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Thunes NC, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Ghigo JM, McBride MJ. Gliding motility proteins GldJ and SprB contribute to Flavobacterium columnare virulence. J Bacteriol 2024; 206:e0006824. [PMID: 38517170 PMCID: PMC11025331 DOI: 10.1128/jb.00068-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024] Open
Abstract
Flavobacterium columnare causes columnaris disease in fish. Columnaris disease is incompletely understood, and adequate control measures are lacking. The type IX secretion system (T9SS) is required for F. columnare gliding motility and virulence. The T9SS and gliding motility machineries share some, but not all, components. GldN (required for gliding and for secretion) and PorV (involved in secretion but not required for gliding) are both needed for virulence, implicating T9SS-mediated secretion in virulence. The role of motility in virulence is uncertain. We constructed and analyzed sprB, sprF, and gldJ mutants that were defective for motility but that maintained T9SS function to understand the role of motility in virulence. Wild-type cells moved rapidly and formed spreading colonies. In contrast, sprB and sprF deletion mutants were partially defective in gliding and formed nonspreading colonies. Both mutants exhibited reduced virulence in rainbow trout fry. A gldJ deletion mutant was nonmotile, secretion deficient, and avirulent in rainbow trout fry. To separate the roles of GldJ in secretion and in motility, we generated gldJ truncation mutants that produce nearly full-length GldJ. Mutant gldJ563, which produces GldJ truncated at amino acid 563, was defective for gliding but was competent for secretion as measured by extracellular proteolytic activity. This mutant displayed reduced virulence in rainbow trout fry, suggesting that motility contributes to virulence. Fish that survived exposure to the sprB deletion mutant or the gldJ563 mutant exhibited partial resistance to later challenge with wild-type cells. The results aid our understanding of columnaris disease and may suggest control strategies.IMPORTANCEFlavobacterium columnare causes columnaris disease in many species of freshwater fish in the wild and in aquaculture systems. Fish mortalities resulting from columnaris disease are a major problem for aquaculture. F. columnare virulence is incompletely understood, and control measures are inadequate. Gliding motility and protein secretion have been suggested to contribute to columnaris disease, but evidence directly linking motility to disease was lacking. We isolated and analyzed mutants that were competent for secretion but defective for motility. Some of these mutants exhibited decreased virulence. Fish that had been exposed to these mutants were partially protected from later exposure to the wild type. The results contribute to our understanding of columnaris disease and may aid development of control strategies.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - David Pérez-Pascual
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Jean-Marc Ghigo
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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Fraslin C, Robledo D, Kause A, Houston RD. Potential of low-density genotype imputation for cost-efficient genomic selection for resistance to Flavobacterium columnare in rainbow trout (Oncorhynchus mykiss). Genet Sel Evol 2023; 55:59. [PMID: 37580697 PMCID: PMC10424455 DOI: 10.1186/s12711-023-00832-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023] Open
Abstract
BACKGROUND Flavobacterium columnare is the pathogen agent of columnaris disease, a major emerging disease that affects rainbow trout aquaculture. Selective breeding using genomic selection has potential to achieve cumulative improvement of the host resistance. However, genomic selection is expensive partly because of the cost of genotyping large numbers of animals using high-density single nucleotide polymorphism (SNP) arrays. The objective of this study was to assess the efficiency of genomic selection for resistance to F. columnare using in silico low-density (LD) panels combined with imputation. After a natural outbreak of columnaris disease, 2874 challenged fish and 469 fish from the parental generation (n = 81 parents) were genotyped with 27,907 SNPs. The efficiency of genomic prediction using LD panels was assessed for 10 panels of different densities, which were created in silico using two sampling methods, random and equally spaced. All LD panels were also imputed to the full 28K HD panel using the parental generation as the reference population, and genomic predictions were re-evaluated. The potential of prioritizing SNPs that are associated with resistance to F. columnare was also tested for the six lower-density panels. RESULTS The accuracies of both imputation and genomic predictions were similar with random and equally-spaced sampling of SNPs. Using LD panels of at least 3000 SNPs or lower-density panels (as low as 300 SNPs) combined with imputation resulted in accuracies that were comparable to those of the 28K HD panel and were 11% higher than the pedigree-based predictions. CONCLUSIONS Compared to using the commercial HD panel, LD panels combined with imputation may provide a more affordable approach to genomic prediction of breeding values, which supports a more widespread adoption of genomic selection in aquaculture breeding programmes.
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Affiliation(s)
- Clémence Fraslin
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
| | - Diego Robledo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Antti Kause
- Natural Resources Institute Finland (Luke), Myllytie 1, 31600, Jokioinen, Finland
| | - Ross D Houston
- Benchmark Genetics, Edinburgh Technopole, 1 Pioneer Building, Penicuik, EH26 0GB, UK
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3
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Couch CE, Neal WT, Herron CL, Kent ML, Schreck CB, Peterson JT. Gut microbiome composition associates with corticosteroid treatment, morbidity, and senescence in Chinook salmon (Oncorhynchus tshawytscha). Sci Rep 2023; 13:2567. [PMID: 36782001 PMCID: PMC9925776 DOI: 10.1038/s41598-023-29663-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/08/2023] [Indexed: 02/15/2023] Open
Abstract
Pacific salmon experience prolonged elevation in corticosteroid hormones during important life history events including migration, reproduction, and senescence. These periods of elevated corticosteroids correspond with changes to immunity and energy metabolism; therefore, fish may be particularly vulnerable to mortality at these times. Recent studies found that stress-induced cortisol release associated with microbial community shifts in salmonids, raising the question of how longer-term corticosteroid dynamics that accompany life history transitions affect salmonid microbiomes. In this work, we experimentally evaluated the relationships between gut microbiome composition, chronically elevated corticosteroids, and mortality in juvenile Chinook salmon (Oncorhynchus tshawytscha). We found that treatment with slow-release implants of the corticosteroids cortisol or dexamethasone resulted in changes to the gut microbiome. Morbidity was also associated with microbiome composition, suggesting that the gut microbiome reflects individual differences in susceptibility to opportunistic pathogens. Additionally, we analyzed a small number of samples from adult fish at various stages of senescence. Results from these samples suggest that microbiome composition associated with gut integrity, and that the microbial communities of corticosteroid treated juveniles shift in composition toward those of senescent adults. Overall, findings from this work indicate that the gut microbiome correlates with mortality risk during periods of chronic corticosteroid elevation.
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Affiliation(s)
- Claire E Couch
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, USA.
| | - William T Neal
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, USA
| | - Crystal L Herron
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, USA
| | - Michael L Kent
- Department of Microbiology, Oregon State University, Corvallis, OR, USA
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
| | - Carl B Schreck
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, USA
| | - James T Peterson
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, USA
- U.S. Geological Survey Oregon Cooperative Fish and Wildlife Research Unit, Corvallis, OR, USA
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Thunes NC, Mohammed HH, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Conrad RA, Ghigo JM, McBride MJ. Secreted peptidases contribute to virulence of fish pathogen Flavobacterium columnare. Front Cell Infect Microbiol 2023; 13:1093393. [PMID: 36816589 PMCID: PMC9936825 DOI: 10.3389/fcimb.2023.1093393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
Flavobacterium columnare causes columnaris disease in freshwater fish in both natural and aquaculture settings. This disease is often lethal, especially when fish population density is high, and control options such as vaccines are limited. The type IX secretion system (T9SS) is required for F. columnare virulence, but secreted virulence factors have not been fully identified. Many T9SS-secreted proteins are predicted peptidases, and peptidases are common virulence factors of other pathogens. T9SS-deficient mutants, such as ΔgldN and ΔporV, exhibit strong defects in secreted proteolytic activity. The F. columnare genome has many peptidase-encoding genes that may be involved in nutrient acquisition and/or virulence. Mutants lacking individual peptidase-encoding genes, or lacking up to ten peptidase-encoding genes, were constructed and examined for extracellular proteolytic activity, for growth defects, and for virulence in zebrafish and rainbow trout. Most of the mutants retained virulence, but a mutant lacking 10 peptidases, and a mutant lacking the single peptidase TspA exhibited decreased virulence in rainbow trout fry, suggesting that peptidases contribute to F. columnare virulence.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Haitham H. Mohammed
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States,Department of Rangeland, Wildlife and Fisheries Management, Texas A&M University, College Station, TX, United States
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - David Pérez-Pascual
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, WV, United States
| | - Rachel A. Conrad
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Jean-Marc Ghigo
- Institut Pasteur, Université de Paris-Cité, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States,*Correspondence: Mark J. McBride,
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Zhang Z, Hao S, Bai X, You H, Wu Y, Feng S, Zhang L, Luo Z. Prolonged low-salt immersion effectively controls Flavobacterium columnare infection in Murray cod Maccullochella peelii peelii. DISEASES OF AQUATIC ORGANISMS 2022; 150:53-60. [PMID: 35796511 DOI: 10.3354/dao03674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A disease outbreak occurred in Murray cod Maccullochella peelii peelii in a recirculating aquaculture farm in Tianjin city, China, in 2019. Strain MRX-2019 was isolated and considered to be the etiological pathogen; it was identified as Flavobacterium columnare based on a 16S rDNA gene sequence analysis and physiological and biochemical tests. The effect of salinity on the growth of MRX-2019 was investigated in vitro. Salinity >4‰ (i.e. 6‰) inhibited MRX-2019 growth, whereas 8 and 10‰ salinity killed it. The effect of 4‰ salinity on F. columnare was not significant (p > 0.05). When MRX-2019-infected Murray cod were treated with 4, 6, or 8‰ salinity, the mortality rate was reduced by 8.9, 67.76, or 75.56%, respectively, compared with that of the control. However, the mortality rate increased by 7.77% at 10‰ salinity. In this study, we found that maintaining the fish in freshwater with 6-8‰ salinity effectively reduced the mortality of these fish when infected with F. columnare. The findings provide an environmentally friendly control strategy for columnaris disease in Murray cod.
