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Saleh M, Hummel K, Schlosser S, Razzazi-Fazeli E, Bartholomew JL, Holzer A, Secombes CJ, El-Matbouli M. The myxozoans Myxobolus cerebralis and Tetracapsuloides bryosalmonae modulate rainbow trout immune responses: quantitative shotgun proteomics at the portals of entry after single and co-infections. Front Cell Infect Microbiol 2024; 14:1369615. [PMID: 38803570 PMCID: PMC11129561 DOI: 10.3389/fcimb.2024.1369615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 04/05/2024] [Indexed: 05/29/2024] Open
Abstract
Introduction Little is known about the proteomic changes at the portals of entry in rainbow trout after infection with the myxozoan parasites, Myxobolus cerebralis, and Tetracapsuloides bryosalmonae. Whirling disease (WD) is a severe disease of salmonids, caused by the myxosporean M. cerebralis, while, proliferative kidney disease (PKD) is caused by T. bryosalmonae, which instead belongs to the class Malacosporea. Climate change is providing more suitable conditions for myxozoan parasites lifecycle, posing a high risk to salmonid aquaculture and contributing to the decline of wild trout populations in North America and Europe. Therefore, the aim of this study was to provide the first proteomic profiles of the host in the search for evasion strategies during single and coinfection with M. cerebralis and T. bryosalmonae. Methods One group of fish was initially infected with M. cerebralis and another group with T. bryosalmonae. After 30 days, half of the fish in each group were co-infected with the other parasite. Using a quantitative proteomic approach, we investigated proteomic changes in the caudal fins and gills of rainbow trout before and after co-infection. Results In the caudal fins, 16 proteins were differentially regulated post exposure to M. cerebralis, whereas 27 proteins were differentially modulated in the gills of the infected rainbow trout post exposure to T. bryosalmonae. After co-infection, 4 proteins involved in parasite recognition and the regulation of host immune responses were differentially modulated between the groups in the caudal fin. In the gills, 11 proteins involved in parasite recognition and host immunity, including 4 myxozoan proteins predicted to be virulence factors, were differentially modulated. Discussion The results of this study increase our knowledge on rainbow trout co-infections by myxozoan parasites and rainbow trout immune responses against myxozoans at the portals of entry, supporting a better understanding of these host-parasite interactions.
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Affiliation(s)
- Mona Saleh
- Division of Fish Health, University of Veterinary Medicine, Vienna, Austria
| | - Karin Hummel
- VetCore, University of Veterinary Medicine, Vienna, Austria
| | | | | | - Jerri L. Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Astrid Holzer
- Division of Fish Health, University of Veterinary Medicine, Vienna, Austria
| | - Christopher J. Secombes
- Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Scotland, United Kingdom
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Sandberg TOM, Yahalomi D, Bracha N, Haddas-Sasson M, Pupko T, Atkinson SD, Bartholomew JL, Zhang JY, Huchon D. Evolution of myxozoan mitochondrial genomes: insights from myxobolids. BMC Genomics 2024; 25:388. [PMID: 38649808 PMCID: PMC11034133 DOI: 10.1186/s12864-024-10254-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Myxozoa is a class of cnidarian parasites that encompasses over 2,400 species. Phylogenetic relationships among myxozoans remain highly debated, owing to both a lack of informative morphological characters and a shortage of molecular markers. Mitochondrial (mt) genomes are a common marker in phylogeny and biogeography. However, only five complete myxozoan mt genomes have been sequenced: four belonging to two closely related genera, Enteromyxum and Kudoa, and one from the genus Myxobolus. Interestingly, while cytochrome oxidase genes could be identified in Enteromyxum and Kudoa, no such genes were found in Myxobolus squamalis, and another member of the Myxobolidae (Henneguya salminicola) was found to have lost its entire mt genome. To evaluate the utility of mt genomes to reconstruct myxozoan relationships and to understand if the loss of cytochrome oxidase genes is a characteristic of myxobolids, we sequenced the mt genome of five myxozoans (Myxobolus wulii, M. honghuensis, M. shantungensis, Thelohanellus kitauei and, Sphaeromyxa zaharoni) using Illumina and Oxford Nanopore platforms. RESULTS Unlike Enteromyxum, which possesses a partitioned mt genome, the five mt genomes were encoded on single circular chromosomes. An mt plasmid was found in M. wulii, as described previously in Kudoa iwatai. In all new myxozoan genomes, five protein-coding genes (cob, cox1, cox2, nad1, and nad5) and two rRNAs (rnl and rns) were recognized, but no tRNA. We found that Myxobolus and Thelohanellus species shared unidentified reading frames, supporting the view that these mt open reading frames are functional. Our phylogenetic reconstructions based on the five conserved mt genes agree with previously published trees based on the 18S rRNA gene. CONCLUSIONS Our results suggest that the loss of cytochrome oxidase genes is not a characteristic of all myxobolids, the ancestral myxozoan mt genome was likely encoded on a single circular chromosome, and mt plasmids exist in a few lineages. Our findings indicate that myxozoan mt sequences are poor markers for reconstructing myxozoan phylogenetic relationships because of their fast-evolutionary rates and the abundance of repeated elements, which complicates assembly.
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Affiliation(s)
| | - Dayana Yahalomi
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Noam Bracha
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Michal Haddas-Sasson
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Stephen D Atkinson
- Department of Microbiology, Oregon State University, 97331, Corvallis, OR, USA
| | - Jerri L Bartholomew
- Department of Microbiology, Oregon State University, 97331, Corvallis, OR, USA
| | - Jin Yong Zhang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Dorothée Huchon
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
- The Steinhardt Museum of Natural History and National Research Center, Tel Aviv University, 6997801, Tel Aviv, Israel.
