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Storesund JE, Nylund CDS, Karlsbakk E, Giulietti L, Bao M, Cipriani P, Levsen A. High prevalence of Ichthyophonus sp. infections in Northeast Atlantic mackerel (Scomber scombrus). JOURNAL OF FISH DISEASES 2022; 45:1243-1249. [PMID: 35604646 PMCID: PMC9543888 DOI: 10.1111/jfd.13652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Julia E. Storesund
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
| | - Caroline da Silva Nylund
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
- Department of Biological SciencesUniversity of Bergen (UiB)BergenNorway
| | - Egil Karlsbakk
- Department of Biological SciencesUniversity of Bergen (UiB)BergenNorway
- Pathogens and Disease TransferInstitute of Marine Research (IMR)BergenNorway
| | - Lucilla Giulietti
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
| | - Miguel Bao
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
| | - Paolo Cipriani
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
- Department of Public Health and Infectious DiseasesSection of Parasitology, Sapienza University of RomeRomeItaly
| | - Arne Levsen
- Section of Contaminants and BiohazardsInstitute of Marine Research (IMR)BergenNorway
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Fuller AM, VanBlaricom GR, Neuman MJ, Witting DA, Friedman CS. A field sentinel study investigating withering syndrome transmission dynamics in California abalones. MARINE ENVIRONMENTAL RESEARCH 2022; 173:105540. [PMID: 34864337 DOI: 10.1016/j.marenvres.2021.105540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 11/24/2021] [Accepted: 11/26/2021] [Indexed: 06/13/2023]
Abstract
We examined the risk of withering syndrome (WS) rickettsia-like organism (WS-RLO) infection in sentinel red abalone (Haliotis rufescens) deployed in modules at two Southern California field sites, one adjacent to an abalone farm and one adjacent to wild abalones. WS-RLO DNA was detected in seawater near modules at the wild abalone site but not near the farm (WS-RLO DNA was detected in the farm effluent). More WS-RLO DNA was detected in tissue from abalone near the farm relative to those near wild abalones (p < 0.05). However, infection prevalence and intensity based on histology were low and similar between sites (p > 0.05) and were independent of WS-RLO DNA loads in abalone tissue and seawater. More stippled (ST)-RLO than WS-RLO were observed with more ST-RLO infections near wild abalone than near the abalone farm (p < 0.05). We demonstrate the utility of caged sentinel abalone to better understand pathogen transmission patterns in the field.
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Affiliation(s)
- Ava M Fuller
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA.
| | - Glenn R VanBlaricom
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA; US Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, University of Washington, Box 355020, Seattle, WA, 98195, USA
| | - Melissa J Neuman
- NOAA National Marine Fisheries Service Protected Resources Division, 501 West Ocean Blvd, Suite 4200 Long Beach, CA, 90802, USA
| | - David A Witting
- NOAA National Marine Fisheries Service Protected Resources Division, 501 West Ocean Blvd, Suite 4200 Long Beach, CA, 90802, USA
| | - Carolyn S Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, 98195, USA
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Deeg CM, Kanzeparova AN, Somov AA, Esenkulova S, Di Cicco E, Kaukinen KH, Tabata A, Ming TJ, Li S, Mordecai G, Schulze A, Miller KM. Way out there: pathogens, health, and condition of overwintering salmon in the Gulf of Alaska. Facets (Ott) 2022. [DOI: 10.1139/facets-2021-0052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Salmon are keystone species across the North Pacific, supporting ecosystems, commercial opportunities, and cultural identity. Nevertheless, many wild salmon stocks have experienced significant declines. Salmon restoration efforts focus on fresh and coastal waters, but little is known about the open ocean environment. Here we use high throughput RT-qPCR tools to provide the first report on the health, condition, and infection profile of coho, chum, pink, and sockeye salmon in the Gulf of Alaska during the 2019 winter. We found lower infectious agent number, diversity, and burden compared with coastal British Columbia in all species except coho, which exhibited elevated stock-specific infection profiles. We identified Loma sp. and Ichthyophonus hoferi as key pathogens, suggesting transmission in the open ocean. Reduced prey availability, potentially linked to change in ocean conditions due to an El Niño event, correlated with energetic deficits and immunosuppression in salmon. Immunosuppressed individuals showed higher relative infection burden and higher prevalence of opportunistic pathogens. We highlight the cumulative effects of infection and environmental stressors on overwintering salmon, establishing a baseline to document the impacts of a changing ocean on salmon.
