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Bartholomew JL, Alexander JD, Hallett SL, Alama-Bermejo G, Atkinson SD. Ceratonova shasta: a cnidarian parasite of annelids and salmonids. Parasitology 2022; 149:1862-1875. [PMID: 36081219 PMCID: PMC11010528 DOI: 10.1017/s0031182022001275] [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: 06/16/2022] [Revised: 08/16/2022] [Accepted: 08/20/2022] [Indexed: 12/29/2022]
Abstract
The myxozoan Ceratonova shasta was described from hatchery rainbow trout over 70 years ago. The parasite continues to cause severe disease in salmon and trout, and is recognized as a barrier to salmon recovery in some rivers. This review incorporates changes in our knowledge of the parasite's life cycle, taxonomy and biology and examines how this information has expanded our understanding of the interactions between C. shasta and its salmonid and annelid hosts, and how overarching environmental factors affect this host–parasite system. Development of molecular diagnostic techniques has allowed discrimination of differences in parasite genotypes, which have differing host affinities, and enabled the measurement of the spatio-temporal abundance of these different genotypes. Establishment of the C. shasta life cycle in the laboratory has enabled studies on host–parasite interactions and the availability of transcriptomic data has informed our understanding of parasite virulence factors and host defences. Together, these advances have informed the development of models and management actions to mitigate disease.
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Affiliation(s)
- Jerri L. Bartholomew
- Department of Microbiology, Oregon State University, Nash Hall 226, Corvallis, Oregon 97331, USA
| | - Julie D. Alexander
- Department of Microbiology, Oregon State University, Nash Hall 226, Corvallis, Oregon 97331, USA
| | - Sascha L. Hallett
- Department of Microbiology, Oregon State University, Nash Hall 226, Corvallis, Oregon 97331, USA
| | - Gema Alama-Bermejo
- Institute of Parasitology, Biology Center of the Czech Academy of Sciences, Branisovska 31, 37005 Ceske Budejovice, Czech Republic
- Division of Fish Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Stephen D. Atkinson
- Department of Microbiology, Oregon State University, Nash Hall 226, Corvallis, Oregon 97331, USA
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Zatti SA, Marinho AMR, Adriano EA, Maia AAM. Integrative Taxonomy Reveals a Panmictic Population of Henneguya longisporoplasma n. sp. (Cnidaria: Myxozoa) in the Amazon Basin. Acta Parasitol 2022; 67:1644-1656. [DOI: 10.1007/s11686-022-00615-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 09/01/2022] [Indexed: 11/01/2022]
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Homel K, Alexander JD. Spatiotemporal distribution of Ceratonova shasta in the lower Columbia River Basin and effects of exposure on survival of juvenile chum salmon Oncorhynchus keta. PLoS One 2022; 17:e0273438. [PMID: 36018896 PMCID: PMC9417023 DOI: 10.1371/journal.pone.0273438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 08/08/2022] [Indexed: 11/18/2022] Open
Abstract
In the Columbia River Basin (CRB), USA, anthropogenic factors ranging from dam construction to land use changes have modified riverine flow and temperature regimes and degraded salmon habitat. These factors are directly implicated in native salmon and steelhead (Oncorhynchus species) population declines and also indirectly cause mortality by altering outcomes of ecological interactions. For example, attenuated flows and warmer water temperatures drive increased parasite densities and in turn, overwhelm salmonid resistance thresholds, resulting in high disease and mortality. Outcomes of interactions between the freshwater myxozoan parasite, Ceratonova shasta, and its salmonid hosts (e.g., coho O. kisutch and Chinook salmon O. tshawytscha) are well-described, but less is known about effects on chum salmon O. keta, which have a comparatively brief freshwater residency. The goal of this study was to describe the distribution of C. shasta relative to chum salmon habitat in the CRB and assess its potential to cause mortality in juvenile chum salmon (listed as threatened in the CRB under the U.S. Endangered Species Act). We measured C. shasta densities in water samples collected from chum salmon habitat throughout the lower CRB during the period of juvenile chum salmon outmigration, 2018–2020. In 2019, we exposed caged chum salmon fry from two hatchery stocks at three C. shasta-positive sites to assess infection prevalence and survival. Results demonstrated: (1) C. shasta was detected in spawning streams from which chum salmon have been extirpated but was not detected in contemporary spawning habitat while juvenile chum salmon were present, (2) spatiotemporal overlap occurs between C. shasta and juvenile chum salmon in the Columbia River mainstem, and (3) low densities of C. shasta caused lethal infection in chum salmon fry from both hatchery stocks. Collectively, our results suggest C. shasta may limit recovery of chum salmon now and in the future.
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Affiliation(s)
- Kristen Homel
- Oregon Department of Fish and Wildlife, Corvallis, Oregon, United States of America
- * E-mail:
| | - Julie D. Alexander
- Department of Microbiology, Oregon State University, Corvallis, Oregon, United States of America
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Robinson HE, Alexander JD, Bartholomew JL, Hallett SL, Hetrick NJ, Perry RW, Som NA. Using a mechanistic framework to model the density of an aquatic parasite Ceratonova shasta. PeerJ 2022; 10:e13183. [PMID: 35441056 PMCID: PMC9013479 DOI: 10.7717/peerj.13183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 03/07/2022] [Indexed: 01/12/2023] Open
Abstract
Ceratonova shasta is a myxozoan parasite endemic to the Pacific Northwest of North America that is linked to low survival rates of juvenile salmonids in some watersheds such as the Klamath River basin. The density of C. shasta actinospores in the water column is typically highest in the spring (March-June), and directly influences infection rates for outmigrating juvenile salmonids. Current management approaches require quantities of C. shasta density to assess disease risk and estimate survival of juvenile salmonids. Therefore, we developed a model to simulate the density of waterborne C. shasta actinospores using a mechanistic framework based on abiotic drivers and informed by empirical data. The model quantified factors that describe the key features of parasite abundance during the period of juvenile salmon outmigration, including the week of initial detection (onset), seasonal pattern of spore density, and peak density of C. shasta. Spore onset was simulated by a bio-physical degree-day model using the timing of adult salmon spawning and accumulation of thermal units for parasite development. Normalized spore density was simulated by a quadratic regression model based on a parabolic thermal response with river water temperature. Peak spore density was simulated based on retained explanatory variables in a generalized linear model that included the prevalence of infection in hatchery-origin Chinook juveniles the previous year and the occurrence of flushing flows (≥171 m3/s). The final model performed well, closely matched the initial detections (onset) of spores, and explained inter-annual variations for most water years. Our C. shasta model has direct applications as a management tool to assess the impact of proposed flow regimes on the parasite, and it can be used for projecting the effects of alternative water management scenarios on disease-induced mortality of juvenile salmonids such as with an altered water temperature regime or with dam removal.