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Lauringson M, Kahar S, Veevo T, Silm M, Philpott D, Svirgsden R, Rohtla M, Päkk P, Gross R, Kaart T, Vasemägi A. Spatial and intra-host distribution of myxozoan parasite Tetracapsuloides bryosalmonae among Baltic sea trout (Salmo trutta). JOURNAL OF FISH DISEASES 2023; 46:1073-1083. [PMID: 37387198 DOI: 10.1111/jfd.13827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 07/01/2023]
Abstract
Proliferative kidney disease caused by the myxozoan parasite Tetracapsuloides bryosalmonae has been actively studied in juvenile salmonids for decades. However, very little is known about parasite prevalence and its geographical and intra-host distribution at older life stages. We screened T. bryosalmonae among adult sea trout (Salmo trutta) (n = 295) collected along the Estonian Baltic Sea coastline together with juvenile trout from 33 coastal rivers (n = 1752) to assess spatial infection patterns of the adult and juvenile fish. The parasite was detected among 38.6% of adult sea trout with the prevalence increasing from west to east, and south to north, along the coastline. A similar pattern was observed in juvenile trout. Infected sea trout were also older than uninfected fish and the parasite was detected in sea trout up to the age of 6 years. Analysis of intra-host distribution of the parasite and strontium to calcium ratios from the otoliths revealed that (re)infection through freshwater migration may occur among adult sea trout. The results of this study indicate that T. bryosalmonae can persist in a brackish water environment for several years and that returning sea trout spawners most likely contribute to the parasite life cycle by transmitting infective spores.
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Affiliation(s)
- Magnus Lauringson
- Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Siim Kahar
- Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Taigor Veevo
- Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Maidu Silm
- Centre for Limnology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Duncan Philpott
- Department of Aquatic Resources, Institute of Freshwater Research, Swedish University of Agricultural Sciences, Drottningholm, Sweden
| | | | - Mehis Rohtla
- Estonian Marine Institute, University of Tartu, Tartu, Estonia
| | - Priit Päkk
- Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Riho Gross
- Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Tanel Kaart
- Chair of Animal Breeding and Biotechnology, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Anti Vasemägi
- Chair of Aquaculture, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia
- Department of Aquatic Resources, Institute of Freshwater Research, Swedish University of Agricultural Sciences, Drottningholm, Sweden
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Ros A, Schmidt-Posthaus H, Brinker A. Mitigating human impacts including climate change on proliferative kidney disease in salmonids of running waters. JOURNAL OF FISH DISEASES 2022; 45:497-521. [PMID: 35100455 DOI: 10.1111/jfd.13585] [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: 08/30/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Over the last two decades, an increasing number of reports have identified a decline in salmonid populations, possibly linked to infection with the parasite Tetracapsuloides bryosalmonae and the corresponding disease, that is, proliferative kidney disease (PKD). The life cycle of this myxozoan parasite includes sessile bryozoan species as invertebrate host, which facilitates the distribution of the parasite in running waters. As the disease outcome is temperature dependent, the impact of the disease on salmonid populations is increasing with global warming due to climate change. The goal of this review is to provide a detailed overview of measures to mitigate the effects of PKD on salmonid populations. It first summarizes the parasite life cycle, temperature-driven disease dynamics and new immunological and molecular research into disease resistance and, based on this, discusses management possibilities. Sophisticated management actions focusing on local adaptation of salmonid populations, restoration of the riverine ecosystem and keeping water temperatures cool are necessary to reduce the negative effects of PKD. Such actions include temporary stocking with PKD-resistant salmonids, as this may assist in conserving current populations that fail to reproduce.
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Affiliation(s)
- Albert Ros
- Fisheries Research Station of Baden-Württemberg, LAZBW, Langenargen, Germany
| | - Heike Schmidt-Posthaus
- Institute for Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Alexander Brinker
- Fisheries Research Station of Baden-Württemberg, LAZBW, Langenargen, Germany
- University of Konstanz, Konstanz, Germany
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Oredalen TJ, Saebø M, Mo TA. Patterns of Tetracapsuloides bryosalmonae infection of three salmonid species in large, deep Norwegian lakes. JOURNAL OF FISH DISEASES 2022; 45:185-202. [PMID: 34747501 DOI: 10.1111/jfd.13548] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Proliferative kidney disease (PKD), caused by the myxozoan endoparasite Tetracapsuloides bryosalmonae, is of serious ecological and economical concern to wild and farmed salmonids. Wild salmonid populations have declined due to PKD, primarily in rivers, in Europe and North America. Deep lakes are also important habitats for salmonids, and this work aimed to investigate parasite presence in five deep Norwegian lakes. Kidney samples from three salmonid species from deep lakes were collected and tested using real-time PCR to detect PKD parasite presence. We present the first detection of T. bryosalmonae in European whitefish in Norway for the first time, as well as the first published documentation of the parasite in kidneys of Arctic charr, brown trout and whitefish in four lakes. The observed prevalence of the parasite was higher in populations of brown trout than of Arctic charr and whitefish. The parasite was detected in farmed, but not in wild, charr in one lake. This suggests a possible link with a depth of fish habitat and fewer T. bryosalmonae-infected and PKD-affected fish. Towards a warmer climate, cold hypolimnion in deep lakes may act as a refuge for wild salmonids, while cold deep water may be used to control PKD in farmed salmonids.
