and a mutated virus (Mut247+270Dl956, RGNNV virus displaying SJNNV-type amino acids at positions 247 and 270 of the capsid protein), presenting lower virulence. This study has been performed in brain and head kidney, and the main differences between the immunogene responses triggered by both viruses have been observed in brain. The immunogene response in this organ is stronger after inoculation with the most virulent virus, and the main differences involved genes related with IFN I system, inflammatory response, cell-mediated response, and apoptosis. The lower virulence of Mut247+270Dl956 to European sea bass can be associated with a delayed IFN I response, as well as an early and transitory inflammation and cell-mediated responses, suggesting that those can be pivotal elements in controlling the viral infection, and therefore, their functional activity could be analysed in future studies. In addition, this study supports the role of capsid amino acids at positions 247 and 270 as important determinants of RGNNV virulence to European sea bass.
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Affiliation(s)
- Patricia Moreno
- Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA, Departamento de Microbiología, Facultad de Ciencias, 29071, Málaga, Spain
| | - Juan Gemez-Mata
- Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA, Departamento de Microbiología, Facultad de Ciencias, 29071, Málaga, Spain
| | - Esther Garcia-Rosado
- Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA, Departamento de Microbiología, Facultad de Ciencias, 29071, Málaga, Spain
| | - Julia Bejar
- Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA, Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, 29071, Málaga, Spain
| | - Alejandro M Labella
- Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA, Departamento de Microbiología, Facultad de Ciencias, 29071, Málaga, Spain
| | - Sandra Souto
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - M Carmen Alonso
- Universidad de Málaga, Instituto de Biotecnología y Desarrollo Azul, IBYDA, Departamento de Microbiología, Facultad de Ciencias, 29071, Málaga, Spain.
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14
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Boukedjouta R, Pretto T, Abbadi M, Biasini L, Toffan A, Mezali K. Viral encephalopathy and retinopathy is endemic in wild groupers (genus Epinephelus spp.) of the Algerian coast. JOURNAL OF FISH DISEASES 2020; 43:801-812. [PMID: 32462696 DOI: 10.1111/jfd.13181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 05/07/2023]
Abstract
This work describes betanodavirus infection in two species of groupers (family Serranidae) from the Algerian coast: the dusky grouper Epinephelus marginatus and the golden grouper Epinephelus costae. At necropsy, characteristic clinical signs, external injuries, clouded eyes and brain congestion, generally associated with viral encephalopathy and retinopathy (VER) infection were observed. The partial sequences of RNA1 and RNA2 from two viral strains were obtained, and the phylogenetic analysis revealed the presence of the red-spotted grouper nervous necrosis virus (RGNNV) genotype closely related to strains previously detected in groupers in the same geographic area. Results obtained in this study support the hypothesis that VER disease is endemic in the Algerian grouper population.
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Affiliation(s)
- Rachid Boukedjouta
- Department of Marine Science and Aquaculture, Faculty of Natural Sciences and Life, Protection, Valorization of Coastal Marine Resources and Molecular Systematics Laboratory, Université Abdelhamid Ibn Badis - Mostaganem, Mostaganem, Algeria
- National Centre for Research and Development of Fisheries and Aquaculture (NCRDFA), Bou-Ismaïl, Algeria
| | - Tobia Pretto
- Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), OIE Reference Laboratory for Viral Encephalopathy and Retinopathy, Legnaro (Padova), Italy
| | - Miriam Abbadi
- Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), OIE Reference Laboratory for Viral Encephalopathy and Retinopathy, Legnaro (Padova), Italy
| | - Lorena Biasini
- Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), OIE Reference Laboratory for Viral Encephalopathy and Retinopathy, Legnaro (Padova), Italy
| | - Anna Toffan
- Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), OIE Reference Laboratory for Viral Encephalopathy and Retinopathy, Legnaro (Padova), Italy
| | - Karim Mezali
- Department of Marine Science and Aquaculture, Faculty of Natural Sciences and Life, Protection, Valorization of Coastal Marine Resources and Molecular Systematics Laboratory, Université Abdelhamid Ibn Badis - Mostaganem, Mostaganem, Algeria
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15
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Leiva-Rebollo R, Labella AM, Valverde EJ, Castro D, Borrego JJ. Persistence of Lymphocystis Disease Virus (LCDV) in Seawater. FOOD AND ENVIRONMENTAL VIROLOGY 2020; 12:174-179. [PMID: 32086771 DOI: 10.1007/s12560-020-09420-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/06/2020] [Indexed: 06/10/2023]
Abstract
Lymphocystis disease virus (LCDV), the causative agent of lymphocystis disease (LCD), is a waterborne pathogen that uses the external surfaces, including the gills, as portals to gain access to fish host. However, there are no data on LCDV persistence in the aquatic environment. In this study, the persistence of LCDV in natural (raw), treated (autoclaved and filtered) and synthetic seawater held at 22 and 18 °C has been evaluated. The estimated T99 values for LCDV in seawater ranged from 2.7 to 242 days depending on seawater type and temperature, with the highest value recorded at 22 °C in autoclaved seawater. Microbiota and temperature seem to be the main factors affecting the persistence of LCDV in seawater. The results indicated that LCDV is more stable in treated seawater than most of the fish pathogenic viruses studied so far, supporting the relevance of this medium for the prevalence of LCD in fish farms.