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Affiliation(s)
- H. Eve Robinson
- Arcata Fish and Wildlife Office, U.S. Fish and Wildlife Service, Arcata, CA, United States of America,California State Polytechnic University, Humboldt, Arcata, CA, United States of America
| | - Julie D. Alexander
- Department of Microbiology, Oregon State University, Corvallis, OR, United States of America
| | - Jerri L. Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, OR, United States of America
| | - Sascha L. Hallett
- Department of Microbiology, Oregon State University, Corvallis, OR, United States of America
| | - Nicholas J. Hetrick
- Arcata Fish and Wildlife Office, U.S. Fish and Wildlife Service, Arcata, CA, United States of America
| | - Russell W. Perry
- U.S. Geological Survey, Western Fisheries Research Center, Cook, WA, United States of America
| | - Nicholas A. Som
- Arcata Fish and Wildlife Office, U.S. Fish and Wildlife Service, Arcata, CA, United States of America,California State Polytechnic University, Humboldt, Arcata, CA, United States of America
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5
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Alama-Bermejo G, Meyer E, Atkinson SD, Holzer AS, Wiśniewska MM, Kolísko M, Bartholomew JL. Transcriptome-Wide Comparisons and Virulence Gene Polymorphisms of Host-Associated Genotypes of the Cnidarian Parasite Ceratonova shasta in Salmonids. Genome Biol Evol 2021; 12:1258-1276. [PMID: 32467979 PMCID: PMC7487138 DOI: 10.1093/gbe/evaa109] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2020] [Indexed: 12/15/2022] Open
Abstract
Ceratonova shasta is an important myxozoan pathogen affecting the health of salmonid fishes in the Pacific Northwest of North America. Ceratonova shasta exists as a complex of host-specific genotypes, some with low to moderate virulence, and one that causes a profound, lethal infection in susceptible hosts. High throughput sequencing methods are powerful tools for discovering the genetic basis of these host/virulence differences, but deep sequencing of myxozoans has been challenging due to extremely fast molecular evolution of this group, yielding strongly divergent sequences that are difficult to identify, and unavoidable host contamination. We designed and optimized different bioinformatic pipelines to address these challenges. We obtained a unique set of comprehensive, host-free myxozoan RNA-seq data from C. shasta genotypes of varying virulence from different salmonid hosts. Analyses of transcriptome-wide genetic distances and maximum likelihood multigene phylogenies elucidated the evolutionary relationship between lineages and demonstrated the limited resolution of the established Internal Transcribed Spacer marker for C. shasta genotype identification, as this marker fails to differentiate between biologically distinct genotype II lineages from coho salmon and rainbow trout. We further analyzed the data sets based on polymorphisms in two gene groups related to virulence: cell migration and proteolytic enzymes including their inhibitors. The developed single-nucleotide polymorphism-calling pipeline identified polymorphisms between genotypes and demonstrated that variations in both motility and protease genes were associated with different levels of virulence of C. shasta in its salmonid hosts. The prospective use of proteolytic enzymes as promising candidates for targeted interventions against myxozoans in aquaculture is discussed. We developed host-free transcriptomes of a myxozoan model organism from strains that exhibited different degrees of virulence, as a unique source of data that will foster functional gene analyses and serve as a base for the development of potential therapeutics for efficient control of these parasites.
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Affiliation(s)
- Gema Alama-Bermejo
- Department of Microbiology, Oregon State University.,Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.,Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos Almirante Storni (CIMAS), CCT CONICET - CENPAT, San Antonio Oeste, Argentina
| | - Eli Meyer
- Department of Integrative Biology, Oregon State University
| | | | - Astrid S Holzer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Monika M Wiśniewska
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Martin Kolísko
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.,Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Zhang L, Lin X, Leng L, Zeng Y. Spatial distribution of rural population from a climate perspective: Evidence from Jiangxi Province in China. PLoS One 2021; 16:e0248078. [PMID: 33662002 PMCID: PMC7932106 DOI: 10.1371/journal.pone.0248078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 02/19/2021] [Indexed: 11/18/2022] Open
Abstract
The research on rural population distribution from a climate perspective is rare. Therefore, this study adopts this perspective and uses the ordinary least squares and spatial econometric models to explore the spatial distribution characteristics of the rural population in the Poyang Lake ecological economic zone. Results show that (1) a significant spatial autocorrelation is present in the distribution of rural population, and a spatial correlation exists between the population distribution and climatic factors, (2) the influence of climatic factors on the distribution of rural population in the Poyang Lake ecological economic zone is greater than that of economic factors, and (3) the annual average sunshine and annual average rainfall have a significant negative effect on the distribution of the regional rural population, which is contrary to the expectations., so we then analyze this negative effect on the regional rural population distribution. It is found that (1) the influence of climate factors on the distribution of rural population in lake area is far more than that of economic factors, and more consideration should be given to the influence of climate factors on the population distribution in the lake area, (2) different geographical capital and natural resource endowment, the influence of climate on micro-regional population distribution may be different from the general law, (3) the spatial measurement model which takes spatial dependence into account can reveal the influence of climate on rural population distribution more accurately.