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Affiliation(s)
- Zhenguo Zhang
- College of Fisheries, Tianjin Agricultural University, Tianjin 300384, PR China
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Kaimal S, Farmer BD, Renukdas NN, Abdelrahman HA, Kelly AM. Evaluating Stress-Mediated Microbial Pathogenesis in Golden Shiners, Notemigonus crysoleucas. Front Physiol 2022; 13:886480. [PMID: 35634142 PMCID: PMC9132093 DOI: 10.3389/fphys.2022.886480] [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: 02/28/2022] [Accepted: 04/11/2022] [Indexed: 11/22/2022] Open
Abstract
Flavobacterium covae (columnaris) is a microbial pathogen of the Golden Shiner (Notemigonus crysoleucas), a principal bait species. We investigated the effects of density and water temperature on the survival of fish subjected to a columnaris challenge and whether flow cytometry (FCM) could be a fast and reliable method to distinguish and enumerate F. covae populations from water and fish in experimental tanks. Juvenile Golden Shiners averaging 2.62 (±0.78 S.D.) g (negative for F. covae) were used in simultaneous trials at 22°C and 28°C in two ultra-low flow-through systems: each consisting of four treatments and five replicates per treatment. Treatments were fish stocked at either 600 fish/m3 or 2,400 fish/m3 and either challenged with F. covae or not; survival was observed for 48 h after challenge. Samples of water and fish tissue were obtained for FCM enumerations and validation by qPCR. No significant differences in survival were recorded between density treatments; however, high temperature and columnaris challenge treatments showed significantly higher mortality. Bacterial enumeration (number/mL) by FCM highly correlated with bacterial counts r = 0.81 (p = 0.001) in the water samples. Higher water temperatures may have increased columnaris infections and mortality in Golden Shiners. Flow cytometry is a reliable method of enumerating F. covae from experimental tank water samples.
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Affiliation(s)
- Sindhu Kaimal
- Department of Aquaculture and Fisheries, The University of Arkansas at Pine Bluff, Pine Bluff, AR, United States
| | - Bradley D. Farmer
- United States Department of Agriculture, Agriculture Research Service, Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, AR, United States
| | - Nilima N. Renukdas
- Department of Aquaculture and Fisheries, The University of Arkansas at Pine Bluff, Pine Bluff, AR, United States
| | - Hisham A. Abdelrahman
- Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
- Alabama Fish Farming Center, Auburn University, Greensboro, AL, United States
| | - Anita M. Kelly
- Department of Aquaculture and Fisheries, The University of Arkansas at Pine Bluff, Pine Bluff, AR, United States
- *Correspondence: Anita M. Kelly,
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7
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Runtuvuori-Salmela A, Kunttu H, Laanto E, Almeida G, Mäkelä K, Middelboe M, Sundberg LR. Prevalence of genetically similar Flavobacterium columnare phages across aquaculture environments reveals a strong potential for pathogen control. Environ Microbiol 2022; 24:2404-2420. [PMID: 35049114 PMCID: PMC9304149 DOI: 10.1111/1462-2920.15901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/11/2022] [Indexed: 11/28/2022]
Abstract
Intensive aquaculture conditions expose fish to bacterial infections, leading to significant financial losses, extensive antibiotic use and risk of antibiotic resistance in target bacteria. Flavobacterium columnare causes columnaris disease in aquaculture worldwide. To develop a bacteriophage‐based control of columnaris disease, we isolated and characterized 126 F. columnare strains and 63 phages against F. columnare from Finland and Sweden in 2017. Bacterial isolates were virulent on rainbow trout (Oncorhynchus mykiss) and fell into four previously described genetic groups A, C, E and G, with genetic groups C and E being the most virulent. Phage host range studied against a collection of 227 bacterial isolates (from 2013 to 2017) demonstrated modular infection patterns based on host genetic group. Phages infected contemporary and previously isolated bacterial hosts, but bacteria isolated most recently were generally resistant to previously isolated phages. Despite large differences in geographical origin, isolation year or host range of the phages, whole‐genome sequencing of 56 phages showed high level of genetic similarity to previously isolated F. columnare phages (Ficleduovirus, Myoviridae). Altogether, this phage collection demonstrates a potential for use in phage therapy.
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Affiliation(s)
- A Runtuvuori-Salmela
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Hmt Kunttu
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - E Laanto
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.,Department Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Gmf Almeida
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.,Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - K Mäkelä
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - M Middelboe
- Department of Biology, Marine Biological Section, University of Copenhagen, Helsingør, Denmark
| | - L-R Sundberg
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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Glochidial infection by the endangered Margaritifera margaritifera (Mollusca) increased survival of salmonid host (Pisces) during experimental Flavobacterium disease outbreak. Parasitol Res 2021; 120:3487-3496. [PMID: 34427787 PMCID: PMC8460588 DOI: 10.1007/s00436-021-07285-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 08/09/2021] [Indexed: 11/24/2022]
Abstract
Co-infections are common in host-parasite interactions, but studies about their impact on the virulence of parasites/diseases are still scarce. The present study compared mortality induced by a fatal bacterial pathogen, Flavobacterium columnare between brown trout infected with glochidia from the endangered freshwater pearl mussel, Margaritifera margaritifera, and uninfected control fish during the parasitic period and after the parasitic period (i.e. glochidia detached) in a laboratory experiment. We hypothesised that glochidial infection would increase host susceptibility to and/or pathogenicity of the bacterial infection. We found that the highly virulent strain of F. columnare caused an intense disease outbreak, with mortality reaching 100% within 29 h. Opposite to the study hypothesis, both fresh ongoing and past infection (14 months post-infection) with glochidia prolonged the fish host’s survival statistically significantly by 1 h compared to the control fish (two-way ANOVA: fresh-infection, F1, 82 = 7.144, p = 0.009 and post-infection, F1, 51 = 4.227, p = 0.044). Furthermore, fish survival time increased with glochidia abundance (MLR: post-infection, t = 2.103, p = 0.045). The mechanism could be connected to an enhanced non-specific immunity or changed gill structure of the fish, as F. columnare enters the fish body mainly via the gills, which is also the glochidia’s attachment site. The results increase current knowledge about the interactions between freshwater mussels and their (commercially important) fish hosts and fish pathogens and also emphasise the importance of (unknown) ecosystem services (e.g., protection against pathogens) potentially associated with imperilled freshwater mussels.
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Donati VL, Dalsgaard I, Runtuvuori-Salmela A, Kunttu H, Jørgensen J, Castillo D, Sundberg LR, Middelboe M, Madsen L. Interactions between Rainbow Trout Eyed Eggs and Flavobacterium spp. Using a Bath Challenge Model: Preliminary Evaluation of Bacteriophages as Pathogen Control Agents. Microorganisms 2021; 9:971. [PMID: 33946270 PMCID: PMC8146780 DOI: 10.3390/microorganisms9050971] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/10/2021] [Accepted: 04/14/2021] [Indexed: 11/17/2022] Open
Abstract
The microbial community surrounding fish eyed eggs can harbor pathogenic bacteria. In this study we focused on rainbow trout (Oncorhynchus mykiss) eyed eggs and the potential of bacteriophages against the pathogenic bacteria Flavobacterium psychrophilum and F. columnare. An infection bath method was first established, and the effects of singular phages on fish eggs was assessed (survival of eyed eggs, interaction of phages with eyed eggs). Subsequently, bacteria-challenged eyed eggs were exposed to phages to evaluate their effects in controlling the bacterial population. Culture-based methods were used to enumerate the number of bacteria and/or phages associated with eyed eggs and in the surrounding environment. The results of the study showed that, with our infection model, it was possible to re-isolate F. psychrophilum associated with eyed eggs after the infection procedure, without affecting the survival of the eggs in the short term. However, this was not possible for F. columnare, as this bacterium grows at higher temperatures than the ones recommended for incubation of rainbow trout eyed eggs. Bacteriophages do not appear to negatively affect the survival of rainbow trout eyed eggs and they do not seem to strongly adhere to the surface of eyed eggs either. Finally, the results demonstrated a strong potential for short term (24 h) phage control of F. psychrophilum. However, further studies are needed to explore if phage control can be maintained for a longer period and to further elucidate the mechanisms of interactions between Flavobacteria and their phages in association with fish eggs.
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Affiliation(s)
- Valentina L. Donati
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (I.D.); (L.M.)
| | - Inger Dalsgaard
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (I.D.); (L.M.)
| | - Anniina Runtuvuori-Salmela
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland; (A.R.-S.); (H.K.); (L.-R.S.)
| | - Heidi Kunttu
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland; (A.R.-S.); (H.K.); (L.-R.S.)
| | - Johanna Jørgensen
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000 Helsingør, Denmark; (J.J.); (D.C.); (M.M.)
| | - Daniel Castillo
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000 Helsingør, Denmark; (J.J.); (D.C.); (M.M.)
| | - Lotta-Riina Sundberg
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland; (A.R.-S.); (H.K.); (L.-R.S.)
| | - Mathias Middelboe
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000 Helsingør, Denmark; (J.J.); (D.C.); (M.M.)
| | - Lone Madsen
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (I.D.); (L.M.)
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Iaria C, Spanò N, Smeriglio A, Capparucci F, De Benedetto G, Lanteri G, Marino F, Macheda S, Macrì F, Belvedere A, D'Agostino M, Caridi F, Marguccio S, Salvo A, Acri G, Siclari A, Brundo MV, Trombetta D. Massive infection of Cystidicoloides ephemeridarum in brown trout Salmo trutta with skeletal deformities. DISEASES OF AQUATIC ORGANISMS 2021; 143:159-168. [PMID: 33632994 DOI: 10.3354/dao03559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We investigated the cause of skeletal deformities found in brown trout from the Aspromonte mountain area in Reggio Calabria, Italy. Toxicological, histopathological and parasitological analyses were carried out on 14 fish with evident macro-morphological alterations from 2 different locations in the same river, and 4 control fish without morphological alterations from a different river (far from the first river but still within the area under study). Histopathological and radiological observations confirmed severe skeletal deformities in the specimens investigated. Parasitological examinations highlighted the presence of the nematode Cystidicoloides ephemeridarum, found only within the gastrointestinal tract of specimens showing deformities. Moreover, a direct correlation between parasite number and fish size was found. Given the low heavy metal levels and the presence of a massive parasitosis in teleosts showing deformities, we postulate a correlation between skeletal deformities and nematode infestation: the parasites caused a serious vitamin and mineral deficiency in the fish, which led to a dysplastic vertebral column. The low calcium levels found in malformed specimens compared with negative controls effectively confirm this hypothesis.