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Affiliation(s)
| | | | | | - Dolores Castro
- Departamento de Microbiología, Universidad de Málaga, 29071, Málaga, Spain
| | - Juan J Borrego
- Departamento de Microbiología, Universidad de Málaga, 29071, Málaga, Spain.
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16
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Indigenous versus Lessepsian Hosts: Nervous Necrosis Virus (NNV) in Eastern Mediterranean Sea Fish. Viruses 2020; 12:v12040430. [PMID: 32290177 PMCID: PMC7232404 DOI: 10.3390/v12040430] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/05/2020] [Accepted: 04/08/2020] [Indexed: 11/17/2022] Open
Abstract
Viruses are among the most abundant and diverse biological components in the marine environment. In finfish, viruses are key drivers of host diversity and population dynamics, and therefore, their effect on the marine environment is far-reaching. Viral encephalopathy and retinopathy (VER) is a disease caused by the marine nervous necrosis virus (NNV), which is recognized as one of the main infectious threats for marine aquaculture worldwide. For over 140 years, the Suez Canal has acted as a conduit for the invasion of Red Sea marine species into the Mediterranean Sea. In 2016–2017, we evaluated the prevalence of NNV in two indigenous Mediterranean species, the round sardinella (Sardinella aurita) and the white steenbras (Lithognathus mormyrus) versus two Lessepsian species, the Randall’s threadfin bream (Nemipterus randalli) and the Lessepsian lizardfish (Saurida lessepsianus). A molecular method was used to detect NNV in all four fish species tested. In N. randalli, a relatively newly established invasive species in the Mediterranean Sea, the prevalence was significantly higher than in both indigenous species. In S. lessepsianus, prevalence varied considerably between years. While the factors that influence the effective establishment of invasive species are poorly understood, we suggest that the susceptibility of a given invasive fish species to locally acquired viral pathogens such as NVV may be important, in terms of both its successful establishment in its newly adopted environment and its role as a reservoir ‘host’ in the new area.
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17
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Betanodavirus and VER Disease: A 30-year Research Review. Pathogens 2020; 9:pathogens9020106. [PMID: 32050492 PMCID: PMC7168202 DOI: 10.3390/pathogens9020106] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/22/2020] [Accepted: 02/04/2020] [Indexed: 12/18/2022] Open
Abstract
The outbreaks of viral encephalopathy and retinopathy (VER), caused by nervous necrosis virus (NNV), represent one of the main infectious threats for marine aquaculture worldwide. Since the first description of the disease at the end of the 1980s, a considerable amount of research has gone into understanding the mechanisms involved in fish infection, developing reliable diagnostic methods, and control measures, and several comprehensive reviews have been published to date. This review focuses on host–virus interaction and epidemiological aspects, comprising viral distribution and transmission as well as the continuously increasing host range (177 susceptible marine species and epizootic outbreaks reported in 62 of them), with special emphasis on genotypes and the effect of global warming on NNV infection, but also including the latest findings in the NNV life cycle and virulence as well as diagnostic methods and VER disease control.