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Affiliation(s)
- Liguo Zhang
- School of Economics, Jiangxi University of Finance and Economics, Jiangxi, China
| | - Xi Lin
- School of Economics, Jiangxi University of Finance and Economics, Jiangxi, China
- * E-mail:
| | - Langping Leng
- School of Economics, Jiangxi University of Finance and Economics, Jiangxi, China
| | - Yongming Zeng
- School of Economics, Jiangxi University of Finance and Economics, Jiangxi, China
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A tale of two fish: Comparative transcriptomics of resistant and susceptible steelhead following exposure to Ceratonova shasta highlights differences in parasite recognition. PLoS One 2021; 16:e0234837. [PMID: 33621237 PMCID: PMC7901748 DOI: 10.1371/journal.pone.0234837] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 02/10/2021] [Indexed: 12/13/2022] Open
Abstract
Diseases caused by myxozoan parasites represent a significant threat to the health of salmonids in both the wild and aquaculture setting, and there are no effective therapeutants for their control. The myxozoan Ceratonova shasta is an intestinal parasite of salmonids that causes severe enteronecrosis and mortality. Most fish populations appear genetically fixed as resistant or susceptible to the parasite, offering an attractive model system for studying the immune response to myxozoans. We hypothesized that early recognition of the parasite is a critical factor driving resistance and that susceptible fish would have a delayed immune response. RNA-seq was used to identify genes that were differentially expressed in the gills and intestine during the early stages of C. shasta infection in both resistant and susceptible steelhead (Oncorhynchus mykiss). This revealed a downregulation of genes involved in the IFN-γ signaling pathway in the gills of both phenotypes. Despite this, resistant fish quickly contained the infection and several immune genes, including two innate immune receptors were upregulated. Susceptible fish, on the other hand, failed to control parasite proliferation and had no discernible immune response to the parasite, including a near-complete lack of differential gene expression in the intestine. Further sequencing of intestinal samples from susceptible fish during the middle and late stages of infection showed a vigorous yet ineffective immune response driven by IFN-γ, and massive differential expression of genes involved in cell adhesion and the extracellular matrix, which coincided with the breakdown of the intestinal structure. Our results suggest that the parasite may be suppressing the host’s immune system during the initial invasion, and that susceptible fish are unable to recognize the parasite invading the intestine or mount an effective immune response. These findings improve our understanding of myxozoan-host interactions while providing a set of putative resistance markers for future studies.
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Tahir UB, Guo Q, Gu Z. Fins infestation induced by Myxobolus xiantaoensis in yellow catfish Tachysurus fulvidraco Richardson, 1846: Some pathophysiological and molecular insights. Microb Pathog 2021; 153:104772. [PMID: 33529735 DOI: 10.1016/j.micpath.2021.104772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 01/17/2021] [Accepted: 01/26/2021] [Indexed: 11/17/2022]
Abstract
The myxozoan parasite Myxobolus xiantaoensis is a fin pathogen of commercially important yellow catfish Tachysurus fulvidraco Richardson, 1846, in the freshwater ponds of China. In the present work, four geographical isolates of M. xiantaoensis were sampled from the fins of yellow catfish. It was found that the spores of four isolates exhibited few markable differences in morphometrics. The small subunit ribosomal DNA (SSU rDNA) sequences of four isolates were conspecific to the SSU rDNA sequence of M. xiantaoensis. No genetic level variation was observed, even in the characteristically more variable internal transcribed spacer (ITS) region. This absence of variability suggests high gene flow as a result of panmixia in the parasitic populations. ITS phylogeny placed four isolates of M. xiantaoensis in a clade together with myxozoans species infecting Siluriformes. The M. xiantaoensis infection inflicted severe hemorrhages on epidermis of ray-fins, which grew into inflammatory epithelial hyperplasia and lytic cartilage signs. The histochemical analysis of infected fins biopsies is characterized by damage of collagen components of cartilage, resulting in weakness, breaks, and missing fin rays. These tissue sections also had a remarkable inflammatory response around the fin cartilage, with the absence of mature spores and chondrocytes. These results indicate that the fin cartilage damage appeared before the development of tissue inflammation and the parasitic infestation of the fins. The present four geographical isolates of M. xiantaoensis were identified by a holistic approach of species characterization based on biological, morphological, and molecular evidence. These four isolates showed some morphological and genetic variations but within the intraspecific range.
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Affiliation(s)
- Urfa Bin Tahir
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, People's Republic of China; Hubei Engineering Technology Research Center of Aquatic Animal Diseases, Control, and Prevention, Wuhan, People's Republic of China; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, People's Republic of China.
| | - Qingxiang Guo
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, People's Republic of China; Hubei Engineering Technology Research Center of Aquatic Animal Diseases, Control, and Prevention, Wuhan, People's Republic of China; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, People's Republic of China
| | - Zemao Gu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, People's Republic of China; Hubei Engineering Technology Research Center of Aquatic Animal Diseases, Control, and Prevention, Wuhan, People's Republic of China; Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan, People's Republic of China.
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9
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Taggart-Murphy L, Alama-Bermejo G, Dolan B, Takizawa F, Bartholomew J. Differences in inflammatory responses of rainbow trout infected by two genotypes of the myxozoan parasite Ceratonova shasta. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 114:103829. [PMID: 32846161 PMCID: PMC7655565 DOI: 10.1016/j.dci.2020.103829] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 08/10/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Two genotypes of the intestinal parasite Ceratonova shasta infect Oncorhynchus mykiss: genotype 0 results in a chronic infection with low mortality while genotype IIR causes disease with high mortality. We determined parasite load and the relative expression of six immune factors (IgT, IgM, IL-6, IL-8, IL-10, IFNG) in fish infected with either genotype over 29 days post-exposure. In genotype IIR infections the host responded with upregulation of inflammatory and regulatory cytokines. In contrast, genotype 0 infection did not elicit an inflammatory response and expression of IFNG and IL-10 was lower. Antibody expression was upregulated in both infections but appeared to have limited efficacy in the virulent genotype IIR infections. Histologically, in genotype 0 infections the parasite migrated through the tissue layers causing inflammation but minimal damage to the mucosal epithelium, which contrasts with the severe pathology found in genotype IIR infections.
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Affiliation(s)
- Laura Taggart-Murphy
- Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, OR, 97331, USA
| | - Gema Alama-Bermejo
- Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, OR, 97331, USA; Institute of Parasitology, Biology Center of the Czech Academy of Sciences, České Budějovice, 37005, Czech Republic
| | - Brian Dolan
- Department of Biomedical Sciences, 106 Dryden Hall, Oregon State University, Corvallis, OR, 97331, USA
| | - Fumio Takizawa
- Faculty of Marine Science and Technology, Fukui Prefectural University, Obama, Fukui, Japan
| | - Jerri Bartholomew
- Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, OR, 97331, USA.