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Affiliation(s)
- C Iaria
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166, Italy
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11
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Gordola KMC, Boctuanon FAU, Diolata RAA, Pedro MBD, Gutierrez TAD, Papa RDS, Papa DMD. Evaluation of Phage Delivery Systems on Induced Motile Aeromonas Septicemia in Oreochromis niloticus. PHAGE (NEW ROCHELLE, N.Y.) 2020; 1:189-197. [PMID: 36147284 PMCID: PMC9041466 DOI: 10.1089/phage.2020.0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Background: The success of phage therapy is affected by the method of treatment delivery. This study focused on comparing different phage delivery routes, specifically oral (phage-impregnated feed), intraperitoneal (IP), and bath (immersion), in treatment of induced motile Aeromonas septicemia (MAS). Materials and Methods: The efficacy of Aeromonas hydrophila phage cocktail in treating MAS-infected Oreochromis niloticus through different delivery routes was assessed by challenging the fish with 100% lethal dose of A. hydrophila and conducting a 15-day treatment regimen. Blood and kidney samples were analyzed for bacterial and phage concentrations. Results: All routes exhibited reduction of disease symptoms, significant (p < 0.05) decrease in bacterial count, and increase in phage count. Notably, IP route showed significant activity in reducing bacterial load. Conclusions: Phage therapy through IP route is the most effective yet invasive in controlling MAS infection in O. niloticus. The efficacy of oral route depends on the fish's intake of feeds, whereas the bath route was the least effective.
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Affiliation(s)
- Kathleen May C. Gordola
- Department of Biological Sciences, College of Science, University of Santo Tomas, Manila, Philippines
| | | | - Raylene Audrey A. Diolata
- Department of Biological Sciences, College of Science, University of Santo Tomas, Manila, Philippines
| | - Maria Bernadette D. Pedro
- Department of Biological Sciences, College of Science, University of Santo Tomas, Manila, Philippines
| | | | - Rey Donne S. Papa
- Department of Biological Sciences, College of Science, University of Santo Tomas, Manila, Philippines
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Research Center for Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines
| | - Donna May D. Papa
- Department of Biological Sciences, College of Science, University of Santo Tomas, Manila, Philippines
- The Graduate School, University of Santo Tomas, Manila, Philippines
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12
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Birkett C, Lipscomb R, Moreland T, Leeds T, Evenhuis JP. Recirculation versus flow-through rainbow trout laboratory Flavobacterium columnare challenge. DISEASES OF AQUATIC ORGANISMS 2020; 139:213-221. [PMID: 32495747 DOI: 10.3354/dao03487] [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] [Indexed: 06/11/2023]
Abstract
Flavobacterium columnare immersion challenges are affected by water-related environmental parameters and thus are difficult to reproduce. Whereas these challenges are typically conducted using flow-through systems, use of a recirculating challenge system to control environmental parameters may improve reproducibility. We compared mortality, bacterial concentration, and environmental parameters between flow-through and recirculating immersion challenge systems under laboratory conditions using 20 rainbow trout families. Despite identical dose concentration (1:75 dilution), duration of challenge, lot of fish, and temperature, average mortality in the recirculating system (42%) was lower (p < 0.01) compared to the flow-through system (77%), and there was low correlation (r = 0.24) of family mortality. Mean days to death (3.25 vs. 2.99 d) and aquaria-to-aquaria variation (9.6 vs. 10.4%) in the recirculating and flow-through systems, respectively, did not differ (p ≥ 0.30). Despite 10-fold lower water replacement rate in the recirculating (0.4 exchanges h-1) compared to flow-through system (4 exchanges h-1), differences in bacterial concentration between the 2 systems were modest (≤0.6 orders of magnitude) and inconsistent throughout the 21 d challenge. Compared to the flow-through system, dissolved oxygen during the 1 h exposure and pH were greater (p ≤ 0.02), and calcium and hardness were lower (p ≤ 0.03), in the recirculating system. Although this study was not designed to test effects of specific environmental parameters on mortality, it demonstrates that the cumulative effects of these parameters result in poor reproducibility. A recirculating immersion challenge model may be warranted to empirically identify and control environmental parameters affecting mortality and thus may serve as a more repeatable laboratory challenge model.
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Affiliation(s)
- Clayton Birkett
- National Center for Cool and Cold Water Aquaculture (NCCCWA), USDA-ARS, Kearneysville, WV 25430, USA
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13
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Su L, Xu C, Cai L, Qiu N, Hou M, Wang J. Susceptibility and immune responses after challenge with Flavobacterium columnare and Pseudomonas fluorescens in conventional and specific pathogen-free rare minnow (Gobiocypris rarus). FISH & SHELLFISH IMMUNOLOGY 2020; 98:875-886. [PMID: 31751657 DOI: 10.1016/j.fsi.2019.11.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 11/16/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
The susceptibility of fish from different culture environments to bacterial infection is not well known. The susceptibility and pathological changes of conventional (CV) and specific pathogen-free (SPF) rare minnow (Gobiocypris rarus) infected with two gram-negative bacteria, Flavobacterium columnare and Pseudomonas fluorescens are investigated. Rare minnows were intraperitoneally challenged with two bacterial species to first determine semi-lethal doses (LD50), and then with the LD50 dose, determine innate immune response. Infected rare minnows developed characteristic red bellies and then died. LD50 doses of F. columnare and P. fluorescens were 4.586 × 108 cfu/mL and 2.319 × 1010 cfu/mL for CV rare minnow, and 2.575 × 108 cfu/mL and 1.935 × 1010 cfu/mL, respectively, for SPF rare minnow. The results of RT-PCR showed that the highest levels of toll-like receptor 3 (TLR3), interleukin-6 (IL-6), interferon-2 (IFN-2) and rare minnow Z-DNA binding protein kinase (GrPKZ) mRNA were noticed at 6-48 h post-infection (hpi). In addition, TLR3, IL-6 and IFN-2 in F. columnare challenged rare minnow were more highly expressed than those in P. fluorescens challenged rare minnow, whereas as opposed in the expression of GrPKZ mRNA. Stimulation of innate immune responses is closely related to bacterial virulence. SPF rare minnow might be more susceptible to these bacteria than CV rare minnow, possibly due to their clean environment and lack of resistance. We speculate that clean environment renders rare minnow more susceptible to bacterial infections.
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Affiliation(s)
- Liangxia Su
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China; University of Chinese Academy of Sciences, Beijing, China
| | - Chunsen Xu
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China; University of Chinese Academy of Sciences, Beijing, China
| | - Lei Cai
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China; University of Chinese Academy of Sciences, Beijing, China; Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong, China
| | - Ning Qiu
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China; University of Chinese Academy of Sciences, Beijing, China
| | - Miaomiao Hou
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Jianwei Wang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China.
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14
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Tan S, Wang W, Tian C, Niu D, Zhou T, Yang Y, Gao D, Liu Z. Post-transcriptional regulation through alternative splicing after infection with Flavobacterium columnare in channel catfish (Ictalurus punctatus). FISH & SHELLFISH IMMUNOLOGY 2019; 91:188-193. [PMID: 31077849 DOI: 10.1016/j.fsi.2019.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/29/2019] [Accepted: 05/04/2019] [Indexed: 05/22/2023]
Abstract
Columnaris disease has long been recognized as a serious problem worldwide which affects both wild and cultured freshwater fish including the commercially important channel catfish (Ictalurus punctatus). The fundamental molecular mechanisms of the host immune response to the causative agent Flavobacterium columnare remain unclear, though gene expression analysis after the bacterial infection has been conducted. Alternative splicing, a post-transcriptional regulation process to modulate gene expression and increase the proteomic diversity, has not yet been studied in channel catfish following infection with F. columnare. In this study, genomic information and RNA-Seq datasets of channel catfish were used to characterize the changes of alternative splicing after the infection. Alternative splicing was shown to be induced by F. columnare infection, with 8.0% increase in alternative splicing event at early infection stage. Intriguingly, genes involved in RNA binding and RNA splicing themselves were significantly enriched in differentially alternatively spliced (DAS) gene sets after infection. This finding was consistent with our previous study in channel catfish following infection with Edwardsiella ictaluri. It was suggested to be a universal mechanism that genes involved in RNA binding and splicing were regulated to undergo differential alternative splicing after stresses in channel catfish. Moreover, many immune genes were observed to be differentially alternatively spliced after infection. Further studies need to be performed to get a deeper view of molecular regulation on alternative splicing after stresses, setting a foundation for developing catfish broodstocks with enhanced disease resistance.
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Affiliation(s)
- Suxu Tan
- The Fish Molecular Genetics and Biotechnology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Wenwen Wang
- The Fish Molecular Genetics and Biotechnology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Changxu Tian
- The Fish Molecular Genetics and Biotechnology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Donghong Niu
- The Fish Molecular Genetics and Biotechnology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA; College of Life Sciences, Shanghai Ocean University, Shanghai, China
| | - Tao Zhou
- The Fish Molecular Genetics and Biotechnology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Yujia Yang
- The Fish Molecular Genetics and Biotechnology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Dongya Gao
- The Fish Molecular Genetics and Biotechnology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Zhanjiang Liu
- Department of Biology, College of Art and Sciences, Syracuse University, Syracuse, NY, 13244, USA.