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18
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Ferreira IA, Costa JZ, Macchia V, Dawn Thompson K, Baptista T. Detection of Betanodavirus in experimentally infected European seabass (Dicentrarchus labrax, Linnaeus 1758) using non-lethal sampling methods. JOURNAL OF FISH DISEASES 2019; 42:1097-1105. [PMID: 31180142 DOI: 10.1111/jfd.13015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/09/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
One of the major disease threats affecting the Mediterranean aquaculture industry is viral encephalopathy and retinopathy (VER). The target organs for Betanodavirus detection are the brain and eyes, obtained through lethal sampling. This study aimed to evaluate the efficacy and suitability of non-lethal samples for detecting Betanodavirus in European seabass (Dicentrarchus labrax). European seabass juveniles were infected with Betanodavirus, by either an intramuscular injection or immersion (107 TCID50 /ml and 106 TCID50 /ml, respectively), and samples collected 7, 15 and 30 days post-infection (dpi). The brain was collected as a lethal sample, and gills, caudal fin and blood as non-lethal tissues for detecting Betanodavirus by quantitative reverse transcription PCR (RT-qPCR). The presence of virus in non-lethal tissues was inconsistent, with lower viral loads than in the brain. For blood, higher viral loads were detected in intramuscular-infected fish at 15 dpi until the end of the challenge. Serum antibodies against Betanodavirus were assessed using an enzyme-linked immunosorbent assay (ELISA). Antibodies were detected as early as 7 dpi, with higher mean antibody titres at 15 and 30 dpi. The presence of Betanodavirus-specific antibodies indicates that this is a suitable evaluation method for detecting early stages of the infection.
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Affiliation(s)
- Inês Almeida Ferreira
- MARE - Marine and Environmental Sciences Centre, ESTM, Polytechnic Institute of Leiria, Peniche, Portugal
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - Janina Z Costa
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - Valeria Macchia
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | | | - Teresa Baptista
- MARE - Marine and Environmental Sciences Centre, ESTM, Polytechnic Institute of Leiria, Peniche, Portugal
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19
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Souto S, Vázquez-Salgado L, Olveira JG, Bandín I. Amino acidic substitutions in the polymerase N-terminal region of a reassortant betanodavirus strain causing poor adaptation to temperature increase. Vet Res 2019; 50:50. [PMID: 31227007 PMCID: PMC6588924 DOI: 10.1186/s13567-019-0669-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/12/2019] [Indexed: 11/17/2022] Open
Abstract
Nervous necrosis virus (NNV), Genus Betanodavirus, is the causative agent of viral encephalopathy and retinopathy (VER), a neuropathological disease that causes fish mortalities worldwide. The NNV genome is composed of two single-stranded RNA molecules, RNA1 and RNA2, encoding the RNA polymerase and the coat protein, respectively. Betanodaviruses are classified into four genotypes: red-spotted grouper nervous necrosis virus (RGNNV), striped jack nervous necrosis virus (SJNNV), barfin flounder nervous necrosis virus (BFNNV) and tiger puffer nervous necrosis virus (TPNNV). In Southern Europe the presence of RGNNV, SJNNV and their natural reassortants (in both RNA1/RNA2 forms: RGNNV/SJNNV and SJNNV/RGNNV) has been reported. Pathology caused by these genotypes is closely linked to water temperature and the RNA1 segment encoding amino acids 1–445 has been postulated to regulate viral adaptation to temperature. Reassortants isolated from sole (RGNNV/SJNNV) show 6 substitutions in this region when compared with the RGNNV genotype (positions 41, 48, 218, 223, 238 and 289). We have demonstrated that change of these positions to those present in the RGNNV genotype cause low and delayed replication in vitro when compared with that of the wild type strain at 25 and 30 °C. The experimental infections confirmed the impact of the mutations on viral replication because at 25 °C the viral load and the mortality were significantly lower in fish infected with the mutant than in those challenged with the non-mutated virus. It was not possible to challenge fish at 30 °C because of the scarce tolerance of sole to this temperature.