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10
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Richey CA, Kenelty KV, Hopkins KVS, Stevens BN, Martínez-López B, Hallett SL, Atkinson SD, Bartholomew JL, Soto E. Validation of environmental DNA sampling for determination of Ceratonova shasta (Cnidaria: Myxozoa) distribution in Plumas National Forest, CA. Parasitol Res 2020; 119:859-870. [PMID: 31897785 DOI: 10.1007/s00436-019-06509-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 10/11/2019] [Indexed: 10/25/2022]
Abstract
Ceratonova shasta is the etiological agent of myxozoan-associated enteronecrosis in North American salmonids. The parasite's life cycle involves waterborne spores and requires both a salmonid fish and a freshwater fabriciid annelid. The success and survival of annelids can be enhanced by flow moderation by dams, and through the erosion of fine sediments into stream channels following wildfires. In this study, the presence of C. shasta environmental/ex-host DNA (eDNA) in river water and substrate samples collected from areas affected by recent fire activity in California, USA, was investigated. Additionally, DNA loads in the environment were compared to C. shasta infection in sentinel-exposed rainbow trout (Oncorhynchus mykiss). Significant associations between C. shasta detection in environmental samples and location within a wildfire perimeter (p = 0.002), between C. shasta detection in sentinel fish and exposure location within a wildfire perimeter (p = 0.015), and between C. shasta detection in fish and locations where water temperature was above the median (p < 0.001) were observed. Additionally, a higher prevalence of C. shasta infection in fish was detected where C. shasta was also detected in environmental samples (p < 0.001). Results suggest that pathogen eDNA sampling can be used as a non-invasive, rapid, specific, and sensitive method for establishing risk of C. shasta infection in wild populations. Knowledge of the complete life cycle of the target parasite, including ecology of each host, can inform the choice of eDNA sampling strategy. Environmental DNA sampling also revealed a novel species of Ceratonova, not yet observed in a host.
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Affiliation(s)
- Christine A Richey
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA
| | - Kirsten V Kenelty
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA
| | | | - Brittany N Stevens
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA
| | - Beatriz Martínez-López
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA
| | - Sascha L Hallett
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA
| | - Stephen D Atkinson
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA
| | - Jerri L Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA
| | - Esteban Soto
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA.
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Breyta R, Atkinson SD, Bartholomew JL. Evolutionary dynamics of Ceratonova species (Cnidaria: Myxozoa) reveal different host adaptation strategies. INFECTION GENETICS AND EVOLUTION 2019; 78:104081. [PMID: 31676446 DOI: 10.1016/j.meegid.2019.104081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/16/2019] [Accepted: 10/22/2019] [Indexed: 10/25/2022]
Abstract
The myxozoan parasite Ceratonova shasta is an important pathogen that infects multiple species of Pacific salmonids. Ongoing genetic surveillance has revealed stable host-parasite relationships throughout the parasite's endemic range. We applied Bayesian phylogenetics to test specific hypotheses about the evolution of these host-parasite relationships within the well-studied Klamath River watershed in Oregon and California, USA. The results provide statistical support that different genotypes of C. shasta are distinct lineages of one species, which is related to two other Ceratonova species in the same ecosystems; Ceratonova X in speckled dace and C. gasterostea in threespine stickleback. Furthermore, we found strong support for the hypothesis that C. shasta type 0 in native steelhead trout and type I in Chinook salmon each evolved with a specialist host adaptation strategy, while C. shasta type II in coho salmon resulted from a generalist host adaptation strategy. Inferred date and host species of the most recent common ancestor of extant Klamath basin types indicate that it occurred between 14,000 and 21,000 years ago, and most likely infected a native steelhead or rainbow trout host.
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Affiliation(s)
- Rachel Breyta
- Department of Microbiology, Oregon State University, Corvallis, OR, USA; US Geological Survey, Western Fisheries Research Center, Seattle, WA, USA.
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Alama-Bermejo G, Holzer AS, Bartholomew JL. Myxozoan Adhesion and Virulence: Ceratonova shasta on the Move. Microorganisms 2019; 7:E397. [PMID: 31561529 PMCID: PMC6843538 DOI: 10.3390/microorganisms7100397] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/20/2019] [Accepted: 09/22/2019] [Indexed: 02/07/2023] Open
Abstract
Motility factors are fundamental for parasite invasion, migration, proliferation and immune evasion and thus can influence parasitic disease pathogenesis and virulence. Salmonid enteronecrosis is caused by a myxozoan (Phylum Cnidarian) parasite, Ceratonova shasta. Three parasite genotypes (0, I, II) occur, with varying degrees of virulence in its host, making it a good model for examining the role of motility in virulence. We compare C. shasta cell motility between genotypes and describe how the cellular protrusions interact with the host. We support these observations with motility gene expression analyses. C. shasta stages can move by single or combined used of filopodia, lamellipodia and blebs, with different behaviors such as static adhesion, crawling or blebbing, some previously unobserved in myxozoans. C. shasta stages showed high flexibility of switching between different morphotypes, suggesting a high capacity to adapt to their microenvironment. Exposure to fibronectin showed that C. shasta stages have extraordinary adhesive affinities to glycoprotein components of the extracellular matrix (ECM). When comparing C. shasta genotypes 0 (low virulence, no mortality) and IIR (high virulence, high mortality) infections in rainbow trout, major differences were observed with regard to their migration to the target organ, gene expression patterns and proliferation rate in the host. IIR is characterized by rapid multiplication and fast amoeboid bleb-based migration to the gut, where adhesion (mediated by integrin-β and talin), ECM disruption and virulent systemic dispersion of the parasite causes massive pathology. Genotype 0 is characterized by low proliferation rates, slow directional and early adhesive migration and localized, non-destructive development in the gut. We conclude that parasite adhesion drives virulence in C. shasta and that effectors, such as integrins, reveal themselves as attractive therapeutic targets in a group of parasites for which no effective treatments are known.
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Affiliation(s)
- Gema Alama-Bermejo
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA.
- Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos Almirante Storni (CIMAS-CCT CONICET-CENPAT), 8520 San Antonio Oeste, Argentina.
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic.
| | - Astrid S Holzer
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic.
| | - Jerri L Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA.