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15
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Identifying some pathogenic Vibrio/Photobacterium species during mass mortalities of cultured Gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) from some Egyptian coastal provinces. Int J Vet Sci Med 2019. [DOI: 10.1016/j.ijvsm.2013.10.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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16
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Räihä V, Sundberg L, Ashrafi R, Hyvärinen P, Karvonen A. Rearing background and exposure environment together explain higher survival of aquaculture fish during a bacterial outbreak. J Appl Ecol 2019. [DOI: 10.1111/1365-2664.13393] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ville Räihä
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Lotta‐Riina Sundberg
- Department of Biological and Environmental Science and Nanoscience Center Centre of Excellence in Biological Interactions University of Jyväskylä Jyväskylä Finland
| | - Roghaieh Ashrafi
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
| | - Pekka Hyvärinen
- Aquatic Population Dynamics Natural Resources Institute Finland (Luke) Paltamo Finland
| | - Anssi Karvonen
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä Finland
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17
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Wäge J, Strassert JFH, Landsberger A, Loick-Wilde N, Schmale O, Stawiarski B, Kreikemeyer B, Michel G, Labrenz M. Microcapillary sampling of Baltic Sea copepod gut microbiomes indicates high variability among individuals and the potential for methane production. FEMS Microbiol Ecol 2019; 95:5347944. [PMID: 30785612 DOI: 10.1093/femsec/fiz024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 02/19/2019] [Indexed: 11/13/2022] Open
Abstract
The paradox of methane oversaturation in oxygenated surface water has been described in many pelagic systems and still raises the question of the source. Temora sp. and Acartia sp. commonly dominate the surface and subsurface waters of the central Baltic Sea. It is hypothesised that their gut microbiome at least partly contributes to the methane anomaly in this ecosystem. However, the potential pathway for this methane production remains unclear. Using a microcapillary technique, we successfully overcame the challenge of sampling the gut microbiome of copepods <1 mm. 16S rRNA gene amplicon sequencing revealed differences among the dominant bacterial communities associated with Temora sp. (Actinobacteria, Betaproteobacteria and Flavobacteriia) and Acartia sp. (Actinobacteria, Alphaproteobacteria and Betaproteobacteria) and the surrounding water (Proteobacteria, Cyanobacteria and Verrucomicrobia), but also intraspecific variability. In both copepods, gut-specific prokaryotic taxa and indicative species for methane production pathways (methanogenesis, dimethylsulfoniopropionate or methylphosphonate) were present. The relative abundance of archaea and methanogens was investigated using droplet digital polymerase chain reaction and showed a high variability among copepod individuals, underlining intra- and interspecific differences in copepod-associated prokaryotic communities. Overall, this work highlights that the guts of Temora sp. and Acartia sp. have the potential for methane production but are probably no hotspot.
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Affiliation(s)
- J Wäge
- Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - J F H Strassert
- Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | | | - N Loick-Wilde
- Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - O Schmale
- Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - B Stawiarski
- Leibniz Institute for Baltic Sea Research, Rostock, Germany
| | - B Kreikemeyer
- University Hospital Rostock, Department of Medical Microbiology and Hospital Hygiene, Rostock, Germany
| | - G Michel
- Transgenic Technologies Charité , Berlin, Germany
| | - M Labrenz
- Leibniz Institute for Baltic Sea Research, Rostock, Germany
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18
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Gossieaux P, Sirois P, Bernatchez L, Garant D. Introgressive hybridization between wild and domestic individuals and its relationship with parasitism in brook charr Salvelinus fontinalis. JOURNAL OF FISH BIOLOGY 2018; 93:664-673. [PMID: 29992561 DOI: 10.1111/jfb.13752] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
The effects of introgression on parasitism in brook charr Salvelinus fontinalis were investigated in 28 lakes with various levels of stocking in Québec, Canada. No effect of genetic background on parasitism was found at the individual level. Body length seemed to explain most of the variation observed at this level, with largest fish being more infected. However, lakes with the greater average domestic genetic background were found to display significantly lower parasite prevalence and diversity. Since our results indicate no effect of domestic genes at the individual level, the negative association with introgression found at the population level may be mainly attributed to differences in intrinsic environmental quality of lakes (e.g. fishing pressure, availability of food resources, abiotic characteristics).
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Affiliation(s)
- Philippine Gossieaux
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Pascal Sirois
- Chaire de recherche sur les espèces aquatiques exploitées, Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada
| | - Louis Bernatchez
- Département de biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Pavillon Charles-Eugène-Marchand, Québec, Québec, Canada
| | - Dany Garant
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
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19
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Klíma O, Kohút L, Mareš J, Kopp R. The Effect of Feeding Frequency on the Fin Condition in Rainbow Trout (Oncorhynchus mykiss). ACTA UNIVERSITATIS AGRICULTURAE ET SILVICULTURAE MENDELIANAE BRUNENSIS 2018. [DOI: 10.11118/actaun201866030669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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20
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Rozi, Rahayu K, Daruti DN, Stella MSP. Study on characterization, pathogenicity and histopathology of disease caused byAeromonas hydrophilain gourami (Osphronemus gouramy). ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1755-1315/137/1/012003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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21
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LaFrentz BR, García JC, Waldbieser GC, Evenhuis JP, Loch TP, Liles MR, Wong FS, Chang SF. Identification of Four Distinct Phylogenetic Groups in Flavobacterium columnare With Fish Host Associations. Front Microbiol 2018; 9:452. [PMID: 29593693 PMCID: PMC5859164 DOI: 10.3389/fmicb.2018.00452] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/27/2018] [Indexed: 12/04/2022] Open
Abstract
Columnaris disease, caused by the Gram-negative bacterium Flavobacterium columnare, is one of the most prevalent fish diseases worldwide. An exceptionally high level of genetic diversity among isolates of F. columnare has long been recognized, whereby six established genomovars have been described to date. However, little has been done to quantify or characterize this diversity further in a systematic fashion. The objective of this research was to perform phylogenetic analyses of 16S rRNA and housekeeping gene sequences to decipher the genetic diversity of F. columnare. Fifty isolates and/or genomes of F. columnare, originating from diverse years, geographic locations, fish hosts, and representative of the six genomovars were analyzed in this study. A multilocus phylogenetic analysis (MLPA) of the 16S rRNA and six housekeeping genes supported four distinct F. columnare genetic groups. There were associations between genomovar and genetic group, but these relationships were imperfect indicating that genomovar assignment does not accurately reflect F. columnare genetic diversity. To expand the dataset, an additional 90 16S rRNA gene sequences were retrieved from GenBank and a phylogenetic analysis of this larger dataset also supported the establishment of four genetic groups. Examination of isolate historical data indicated biological relevance to the identified genetic diversity, with some genetic groups isolated preferentially from specific fish species or families. It is proposed that F. columnare isolates be assigned to the four genetic groups defined in this study rather than genomovar in order to facilitate a standard nomenclature across the scientific community. An increased understanding of which genetic groups are most prevalent in different regions and/or aquaculture industries may allow for the development of improved targeted control and treatment measures for columnaris disease.
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Affiliation(s)
- Benjamin R LaFrentz
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service, Auburn, AL, United States
| | - Julio C García
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service, Auburn, AL, United States
| | - Geoffrey C Waldbieser
- Warmwater Aquaculture Research Unit, Thad Cochran National Warmwater Aquaculture Center, United States Department of Agriculture - Agricultural Research Service, Stoneville, MS, United States
| | - Jason P Evenhuis
- National Center for Cool and Cold Water Aquaculture, United States Department of Agriculture - Agricultural Research Service, Kearneysville, WV, United States
| | - Thomas P Loch
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Mark R Liles
- Department of Biological Sciences, Auburn University, Auburn, AL, United States
| | - Fong S Wong
- MSD Animal Health Innovation Pte. Ltd., Singapore, Singapore
| | - Siow F Chang
- MSD Animal Health Innovation Pte. Ltd., Singapore, Singapore
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22
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Wonmongkol P, Sukhavachana S, Ampolsak K, Srisapoome P, Suwanasopee T, Poompuang S. Genetic parameters for resistance against Flavobacterium columnare in Nile tilapia Oreochromis niloticus (Linnaeus, 1758). JOURNAL OF FISH DISEASES 2018; 41:321-328. [PMID: 29064113 DOI: 10.1111/jfd.12728] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
Columnaris disease is a major cause of mortality in tilapia hatcheries and commonly occurs during the summer season in Thailand. One way of reducing the problem is by selective breeding for increased disease resistance. The objective of this study was to estimate quantitative genetic parameters for resistance against columnaris in the Chitralada 4 strain of Nile tilapia. Data from 43 full-sib families (2,580 records) of fry (age = 32 ± 4 days post-hatch) were used in the analyses. Initially, fry were subjected to bath challenge with Flavobacterium columnare (LD50 concentration = 1.2 × 106 CFU/ml) for 14 days. Disease resistance was defined as the number of days from challenge until death (DD) or as a binary trait (dead/alive) on day 14. Linear animal and sire-dam models were used for DD, while threshold animal, threshold sire-dam, binary linear animal and binary linear sire-dam models were used for binary outcomes. Covariate effect of age, fixed effect of challenge day and random effects of the individual animals or sires and dams were included in the models. Mean survival was 32.4 ± 11.6%, and survival rates of the best and poorest families were 70% and 8%, respectively. The highest estimate of heritability (0.30 ± 0.025) was obtained under the threshold sire-dam model. Heritability estimates for DD (0.16 ± 0.034 and 0.17 ± 0.046) were comparable to those obtained from the threshold animal (0.15 ± 0.031) and the binary linear (0.14 ± 0.045 and 0.15 ± 0.044) models. The linear animal and sire-dam models for DD and the threshold sire-dam models performed equally with similar values of rEBV (0.629, 0.628 and 0.627) and accuracy of selection (0.793, 0.793 and 0.791). This study reveals the potential of selective breeding to increase disease resistance to F. columnare in the studied population of Nile tilapia.
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Affiliation(s)
- P Wonmongkol
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
- Center for Advanced Study in Agriculture and Food, Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
| | - S Sukhavachana
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - K Ampolsak
- Phathumthani Aquaculture Genetic Research and Development Center, Department of Fisheries, Ministry of Agriculture and Cooperatives, Phathumthani, Thailand
| | - P Srisapoome
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - T Suwanasopee
- Department of Animal Science, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - S Poompuang
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
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23
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Yang Y, Miao P, Li H, Tan S, Yu H, Yu H. Antibiotic susceptibility and molecular characterization of
Aeromonas hydrophila
from grass carp. J Food Saf 2017. [DOI: 10.1111/jfs.12393] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ying Yang
- School of Life Science and EngineeringFoshan UniversityFoshan Guangdong China
| | - Pengfei Miao
- School of Life Science and EngineeringFoshan UniversityFoshan Guangdong China
| | - Hua Li
- School of Life Science and EngineeringFoshan UniversityFoshan Guangdong China
| | - Shuwen Tan
- School of Life Science and EngineeringFoshan UniversityFoshan Guangdong China
| | - Haiyi Yu
- School of Life Science and EngineeringFoshan UniversityFoshan Guangdong China
| | - Hui Yu
- School of Life Science and EngineeringFoshan UniversityFoshan Guangdong China
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24
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Seghouani H, Garcia-Rangel CE, Füller J, Gauthier J, Derome N. Walleye Autochthonous Bacteria as Promising Probiotic Candidates against Flavobacterium columnare. Front Microbiol 2017; 8:1349. [PMID: 28769909 PMCID: PMC5513935 DOI: 10.3389/fmicb.2017.01349] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 07/03/2017] [Indexed: 11/13/2022] Open
Abstract
Walleye (Sander vitreus) is the second most fished freshwater species in Canada. While much sought by anglers, walleye also supports substantial commercial fisheries. To cope with the recent decline of wild walleye populations, fish farmers produce juveniles for lake stocking. However, walleye breeding is particularly tedious, mostly due to high disease susceptibility at larval and juvenile developmental stages. The main threat is the columnaris disease, which is caused by Flavobacterium columnare, an opportunistic bacteria. As F. columnare strains exhibit increasing antibiotic resistance, there is a strong need to develop efficient and sustainable alternative strategies to control columnaris disease. Bacterial probiotics have been shown to mitigate infections either by enhancing host immune response or by inhibiting pathogen growth. Being successfully assessed in many fish/pathogen combinations, we developed a tailored probiotic strategy for walleye to prevent and treat columnaris disease. Thirty-seven endogenous bacterial strains were isolated from healthy walleye’s skin and gut, were tested in vitro against F. columnare. Significant antagonistic effect against F. columnare was measured for 2 out of 37 endogenous strains. These two probiotic strains were identified as Pseudomonas fluorescens. The antagonistic effect of these two successful probiotics was further validated in vivo during a 2-month stress trial: groups receiving probiotic treatments showed on average 53.74% survival improvement.