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Affiliation(s)
- Tone Jøran Oredalen
- Department of Natural Sciences and Environmental Health, Faculty of Technology, Natural Sciences and Maritime Sciences, University of South-Eastern Norway (USN), Boe in Telemark, Norway
| | - Mona Saebø
- Department of Natural Sciences and Environmental Health, Faculty of Technology, Natural Sciences and Maritime Sciences, University of South-Eastern Norway (USN), Boe in Telemark, Norway
| | - Tor Atle Mo
- Norwegian Institute for Nature Research (NINA), Oslo, Norway
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The role of migration barriers for dispersion of Proliferative Kidney Disease-Balance between disease emergence and habitat connectivity. PLoS One 2021; 16:e0247482. [PMID: 33730108 PMCID: PMC7968629 DOI: 10.1371/journal.pone.0247482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 02/08/2021] [Indexed: 11/19/2022] Open
Abstract
Natural and uninterrupted water courses are important for biodiversity and fish population stability. Nowadays, many streams and rivers are obstructed by artificial migration barriers, often preventing the migration of fish. On the other hand, distribution of pathogens by migrating fishes is still a point of concern. Pathogen transport and transmission is a driving force in the dynamics of many infectious diseases. The aim of the study was to investigate the possible consequences of the removal of an artificial migration barrier for the upstream transport of Tetracapsuloides bryosalmonae, the causative agent of Proliferative Kidney Disease (PKD) in brown trout, by migrating fish. To test this question, a river system was selected with a migration barrier separating a PKD positive river from a PKD negative tributary. After removal of the barrier, PKD prevalence and pathology was examined during five years after elimination of the barrier. In the tributary, no PKD was recorded at any time of the survey. By means of unidirectional PIT (passive integrated transponder)-tagging, we confirmed upstream migration of adult brown trout into the tributary during the cold season, presumably for spawning. By eDNA, we confirmed presence of T. bryoalmonae and Fredericella sp., the definitive host, DNA in water from the PKD positive river stretch, but not in the PKD negative tributary. Our study illustrates the importance of the connectivity of streams for habitat maintenance. Although migration of brown trout from a PKD-positive river into a PKD-negative tributary, mainly for spawning, was confirmed, upstream spreading of PKD was not observed.
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Schmidt-Posthaus H, Koch M, Seuberlich T, Birrer C, Hirschi R, Kugler M. Mysterious syndrome causing high mortality in wild brown trout in Eastern Switzerland, pathology and search for a possible cause. JOURNAL OF FISH DISEASES 2020; 43:1317-1324. [PMID: 32830324 DOI: 10.1111/jfd.13241] [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: 06/18/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Since 2016, annually occurring species-specific die-offs of brown trout (Salmo trutta fario) occurred in the Thur River, situated in the Eastern part of Switzerland. These events lead to drastically reduced population densities in the impacted river regions. Clinical signs in brown trout and mortality were restricted to few weeks in August/September. To characterize the syndrome and to find possible causes, from end of March to November 2018, one-year-old brown trout (Salmo trutta fario) and rainbow trout (Oncorhynchus mykiss) were exposed to water from Thur River, fish were sampled regularly and screened for infectious agents, including viral metagenomics, and pathology was described. Starting approximately four months post-exposure, brown trout showed severe lymphohistiocytic pancarditis and necrotizing and haemorrhagic hepatitis. These lesions were recorded until the end of the experiment in November. Rainbow trout were not affected at any point in time. No infectious agents could be identified so far as cause of disease, especially no viral aetiology. Even if pathogenesis and pathology point in the direction of an infectious agent, a causative relationship could not be confirmed and aetiology remains unclear.
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Affiliation(s)
- Heike Schmidt-Posthaus
- Centre for Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Michel Koch
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Torsten Seuberlich
- Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Christoph Birrer
- Canton St. Gallen, Department of Economic Affairs, Office for Nature, Hunting and Fisheries, St. Gallen, Switzerland
| | - Regula Hirschi
- Centre for Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University Bern, Bern, Switzerland
| | - Michael Kugler
- Canton St. Gallen, Department of Economic Affairs, Office for Nature, Hunting and Fisheries, St. Gallen, Switzerland
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Syrová E, Palíková M, Mendel J, Seidlová V, Papežíková I, Schmidt-Posthaus H, Somerlíková K, Minářová H, Mareš L, Mikulíková I, Pikula J, Mareš J. Field study indicating susceptibility differences between salmonid species and their lineages to proliferative kidney disease. JOURNAL OF FISH DISEASES 2020; 43:1201-1211. [PMID: 32740949 DOI: 10.1111/jfd.13221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Tetracapsuloides bryosalmonae (Myxozoa: Malacosporea) is the causative agent of proliferative kidney disease (PKD), which affects both wild and farmed salmonid fish. The objective of this study was to outline differences in susceptibility to PKD in different salmonid species, hybrids and breeding lineages. Susceptibility to T. bryosalmonae infection was established based on cumulative mortality, pathological findings and detection of T. bryosalmonae in the kidney using immunohistochemistry and molecular methods. Determination of pure and hybrid individuals of different species in the genus Salvelinus, and dissimilarity of rainbow trout lineages, was performed using traditional polymerase chain reaction (PCR) and microsatellite analyses. Rainbow trout displayed higher disease severity compared with brook trout and Alsatian charr. Moreover, the results indicated differences in infection susceptibility, not only among different salmonid species but also among different lineages of charr and rainbow trout. Our study indicated that some salmonid species and even different lineages of the same species are more suitable for farming under PKD pressure.
