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Duval E, Blanchet S, Quéméré E, Jacquin L, Veyssière C, Loot G. When does a parasite become a disease? eDNA unravels complex host-pathogen dynamics across environmental stress gradients in wild salmonid populations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174367. [PMID: 38955267 DOI: 10.1016/j.scitotenv.2024.174367] [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: 05/09/2024] [Revised: 06/20/2024] [Accepted: 06/27/2024] [Indexed: 07/04/2024]
Abstract
Infectious diseases stem from disrupted interactions among hosts, parasites, and the environment. Both abiotic and biotic factors can influence infection outcomes by shaping the abundance of a parasite's infective stages, as well as the host's ability to fight infection. However, disentangling these mechanisms within natural ecosystems remains challenging. Here, combining environmental DNA analysis and niche modelling at a regional scale, we uncovered the biotic and abiotic drivers of an infectious disease of salmonid fish, triggered by the parasite Tetracapsuloides bryosalmonae. We found that the occurrence and abundance of the parasite in the water-i.e., the propagule pressure- were mainly correlated to the abundances of its two primary hosts, the bryozoan Fredericella sultana and the fish Salmo trutta, but poorly to local abiotic environmental stressors. In contrast, the occurrence and abundance of parasites within fish hosts-i.e., proxies for disease emergence-were closely linked to environmental stressors (water temperature, agricultural activities, dams), and to a lesser extent to parasite propagule pressure. These results suggest that pathogen distribution alone cannot predict the risk of disease in wildlife, and that local anthropogenic stressors may play a pivotal role in disease emergence among wild host populations, likely by modulating the hosts' immune response. Our study sheds light on the intricate interplay between biotic and abiotic factors in shaping pathogen distribution and raises concerns about the effects of global change on pathogen emergence.
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Affiliation(s)
- Eloïse Duval
- Bureau d'études Fish-Pass, 18 rue de la plaine, 35890 Laillé, France.
| | - Simon Blanchet
- CNRS, Station d'Écologie Théorique et Expérimentale du CNRS, UAR-2029, 2 route du CNRS, F-09200 Moulis, France.
| | - Erwan Quéméré
- DECOD (Ecosystem Dynamics and Sustainability), INRAE, Institut Agro, IFREMER, 65 rue de Saint Brieuc F-35042, Rennes, France
| | - Lisa Jacquin
- Université Toulouse III Paul Sabatier, CNRS, IRD, UMR-5300 CRBE (Centre de Recherche sur la Biodiversité et l'Environnement), 118 route de Narbonne, F-31062 Toulouse, France; Institut Universitaire de France, Paris, France
| | - Charlotte Veyssière
- Université Toulouse III Paul Sabatier, CNRS, IRD, UMR-5300 CRBE (Centre de Recherche sur la Biodiversité et l'Environnement), 118 route de Narbonne, F-31062 Toulouse, France
| | - Géraldine Loot
- Université Toulouse III Paul Sabatier, CNRS, IRD, UMR-5300 CRBE (Centre de Recherche sur la Biodiversité et l'Environnement), 118 route de Narbonne, F-31062 Toulouse, France; Institut Universitaire de France, Paris, France
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Ros A, Brinker A. Thermotactic behaviour in lacustrine and riverine forms of Salmo trutta and its relevance to an emerging parasitic disease (PKD) in the wake of climate change. Sci Rep 2024; 14:13539. [PMID: 38866937 PMCID: PMC11169546 DOI: 10.1038/s41598-024-64137-x] [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: 01/09/2024] [Accepted: 06/05/2024] [Indexed: 06/14/2024] Open
Abstract
The thermotactic response of brown trout (Salmo trutta) was examined with the goal to investigate potential effects of the emerging temperature-dependent fatal trout disease PKD (proliferative kidney disease). First the differences in cold-water preferences of two forms of brown trout, lacustrine (migratory) and riverine, were determined. Second, it was studied whether this preference was changed in fish infected with PKD. The experiment involved a one-week habituation period at 14 °C in a two-chamber runway followed by a week of 3 °C temperature difference between the two runways. The fish could freely move between lanes via an opening at the end where food was provided. The temperature manipulation was repeated twice, and there were 3 trials per experimental group. All fish developed a clear spatial preference in the test. Lacustrine trout demonstrated a preference for warmer water, while riverine trout preferred cooler water. This may increase the risk to PKD in the lacustrine form. Most strikingly, riverine trout experimentally exposed to Tetracapsuloides bryosalmonae, the parasite that causes PKD, demonstrated stronger cold-seeking behaviour than control fish. Cold seeking behaviour suggests the occurrence of a disease-induced behavioural chill response, which may play an important role in disease recovery. This demonstrates the significance of protecting river connectivity and cold-water sanctuaries as management strategies for preserving salmonid populations in a warming climate.