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Hurst CN, Alexander JD, Dolan BP, Jia L, Bartholomew JL. Outcome of within-host competition demonstrates that parasite virulence doesn't equal success in a myxozoan model system. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2019; 9:25-35. [PMID: 30976514 PMCID: PMC6441732 DOI: 10.1016/j.ijppaw.2019.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/18/2019] [Accepted: 03/09/2019] [Indexed: 11/25/2022]
Abstract
Within-host competition can affect outcomes of infections when parasites occupy the same niche. We investigated within-host competition and infection outcomes in Chinook salmon exposed to two genotypes of Ceratonova shasta (myxozoan parasite). We assessed i) virulence (host mortality, median days to death), ii) within-host competition (abundance in host), and iii) success (spore production, proportion of myxospore-producing hosts) following concurrent and sequential exposures to single or mixed-genotype treatments. In single treatments, genotype-I replicated faster, and caused higher and earlier host mortality (higher virulence) but genotype-II produced more myxospores (higher success). In mixed treatments, costs of competition were observed for both genotypes evidenced by reduced replication or myxospore production following concurrent exposures, but only the less-virulent genotype suffered costs of competition when hosts were exposed to genotypes sequentially. To understand potential host effects on competition outcomes, we characterized systemic (spleen) and local (intestine) cytokine and immunoglobulin expression in single and mixed infections. We observed delayed systemic and immunosuppressive responses to the virulent genotype (I), rapid, localized and non-suppressive responses to the less-virulent genotype (II), and a combination of responses to mixed-genotypes. Thus, competition outcomes favoring the virulent genotype may be partially explained by the localized response to genotype-II that facilitates myxospore production (success) offsetting the systemic response to genotype-I that results in early inflammation and immunosuppression (that increases onset of mortality). This evidence for different but simultaneous responses to each genotype suggests selection should favor the exclusion of the weaker competitor and the evolution of increased virulence in the stronger competitor because the outcome was generally more costly for the less-virulent genotype. With caveats, our results are relevant for understanding infection outcomes in commercially and ecologically important salmonids in C. shasta endemic regions where mixed infections are commonplace. Competition between two genotypes of Ceratonova shasta was asymmetric in Chinook salmon hosts. Genotype I was more virulent but genotype-II was more successful (produced more myxospores). Costs of competition differed between genotypes, may be mediated by host immune response. Host immune response to genotype-I was delayed systemic and immunosuppressive. Host immune response to genotype-II was rapid, localized and non-suppressive.
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Affiliation(s)
- C N Hurst
- Department of Microbiology, Oregon State University, Corvallis, USA
| | - J D Alexander
- Department of Microbiology, Oregon State University, Corvallis, USA
| | - B P Dolan
- Department of Microbiology, Oregon State University, Corvallis, USA
| | - L Jia
- Department of Microbiology, Oregon State University, Corvallis, USA
| | - J L Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, USA
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Stinson MET, Atkinson SD, Bartholomew JL. Widespread Distribution of Ceratonova shasta (Cnidaria: Myxosporea) Genotypes Indicates Evolutionary Adaptation to its Salmonid Fish Hosts. J Parasitol 2018; 104:645-650. [DOI: 10.1645/18-79] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Matthew E. T. Stinson
- Northwest Indian Fisheries Commission, Tribal Fish Health Laboratory, 6730 Martin Way East, Olympia, Washington 98516
| | - Stephen D. Atkinson
- Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, Oregon 97331
| | - Jerri L. Bartholomew
- Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, Oregon 97331
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Genotyping of individual Ceratonova shasta (Cnidaria: Myxosporea) myxospores reveals intra-spore ITS-1 variation and invalidates the distinction of genotypes II and III. Parasitology 2018; 145:1588-1593. [PMID: 29580305 DOI: 10.1017/s0031182018000422] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Genotypes of the myxosporean parasite Ceratonova shasta are defined by the number of ATC repeats in the parasite's ribosomal DNA internal transcribed spacer region 1. These genotypes correlate with specific salmonid fish hosts. We observed coho salmon (Oncorhynchus kisutch) and rainbow trout (Oncorhynchus mykiss) with mixtures of genotypes II and III, and assumed that this was a consequence of fish having an aggregate infection from multiple individual parasites. We hypothesized that although multiple ITS copies are present within a parasite spore, the DNA sequences of these copies are identical, and thus individual C. shasta spores are a single genotype. We tested this by extracting and sequencing DNA from individual myxospores. We trialed three approaches for in-tube DNA extraction; digestion with proteinase K was superior to simply rehydrating spores, or incubation in the buffer. Sequences from 14 myxospores were each a mixture of genotypes II and III. Therefore, intra-genomic ribosomal DNA variants exist within individual parasite spores, and II and III should no longer be regarded as discrete C. shasta genotypes. This single-spore genotyping approach will be a useful tool for testing validity of other C. shasta genotypes, and for correctly matching genotype with phenotype for mixed infections of other myxozoan species.
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Bartošová-Sojková P, Lövy A, Reed CC, Lisnerová M, Tomková T, Holzer AS, Fiala I. Life in a rock pool: Radiation and population genetics of myxozoan parasites in hosts inhabiting restricted spaces. PLoS One 2018; 13:e0194042. [PMID: 29561884 PMCID: PMC5862482 DOI: 10.1371/journal.pone.0194042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/25/2018] [Indexed: 12/11/2022] Open
Abstract
Introduction Intertidal rock pools where fish and invertebrates are in constant close contact due to limited space and water level fluctuations represent ideal conditions to promote life cycles in parasites using these two alternate hosts and to study speciation processes that could contribute to understanding the roles of parasitic species in such ecosystems. Material and methods Gall bladder and liver samples from five clinid fish species (Blenniiformes: Clinidae) were morphologically and molecularly examined to determine the diversity, prevalence, distribution and host specificity of Ceratomyxa parasites (Cnidaria: Myxozoa) in intertidal habitats along the coast of South Africa. Phylogenetic relationships of clinid ceratomyxids based on the SSU rDNA, LSU rDNA and ITS regions were assessed additionally to the investigation of population genetic structure of Ceratomyxa cottoidii and subsequent comparison with the data known from type fish host Clinus cottoides. Results and discussion Seven Ceratomyxa species including previously described Ceratomyxa dehoopi and C. cottoidii were recognized in clinids. They represent a diverse group of rapidly evolving, closely related species with a remarkably high prevalence in their hosts, little host specificity and frequent concurrent infections, most probably as a result of parasite radiation after multiple speciation events triggered by limited host dispersal within restricted spaces. C. cottoidii represents the most common clinid parasite with a population structure characterized by young expanding populations in the south west and south east coast and by older populations in equilibrium on the west coast of its distribution. Parasite and fish host population structures show overlapping patterns and are very likely affected by similar oceanographic barriers possibly due to reduced host dispersal enhancing parasite community differentiation. While fish host specificity had little impact on parasite population structure, the habitat preference of the alternate invertebrate host as well as tidal water exchange may be additional crucial variables affecting the dispersal and associated population structure of C. cottoidii.