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Affiliation(s)
- Christoph M. Deeg
- Department of Forest & Conservation Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Pacific Salmon Foundation, Vancouver, BC V6J 4S6, Canada
| | | | - Alexei A. Somov
- Pacific branch of VNIRO (“TINRO”), Vladivostok, Russia 690091
| | | | | | - Karia H. Kaukinen
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
| | - Amy Tabata
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
| | - Tobi J. Ming
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
| | - Shaorong Li
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
| | - Gideon Mordecai
- Department of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Angela Schulze
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
| | - Kristina M. Miller
- Department of Forest & Conservation Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
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4
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Teffer AK, Carr J, Tabata A, Schulze A, Bradbury I, Deschamps D, Gillis CA, Brunsdon EB, Mordecai G, Miller KM. A molecular assessment of infectious agents carried by Atlantic salmon at sea and in three eastern Canadian rivers, including aquaculture escapees and North American and European origin wild stocks. Facets (Ott) 2020. [DOI: 10.1139/facets-2019-0048] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Infectious agents are key components of animal ecology and drivers of host population dynamics. Knowledge of their diversity and transmission in the wild is necessary for the management and conservation of host species like Atlantic salmon ( Salmo salar). Although pathogen exchange can occur throughout the salmon life cycle, evidence is lacking to support transmission during population mixing at sea or between farmed and wild salmon due to aquaculture exposure. We tested these hypotheses using a molecular approach that identified infectious agents and transmission potential among sub-adult Atlantic salmon at marine feeding areas and adults in three eastern Canadian rivers with varying aquaculture influence. We used high-throughput qPCR to quantify infection profiles and next generation sequencing to measure genomic variation among viral isolates. We identified 14 agents, including five not yet described as occurring in Eastern Canada. Phylogenetic analysis of piscine orthoreovirus showed homology between isolates from European and North American origin fish at sea, supporting the hypothesis of intercontinental transmission. We found no evidence to support aquaculture influence on wild adult infections, which varied relative to environmental conditions, life stage, and host origin. Our findings identify research opportunities regarding pathogen transmission and biological significance for wild Atlantic salmon populations.
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Affiliation(s)
- Amy K. Teffer
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jonathan Carr
- Atlantic Salmon Federation, Chamcook, NB E5B 3A9, Canada
| | - Amy Tabata
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC V9T 6N7, Canada
| | - Angela Schulze
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC V9T 6N7, Canada
| | - Ian Bradbury
- Salmonids Section, Fisheries and Oceans Canada, St. John’s, NF A1C 5X1, Canada
| | - Denise Deschamps
- Ministère des Forêts, de la Faune et des Parcs du Québec, Direction de l’expertise sur la faune aquatique, Quebec, QC G1S 4X4, Canada
| | | | | | - Gideon Mordecai
- Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kristina M. Miller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC V9T 6N7, Canada
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Teffer AK, Miller KM. A Comparison of Nonlethal and Destructive Methods for Broad-Based Infectious Agent Screening of Chinook Salmon Using High-Throughput qPCR. JOURNAL OF AQUATIC ANIMAL HEALTH 2019; 31:274-289. [PMID: 31343778 DOI: 10.1002/aah.10079] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/20/2019] [Indexed: 06/10/2023]
Abstract
Molecular tools, such as high-throughput quantitative polymerase chain reaction (HT-qPCR), are useful for monitoring multiple infectious agents in wild animal populations (i.e., broad-based screening). If destructive tissue samples cannot be obtained due to experimental design requirements (e.g., bio-telemetry; holding with repeated biopsy) or the conservation status of host species, then nonlethally sampled tissues can be substituted. However, infection profiles have been found to differ between nonlethally and destructively sampled tissues. We present a comparative analysis of nonlethal (gill and blood) and destructive (pool of internal and external tissue) approaches for broad-based infectious agent screening of adult Chinook Salmon Oncorhynchus tshawytscha. Of a possible 47 agents, 16 were detected overall by nonlethal and destructive methods. Our results indicated moderate differences in infection profiles among tissues, with limitations of each tissue type dependent on the ecology of each agent. The gill was the most comprehensive screening tissue, as more infectious agents were detected overall in gill (n = 16) than in blood (n = 12) or multi-tissue pools (n = 15). The agreement in the estimated agent prevalence between tissue types ranged from poor to excellent, while overall agent community structure (the combined prevalence of all agents) showed low agreement between tissue types. Two agents occurred at 100% prevalence in all tissue types. Nine agents, including types of bacteria and gill parasites, were more prevalent in gill than in blood, while five agents, including one virus and several microparasites, were more prevalent in blood. Future studies should pair microscopy and histopathology with HT-qPCR to better characterize host health and disease development relative to molecular detection of agents across tissue types.