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Affiliation(s)
- Hamza Seghouani
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, QuebecQC, Canada
| | - Carlos-Enrique Garcia-Rangel
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, QuebecQC, Canada.,Centre Hospitalier de l'Université Laval, QuebecQC, Canada
| | - Jérémie Füller
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, QuebecQC, Canada
| | - Jeff Gauthier
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, QuebecQC, Canada
| | - Nicolas Derome
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, QuebecQC, Canada
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25
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Anttila J, Kaitala V, Laakso J, Ruokolainen L. Environmental Variation Generates Environmental Opportunist Pathogen Outbreaks. PLoS One 2015; 10:e0145511. [PMID: 26710238 PMCID: PMC4692394 DOI: 10.1371/journal.pone.0145511] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 12/05/2015] [Indexed: 11/18/2022] Open
Abstract
Many socio-economically important pathogens persist and grow in the outside host environment and opportunistically invade host individuals. The environmental growth and opportunistic nature of these pathogens has received only little attention in epidemiology. Environmental reservoirs are, however, an important source of novel diseases. Thus, attempts to control these diseases require different approaches than in traditional epidemiology focusing on obligatory parasites. Conditions in the outside-host environment are prone to fluctuate over time. This variation is a potentially important driver of epidemiological dynamics and affect the evolution of novel diseases. Using a modelling approach combining the traditional SIRS models to environmental opportunist pathogens and environmental variability, we show that epidemiological dynamics of opportunist diseases are profoundly driven by the quality of environmental variability, such as the long-term predictability and magnitude of fluctuations. When comparing periodic and stochastic environmental factors, for a given variance, stochastic variation is more likely to cause outbreaks than periodic variation. This is due to the extreme values being further away from the mean. Moreover, the effects of variability depend on the underlying biology of the epidemiological system, and which part of the system is being affected. Variation in host susceptibility leads to more severe pathogen outbreaks than variation in pathogen growth rate in the environment. Positive correlation in variation on both targets can cancel the effect of variation altogether. Moreover, the severity of outbreaks is significantly reduced by increase in the duration of immunity. Uncovering these issues helps in understanding and controlling diseases caused by environmental pathogens.
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Affiliation(s)
- Jani Anttila
- Integrative Ecology Unit, Department of Biosciences, FI-00014 University of Helsinki, Helsinki, Finland
| | - Veijo Kaitala
- Integrative Ecology Unit, Department of Biosciences, FI-00014 University of Helsinki, Helsinki, Finland
| | - Jouni Laakso
- Integrative Ecology Unit, Department of Biosciences, FI-00014 University of Helsinki, Helsinki, Finland
| | - Lasse Ruokolainen
- Integrative Ecology Unit, Department of Biosciences, FI-00014 University of Helsinki, Helsinki, Finland
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Karvonen A, Aalto-Araneda M, Virtala AM, Kortet R, Koski P, Hyvärinen P. Enriched rearing environment and wild genetic background can enhance survival and disease resistance of salmonid fishes during parasite epidemics. J Appl Ecol 2015. [DOI: 10.1111/1365-2664.12568] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Anssi Karvonen
- Department of Biological and Environmental Science; University of Jyväskylä; PO Box 35 FI-40014 Jyväskylä Finland
| | - Mariella Aalto-Araneda
- Faculty of Veterinary Medicine; University of Helsinki; PO Box 66 FI-00014 Helsinki Finland
| | - Anna-Maija Virtala
- Faculty of Veterinary Medicine; University of Helsinki; PO Box 66 FI-00014 Helsinki Finland
| | - Raine Kortet
- Department of Biology; University of Eastern Finland; PO Box 111 FI-80101 Joensuu Finland
| | - Perttu Koski
- Finnish Food Safety Authority Evira; Elektroniikkatie 3 90590 Oulu Finland
| | - Pekka Hyvärinen
- Natural Resources Institute Finland (Luke); Natural Resources and Bioproduction; Manamansalontie 90 88300 Paltamo Finland
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Roon SR, Alexander JD, Jacobson KC, Bartholomew JL. Effect of Nanophyetus salmincola and Bacterial Co-Infection on Mortality of Juvenile Chinook Salmon. JOURNAL OF AQUATIC ANIMAL HEALTH 2015; 27:209-216. [PMID: 26671546 DOI: 10.1080/08997659.2015.1094150] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The freshwater trematode Nanophyetus salmincola has been demonstrated to impair salmonid immune function and resistance to the marine pathogen Vibrio anguillarum, potentially resulting in ocean mortality. We examined whether infection by the parasite N. salmincola similarly increases mortality of juvenile Chinook Salmon Oncorhynchus tshawytscha when they are exposed to the freshwater pathogens Flavobacterium columnare or Aeromonas salmonicida, two bacteria that juvenile salmonids might encounter during their migration to the marine environment. We used a two-part experimental design where juvenile Chinook Salmon were first infected with N. salmincola through cohabitation with infected freshwater snails, Juga spp., and then challenged with either F. columnare or A. salmonicida. Cumulative percent mortality from F. columnare infection was higher in N. salmincola-parasitized fish than in nonparasitized fish. In contrast, cumulative percent mortality from A. salmonicida infection did not differ between N. salmincola-parasitized and nonparasitized groups. No mortalities were observed in the N. salmincola-parasitized-only and control groups from either challenge. Our study demonstrates that a relatively high mean intensity (>200 metacercariae per posterior kidney) of encysted N. salmincola metacercariae can alter the outcomes of bacterial infection in juvenile Chinook Salmon, which might have implications for disease in wild fish populations.
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Affiliation(s)
- Sean R Roon
- a Department of Microbiology , Oregon State University , 226 Nash Hall, Corvallis , Oregon 97331 , USA
| | - Julie D Alexander
- a Department of Microbiology , Oregon State University , 226 Nash Hall, Corvallis , Oregon 97331 , USA
| | - Kym C Jacobson
- b National Oceanographic and Atmospheric Administration-Fisheries , Northwest Fisheries Science Center , Newport Research Station, 2030 Southeast OSU Drive, Newport , Oregon 97365 , USA
| | - Jerri L Bartholomew
- a Department of Microbiology , Oregon State University , 226 Nash Hall, Corvallis , Oregon 97331 , USA
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Kinnula H, Mappes J, Valkonen JK, Sundberg LR. The Influence of Infective Dose on the Virulence of a Generalist Pathogen in Rainbow Trout (Oncorhynchus mykiss) and Zebra Fish (Danio rerio). PLoS One 2015; 10:e0139378. [PMID: 26421435 PMCID: PMC4589314 DOI: 10.1371/journal.pone.0139378] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/11/2015] [Indexed: 12/24/2022] Open
Abstract
Pathogen density and genetic diversity fluctuate in the outside-host environment during and between epidemics, affecting disease emergence and the severity and probability of infections. Although the importance of these factors for pathogen virulence and infection probability has been acknowledged, their interactive effects are not well understood. We studied how an infective dose in an environmentally transmitted opportunistic fish pathogen, Flavobacterium columnare, affects its virulence both in rainbow trout, which are frequently infected at fish farms, and in zebra fish, a host that is not naturally infected by F. columnare. We used previously isolated strains of confirmed high and low virulence in a single infection and in a co-infection. Infection success (measured as host morbidity) correlated positively with dose when the hosts were exposed to the high-virulence strain, but no response for the dose increase was found when the hosts were exposed to the low-virulence strain. Interestingly, the co-infection resulted in poorer infection success than the single infection with the high-virulence strain. The rainbow trout were more susceptible to the infection than the zebra fish but, in both species, the effects of the doses and the strains were qualitatively similar. We suggest that as an increase in dose can lead to increased host morbidity, both the interstrain interactions and differences in infectivity in different hosts may influence the severity and consequently the evolution of disease. Our results also confirm that the zebra fish is a good laboratory model to study F. columnare infection.
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Affiliation(s)
- Hanna Kinnula
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyvaskyla, Finland
- * E-mail:
| | - Johanna Mappes
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyvaskyla, Finland
| | - Janne K. Valkonen
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyvaskyla, Finland
| | - Lotta-Riina Sundberg
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyvaskyla, Finland
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29
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Mikheev VN, Pasternak AF, Valtonen ET. Behavioural adaptations of argulid parasites (Crustacea: Branchiura) to major challenges in their life cycle. Parasit Vectors 2015; 8:394. [PMID: 26205259 PMCID: PMC4513377 DOI: 10.1186/s13071-015-1005-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/12/2015] [Indexed: 12/02/2022] Open
Abstract
Fish lice (Argulus spp.) are obligate ectoparasites, which contrary to most aquatic parasites, retain the ability to swim freely throughout the whole of their life. In fish farms, they can quickly increase in numbers and without effective control cause argulosis, which results in the reduced growth and survival of their fish hosts. The morphology of Argulus spp, including their sensory organs, is suitable for both parasitism and free-swimming. By spending a considerable amount of time away from their host, these parasites risk being excessively dispersed, which could endanger mating success. Here we present a review of recent studies on the behaviour of Argulus spp, especially the aggregative behaviour that mitigates the dilution of the parasite population. Aggregation of parasites, which is especially important during the period of reproduction, occurs on different scales and involves both the aggregation of the host and the aggregation of the parasites on the host. The main behavioural adaptations of Argulus spp, including searches for hosts and mates, host manipulation and host choice, are all focused on the fish. As these ectoparasites repeatedly change hosts and inflict skin damage, they can act as vectors for fish pathogens. The development of environmentally friendly measures for the control and prevention of argulosis needs to take into account the behaviour of the parasites.