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Affiliation(s)
- Sandra Souto
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología-Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain. .,Unité de Virologie et d'Immunologie Moléculaires, INRA, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
| | - Lucía Vázquez-Salgado
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología-Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - José G Olveira
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología-Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Isabel Bandín
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología-Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
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20
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Altered conformational structures of nervous necrosis virus surface protrusions and free coat proteins after incubation at moderate-low temperatures. Sci Rep 2019; 9:8647. [PMID: 31201359 PMCID: PMC6573060 DOI: 10.1038/s41598-019-45094-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/29/2019] [Indexed: 12/18/2022] Open
Abstract
Nervous necrosis virus (NNV) is a pathogenic fish virus belonging to family Nodaviridae. The objective of this study was to analyze stabilities of NNV surface protrusion and free coat protein (CP) conformational structures by analyzing changes of NNV infectivity and antigenicity after incubation at moderate-low temperatures. When cultured NNV suspension was incubated at 45 °C, its infectivity declined gradually but its antigenicity maintained. In contrast, both infectivity and antigenicity of purified NNV declined after incubation at 45 °C. After heat-treatment, surface protrusions of NNV particles disappeared completely, although viral particle structures maintained. Therefore, the reduction in NNV infectivity appeared to specifically occur as a result of heat-denaturation of virus surface protrusions. The loss of NNV infectivity in the presence of fetal bovine serum (FBS) was delayed compared to virus heated in the absence of FBS, demonstrating that FBS could function as a stabilizer for conformational structures of NNV surface protrusions. Moreover, the stabilizing function of FBS changed depending on salt concentration. Continued maintenance of antigenicity for heated cultured NNV suspension containing free-CPs may suggest that conformational structures corresponding to protrusion-domain of free-CP are more heat-stable than those of surface protrusions on NNV particles.
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21
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Buonocore F, Nuñez-Ortiz N, Picchietti S, Randelli E, Stocchi V, Guerra L, Toffan A, Pascoli F, Fausto AM, Mazzini M, Scapigliati G. Vaccination and immune responses of European sea bass (Dicentrarchus labrax L.) against betanodavirus. FISH & SHELLFISH IMMUNOLOGY 2019; 85:78-84. [PMID: 29175472 DOI: 10.1016/j.fsi.2017.11.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/18/2017] [Accepted: 11/22/2017] [Indexed: 05/22/2023]
Abstract
This review summarizes the available knowledge on the immune defences of European sea bass against antigenic preparations derived from the viral encephalopathy and retinopathy virus (betanodavirus), which represents a major threat to the health of this fish species. The nodavirus is widely present and differentiates into several strains that infect invertebrates (in insects, alphanodavirus) and teleost fish, and thus may represent a great problem for farmed fish species. Many efforts have been directed to discovering new immunizations to induce protection in sea bass, especially at young stages, and these efforts have included employing diverse betanodavirus strains, antigen preparation, vaccination routes, and the addition of adjuvants and/or immunostimulants. The obtained results showed that inactivated preparations of betanodavirus that were administered intraperitoneally may induce both immune recognition and protection. Attempts at performing mucosal immunization by immersion and/or oral administration, which is a vaccination route that is highly preferred for sea bass, have shown intriguing results, and more studies are necessary for its improvement. Overall, the objective of identifying a reliable vaccine that also cross-protects against different genotypes or reassortant viruses for use in European sea bass against betanodavirus appears to be an attainable goal in the near future.
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Affiliation(s)
- Francesco Buonocore
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy.