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Affiliation(s)
- Amy K Teffer
- Department of Biology, University of Victoria, Post Office Box 1700, Station CSC, Victoria, British Columbia, V8W 2Y2, Canada
| | - Kristina M Miller
- Fisheries and Oceans Canada, Molecular Genetics Section, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, V9T 6N7, Canada
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Rusch JC, Hansen H, Strand DA, Markussen T, Hytterød S, Vrålstad T. Catching the fish with the worm: a case study on eDNA detection of the monogenean parasite Gyrodactylus salaris and two of its hosts, Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Parasit Vectors 2018; 11:333. [PMID: 29866158 PMCID: PMC5987472 DOI: 10.1186/s13071-018-2916-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/25/2018] [Indexed: 01/20/2023] Open
Abstract
Background Environmental DNA (eDNA) monitoring is growing increasingly popular in aquatic systems as a valuable complementary method to conventional monitoring. However, such tools have not yet been extensively applied for metazoan fish parasite monitoring. The fish ectoparasite Gyrodactylus salaris, introduced into Norway in 1975, has caused severe damage to Atlantic salmon populations and fisheries. Successful eradication of the parasite has been carried out in several river systems in Norway, and Atlantic salmon remain infected in only seven rivers, including three in the Drammen region. In this particular infection region, a prerequisite for treatment is to establish whether G. salaris is also present on rainbow trout upstream of the salmon migration barrier. Here, we developed and tested eDNA approaches to complement conventional surveillance methods. Methods Water samples (2 × 5 l) were filtered on-site through glass fibre filters from nine locations in the Drammen watercourse, and DNA was extracted with a CTAB protocol. We developed a qPCR assay for G. salaris targeting the nuclear ribosomal ITS1 region, and we implemented published assays targeting the mitochondrial cytochrome-b and NADH-regions for Atlantic salmon and rainbow trout, respectively. All assays were transferred successfully to droplet digital PCR (ddPCR). Results All qPCR/ddPCR assays performed well both on tissue samples and on field samples, demonstrating the applicability of eDNA detection for G. salaris, rainbow trout and Atlantic salmon in natural water systems. With ddPCR we eliminated a low cross-amplification of Gyrodactylus derjavinoides observed using qPCR, thus increasing specificity and sensitivity substantially. Duplex ddPCR for G. salaris and Atlantic salmon was successfully implemented and can be used as a method in future surveillance programs. The presence of G. salaris eDNA in the infected River Lierelva was documented, while not elsewhere. Rainbow trout eDNA was only detected at localities where the positives could be attributed to eDNA release from upstream land-based rainbow trout farms. Electrofishing supported the absence of rainbow trout in all of the localities. Conclusions We provide a reliable field and laboratory protocol for eDNA detection of G. salaris, Atlantic salmon and rainbow trout, that can complement conventional surveillance programs and substantially reduce the sacrifice of live fish. We also show that ddPCR outperforms qPCR with respect to the specific detection of G. salaris.
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Affiliation(s)
- Johannes C Rusch
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway.,Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, NO-0316, Oslo, Norway
| | - Haakon Hansen
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway.
| | - David A Strand
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway
| | - Turhan Markussen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 8146, Dep, NO-0033, Oslo, Norway
| | - Sigurd Hytterød
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway
| | - Trude Vrålstad
- Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway
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Lowe VC, Hershberger PK, Friedman CS. Analytical and diagnostic performance of a qPCR assay for Ichthyophonus spp. compared to the tissue culture 'gold standard'. DISEASES OF AQUATIC ORGANISMS 2018; 128:215-224. [PMID: 29862979 DOI: 10.3354/dao03221] [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: 06/08/2023]
Abstract
Parasites of the genus Ichthyophonus infect many fish species and have a non-uniform distribution within host tissues. Due in part to this uneven distribution, the comparative sensitivity and accuracy of using molecular-based detection methods versus culture to estimate parasite prevalence is under debate. We evaluated the analytical and diagnostic performance of an existing qPCR assay in comparison to the 'gold standard' culture method using Pacific herring Clupea pallasii with known exposure history. We determined that the assay is suitable for use in this host, and diagnostic specificity was consistently high (>98%) in both heart and liver tissues. Diagnostic sensitivity could not be fully assessed due to low infection rates, but our results suggest that qPCR is not as sensitive as culture under all circumstances. Diagnostic sensitivity of qPCR relative to culture is likely affected by the amount of sample processed. The prevalence values estimated by the 2 methods were not significantly different when sample amounts were equal (heart tissue), but when the assayed sample amounts were unequal (liver tissue), the culture method detected a significantly higher prevalence of the parasite than qPCR. Further, culture of liver also detected significantly more Ichthyophonus infections than culture of heart, suggesting that the density and distribution of parasites in tissues also plays a role in assay sensitivity. This sensitivity issue would be most problematic for fish with light infections. Although qPCR does not detect the presence of a live organism, DNA-based pathogen detection methods provide the opportunity for alternate testing strategies when culture is not possible.