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Affiliation(s)
- Pavla Bartošová-Sojková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
- * E-mail:
| | - Alena Lövy
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Cecile C. Reed
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Martina Lisnerová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
| | - Tereza Tomková
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
| | - Astrid S. Holzer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
| | - Ivan Fiala
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
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Ceratomyxa gracillima n. sp. (Cnidaria: Myxosporea) provides evidence of panmixia and ceratomyxid radiation in the Amazon basin. Parasitology 2018; 145:1137-1146. [DOI: 10.1017/s0031182017002323] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
AbstractWe describe a new freshwater myxosporean species Ceratomyxa gracillima n. sp. from the gall bladder of the Amazonian catfish Brachyplatystoma rousseauxii; the first myxozoan recorded in this host. The new Ceratomyxa was described on the basis of its host, myxospore morphometry, ssrDNA and internal transcribed spacer region (ITS-1) sequences. Infected fish were sampled from geographically distant localities: the Tapajós River, Pará State, the Amazon River, Amapá State and the Solimões River, Amazonas State. Immature and mature plasmodia were slender, tapered at both ends, and exhibited vermiform motility. The ribosomal sequences from parasite isolates from the three localities were identical, and distinct from all other Ceratomyxa sequences. No population-level genetic variation was observed, even in the typically more variable ITS-1 region. This absence of genetic variation in widely separated parasite samples suggests high gene flow as a result of panmixia in the parasite populations. Maximum likelihood and maximum parsimony analyses placed C. gracillima n. sp. sister to Ceratomyxa vermiformis in a subclade together with Ceratomyxa brasiliensis and Ceratomyxa amazonensis, all of which have Amazonian hosts. This subclade, together with other Ceratomyxa from freshwater hosts, formed an apparently early diverging lineage. The Amazonian freshwater Ceratomyxa species may represent a radiation that originated during marine incursions into the Amazon basin that introduced an ancestral lineage in the late Oligocene or early Miocene.
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18
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Wünnemann H, Holzer AS, Pecková H, Bartošová-Sojková P, Eskens U, Lierz M. Repatriation of an old fish host as an opportunity for myxozoan parasite diversity: The example of the allis shad, Alosa alosa (Clupeidae), in the Rhine. Parasit Vectors 2016; 9:505. [PMID: 27628643 PMCID: PMC5024467 DOI: 10.1186/s13071-016-1760-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/16/2016] [Indexed: 11/18/2022] Open
Abstract
Background Wildlife repatriation represents an opportunity for parasites. Reintroduced hosts are expected to accumulate generalist parasites via spillover from reservoir hosts, whereas colonization with specialist parasites is unlikely. We address the question of how myxozoan parasites, which are characterized by a complex life-cycle alternating between annelids and fish, can invade a reintroduced fish species and determine the impact of a de novo invasion on parasite diversity. We investigated the case of the anadromous allis shad, Alosa alosa (L.), which was reintroduced into the Rhine approximately 70 years after its extinction in this river system. Methods We studied parasites belonging to the Myxozoa (Cnidaria) in 196 allis shad from (i) established populations in the French rivers Garonne and Dordogne and (ii) repatriated populations in the Rhine, by screening the first adults returning to spawn in 2014. Following microscopical detection of myxozoan infections general myxozoan primers were used for SSU rDNA amplification and sequencing. Phylogenetic analyses were performed and cloned sequences were analyzed from individuals of different water sources to better understand the diversity and population structure of myxozoan isolates in long-term coexisting vs recently established host-parasite systems. Results We describe Hoferellus alosae n. sp. from the renal tubules of allis shad by use of morphological and molecular methods. A species-specific PCR assay determined that the prevalence of H. alosae n. sp. is 100 % in sexually mature fish in the Garonne/Dordogne river systems and 22 % in the first mature shad returning to spawn in the Rhine. The diversity of SSU rDNA clones of the parasite was up to four times higher in the Rhine and lacked a site-specific signature of SNPs such as in the French rivers. A second myxozoan, Ortholinea sp., was detected exclusively in allis shad from the Rhine. Conclusions Our data demonstrate that the de novo establishment of myxozoan infections in rivers is slow but of great genetic diversity, which can only be explained by the introduction of spores from genetically diverse sources, predominantly via straying fish or by migratory piscivorous birds. Long-term studies will show if and how the high diversity of a de novo introduction of host-specific myxozoans succeeds into the establishment of a local successful strain in vertebrate and invertebrate hosts. Graphical Abstract ![]()
Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1760-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hannah Wünnemann
- Clinic for Birds, Reptiles, Amphibians and Fish, Justus Liebig University, Frankfurter Str. 91, Giessen, 35392, Germany.
| | - Astrid Sybille Holzer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 37005, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, 37005, Czech Republic
| | - Hana Pecková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 37005, Czech Republic
| | - Pavla Bartošová-Sojková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 37005, Czech Republic
| | - Ulrich Eskens
- The Hessen State Laboratory, Schubertstraße 60, Giessen, 35392, Germany
| | - Michael Lierz
- Clinic for Birds, Reptiles, Amphibians and Fish, Justus Liebig University, Frankfurter Str. 91, Giessen, 35392, Germany
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19
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Takeuchi F, Ogasawara Y, Kato K, Sekizuka T, Nozaki T, Sugita-Konishi Y, Ohnishi T, Kuroda M. Genetic variants of Kudoa septempunctata (Myxozoa: Multivalvulida), a flounder parasite causing foodborne disease. JOURNAL OF FISH DISEASES 2016; 39:667-672. [PMID: 26096292 DOI: 10.1111/jfd.12395] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 04/26/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
Foodborne disease outbreaks caused by raw olive flounders (Paralichthys olivaceus) parasitized with Kudoa septempunctata have been reported in Japan. Origins of olive flounders consumed in Japan vary, being either domestic or imported, and aquaculture-raised or natural. Although it is unknown whether different sources are associated with different outcomes, it is desirable to identify whether this is the case by determining whether unique K. septempunctata strains occur and if so, whether some are associated with foodborne illness. We here developed an intraspecific genotyping method, using the sequence variation of mitochondrial genes. We collected olive flounder samples from foodborne disease outbreaks, domestic fish farms or quarantine offices and investigated whether K. septempunctata genotype is associated with pathogenicity or geographic origin. The 104 samples were classified into three genotypes, ST1, ST2 and ST3. Frequency of symptomatic cases differed by genotypes, but the association was not statistically significant. Whereas K. septempunctata detected from aquaculture-raised and natural fish from Japan were either ST1 or ST2, those from fish inspected at quarantine from Korea to Japan were ST3. Our method can be applied to phylogeographic analysis of K. septempunctata and contribute to containing the foodborne disease. The genotype database is hosted in the PubMLST website (http://pubmlst.org/kseptempunctata/).