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Affiliation(s)
- Eva Syrová
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
- Veterinary Research Institute, Brno, Czech Republic
| | - Miroslava Palíková
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
- Department of Zoology, Fisheries, Hydrobiology and Apiculture, Mendel University in Brno, Brno, Czech Republic
| | - Jan Mendel
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Veronika Seidlová
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
- Department of Zoology, Fisheries, Hydrobiology and Apiculture, Mendel University in Brno, Brno, Czech Republic
| | - Ivana Papežíková
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
- Department of Zoology, Fisheries, Hydrobiology and Apiculture, Mendel University in Brno, Brno, Czech Republic
| | - Heike Schmidt-Posthaus
- Centre for Fish and Wildlife Health, Department of Pathobiology, University of Bern, Bern, Switzerland
| | - Kristina Somerlíková
- Department of Regional and Business Economics, Mendel University in Brno, Brno, Czech Republic
| | - Hana Minářová
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
- Veterinary Research Institute, Brno, Czech Republic
| | - Lukáš Mareš
- Department of Zoology, Fisheries, Hydrobiology and Apiculture, Mendel University in Brno, Brno, Czech Republic
| | - Ivana Mikulíková
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Jiří Pikula
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Jan Mareš
- Department of Zoology, Fisheries, Hydrobiology and Apiculture, Mendel University in Brno, Brno, Czech Republic
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Bailey C, Holland JW, Secombes CJ, Tafalla C. A portrait of the immune response to proliferative kidney disease (PKD) in rainbow trout. Parasite Immunol 2020; 42:e12730. [PMID: 32403171 PMCID: PMC7507176 DOI: 10.1111/pim.12730] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/31/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
Proliferative kidney disease (PKD), caused by the myxozoan Tetracapsuloides bryosalmonae, is one of the most serious parasitic diseases of salmonids in which outbreaks cause severe economic constraints for the aquaculture industry and declines of wild species throughout Europe and North America. Given that rainbow trout (Oncorhynchus mykiss) is one of the most widely farmed freshwater fish and an important model species for fish immunology, most of the knowledge on how the fish immune response is affected during PKD is from this organism. Once rainbow trout are infected, PKD pathogenesis results in a chronic kidney immunopathology mediated by decreasing myeloid cells and increasing lymphocytes. Transcriptional studies have revealed the regulation of essential genes related to T-helper (Th)-like functions and a dysregulated B-cell antibody type response. Recent reports have discovered unique details of teleost B-cell differentiation and functionality and characterized the differential immunoglobulin (Ig)-mediated response. These studies have solidified the rainbow trout T. bryosalmonae system as a sophisticated disease model capable of feeding key advances into mainstream immunology and have contributed essential information to design novel parasite disease prevention strategies. In our following perspective, we summarize these efforts to evaluate the immune mechanisms of rainbow trout during PKD pathogenesis.
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Affiliation(s)
- Christyn Bailey
- Centro de Investigación en Sanidad Animal (CISA‐INIA)MadridSpain
| | - Jason W. Holland
- Aberdeen Oomycete LaboratoryInstitute of Medical SciencesUniversity of AberdeenAberdeenUK
| | - Christopher J. Secombes
- Scottish Fish Immunology Research CentreInstitute of Biological and Environmental SciencesUniversity of AberdeenAberdeenUK
| | - Carolina Tafalla
- Centro de Investigación en Sanidad Animal (CISA‐INIA)MadridSpain
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Schmidt-Posthaus H, Mattmann P, Hirschi R, Schneider E. On the potential role of Mergus merganser as transport hosts for Tetracapsuloides bryosalmonae. Transbound Emerg Dis 2020; 67:3056-3060. [PMID: 32640119 DOI: 10.1111/tbed.13719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/29/2020] [Accepted: 07/02/2020] [Indexed: 11/27/2022]
Abstract
Transmission paths in the distribution of proliferative kidney disease (PKD) of salmonids are still largely unknown. In this study, the role of goosander (Mergus merganser) as possible transport host for Tetracapsuloides bryosalmonae through faeces was examined. Goosander fledglings were fed exclusively with diseased brown trout (Salmo trutta fario). In all trout used for feeding, intratubular sporogonic stage of the parasite was confirmed histologically. Between one to 10 hours post-feeding, the goosander faeces were sampled and tested for T. bryosalmonae DNA. In qPCR, only DNA fragments were found, and in conventional PCR, no amplification was confirmed. Therefore, we hypothesize that the role of goosander as transport hosts for T. bryosalmonae via their faeces can be neglected.
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Affiliation(s)
- Heike Schmidt-Posthaus
- Centre for Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | - Regula Hirschi
- Centre for Fish and Wildlife Health, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Proliferative kidney disease in Alaskan salmonids with evidence that pathogenic myxozoans may be emerging north. Int J Parasitol 2020; 50:797-807. [PMID: 32479830 DOI: 10.1016/j.ijpara.2020.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 12/13/2022]
Abstract
Proliferative kidney disease (PKD) of salmonids, a chronic immunopathology caused by the myxozoan parasite Tetracapsuloides bryosalmonae, is exacerbated by increased water temperatures. PKD causes economic concerns to trout farmers and contributes to the decline of wild salmonid populations in North America and Europe. The parasite occurs as far north as Norway and Iceland in Europe and was confirmed from California to southern British Columbia in the American continent. In mid-September 2011 adult chum salmon (Oncorhynchus keta) were sampled from Kantishna River, a tributary to Yukon River in Alaska. Clinical PKD was diagnosed based on the macroscopic appearance of mottled kidneys that were uniformly swollen and by the detection of tumultuous histozoic extrasporogonic and coelozoic sporogonic stages of T. bryosalmonae in renal tissue by histopathology. Archived samples provided the molecular confirmation and local strain identification, representing the first confirmed case of PKD in wild adult chum salmon, also co-infected with Parvicapsula minibicornis that represents another novel myxozoan detection in Alaska. Our investigation was extended to another case from August/September 1997, with mortality following furunculosis and ectoparasite co-infections, in sockeye salmon (Oncorhynchus nerka) pre-smolts net-pen reared in English Bay Lakes, Alaska. Immunohistochemistry on archived histological preparations confirmed T. bryosalmonae sporogonic and extrasporogonic stages, indicating a severe to resolving PKD, with concomitant Chloromyxum spp. infection. Those cases provide the first documentation that this parasite is present in Alaska and causes PKD in wild and cultured salmonids in the region. The known geographic range of T. bryosalmonae can be extended to ~267 km south of the Arctic Circle, representing the northernmost detection in America. Given the vast size of Alaska and small resident population, it is likely that T. bryosalmonae remained undetected, but more recently became evident due to the clinical manifestation of PKD, possibly linked to increasing water temperatures reported at the sample locations.