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Affiliation(s)
- Vanessa C Lowe
- Resource Assessment and Conservation Engineering Division, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
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Teffer AK, Hinch SG, Miller KM, Patterson DA, Farrell AP, Cooke SJ, Bass AL, Szekeres P, Juanes F. Capture severity, infectious disease processes and sex influence post-release mortality of sockeye salmon bycatch. CONSERVATION PHYSIOLOGY 2017; 5:cox017. [PMID: 28852514 PMCID: PMC5569998 DOI: 10.1093/conphys/cox017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 02/17/2017] [Accepted: 03/07/2017] [Indexed: 05/21/2023]
Abstract
Bycatch is a common occurrence in heavily fished areas such as the Fraser River, British Columbia, where fisheries target returning adult Pacific salmon (Oncorhynchus spp.) en route to spawning grounds. The extent to which these encounters reduce fish survival through injury and physiological impairment depends on multiple factors including capture severity, river temperature and infectious agents. In an effort to characterize the mechanisms of post-release mortality and address fishery and managerial concerns regarding specific regulations, wild-caught Early Stuart sockeye salmon (Oncorhynchus nerka) were exposed to either mild (20 s) or severe (20 min) gillnet entanglement and then held at ecologically relevant temperatures throughout their period of river migration (mid-late July) and spawning (early August). Individuals were biopsy sampled immediately after entanglement and at death to measure indicators of stress and immunity, and the infection intensity of 44 potential pathogens. Biopsy alone increased mortality (males: 33%, females: 60%) when compared with non-biopsied controls (males: 7%, females: 15%), indicating high sensitivity to any handling during river migration, especially among females. Mortality did not occur until 5-10 days after entanglement, with severe entanglement resulting in the greatest mortality (males: 62%, females: 90%), followed by mild entanglement (males: 44%, females: 70%). Infection intensities of Flavobacterium psychrophilum and Ceratonova shasta measured at death were greater in fish that died sooner. Physiological indicators of host stress and immunity also differed depending on longevity, and indicated anaerobic metabolism, osmoregulatory failure and altered immune gene regulation in premature mortalities. Together, these results implicate latent effects of entanglement, especially among females, resulting in mortality days or weeks after release. Although any entanglement is potentially detrimental, reducing entanglement durations can improve post-release survival.
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Affiliation(s)
- Amy K. Teffer
- Department of Biology, University of Victoria, Victoria, BC V8P 5C2, Canada
- Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Scott G. Hinch
- Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Kristi M. Miller
- Fisheries and Oceans Canada, Molecular Genetics Section, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada
| | - David A. Patterson
- Fisheries and Oceans Canada, Cooperative Resource Management Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Anthony P. Farrell
- Department of Zoology, Department of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Steven J. Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Arthur L. Bass
- Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Petra Szekeres
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Francis Juanes
- Department of Biology, University of Victoria, Victoria, BC V8P 5C2, Canada
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Bass D, Stentiford GD, Littlewood D, Hartikainen H. Diverse Applications of Environmental DNA Methods in Parasitology. Trends Parasitol 2015; 31:499-513. [DOI: 10.1016/j.pt.2015.06.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 01/05/2023]
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10
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Conway CM, Purcell MK, Elliott DG, Hershberger PK. Detection of Ichthyophonus by chromogenic in situ hybridization. JOURNAL OF FISH DISEASES 2015; 38:853-857. [PMID: 25271555 DOI: 10.1111/jfd.12300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/10/2014] [Accepted: 07/21/2014] [Indexed: 06/03/2023]
Affiliation(s)
- C M Conway
- US Geological Survey-Western Fisheries Research Center, Seattle, WA, USA
| | - M K Purcell
- US Geological Survey-Western Fisheries Research Center, Seattle, WA, USA
| | - D G Elliott
- US Geological Survey-Western Fisheries Research Center, Seattle, WA, USA
| | - P K Hershberger
- US Geological Survey-Marrowstone Marine Field Station, Nordland, WA, USA
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Kiryu Y, Landsberg JH. Neurotropic mesomycetozoean-like infection in larvae of the southern toad Anaxyrus terrestris in Florida, USA. DISEASES OF AQUATIC ORGANISMS 2015; 113:157-162. [PMID: 25751858 DOI: 10.3354/dao02836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