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Affiliation(s)
- V N Mikheev
- Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskii pr, 119071, Moscow, Russia.
| | - A F Pasternak
- Institute of Oceanology, Russian Academy of Sciences, 36 Nakhimovskii pr, 117997, Moscow, Russia.
| | - E T Valtonen
- Department of Biological and Environmental Science, University of Jyväskylä, PL 35, 40351, Jyväskylä, Finland.
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Wu B, Luo S, Wang J. Effects of temperature and feeding frequency on ingestion and growth for rare minnow. Physiol Behav 2014; 140:197-202. [PMID: 25542891 DOI: 10.1016/j.physbeh.2014.12.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
Abstract
Water temperature and feeding frequency are two important components in feeding strategy that directly affect the growth and physiology of fishes. The rare minnow (Gobiocypris rarus) has been cultured for decades in the laboratory as an experimental fish and is widely used in environmental science research. An 8-week factorial feeding experiment was conducted on juvenile rare minnows to investigate the interaction between water temperature (ambient, 20, 24, 28°C) and feeding frequency (one, two, three meals per day) on growth performance, feed utilization, gut evacuation and adaptability to variable environmental conditions. Groups fed three times a day at 28°C attained the maximum final body weight, followed by those fed two times a day at 24°C. There was an obvious curvilinear relationship between specific growth rate and temperature. Increased temperature significantly promoted food consumption and growth rate, but there were no benefits on growth by feeding multiple times at temperatures of 18°C or lower. Temperature and feeding frequency also affected gut evacuation rates: high temperature and frequency lead to fast evacuation. These results show that the optimal temperature and feeding frequency for rare minnow is 24°C and two meals a day for maximal growth, feeding efficiency, and daily management. The findings also suggest that the rare minnow has the ability to rapidly adapt to changing culture conditions by adjusting physiological activities in the short term.
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Affiliation(s)
- Benli Wu
- Institution of Hydrobiology, Chinese Academy of Science, Wuhan, Hubei 430042, PR China; University of Chinese Academy of Science, Beijing 100049, PR China.
| | - Si Luo
- Institution of Hydrobiology, Chinese Academy of Science, Wuhan, Hubei 430042, PR China; University of Chinese Academy of Science, Beijing 100049, PR China.
| | - Jianwei Wang
- Institution of Hydrobiology, Chinese Academy of Science, Wuhan, Hubei 430042, PR China.
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Liu L, Li YW, He RZ, Xiao XX, Zhang X, Su YL, Wang J, Li AX. Outbreak of Streptococcus agalactiae infection in barcoo grunter, Scortum barcoo (McCulloch & Waite), in an intensive fish farm in China. JOURNAL OF FISH DISEASES 2014; 37:1067-1072. [PMID: 24117712 DOI: 10.1111/jfd.12187] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/24/2013] [Accepted: 08/26/2013] [Indexed: 06/02/2023]
Affiliation(s)
- L Liu
- Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Bebak J, Wagner B, Burnes B, Hanson T. Farm size, seining practices, and salt use: risk factors for Aeromonas hydrophila outbreaks in farm-raised catfish, Alabama, USA. Prev Vet Med 2014; 118:161-8. [PMID: 25466218 DOI: 10.1016/j.prevetmed.2014.11.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 10/31/2014] [Accepted: 11/01/2014] [Indexed: 10/24/2022]
Abstract
In freshwater aquaculture systems, Aeromonas hydrophila is usually considered to be an opportunistic pathogen most often associated with secondary bacterial infections. Since 2009, the U.S. catfish industry, especially in West Alabama, has been affected by mortality from a strain of A. hydrophila that has been acting as a primary pathogen. Tens of millions of pounds of catfish production have been lost as a consequence of this disease. This study used data from two whole-population farmer surveys to examine farm-level risk factors for two A. hydrophila outbreaks in foodsize Alabama catfish, one in 2009 (surveyed in 2010), and one in 2011 (surveyed in 2012). The response to the 2010 survey was 85% and the response to the 2012 survey was 82%. Univariate analyses were used to examine biologically plausible variables (farm size, pond stocking density, seine exposure, use of salt (NaCl) in ponds), and used categorical disease outcome and dependent variables. Farm size was included in bivariate analyses with the other variables, because it was a potential confounding variable. For both study years, the odds of an A. hydrophila outbreak were significantly greater for farms larger than the mean size (2009: mean=132 acres (53.4 hectares), odds ratio (OR)=8.2; 95% confidence interval (CI)=3.3-20.6, p<0.001; 2011: mean=116 acres (46.9 hectares), OR=5.3, CI=1.7-17.0, p=0.009). Compared with 42% of control farms, every case farm was seined by a commercial or processing plant seining crew in 2009. The bivariate analysis of the 2011 variable "average number of times each pond was seined per year" indicated that regardless of farm size, farms with ponds that were seined more than twice per year had a significantly greater odds of an A. hydrophila outbreak (OR=4.1, CI=1.2-14.4, p=0.02). For 2009, the results of the bivariate analyses of chloride concentrations indicated that farms that had chloride concentrations >135 ppm had a significantly lower odds of experiencing A. hydrophila outbreaks (OR=0.2, CI=0.05-0.6, p-value=0.004). To achieve economies of scale, catfish farmers raise fish on large farms at higher stocking densities, but this practice may result in increased susceptibility to disease outbreaks. Producers should prioritize implementing biosecurity measures such as improved seining practices and other management practices to protect fish grown at high population densities. Further work will determine what the detailed seining protocols should include, and whether the use of salt, and at what concentrations, reduces the risk of A. hydrophila outbreaks.
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Affiliation(s)
- Julie Bebak
- Aquaculture Biosecurity, LLC, Post Office Box 24, Auburn, AL 36831, USA.
| | - Bruce Wagner
- USDA:APHIS:VS, 2150 Centre Ave, Fort Collins, CO 80526, USA
| | - Brian Burnes
- University of West Alabama, Hwy 100, Livingston, AL 35470, USA
| | - Terry Hanson
- Auburn University, School of Fisheries, Aquaculture and Aquatic Sciences, 203 Swingle Hall, Auburn, AL 36849, USA
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Mohammed HH, Arias CR. Epidemiology of columnaris disease affecting fishes within the same watershed. DISEASES OF AQUATIC ORGANISMS 2014; 109:201-211. [PMID: 24991846 DOI: 10.3354/dao02739] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In the southeastern USA, columnaris disease (caused by Flavobacterium columnare) typically affects catfish raised in earthen ponds from early spring until late summer. Recently, unusually severe outbreaks of columnaris disease occurred at the E. W. Shell Fisheries Center located in Auburn, AL, USA. During these outbreaks, catfish and other aquaculture and sport fish species that were in ponds located within the same watershed were affected. Our objective was to investigate the genetic diversity among F. columnare isolates recovered from different sites, sources, and dates to clarify the origin of these outbreaks and, ultimately, to better understand the epidemiology of columnaris disease. A total of 102 F. columnare isolates were recovered from catfishes (channel catfish Ictalurus puntactus, blue catfish I. furcatus, and their hybrid), bluegill Lepomis microchirus, Nile tilapia Oreochromis niloticus, largemouth bass Micropterus salmoides, egg masses, and water during columnaris outbreaks (from spring 2010 to summer 2012). Putative F. columnare colonies were identified following standard protocols. All isolates were ascribed to Genomovar II following restriction fragment length polymorphism analysis of the 16S rRNA gene. Genetic variability among the isolates was revealed by amplified fragment length polymorphism. Date of isolation explained most of the variability among our isolates, while host was the least influential parameter, denoting a lack of host specificity within Genomovar II isolates. The susceptibility of each of the isolates against commonly used antibiotics was tested by antibiogram. Our data showed that 19.6 and 12.7% of the isolates were resistant to oxytetracycline and kanamycin, respectively.
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Affiliation(s)
- Haitham H Mohammed
- Aquatic Microbiology Laboratory, School of Fisheries, Aquaculture and Aquatic Sciences, 203 Swingle Hall, Auburn University, Auburn, Alabama 36849, USA
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Strepparava N, Wahli T, Segner H, Petrini O. Detection and quantification of Flavobacterium psychrophilum in water and fish tissue samples by quantitative real time PCR. BMC Microbiol 2014; 14:105. [PMID: 24767577 PMCID: PMC4005812 DOI: 10.1186/1471-2180-14-105] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 04/22/2014] [Indexed: 11/10/2022] Open
Abstract
Background Flavobacterium psychrophilum is the agent of Bacterial Cold Water Disease and Rainbow Trout Fry Syndrome, two diseases leading to high mortality. Pathogen detection is mainly carried out using cultures and more rapid and sensitive methods are needed. Results We describe a qPCR technique based on the single copy gene β’ DNA-dependent RNA polymerase (rpoC). Its detection limit was 20 gene copies and the quantification limit 103 gene copies per reaction. Tests on spiked spleens with known concentrations of F. psychrophilum (106 to 101 cells per reaction) showed no cross-reactions between the spleen tissue and the primers and probe. Screening of water samples and spleens from symptomless and infected fishes indicated that the pathogen was already present before the outbreaks, but F. psychrophilum was only quantifiable in spleens from diseased fishes. Conclusions This qPCR can be used as a highly sensitive and specific method to detect F. psychrophilum in different sample types without the need for culturing. qPCR allows a reliable detection and quantification of F. psychrophilum in samples with low pathogen densities. Quantitative data on F. psychrophilum abundance could be useful to investigate risk factors linked to infections and also as early warning system prior to potential devastating outbreak.
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Affiliation(s)
- Nicole Strepparava
- Laboratory of Applied Microbiology, University of Applied Sciences and Arts of Southern Switzerland, Via Mirasole 22a, 6500 Bellinzona, Switzerland.