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Sudhagar A, Kumar G, El-Matbouli M. The Malacosporean Myxozoan Parasite Tetracapsuloides bryosalmonae: A Threat to Wild Salmonids. Pathogens 2019; 9:E16. [PMID: 31877926 PMCID: PMC7168663 DOI: 10.3390/pathogens9010016] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/03/2019] [Accepted: 12/20/2019] [Indexed: 01/02/2023] Open
Abstract
Tetracapsuloides bryosalmonae is a myxozoan parasite responsible for proliferative kidney disease (PKD) in a wide range of salmonids. PKD, characterized by high mortality and morbidity, is well known for affecting aquaculture operations and wild salmonid populations across Europe and North America. The life cycle of T. bryosalmonae revolves around freshwater bryozoan and salmonid fish hosts. In recent years, T. bryosalmonae has been reported among wild salmonids from the European countries where it has not been reported previously. T. bryosalmonae is believed to be a possible reason for the diminishing wild salmonid populations in the natural water bodies of many European countries. Climate crisis driven rising water temperature can further accelerate the distribution of T. bryosalmonae. Expansion of the geographical distribution of T. bryosalmonae may further advocate the decline of wild salmonid populations, especially brown trout (Salmo trutta) in their habitats. Mathematical models are used to understand the pattern and distribution of T. bryosalmonae among the host in the natural water bodies. The present manuscript not only summarizes the incidences of T. bryosalmonae among the wild salmonid populations, but also discusses the contemporary understanding about the development of T. bryosalmonae in its hosts and the influences of various factors in the spread of the disease in the wild.
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Affiliation(s)
- Arun Sudhagar
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna 1210, Austria; (A.S.); (M.E.-M.)
- Central Institute of Fisheries Education, Rohtak Centre, Haryana 124411, India
| | - Gokhlesh Kumar
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna 1210, Austria; (A.S.); (M.E.-M.)
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna 1210, Austria; (A.S.); (M.E.-M.)
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Sudhagar A, Ertl R, Kumar G, El-Matbouli M. Transcriptome profiling of posterior kidney of brown trout, Salmo trutta, during proliferative kidney disease. Parasit Vectors 2019; 12:569. [PMID: 31783772 PMCID: PMC6884850 DOI: 10.1186/s13071-019-3823-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 11/21/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Tetracapsuloides bryosalmonae is a myxozoan parasite which causes economically important and emerging proliferative kidney disease (PKD) in salmonids. Brown trout, Salmo trutta is a native fish species of Europe, which acts as asymptomatic carriers for T. bryosalmonae. There is only limited information on the molecular mechanism involved in the kidney of brown trout during T. bryosalmonae development. We employed RNA sequencing (RNA-seq) to investigate the global transcriptome changes in the posterior kidney of brown trout during T. bryosalmonae development. METHODS Brown trout were exposed to the spores of T. bryosalmonae and posterior kidneys were collected from both exposed and unexposed control fish. cDNA libraries were prepared from the posterior kidney and sequenced. Bioinformatics analysis was performed using standard pipeline of quality control, reference mapping, differential expression analysis, gene ontology, and pathway analysis. Quantitative real time PCR was performed to validate the transcriptional regulation of differentially expressed genes, and their correlation with RNA-seq data was statistically analyzed. RESULTS Transcriptome analysis identified 1169 differentially expressed genes in the posterior kidney of brown trout, out of which 864 genes (74%) were upregulated and 305 genes (26%) were downregulated. The upregulated genes were associated with the regulation of immune system process, vesicle-mediated transport, leucocyte activation, and transport, whereas the downregulated genes were associated with endopeptidase regulatory activity, phosphatidylcholine biosynthetic process, connective tissue development, and collagen catabolic process. CONCLUSION To our knowledge, this is the first RNA-seq based transcriptome study performed in the posterior kidney of brown trout during active T. bryosalmonae development. Most of the upregulated genes were associated with the immune system process, whereas the downregulated genes were associated with other metabolic functions. The findings of this study provide insights on the immune responses mounted by the brown trout on the developing parasite, and the host molecular machineries modulated by the parasite for its successful multiplication and release.
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Affiliation(s)
- Arun Sudhagar
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna, Austria
- Central Institute of Fisheries Education, Rohtak Centre, Rohtak, Haryana India
| | - Reinhard Ertl
- VetCore Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - Gokhlesh Kumar
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna, Austria
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna, Austria
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Arndt D, Fux R, Blutke A, Schwaiger J, El-Matbouli M, Sutter G, Langenmayer MC. Proliferative Kidney Disease and Proliferative Darkening Syndrome are Linked with Brown Trout ( Salmo trutta fario) Mortalities in the Pre-Alpine Isar River. Pathogens 2019; 8:pathogens8040177. [PMID: 31590460 PMCID: PMC6963635 DOI: 10.3390/pathogens8040177] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 11/20/2022] Open
Abstract
For many years, brown trout (Salmo trutta fario) mortalities within the pre-alpine Isar River in Germany were reported by the Bavarian Fisheries Association (Landesfischereiverband Bayern e.V.) and local recreational anglers during August and September. Moribund fish seemed to be affected by proliferative darkening syndrome (PDS). In addition, proliferative kidney disease (PKD) caused by Tetracapsuloides bryosalmonae was discussed. To investigate this phenomenon, the present field study monitored brown trout mortalities by daily river inspection in 2017 and 2018. Moribund brown trout (n = 31) were collected and examined using histology, immunohistochemistry, qPCR, and quantitative stereology. Our investigations identified 29 (93.5%) brown trout affected by PKD. Four brown trout (12.9%) displayed combined hepatic and splenic lesions fitting the pathology of PDS. The piscine orthoreovirus 3, suspected as causative agent of PDS, was not detectable in any of the samples. Quantitative stereological analysis of the kidneys revealed a significant increase of the renal tissue volumes with interstitial inflammation and hematopoietic hyperplasia in PKD-affected fish as compared to healthy brown trout. The identified T. bryosalmonae strain was classified as part of the North American clade by phylogenetical analysis. This study highlights PKD and PDS as contributing factors to recurrent autumnal brown trout mortalities.