As part of a state-wide multispecies survey of amphibian diseases, sampling was conducted at Archbold Biological Station, Venus, Florida, USA, on 15 April 2011. Gross examination of southern toad (Anaxyrus terrestris) larvae was unremarkable, but infections by a mesomycetozoean-like organism were observed in longitudinally sectioned routine haematoxylin and eosin-stained histologic slides. In 100% of the sectioned specimens examined (n = 5), a high density of the organism, representing several developmental stages, was found in the central nervous system, mainly in the spinal cord, brain, retina and optic nerve. No host inflammatory responses were found to be associated with the parasitic infection. Free, mature schizonts were occasionally found in the gill chamber and, more commonly, in the dorsal roof area. No organisms were found in other organs examined histologically, i.e. liver, kidney, heart, alimentary tract, exocrine pancreas and skeletal muscles. Presumptive mesomycetozoean ichthyophonids in anurans are usually reported to be pathogenic, especially affecting skeletal muscle tissue and causing death. To our knowledge, this is the first report of a similar organism infecting primarily the central nervous system in an amphibian.
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Affiliation(s)
- Yasunari Kiryu
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida 33701, USA
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Lafferty KD, Harvell CD, Conrad JM, Friedman CS, Kent ML, Kuris AM, Powell EN, Rondeau D, Saksida SM. Infectious diseases affect marine fisheries and aquaculture economics. ANNUAL REVIEW OF MARINE SCIENCE 2015; 7:471-96. [PMID: 25251276 DOI: 10.1146/annurev-marine-010814-015646] [Citation(s) in RCA: 269] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Seafood is a growing part of the economy, but its economic value is diminished by marine diseases. Infectious diseases are common in the ocean, and here we tabulate 67 examples that can reduce commercial species' growth and survivorship or decrease seafood quality. These impacts seem most problematic in the stressful and crowded conditions of aquaculture, which increasingly dominates seafood production as wild fishery production plateaus. For instance, marine diseases of farmed oysters, shrimp, abalone, and various fishes, particularly Atlantic salmon, cost billions of dollars each year. In comparison, it is often difficult to accurately estimate disease impacts on wild populations, especially those of pelagic and subtidal species. Farmed species often receive infectious diseases from wild species and can, in turn, export infectious agents to wild species. However, the impact of disease export on wild fisheries is controversial because there are few quantitative data demonstrating that wild species near farms suffer more from infectious diseases than those in other areas. The movement of exotic infectious agents to new areas continues to be the greatest concern.
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Affiliation(s)
- Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey, c/o Marine Science Institute, University of California, Santa Barbara, California 93106; *
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13
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White VC, Morado JF, Friedman CS. Ichthyophonus-infected walleye pollock Theragra chalcogramma (Pallas) in the eastern Bering Sea: a potential reservoir of infections in the North Pacific. JOURNAL OF FISH DISEASES 2014; 37:641-655. [PMID: 23941303 DOI: 10.1111/jfd.12161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 06/24/2013] [Accepted: 07/09/2013] [Indexed: 06/02/2023]
Abstract
In 2003, the Alaska walleye pollock industry reported product quality issues attributed to an unspecified parasite in fish muscle. Using molecular and histological methods, we identified the parasite in Bering Sea pollock as Ichthyophonus. Infected pollock were identified throughout the study area, and prevalence was greater in adults than in juveniles. This study not only provides the first documented report of Ichthyophonus in any fish species captured in the Bering Sea, but also reveals that the parasite has been present in this region for nearly 20 years and is not a recent introduction. Sequence analysis of 18S rDNA from Ichthyophonus in pollock revealed that consensus sequences were identical to published parasite sequences from Pacific herring and Yukon River Chinook salmon. Results from this study suggest potential for Ichthyophonus exposures from infected pollock via two trophic pathways; feeding on whole fish as prey and scavenging on industry-discharged offal. Considering the notable Ichthyophonus levels in pollock, the low host specificity of the parasite and the role of this host as a central prey item in the Bering Sea, pollock likely serve as a key Ichthyophonus reservoir for other susceptible hosts in the North Pacific.
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Affiliation(s)
- V C White
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center, Resource Assessment and Conservation Engineering Division, Seattle, WA, USA
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