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Declercq AM, Haesebrouck F, Van den Broeck W, Bossier P, Decostere A. Columnaris disease in fish: a review with emphasis on bacterium-host interactions. Vet Res 2013; 44:27. [PMID: 23617544 PMCID: PMC3648355 DOI: 10.1186/1297-9716-44-27] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/10/2013] [Indexed: 11/10/2022] Open
Abstract
Flavobacterium columnare (F. columnare) is the causative agent of columnaris disease. This bacterium affects both cultured and wild freshwater fish including many susceptible commercially important fish species. F. columnare infections may result in skin lesions, fin erosion and gill necrosis, with a high degree of mortality, leading to severe economic losses. Especially in the last decade, various research groups have performed studies aimed at elucidating the pathogenesis of columnaris disease, leading to significant progress in defining the complex interactions between the organism and its host. Despite these efforts, the pathogenesis of columnaris disease hitherto largely remains unclear, compromising the further development of efficient curative and preventive measures to combat this disease. Besides elaborating on the agent and the disease it causes, this review aims to summarize these pathogenesis data emphasizing the areas meriting further investigation.
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Affiliation(s)
- Annelies Maria Declercq
- Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Wim Van den Broeck
- Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Peter Bossier
- Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Ghent, Belgium
| | - Annemie Decostere
- Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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Lafrentz BR, Lapatra SE, Shoemaker CA, Klesius PH. Reproducible challenge model to investigate the virulence of Flavobacterium columnare genomovars in rainbow trout Oncorhynchus mykiss. DISEASES OF AQUATIC ORGANISMS 2012; 101:115-122. [PMID: 23135138 DOI: 10.3354/dao02522] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Flavobacterium columnare is a Gram-negative bacterium that causes columnaris disease and has significant economic impacts on aquaculture production worldwide. Molecular analyses have demonstrated that there is genetic diversity among F. columnare isolates. A review of the published literature that used restriction fragment length polymorphism analysis of the 16S rRNA gene revealed that all isolates typed from salmonids were Genomovar I. Our objective was to develop a laboratory challenge model for F. columnare in rainbow trout Oncorhynchus mykiss (Walbaum) and use the model to determine the virulence of Genomovar I and II isolates. Six F. columnare isolates were obtained from rainbow trout experiencing losses due to columnaris disease and were determined to be Genomovar I. Three of these were chosen for a preliminary assessment of virulence, and isolate 051-10-S5 was chosen for additional experiments to determine the reproducibility of the waterborne challenge model. In 2 independent experiments, cumulative percent mortalities (CPM) were 49 ± 10% and 50 ± 19%. Challenge of rainbow trout with Genomovar I and II isolates demonstrated a difference in the CPM, with the Genomovar II isolates inducing significantly higher CPM. This reproducible waterborne challenge model for columnaris disease in rainbow trout will be useful to investigate host-pathogen interactions, vaccine development, and other potential control strategies. This research also provides a basis for further defining the molecular diversity and virulence associated with F. columnare genomovars in rainbow trout and other salmonid species.
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Affiliation(s)
- B R Lafrentz
- United States Department of Agriculture-Agricultural Research Service, Aquatic Animal Health Research Unit, 990 Wire Road, Auburn, Alabama 36832-4352, USA.
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Oliveira ST, Veneroni-Gouveia G, Costa MM. Molecular characterization of virulence factors in Aeromonas hydrophila obtained from fish. PESQUISA VETERINARIA BRASILEIRA 2012. [DOI: 10.1590/s0100-736x2012000800004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Multiple factors can be involved in the virulence processes of Aeromonas hydrophila. The objective of the present paper was to verify the presence of aerolysin, hidrolipase, elastase and lipase virulence genes through the polymerase chain reaction (PCR) in A. hydrophila isolates obtained from fish of the São Francisco River Valley, and to evaluate virulence according to the presence of these genes in Nile tilapia fingerlings. One hundred and fourteen isolates from the bacteria were used. DNA was heat extracted and PCR undertaken using specific primers described in the literature. For in vivo tests Nile tilapia fingerlings were used. From the PCR tests, negative isolates for all genes tested were selected, positive isolates for two genes (aerolysin and elastase) and positive for the four genes tested. These were inoculated at a concentration of 10(8) UFC/ml into the tilapias, considered as treatments; another group of animals was used as control (with inoculation of saline solution). In all, 12 distinct standards regarding the presence of virulence factors in isolates from A. hydrophila, were observed. Of the 114 isolates analyzed, 100 (87.72%) presented at least one of the virulence factors under study. The virulence factors were widely distributed among the A. hydrophila isolates. Aerolysin was the most frequent virulence factor present in the isolates analyzed. A. hydrophila led to the mortality of the Nile tilapia fingerlings, regardless of the absence or quantity of virulence genes tested.
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Shoemaker CA, Martins ML, Xu DH, Klesius PH. Effect of Ichthyophthirius multifiliis parasitism on the survival, hematology and bacterial load in channel catfish previously exposed to Edwardsiella ictaluri. Parasitol Res 2012; 111:2223-8. [DOI: 10.1007/s00436-012-2988-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 05/25/2012] [Indexed: 10/28/2022]
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Kunttu HMT, Jokinen EI, Valtonen ET, Sundberg LR. Virulent and nonvirulent Flavobacterium columnare colony morphologies: characterization of chondroitin AC lyase activity and adhesion to polystyrene. J Appl Microbiol 2011; 111:1319-26. [PMID: 21914095 DOI: 10.1111/j.1365-2672.2011.05149.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Colony morphology variants of fish pathogenic Flavobacterium columnare were studied to clarify the role of colony morphology change in the virulence of the bacterium. Typical rhizoid colony (Rz) variants are virulent and moderately adherent, nonrhizoid rough (R) colony variants are nonvirulent and highly adherent, and soft colony (S) variants are nonvirulent and poorly adherent. METHODS AND RESULTS Chondroitin AC lyase activity, adhesion to polystyrene at different temperatures and after modification of bacterial surface, and lipopolysaccharide (LPS) profiles of the variants were studied. The chondroitinase activity was significantly higher in the virulent, rhizoid variants than in the rough variants of the same strain. Temperature significantly increased the adhesion of rhizoid variants up to 20°C. Modification of bacterial surface suggested that adhesion molecules contain both carbohydrates and proteins. LPS did not differ between the variants of the same strain. CONCLUSIONS The results suggest that in Fl. columnare both rhizoid colony morphology and high chondroitinase activity are needed for virulence and that temperature may promote the adhesion of the virulent variants to surfaces at fish farms. SIGNIFICANCE AND IMPACT OF THE STUDY New information is produced on the virulence mechanisms of Fl. columnare and the reasons behind the survival of the bacterium at fish farms.
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Affiliation(s)
- H M T Kunttu
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
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40
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Blazer VS, Iwanowicz LR, Starliper CE, Iwanowicz DD, Barbash P, Hedrick JD, Reeser SJ, Mullican JE, Zaugg SD, Burkhardt MR, Kelble J. Mortality of centrarchid fishes in the Potomac drainage: survey results and overview of potential contributing factors. JOURNAL OF AQUATIC ANIMAL HEALTH 2010; 22:190-218. [PMID: 21192549 DOI: 10.1577/h10-002.1] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Skin lesions and spring mortality events of smallmouth bass Micropterus dolomieu and selected other species were first noted in the South Branch of the Potomac River in 2002. Since that year morbidity and mortality have also been observed in the Shenandoah and Monocacy rivers. Despite much research, no single pathogen, parasite, or chemical cause for the lesions and mortality has been identified. Numerous parasites, most commonly trematode metacercariae and myxozoans; the bacterial pathogens Aeromonas hydrophila, Aeromonas salmonicida, and Flavobacterium columnare; and largemouth bass virus have all been observed. None have been consistently isolated or observed at all sites, however, nor has any consistent microscopic pathology of the lesions been observed. A variety of histological changes associated with exposure to environmental contaminants or stressors, including intersex (testicular oocytes), high numbers of macrophage aggregates, oxidative damage, gill lesions, and epidermal papillomas, were observed. The findings indicate that selected sensitive species may be stressed by multiple factors and constantly close to the threshold between a sustainable (healthy) and nonsustainable (unhealthy) condition. Fish health is often used as an indicator of aquatic ecosystem health, and these findings raise concerns about environmental degradation within the Potomac River drainage. Unfortunately, while much information has been gained from the studies conducted to date, due to the multiple state jurisdictions involved, competing interests, and other issues, there has been no coordinated approach to identifying and mitigating the stressors. This synthesis emphasizes the need for multiyear, interdisciplinary, integrative research to identify the underlying stressors and possible management actions to enhance ecosystem health.
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Affiliation(s)
- V S Blazer
- U.S. Geological Survey, National Fish Health Research Laboratory, 11649 Leetown Road, Kearneysville, West Virginia 25430, USA.
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Eissa AE, Zaki MM, Aziz AA. Flavobacterium columnare / Myxobolus tilapiae Concurrent Infection in the Earthen Pond Reared Nile Tilapia (Oreochromis niloticus) during the Early Summer. ACTA ACUST UNITED AC 2010. [DOI: 10.4051/ibc.2010.2.2.0005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Gaunt PS, Gao D, Sun F, Endris R. Efficacy of florfenicol for control of mortality caused by Flavobacterium columnare infection in channel catfish. JOURNAL OF AQUATIC ANIMAL HEALTH 2010; 22:115-122. [PMID: 20848886 DOI: 10.1577/h09-057.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The studied in channel catfish Ictalurus punctatus fingerlings held in 80-L aquaria. Nonabraded fish were challenged by immersion on day 0. Thirty 80-L tanks were randomly assigned in equal numbers to two treatment groups, one in which fish were fed a commercial diet without florfenicol (unmedicated feed) and one in which they were fed a diet containing 10 mg of florfenicol/kg of body weight (medicated feed) for ten consecutive days. Mortality was monitored during the treatment period and a 14-d posttreatment observation period. At the end of the posttreatment period, all fish were euthanized, examined for gross lesions, and cultured for F. columnare. Significantly fewer fish fed the medicated diet died (8.0%) than fish fed the unmedicated diet (54.2%). Flavobacterium columnare was cultured from 15.0% of the medicated fish, compared with 68.9% of the unmedicated fish. The gross lesions in the fish were consistent with columnaris disease, and F. columnare was cultured from 99.5% of the dead fish. No differences were observed in weight gain and appetence between the medicated and unmedicated groups. For the F. columnare strain used in this study, the minimal inhibitory concentration of florfenicol ranged from 0.5 to 1.0 mg/mL in the 30 bacterial cultures obtained from infected fish, and the mean disk diffusion zone of inhibition was 40 mm. There were no adverse effects among the medicated fish. Administration of florfenicol at a dosage of 10 mg/kg body weight for 10 d was efficacious and safe for the control of mortality from F. columnare infection in channel catfish.