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Affiliation(s)
- Albert Ros
- Fisheries Research Station Baden-Württemberg, LAZBW, Argenweg 50/1, 88085, Langenargen, Germany.
| | - Alexander Brinker
- Fisheries Research Station Baden-Württemberg, LAZBW, Argenweg 50/1, 88085, Langenargen, Germany
- University of Konstanz, Mainaustraße 252, 78464, Konstanz, Germany
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Rubin A, Bailey C, Strepparava N, Wahli T, Segner H, Rubin JF. Reliable Field Assessment of Proliferative Kidney Disease in Wild Brown Trout, Salmo trutta, Populations: When Is the Optimal Sampling Period? Pathogens 2022; 11:pathogens11060681. [PMID: 35745535 PMCID: PMC9230507 DOI: 10.3390/pathogens11060681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022] Open
Abstract
Proliferative kidney disease (PKD), caused by the myxozoan parasite Tetracapsuloides bryosalmonae, is suspected to contribute to the decline of wild brown trout Salmo trutta populations. Different factors need to be taken into consideration for PKD outbreaks. Among them, water temperature appears as a main driver of the disease. To understand the epidemiology and impact of the disease on wild fish populations, reliable sampling approaches to detect the presence of T. bryosalmonae-infected fish are needed. This study aimed to characterize the seasonal variation of the prevalence of T. bryosalmonae-infected fish in brown trout populations in two small streams with differing temperature regimes between upstream and downstream sites. As water temperature is known to influence PKD manifestation in brown trout, we hypothesized that the number of T. bryosalmonae-positive fish, as well as their seasonal distribution, will vary between upper and downstream parts of the two streams. Since, in field studies, results can strongly vary across years, we extended the study over a 3-year-period. The number of infected fish and the intensity of infection were assessed by histology. The results confirmed the hypothesis of pronounced temporal- and site-related differences in the percentage of PKD-positive fish and the intensity of the infection. Comparison of water temperatures (total degree days as well as the number of days with a daily mean temperature ≥15 °C) with PKD data indicated that temperature was the driving factor for the temporal development and the intensity of the infection. A mean of 1500 degree days or 30 days with a daily mean temperature ≥15 °C was required before the infection could be detected histologically. From our findings, recommendations are derived for a water temperature-driven sampling strategy campaigns that enables the detection of PKD infection and prevalence in wild brown trout populations.
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Affiliation(s)
- Aurélie Rubin
- Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland; (C.B.); (N.S.); (T.W.); (H.S.)
- La Maison de la Rivière, 1131 Tolochenaz, Switzerland;
- Land, Nature, Environment Institute, University of Applied Sciences and Arts Western Switzerland, 1202 Geneva, Switzerland
- Correspondence: ; Tel.: +41-215-462-060
| | - Christyn Bailey
- Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland; (C.B.); (N.S.); (T.W.); (H.S.)
- Fish Immunology and Pathology Laboratory, Animal Health Research Centre (CISA-INIA), 28130 Madrid, Spain
| | - Nicole Strepparava
- Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland; (C.B.); (N.S.); (T.W.); (H.S.)
| | - Thomas Wahli
- Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland; (C.B.); (N.S.); (T.W.); (H.S.)
| | - Helmut Segner
- Centre for Fish and Wildlife Health, University of Bern, 3012 Bern, Switzerland; (C.B.); (N.S.); (T.W.); (H.S.)
| | - Jean-François Rubin
- La Maison de la Rivière, 1131 Tolochenaz, Switzerland;
- Land, Nature, Environment Institute, University of Applied Sciences and Arts Western Switzerland, 1202 Geneva, Switzerland
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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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Shivam S, El-Matbouli M, Kumar G. Kinetics of Parasite-Specific Antibody and B-Cell-Associated Gene Expression in Brown Trout, Salmo trutta during Proliferative Kidney Disease. BIOLOGY 2021; 10:1244. [PMID: 34943159 PMCID: PMC8698486 DOI: 10.3390/biology10121244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 01/20/2023]
Abstract
Tetracapsuloides bryosalmonae, a myxozoan endoparasite often causes chronic infection in brown trout. Antiparasite immunity mediated by antibodies and B cells is known as an important determinant of host survival and parasite proliferation during chronic infections. Accordingly, studying their time course during proliferative kidney disease (PKD) might be helpful in improving our understanding of its chronic nature. Therefore, we conducted this study to examine parasite specific serum antibody and B-cell-mediated response in laboratory-infected brown trout at different time points. Brown trout were exposed to the spores of T. bryosalmonae, derived from infected bryozoans. Samples were collected at different time points and processed for indirect ELISA, histopathology, and qRT-PCR. T. bryosalmonae specific antibody was detected at 4 weeks post exposure (wpe) and it persisted until 17 wpe. Additionally, the expressions of C4A, CD34, CD79A, BLNK, CD74, BCL7, and CD22 were differentially regulated in the important immune organs, kidney and spleen. To our knowledge, this is the first study addressing anti-T. bryosalmonae antibody response in brown trout at different time points. The results from this study provide valuable insights into the processes leading to changes in B cell development, inflammation and antibody production during the course of PKD in brown trout.
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Affiliation(s)
- Saloni Shivam
- Clinical Division of Fish Medicine, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
- Central Marine Fisheries Research Institute, Karwar 581301, India
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Gokhlesh Kumar
- Clinical Division of Fish Medicine, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
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