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Affiliation(s)
- F Takeuchi
- Pathogen Genomics Center, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - Y Ogasawara
- Pathogen Genomics Center, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - K Kato
- Pathogen Genomics Center, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - T Sekizuka
- Pathogen Genomics Center, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
| | - T Nozaki
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Y Sugita-Konishi
- Department of Food and Life Science, Azabu University, Sagamihara, Kanagawa, Japan
| | - T Ohnishi
- Division of Microbiology, National Institute of Health Sciences, Setagaya-ku, Tokyo, Japan
| | - M Kuroda
- Pathogen Genomics Center, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo, Japan
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20
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Genetic population structure of Gyrodactylus thymalli (Monogenea) in a large Norwegian river system. Parasitology 2015; 142:1693-702. [PMID: 26463886 DOI: 10.1017/s003118201500133x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The extent of geographic genetic variation is the result of several processes such as mutation, gene flow, selection and drift. Processes that structure the populations of parasite species are often directly linked to the processes that influence the host. Here, we investigate the genetic population structure of the ectoparasite Gyrodactylus thymalli Žitňan, 1960 (Monogenea) collected from grayling (Thymallus thymallus L.) throughout the river Glomma, the largest watercourse in Norway. Parts of the mitochondrial dehydrogenase subunit 5 (NADH 5) and cytochrome oxidase I (COI) genes from 309 G. thymalli were analysed to study the genetic variation and investigated the geographical distribution of parasite haplotypes. Three main clusters of haplotypes dominated the three distinct geographic parts of the river system; one cluster dominated in the western main stem of the river, one in the eastern and one in the lower part. There was a positive correlation between pairwise genetic distance and hydrographic distance. The results indicate restricted gene flow between sub-populations of G. thymalli, most likely due to barriers that limit upstream migration of infected grayling. More than 80% of the populations had private haplotypes, also indicating long-time isolation of sub-populations. According to a molecular clock calibration, much of the haplotype diversity of G. thymalli in the river Glomma has developed after the last glaciation.
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21
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Hurst CN, Wong P, Hallett SL, Ray RA, Bartholomew JL. Transmission and persistence of Ceratonova shasta genotypes in Chinook salmon. J Parasitol 2015; 100:773-7. [PMID: 24945751 DOI: 10.1645/13-482.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Ceratonova shasta is a myxozoan parasite of salmon and trout transmitted by waterborne actinospores. Based on DNA sequence data and host specificity, 4 distinct parasite genotypes are recognized. Genotypes I and II are common in the lower reaches of the Klamath River, Oregon-California, but only infection by genotype I causes mortality in Chinook salmon. We conducted sentinel fish exposures and determined genotype composition in river water during exposure, and in fish gills, intestine, and tank water post-exposure to determine whether: (1) transmission of parasites having different genotypes is host-specific and (2) all transmitted genotypes persist in the host through to release as waterborne stages. Initial parasite transmission to the fish host appears indiscriminant, since we detected both genotypes I and II in 83.6% of the fish gills sampled. However, only genotype I was detected in fish that succumbed to infection, while both genotypes persisted in fish that survived. Persistence was likely dependent on exposure dose, initial infection type (mixed or single) and infection outcome (mortality or survival). The transmission of both genotypes to a majority of Chinook salmon and the persistence of multiple genotypes raises questions about how infection with mixed genotypes could result in within-host interactions that affect disease severity.
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Affiliation(s)
- Charlene N Hurst
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331
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22
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Hurst CN, Bartholomew JL. Lack of Protection following Re-Exposure of Chinook Salmon to Ceratonova shasta (Myxozoa). JOURNAL OF AQUATIC ANIMAL HEALTH 2015; 27:20-24. [PMID: 25494609 DOI: 10.1080/08997659.2014.970716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The recent identification of multiple genotypes of the salmonid parasite Ceratonova shasta with different virulence levels in Chinook Salmon Oncorhynchus tshawytscha suggests that it is possible to immunize fish against subsequent infection and disease. We hypothesized that exposure of Chinook Salmon to the less-virulent parasite genotype (II) prior to the more virulent parasite genotype (I) would decrease disease and/or result in fewer mature parasites compared with fish only infected with the more virulent genotype. To test this hypothesis, fish were challenged in a combination of field and laboratory exposures, and we measured infection prevalence, percent morbidity, and mature parasite production. Neither mortality nor mature parasite production were reduced when fish were exposed to genotype II prior to genotype I compared with fish exposed only to genotype I, suggesting that protection against C. shasta using a less-virulent genotype of the parasite does not occur.
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Affiliation(s)
- C N Hurst
- a Department of Microbiology , Oregon State University , Nash Hall 226, Corvallis , Oregon 97331 , USA
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23
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Atkinson SD, Foott JS, Bartholomew JL. Erection of Ceratonova n. gen. (Myxosporea: Ceratomyxidae) to encompass freshwater species C. gasterostea n. sp. from threespine stickleback (Gasterosteus aculeatus) and C. shasta n. comb. from salmonid fishes. J Parasitol 2014; 100:640-5. [PMID: 24754344 DOI: 10.1645/13-434.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Ceratonova gasterostea n. gen. n. sp. is described from the intestine of freshwater Gasterosteus aculeatus L. from the Klamath River, California. Myxospores are arcuate, 22.4 ± 2.6 μm thick, 5.2 ± 0.4 μm long, posterior angle 45° ± 24°, with 2 sub-spherical polar capsules, diameter 2.3 ± 0.2 μm, which lie adjacent to the suture. Its ribosomal small subunit sequence was most similar to an intestinal parasite of salmonid fishes, Ceratomyxa shasta (97%, 1,671/1,692 nucleotides), and distinct from all other Ceratomyxa species (<85%), which are typically coelozoic parasites in the gall bladder or urinary system of marine fishes. We propose erection of genus Ceratonova to contain both intestinal, freshwater species and reassign the salmonid parasite as Ceratonova shasta n. comb.