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Affiliation(s)
- Daniela Arndt
- Institute for Infectious Diseases and Zoonoses, LMU Munich, 80539 Munich, Germany.
| | - Robert Fux
- Institute for Infectious Diseases and Zoonoses, LMU Munich, 80539 Munich, Germany.
- German Center for Infection Research (DZIF), Partner Site Munich, 80539 Munich, Germany.
| | - Andreas Blutke
- Research Unit Analytical Pathology, Helmholtz Zentrum Munich, 85764 Neuherberg, Germany.
| | - Julia Schwaiger
- Bavarian Environment Agency, Unit Aquatic Toxicology, 82407 Wielenbach, Germany.
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210 Vienna, Austria.
| | - Gerd Sutter
- Institute for Infectious Diseases and Zoonoses, LMU Munich, 80539 Munich, Germany.
- German Center for Infection Research (DZIF), Partner Site Munich, 80539 Munich, Germany.
| | - Martin C Langenmayer
- Institute for Infectious Diseases and Zoonoses, LMU Munich, 80539 Munich, Germany.
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Bailey C, von Siebenthal EW, Rehberger K, Segner H. Transcriptomic analysis of the impacts of ethinylestradiol (EE2) and its consequences for proliferative kidney disease outcome in rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol C Toxicol Pharmacol 2019; 222:31-48. [PMID: 31004835 DOI: 10.1016/j.cbpc.2019.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/19/2019] [Accepted: 04/13/2019] [Indexed: 12/11/2022]
Abstract
Freshwater fish are threatened by the cumulative impact of multiple stressors. The purpose of this study was to unravel the molecular and organism level reactions of rainbow trout, Oncorhynchus mykiss, to the combined impact of two such stressors that occur in the natural habitat of salmonids. Fish were infected with either the myxozoan parasite, Tetracapsuloides bryosalmonae, which causes proliferative kidney disease (PKD), or exposed to ethinylestradiol (EE2) an estrogenic endocrine disrupting compound, or to a combination of both (PKD × EE2). PKD is a slow progressive chronic disease here we focused on a later time point (130-day post-infection (d.p.i.)) when parasite intensity in the fish kidney has already started to decrease. At 130 d.p.i., RNA-seq technology was applied to the posterior kidney, the main target organ for parasite development. This resulted with 280 (PKD), 14 (EE2) and 444 (PKD × EE2) differentially expressed genes (DEGs) observed in the experimental groups. In fish exposed to the combination of stressors (PKD × EE2), a number of pathways were regulated that were neither observed in the single stressor groups. Parasite infection, alone and in combination with EE2, only resulted in a low intensity immune response that negatively correlated with an upregulation of genes involved in a variety of metabolic and inflammation resolution processes. This could indicate a trade-off whereby the host increases investment in recovery/resolution processes over immune responses at a later stage of disease. When PKD infection took place under simultaneous exposure to EE2 (PKD × EE2), parasite intensity decreased and pathological alterations in the posterior kidney were reduced in comparison to the PKD only condition. These findings suggest that EE2 modulated these response profiles in PKD infected fish, attenuating the disease impact on the fish.
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Affiliation(s)
- Christyn Bailey
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012 Bern, Switzerland; Fish Immunology and Pathology Laboratory, Animal Health Research Center (CISA-INIA), Madrid, Spain.
| | - Elena Wernicke von Siebenthal
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012 Bern, Switzerland
| | - Kristina Rehberger
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012 Bern, Switzerland
| | - Helmut Segner
- University of Bern, Vetsuisse Faculty, Centre for Fish and Wildlife Health, Länggassstrasse 122, CH-3012 Bern, Switzerland
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Gorgoglione B, Taylor NGH, Holland JW, Feist SW, Secombes CJ. Immune response modulation upon sequential heterogeneous co-infection with Tetracapsuloides bryosalmonae and VHSV in brown trout (Salmo trutta). FISH & SHELLFISH IMMUNOLOGY 2019; 88:375-390. [PMID: 30797951 DOI: 10.1016/j.fsi.2019.02.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 06/09/2023]
Abstract
Simultaneous and sequential infections often occur in wild and farming environments. Despite growing awareness, co-infection studies are still very limited, mainly to a few well-established human models. European salmonids are susceptible to both Proliferative Kidney Disease (PKD), an endemic emergent disease caused by the myxozoan parasite Tetracapsuloides bryosalmonae, and Viral Haemorrhagic Septicaemia (VHS), an OIE notifiable listed disease caused by the Piscine Novirhabdovirus. No information is available as to how their immune system reacts when interacting with heterogeneous infections. A chronic (PKD) + acute (VHS) sequential co-infection model was established to assess if the responses elicited in co-infected fish are modulated, when compared to fish with single infections. Macro- and microscopic lesions were assessed after the challenge, and infection status confirmed by RT-qPCR analysis, enabling the identification of singly-infected and co-infected fish. A typical histophlogosis associated with histozoic extrasporogonic T. bryosalmonae was detected together with acute inflammation, haemorrhaging and necrosis due to the viral infection. The host immune response was measured in terms of key marker genes expression in kidney tissues. During T. bryosalmonae/VHSV-Ia co-infection, modulation of pro-inflammatory and antimicrobial peptide genes was strongly influenced by the viral infection, with a protracted inflammatory status, perhaps representing a negative side effect in these fish. Earlier activation of the cellular and humoral responses was detected in co-infected fish, with a more pronounced upregulation of Th1 and antiviral marker genes. These results reveal that some brown trout immune responses are enhanced or prolonged during PKD/VHS co-infection, relative to single infection.