| | - Noelia Nuñez-Ortiz
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Simona Picchietti
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Elisa Randelli
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Valentina Stocchi
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Laura Guerra
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Anna Toffan
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Francesco Pascoli
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Anna Maria Fausto
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Massimo Mazzini
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Giuseppe Scapigliati
- Department for Innovation in Biological, Agrofood and Forest Systems, University of Tuscia, Viterbo, Italy
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22
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Pascoli F, Guazzo A, Buratin A, Toson M, Buonocore F, Scapigliati G, Toffan A. Lack of in vivo cross-protection of two different betanodavirus species RGNNV and SJNNV in European sea bass Dicentrachus labrax. FISH & SHELLFISH IMMUNOLOGY 2019; 85:85-89. [PMID: 29056488 DOI: 10.1016/j.fsi.2017.10.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/20/2017] [Accepted: 10/18/2017] [Indexed: 05/19/2023]
Abstract
Viral encephalopathy and retinopathy (VER) is a severe infective disease characterized by neuropathological changes in several fish species associated with high mortality. The etiological agent is a virus belonging to the Nodaviridae family, genus Betanodavirus. To date, four different betanodavirus species have been officially recognized by International Committee on Taxonomy of Viruses (ICTV), namely the red-spotted grouper- (RGNNV), the striped jack- (SJNNV), the barfin flounder- (BFNNV) and the tiger puffer nervous necrosis virus (TPNNV). Moreover, two reassortants RGNNV/SJNNV and SJNNV/RGNNV have been described. Betanodaviruses can be classified into three different serotypes (A, B and C) that are antigenically different, so none (between serotype A and C) or partial (between serotype B and C) cross-immunoreactivity has been detected in vitro. In this study we investigated the in vivo cross-protection of the two main betanodavirus species (RGNNV and SJNNV), which belong to distinct serotype, by immunizing intraperitoneally (IP) juvenile sea bass with formalin inactivated RGNNV and SJNNV vaccines, followed by a challenge with RGNNV. Fish IP vaccinated with inactivated RGNNV showed a high protection value (85%). Serological analyses highlighted a great specific anti-NNV immunoglobulin M (IgM) production against the homologous virus, while a good seroconversion with low neutralization property was highlighted against the heterologous virus. In fish IP vaccinated with inactivated SJNNV the protection recorded was equal to 25%, significantly lower respect to the one provided by RGNNV IP vaccine. ELISA test detected good IgM production against the homologous virus, and a lower, but still detectable IgM production against the heterologous one. By contrast, serum neutralization test highlighted a poorly detectable antibody production unable to neutralize either the homologous or the heterologous virus. These results confirm that the two serotypes are not cross-protective in vivo. According to these findings, the production of multivalent formulation, or at least the provision of different types of vaccines based on both fish and virus species requirement, should be recommended in order to broaden the range of protection.
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Affiliation(s)
- Francesco Pascoli
- Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory (NRL) for Diseases of Fish, Mollusk and Crustacean, Legnaro, PD, Italy.
| | - Andrea Guazzo
- Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory (NRL) for Diseases of Fish, Mollusk and Crustacean, Legnaro, PD, Italy
| | - Alessandra Buratin
- Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory (NRL) for Diseases of Fish, Mollusk and Crustacean, Legnaro, PD, Italy
| | - Marica Toson
- Istituto Zooprofilattico Sperimentale delle Venezie, Aquatic Animal Epidemiology Laboratory, Legnaro, PD, Italy
| | - Francesco Buonocore
- Department for Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Giuseppe Scapigliati
- Department for Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, Viterbo, Italy
| | - Anna Toffan
- Istituto Zooprofilattico Sperimentale delle Venezie, National Reference Laboratory (NRL) for Diseases of Fish, Mollusk and Crustacean, Legnaro, PD, Italy
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Samaras A, Papandroulakis N, Lika K, Pavlidis M. Water temperature modifies the acute stress response of European sea bass, Dicentrarchus labrax L. (1758). J Therm Biol 2018; 78:84-91. [DOI: 10.1016/j.jtherbio.2018.09.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 09/10/2018] [Accepted: 09/13/2018] [Indexed: 01/08/2023]
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24
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Toffan A, Pascoli F, Pretto T, Panzarin V, Abbadi M, Buratin A, Quartesan R, Gijón D, Padrós F. Viral nervous necrosis in gilthead sea bream (Sparus aurata) caused by reassortant betanodavirus RGNNV/SJNNV: an emerging threat for Mediterranean aquaculture. Sci Rep 2017; 7:46755. [PMID: 28462930 PMCID: PMC5411978 DOI: 10.1038/srep46755] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/21/2017] [Indexed: 11/23/2022] Open
Abstract
Viral nervous necrosis (VNN) certainly represents the biggest challenge for the sustainability and the development of aquaculture. A large number of economically relevant fish species have proven to be susceptible to the disease. Conversely, gilthead sea bream has generally been considered resistant to VNN, although it has been possible to isolate the virus from apparently healthy sea bream and sporadically from affected larvae and postlarvae. Unexpectedly, in 2014–2016 an increasing number of hatcheries in Europe have experienced mass mortalities in sea bream larvae. Two clinical outbreaks were monitored over this time span and findings are reported in this paper. Despite showing no specific clinical signs, the affected fish displayed high mortality and histological lesions typical of VNN. Fish tested positive for betanodavirus by different laboratory techniques. The isolates were all genetically characterized as being reassortant strains RGNNV/SJNNV. A genetic characterization of all sea bream betanodaviruses which had been isolated in the past had revealed that the majority of the strains infecting sea bream are actually RGNNV/SJNNV. Taken together, this information strongly suggests that RGNNV/SJNNV betanodavirus possesses a particular tropism to sea bream, which can pose a new and unexpected threat to the Mediterranean aquaculture.