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Affiliation(s)
- Patricia S Gaunt
- Thad Cochran National Warmwater Aquaculture Center, College of Veterinary Medicine, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776, USA.
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Pulkkinen K, Suomalainen LR, Read AF, Ebert D, Rintamäki P, Valtonen ET. Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland. Proc Biol Sci 2009; 277:593-600. [PMID: 19864284 DOI: 10.1098/rspb.2009.1659] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ecological changes affect pathogen epidemiology and evolution and may trigger the emergence of novel diseases. Aquaculture radically alters the ecology of fish and their pathogens. Here we show an increase in the occurrence of the bacterial fish disease Flavobacterium columnare in salmon fingerlings at a fish farm in northern Finland over 23 years. We hypothesize that this emergence was owing to evolutionary changes in bacterial virulence. We base this argument on several observations. First, the emergence was associated with increased severity of symptoms. Second, F. columnare strains vary in virulence, with more lethal strains inducing more severe symptoms prior to death. Third, more virulent strains have greater infectivity, higher tissue-degrading capacity and higher growth rates. Fourth, pathogen strains co-occur, so that strains compete. Fifth, F. columnare can transmit efficiently from dead fish, and maintain infectivity in sterilized water for months, strongly reducing the fitness cost of host death likely experienced by the pathogen in nature. Moreover, this saprophytic infectiousness means that chemotherapy strongly select for strains that rapidly kill their hosts: dead fish remain infectious; treated fish do not. Finally, high stocking densities of homogeneous subsets of fish greatly enhance transmission opportunities. We suggest that fish farms provide an environment that promotes the circulation of more virulent strains of F. columnare. This effect is intensified by the recent increases in summer water temperature. More generally, we predict that intensive fish farming will lead to the evolution of more virulent pathogens.
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Affiliation(s)
- K Pulkkinen
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, FI-40014 Jyväskylä, Finland.
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Powell DB, Palm RC, MacKenzie AP, Winton JR. Extremophile extracts and enhancement techniques show promise for the development of a live vaccine against Flavobacterium columnare. Cryobiology 2009; 59:158-63. [DOI: 10.1016/j.cryobiol.2009.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 06/06/2009] [Accepted: 06/10/2009] [Indexed: 11/24/2022]
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Saprophytism of a fish pathogen as a transmission strategy. Epidemics 2009; 1:96-100. [DOI: 10.1016/j.epidem.2009.04.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 04/22/2009] [Accepted: 04/29/2009] [Indexed: 11/23/2022] Open
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Kunttu HMT, Valtonen ET, Suomalainen LR, Vielma J, Jokinen IE. The efficacy of two immunostimulants against Flavobacterium columnare infection in juvenile rainbow trout (Oncorhynchus mykiss). FISH & SHELLFISH IMMUNOLOGY 2009; 26:850-857. [PMID: 19344871 DOI: 10.1016/j.fsi.2009.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 03/19/2009] [Accepted: 03/20/2009] [Indexed: 05/27/2023]
Abstract
Bacterium Flavobacterium columnare is the causative agent of columnaris disease in many wild and farmed fish species. Immunostimulants are used with success in aquaculture against many pathogens, but the ability to improve innate resistance to columnaris disease has not been studied. Fingerling rainbow trout were treated with two immunostimulants, yeast beta-glucan and beta-hydroxy-beta-methylbutyrate (HMB). Selected innate immune function parameters, the production of reactive oxygen species (ROS) by whole blood and by isolated head kidney leukocytes, plasma lysozyme activity and complement bacteriolytic activity, were determined to assess the immune status of fish. The fish were then bath challenged with virulent F. columnare bacteria, and the mortality of fish was recorded. Given orally both stimulants raised the levels of immune function parameters, but did not improve survival in challenge at any concentration of the stimulants used. Intra peritoneal injection of beta-glucan increased parameter values several fold, but no beneficial effect of injected glucan on survival was noted. As a control, antibiotic medication administered prior to and during the challenge infection prevented the mortality. Innate immune mechanisms, even when induced to high levels with immunostimulants, as evidenced here, were not able to increase resistance against F. columnare. This may be connected to the external character of the infection. The results from the treatments with beta-glucan and HMB suggest that there is little prospect of preventing columnaris disease by means of immunostimulants in early life stage of rainbow trout. However, the efficacy of other immune stimulants remains open.
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Affiliation(s)
- Heidi M T Kunttu
- Department of Biological and Environmental Science, University of Jyväskylä, Finland
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Barnes ME, Bergmann D, Jacobs J, Gabel M. Effect of Flavobacterium columnare inoculation, antibiotic treatments and resident bacteria on rainbow trout Oncorhynchus mykiss eyed egg survival and external membrane structure. JOURNAL OF FISH BIOLOGY 2009; 74:576-590. [PMID: 20735580 DOI: 10.1111/j.1095-8649.2008.02147.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This study was conducted to evaluate the potential pathogenicity of the bacterium Flavobacterium columnare on rainbow trout Oncorhynchus mykiss eyed eggs. Survival to hatching was unaffected by the inclusion in the incubation water of either 300 colony-forming units (CFU) ml(-1) or 3000 CFU ml(-1) of F. columnare at either 10 or 12 degrees C in either McConaughy or Shasta strain eyed eggs. Bacterial numbers, obtained via scanning electron microscopy or culture, and external membrane morphology were also not significantly different among eggs receiving different concentrations of F. columnare. Initial F. columnare burdens were significantly and positively correlated to the presence of biofilm on the egg external membrane, and biofilm was in turn significantly correlated with increased membrane degradation. The use of either streptomycin or tetracyclin antibiotics significantly reduced bacterial numbers on McConaughy strain eggs, and more eggs survived to hatch in those dishes treated with antibiotics.
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Affiliation(s)
- M E Barnes
- South Dakota Department of Game, Fish and Parks, 19619 Trout Loop, Spearfish, SD 57783, USA.
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Chen LC, Chen JY, Hour AL, Shiau CY, Hui CF, Wu JL. Molecular cloning and functional analysis of zebrafish (Danio rerio) chemokine genes. Comp Biochem Physiol B Biochem Mol Biol 2008; 151:400-9. [DOI: 10.1016/j.cbpb.2008.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 08/14/2008] [Accepted: 08/15/2008] [Indexed: 01/16/2023]
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Sitjà-Bobadilla A, Pujalte MJ, Macián MC, Pascual J, Alvarez-Pellitero P, Garay E. Interactions between bacteria and Cryptosporidium molnari in gilthead sea bream (Sparus aurata) under farm and laboratory conditions. Vet Parasitol 2006; 142:248-59. [PMID: 16934406 DOI: 10.1016/j.vetpar.2006.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 06/30/2006] [Accepted: 07/06/2006] [Indexed: 11/23/2022]
Abstract
The possible interaction of Cryptosporidium molnari and bacteria in gilthead sea bream (Sparus aurata) was studied. Epidemiological data from a pathological survey under farm conditions were analyzed. In addition, parasite and bacteria burdens were studied in experimental models in which naturally and experimentally parasitized fish were challenged with a particular strain of Vibrio harveyi (H57). All the bacteria species present were studied. Under farm conditions, the parasite was more prevalent when mortality or morbidity cases (study C) occurred than in randomly sampled fish (study B). In study C, parasite abundance was significantly higher in bacteria-negative fish, and total bacteria abundance was significantly higher within non-parasitized fish. V. harveyi and V. splendidus were the most prevalent among bacteria carriers in studies B and C, respectively. In study C, among bacteria carriers, most isolates were slightly more prevalent in parasitized than in non-parasitized fish. Two groups (G1, G2) of naturally parasitized fish were inoculated with H57 by intracoelomic injection (ICI) and by oral intubation (OI). H57 was recovered only in G1 inoculated fish, which had a significantly higher basal abundance of total bacteria, and where the only ones with mortalities. In G1, the mortality rate and the prevalence of other V. harveyi strains different from the H57 molecular type were higher in ICI than in OI fish, and the total bacteria abundance was also significantly higher in ICI fish. C. molnari abundance was significantly higher in G1 than in G2, and also in OI than in ICI fish within G1. When H57 was IC inoculated to fish (G3, from the same farm as G2) experimentally infected with C. molnari, H57 was not recovered from any fish. A low mortality was recorded, and only in those fish inoculated with both pathogens. Also in these fish, the prevalence of infection of C. molnari was higher and histopathological damage to the stomach was greater than in fish inoculated only with the parasite. Therefore, the impact of the parasite would be reduced notably when the bacterial burden or the intensity of parasite infection are low (G2, G3).
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Affiliation(s)
- A Sitjà-Bobadilla
- Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (CSIC), Torre de la Sal s/n, 12595 Ribera de Cabanes, Castellón, Spain.
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Suomalainen LR, Tiirola M, Valtonen ET. Chondroitin AC lyase activity is related to virulence of fish pathogenic Flavobacterium columnare. JOURNAL OF FISH DISEASES 2006; 29:757-63. [PMID: 17169108 DOI: 10.1111/j.1365-2761.2006.00771.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The virulence of eight Flavobacterium columnare strains was studied to find correlations between several virulence-related factors and virulence. Virulence was tested in vivo using rainbow trout, Oncorhynchus mykiss (Walbaum). Suggested virulence-related factors such as production of the degradative enzyme chondroitin lyase, plasmid occurrence and adhesion capability were studied in vitro. Infection with the four most virulent strains resulted in 95-100% mortality within 114 h. Chondroitin lyase activity was found to be significantly related to the virulence of the strains at 25 degrees C and it was also shown to be temperature-dependent, being higher at 25 degrees C than at 20 degrees C. Virulence was not plasmid associated. The adhesion capability of the strains in vitro varied substantially when tested on crude mucus-coated slides and no statistical relationship between adhesion and virulence was found using this method.
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Affiliation(s)
- L-R Suomalainen
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
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