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Affiliation(s)
- Bartolomeo Gorgoglione
- Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Scotland, UK; CEFAS Weymouth Laboratory, The Nothe, Weymouth, Dorset, England, UK.
| | - Nick G H Taylor
- CEFAS Weymouth Laboratory, The Nothe, Weymouth, Dorset, England, UK
| | - Jason W Holland
- Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Scotland, UK
| | - Stephen W Feist
- CEFAS Weymouth Laboratory, The Nothe, Weymouth, Dorset, England, UK
| | - Christopher J Secombes
- Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Scotland, UK.
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17
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Kuehn R, Stoeckle BC, Young M, Popp L, Taeubert JE, Pfaffl MW, Geist J. Identification of a piscine reovirus-related pathogen in proliferative darkening syndrome (PDS) infected brown trout (Salmo trutta fario) using a next-generation technology detection pipeline. PLoS One 2018; 13:e0206164. [PMID: 30346982 PMCID: PMC6197672 DOI: 10.1371/journal.pone.0206164] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/08/2018] [Indexed: 01/02/2023] Open
Abstract
The proliferative darkening syndrome (PDS) is an annually recurring disease that causes species-specific die-off of brown trout (Salmo trutta fario) with a mortality rate of near 100% in pre-alpine rivers of central Europe. So far the etiology and causation of this disease is still unclear. The objective of this study was to identify the cause of PDS using a next-generation technology detection pipeline. Following the hypothesis that PDS is caused by an infectious agent, brown trout specimens were exposed to water from a heavily affected pre-alpine river with annual occurrence of the disease. Specimens were sampled over the entire time period from potential infection through death. Transcriptomic analysis (microarray) and RT-qPCR of brown trout liver tissue evidenced strong gene expression response of immune-associated genes. Messenger RNA of specimens with synchronous immune expression profiles were ultra-deep sequenced using next-generation sequencing technology (NGS). Bioinformatic processing of generated reads and gap-filling Sanger re-sequencing of the identified pathogen genome revealed strong evidence that a piscine-related reovirus is the causative organism of PDS. The identified pathogen is phylogenetically closely related to the family of piscine reoviruses (PRV) which are considered as the causation of different fish diseases in Atlantic and Pacific salmonid species such as Salmo salar and Onchorhynchus kisutch. This study also highlights that the approach of first screening immune responses along a timeline in order to identify synchronously affected stages in different specimens which subsequently were ultra-deep sequenced is an effective approach in pathogen detection. In particular, the identification of specimens with synchronous molecular immune response patterns combined with NGS sequencing and gap-filling re-sequencing resulted in the successful pathogen detection of PDS.
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Affiliation(s)
- Ralph Kuehn
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany.,Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, NM, United States of America
| | - Bernhard C Stoeckle
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany.,Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technical University of Munich, Freising, Germany
| | - Marc Young
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany
| | - Lisa Popp
- Unit of Molecular Zoology, Department of Zoology, Technical University of Munich, Freising, Germany
| | - Jens-Eike Taeubert
- Fachberatung für Fischerei Niederbayern, Bezirk Niederbayern, Landshut, Germany
| | - Michael W Pfaffl
- Department of Animal Physiology and Immunology, Technical University of Munich, Freising, Germany
| | - Juergen Geist
- Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technical University of Munich, Freising, Germany
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18
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Lewisch E, Unfer G, Pinter K, Bechter T, El-Matbouli M. Distribution and prevalence of T. bryosalmonae in Austria: A first survey of trout from rivers with a shrinking population. JOURNAL OF FISH DISEASES 2018; 41:1549-1557. [PMID: 30027582 DOI: 10.1111/jfd.12863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
The first evidence of proliferative kidney disease (PKD) in an Austrian river (the River Kamp) was documented in 2016, and no information on the PKD infection status of trout in other rivers was available. Since then, brown trout (Salmo trutta fario) and rainbow trout (Oncorhynchus mykiss) have been collected from rivers in Upper and Lower Austria for different diagnostic purposes. In this study, we summarize the recent findings of a first survey concerning the distribution of Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (PKD), from these samples. Between September 2015 and October 2017, a total of 280 brown trout and 39 rainbow trout were collected from 21 rivers in the provinces of Upper and Lower Austria. T. bryosalmonae was detected by PCR of kidney tissue in 17 of 21 sampled rivers and in 138 of 280 brown trout as well as in 11 of 39 rainbow trout. Pathological signs of PKD (e.g., hypertrophy of the kidney) were observed in 33 analysed brown trout and six rainbow trout samples. No correlations between fish infected by T. bryosalmonae and the parameters size and age class, condition factor, geological origin of the streams and distribution within the river course were found, while positively tested fish are significantly increased at sampling sites exceeding water temperatures of 15°C for median periods of 115 days. The prevalence within the affected streams or stream sections is highly variable, and in single rivers, infection rates of up to 90% are confirmed.