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Affiliation(s)
- Anna Toffan
- OIE reference centre for viral encephalopathy and retinopathy, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, Legnaro, Padova, Italy
| | - Francesco Pascoli
- OIE reference centre for viral encephalopathy and retinopathy, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, Legnaro, Padova, Italy
| | - Tobia Pretto
- Istituto Zooprofilattico Sperimentale delle Venezie, Fish Pathology Department, Via Leonardo da Vinci 39, Adria, Rovigo, Italy.,Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, Ozzano dell'Emilia, Bologna, Italy
| | - Valentina Panzarin
- OIE reference centre for viral encephalopathy and retinopathy, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, Legnaro, Padova, Italy
| | - Miriam Abbadi
- OIE reference centre for viral encephalopathy and retinopathy, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, Legnaro, Padova, Italy
| | - Alessandra Buratin
- OIE reference centre for viral encephalopathy and retinopathy, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, Legnaro, Padova, Italy
| | - Rosita Quartesan
- OIE reference centre for viral encephalopathy and retinopathy, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, Legnaro, Padova, Italy
| | - Daniel Gijón
- Fish Health Service, Skretting, Ctra. de la Estación S/N, Cojóbar, Spain
| | - Francesc Padrós
- Fish Diseases Diagnostic Service, Facultat de Veterinaria, Universitat Autònoma de Barcelona, Bellaterra, Cerdanyola del Vallès, Spain
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Doan QK, Vandeputte M, Chatain B, Morin T, Allal F. Viral encephalopathy and retinopathy in aquaculture: a review. JOURNAL OF FISH DISEASES 2017; 40:717-742. [PMID: 27633881 DOI: 10.1111/jfd.12541] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/23/2016] [Accepted: 06/27/2016] [Indexed: 05/22/2023]
Abstract
Viral encephalopathy and retinopathy (VER), otherwise known as viral nervous necrosis (VNN), is a major devastating threat for aquatic animals. Betanodaviruses have been isolated in at least 70 aquatic animal species in marine and in freshwater environments throughout the world, with the notable exception of South America. In this review, the main features of betanodavirus, including its diversity, its distribution and its transmission modes in fish, are firstly presented. Then, the existing diagnosis and detection methods, as well as the different control procedures of this disease, are reviewed. Finally, the potential of selective breeding, including both conventional and genomic selection, as an opportunity to obtain resistant commercial populations, is examined.
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Affiliation(s)
- Q K Doan
- Ifremer, UMR 9190 MARBEC, Palavas-les-Flots, France
- TNU, Thai Nguyen University of Agriculture and Forestry (TUAF), Quyet Thang Commune, Thai Nguyen City, Vietnam
| | - M Vandeputte
- Ifremer, UMR 9190 MARBEC, Palavas-les-Flots, France
- INRA, GABI, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - B Chatain
- Ifremer, UMR 9190 MARBEC, Palavas-les-Flots, France
| | - T Morin
- Anses, Ploufragan-Plouzané Laboratory, Unit Viral Diseases of Fish, Plouzané, France
| | - F Allal
- Ifremer, UMR 9190 MARBEC, Palavas-les-Flots, France
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Cho SY, Kim HJ, Lan NT, Han HJ, Lee DC, Hwang JY, Kwon MG, Kang BK, Han SY, Moon H, Kang HA, Kim HJ. Oral vaccination through voluntary consumption of the convict grouper Epinephelus septemfasciatus with yeast producing the capsid protein of red-spotted grouper nervous necrosis virus. Vet Microbiol 2017; 204:159-164. [DOI: 10.1016/j.vetmic.2017.04.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/21/2017] [Accepted: 04/21/2017] [Indexed: 01/16/2023]
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