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Affiliation(s)
- Eva Lewisch
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna, Austria
| | - Guenther Unfer
- Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Kurt Pinter
- Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Thomas Bechter
- Institute of Hydrobiology and Aquatic Ecosystem Management, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Vienna, Austria
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Kotob MH, Kumar G, Saleh M, Gorgoglione B, Abdelzaher M, El-Matbouli M. Differential modulation of host immune genes in the kidney and cranium of the rainbow trout (Oncorhynchus mykiss) in response to Tetracapsuloides bryosalmonae and Myxobolus cerebralis co-infections. Parasit Vectors 2018; 11:326. [PMID: 29848363 PMCID: PMC5977764 DOI: 10.1186/s13071-018-2912-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/22/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Most of the studies on fish diseases focus on single infections, although in nature co-infections occur more often. The two freshwater myxozoan parasites of salmonids, having high economic and ecologic relevance are Tetracapsuloides bryosalmonae (Malacosporea), the etiological agent of proliferative kidney disease, and Myxobolus cerebralis (Myxosporea), the etiological agent of whirling disease. The present study aims to investigate immune modulation in rainbow trouts (Oncorhynchus mykiss) during single and co-infections by these parasites. METHODS Fish were initially infected with T. bryosalmonae (one group) and M. cerebralis (another group) separately. At 30 days post-exposure (dpe), both the single species infected groups were co-infected, respectively, with the other parasite. Posterior kidney and cartilage cranium samples were collected at 30, 60, 90 and 120 dpe and RT-qPCR was performed on them to assess the transcription of suppressors of cytokine signaling (SOCS) -1 and -3, Janus kinase-1 (JAK-1) and signal transducer and activator of transcription-3 (STAT-3) genes. RESULTS Kidney samples from the T. bryosalmonae-infected group showed upregulation of all immune genes tested between 60-120 dpe. Crania from the single M. cerebralis-infected group and the M. cerebralis and T. bryosalmonae co-infected group exhibited upregulation of SOCS-1 and JAK-1 between 60-120 dpe and SOCS-3 at 120 dpe. However, only in the single M. cerebralis-infected group, was a statistically significant expression of STAT-3 observed at 30 and 60 dpe. CONCLUSIONS The results of this study indicate that both T. bryosalmonae and M. cerebralis induce overexpression of SOCS-1 and SOCS-3 genes and modulate the host immune response during the development of parasite to cause immunosuppression.
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Affiliation(s)
- Mohamed H Kotob
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.,Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Assiut, 71526, Egypt
| | - Gokhlesh Kumar
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Mona Saleh
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Bartolomeo Gorgoglione
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.,Department of Biological Sciences, Wright State University, Dayton, OH, 45435, USA
| | - Mahmoud Abdelzaher
- Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Assiut, 71526, Egypt
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.
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Kotob MH, Gorgoglione B, Kumar G, Abdelzaher M, Saleh M, El-Matbouli M. The impact of Tetracapsuloides bryosalmonae and Myxobolus cerebralis co-infections on pathology in rainbow trout. Parasit Vectors 2017; 10:442. [PMID: 28946913 PMCID: PMC5613476 DOI: 10.1186/s13071-017-2347-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 08/28/2017] [Indexed: 11/25/2022] Open
Abstract
Background Myxozoan parasites pose emerging health issues for wild and farmed salmonid fish. Rainbow trout (Oncorhynchus mykiss) is a particularly susceptible species to Tetracapsuloides bryosalmonae (Malacosporea), the etiological agent of Proliferative Kidney Disease (PKD), and to Myxobolus cerebralis (Myxosporea), the etiological agent of Whirling Disease (WD). The objective of this study was to investigate the impact of myxozoan co-infections on the pathogenesis of PKD and WD in the rainbow trout. Methods Two groups of rainbow trout (96 fish each) were primarily infected with T. bryosalmonae and triactinomyxons of M. cerebralis; after 30 days half of the fish in each group were co-infected with these parasites vice versa and remaining half was continued as single infection. Mortalities and clinical signs were recorded at different time points. Histopathology and immunohistochemistry were performed to assess the extent of each infection and estimate the parasite burden between groups. Results Fish firstly infected with M. cerebralis and co-infected with T. bryosalmonae exhibited exacerbated pathological changes of both parasitic diseases and elicited a higher mortality rate. A higher kidney swelling index (grade 4) appeared together with more severe cartilage destruction and displacement, when compared to the pathological changes in fish upon single infections with T. bryosalmonae or M. cerebralis. Conversely, fish firstly infected with T. bryosalmonae and co-infected with M. cerebralis also exhibited typical pathological changes of both parasitic diseases, but with a lower mortality rate, similar as caused by the single T. bryosalmonae or M. cerebralis infection. WD clinical signs were milder, without skeletal deformities, while kidney swelling index was similar to single infection with T. bryosalmonae (grade 2 to 3). Conclusions In this study, a co-infection with myxozoan parasites was for the first time successfully achieved in the laboratory under controlled conditions. The impact of co-infections in concurrent myxozoan infections mainly depends on the primary pathogen infecting the host, which could alter the outcomes of the secondary pathogen infection. The primary M. cerebralis infection followed by T. bryosalmonae had a much more serious impact and elicited a synergistic interaction. Contrasting results were instead seen in rainbow trout primarily infected with T. bryosalmonae and then co-infected with M. cerebralis.
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Affiliation(s)
- Mohamed H Kotob
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.,Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Assiut, 71526, Egypt
| | - Bartolomeo Gorgoglione
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.,Department of Biological Sciences, University of Toledo, Toledo, OH, 43606, USA
| | - Gokhlesh Kumar
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Mahmoud Abdelzaher
- Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Assiut, 71526, Egypt
| | - Mona Saleh
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.
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Migrating zooids allow the dispersal of Fredericella sultana (Bryozoa) to escape from unfavourable conditions and further spreading of Tetracapsuloides bryosalmonae. J Invertebr Pathol 2016; 140:97-102. [DOI: 10.1016/j.jip.2016.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022]
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