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Affiliation(s)
- S D Atkinson
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, Oregon 97331
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24
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Bjork SJ, Zhang YA, Hurst CN, Alonso-Naveiro ME, Alexander JD, Sunyer JO, Bartholomew JL. Defenses of susceptible and resistant Chinook salmon (Oncorhynchus tshawytscha) against the myxozoan parasite Ceratomyxa shasta. FISH & SHELLFISH IMMUNOLOGY 2014; 37:87-95. [PMID: 24412163 PMCID: PMC3996901 DOI: 10.1016/j.fsi.2013.12.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/23/2013] [Accepted: 12/24/2013] [Indexed: 05/13/2023]
Abstract
We investigated intra-specific variation in the response of salmon to infection with the myxozoan Ceratomyxa shasta by comparing the progress of parasite infection and measures of host immune response in susceptible and resistant Chinook salmon Oncorhynchus tshawytscha at days 12, 25 and 90 post exposure. There were no differences in invasion of the gills indicating that resistance does not occur at the site of entry. In the intestine on day 12, infection intensity and Ig(+) cell numbers were higher in susceptible than resistant fish, but histological examination at that timepoint showed more severe inflammation in resistant fish. This suggests a role for the immune response in resistant fish that eliminates some parasites prior to or soon after reaching the intestine. Susceptible fish had a higher IFNγ, IL-6 and IL-10 response at day 12, but all died of fatal enteronecrosis by day 25. The greatest fold change in IFNγ expression was detected at day 25 in resistant Chinook. In addition, the number of Ig(+) cells in resistant Chinook also increased by day 25. By day 90, resistant Chinook had resolved the inflammation, cytokine expression had decreased and Ig(+) cell numbers were similar to uninfected controls. Thus, it appears that the susceptible strain was incapable of containing or eliminating C. shasta but resistant fish: 1) reduced infection intensity during early intestinal infection, 2) elicited an effective inflammatory response in the intestine that eliminated C. shasta, 3) resolved the inflammation and recovered from infection.
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Affiliation(s)
- Sarah J Bjork
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
| | - Yong-An Zhang
- State Key Laboratory of Freshwater Ecology & Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charlene N Hurst
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
| | - Maria E Alonso-Naveiro
- Instituto de Acuicultura Torre de la Sal, Consejo Superior de Investigaciones Científicas (IATS-CSIC), Castellón 12595, Spain
| | - Julie D Alexander
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
| | - J Oriol Sunyer
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jerri L Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA.
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25
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Ishimaru K, Matsuura T, Tsunemoto K, Shirakashi S. Seasonal monitoring of Kudoa yasunagai from sea water and aquaculture water using quantitative PCR. DISEASES OF AQUATIC ORGANISMS 2014; 108:45-52. [PMID: 24492053 DOI: 10.3354/dao02702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Kudoid myxozoans pose serious chronic problems in marine fisheries by causing pathological damage to host fish, reducing the market value of infected fish and potentially threatening public health. Kudoa yasunagai is a cosmopolitan parasite that infects the brains of various marine fishes, including important aquaculture species. We developed a quantitative PCR assay to detect K. yasunagai in sea water, and we used it to monitor abundance of the parasite in the environment and in culture through spring and winter. Quantitative PCR detected K. yasunagai DNA from sea water, with the lowest reliable threshold of 162 copies 28S rDNA l-1. Parasite DNA was detected sporadically in sea water throughout the study period of May through December 2012. The highest level of detected DNA occurred in mid-December (winter), at 117180 copies-equivalent to an estimate of over 200 myxospores l-1. Parasite DNA was generally not detected in August or September, the period with the highest water temperature. The reason for this observation is unknown, but the timing of parasite development may play a role. The amount of detected DNA was not different between unfiltered culture water and water filtered through a high-speed fiber filtration system. This result and the past incidence of high infection rate of fish reared in filtered water indicate that the mechanical removal of K. yasunagai from culture water is difficult. Detecting the precise onset and time window of infection in host fish will be an important step in the development of measures to control this economically important parasite.
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Affiliation(s)
- Katsuya Ishimaru
- Fisheries Laboratory, Kinki University, Shirahama, Wakayama 649-2211, Japan
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Stinson MET, Bartholomew JL. Predicted redistribution of Ceratomyxa shasta genotypes with salmonid passage in the Deschutes River, Oregon. JOURNAL OF AQUATIC ANIMAL HEALTH 2012; 24:274-280. [PMID: 23146111 DOI: 10.1080/08997659.2012.716012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A series of dams on the Deschutes River, Oregon, act as migration barriers that segregate the river system into upper and lower basins. Proposed fish passage between basins would reunite populations of native potamodromous fish and allow anadromous fish of Deschutes River origin access to the upper basin. We assessed the potential redistribution of host-species-specific genotypes (O, I, II, III) of the myxozoan parasite Ceratomyxa shasta that could occur with fish passage and examined the influence of nonnative fish on genotype composition. To determine the present distribution of the parasite genotypes, we exposed eight salmonid species-three native and five stocked for sport fishing-in present and predicted anadromous salmonid habitats. We monitored fish for infection by C. shasta and sequenced a section of the parasite ribosomal DNA gene from fish and water samples to determine parasite genotype. Genotype O was present in both upper and lower basins and detected only in steelhead Oncorhynchus mykiss. Genotype I was spatially limited to the lower basin, isolated predominantly from Chinook salmon O. tshawytscha, and lethal for this species only. Genotype II was detected in both basins and in multiple species, but only as a minor component of the infection. Genotype III was also present in both basins, had a wide host range, and caused mortality in native steelhead and multiple nonnative species. Atlantic salmon Salmo salar and kokanee O. nerka were the least susceptible to infection by any genotype of C. shasta. Our findings confirmed the host-specific patterns of C. shasta infections and indicated that passage of Chinook salmon would probably spread genotype I into the upper Deschutes River basin, but with little risk to native salmonid populations.
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Hurst CN, Bartholomew JL. Ceratomyxa shasta genotypes cause differential mortality in their salmonid hosts. JOURNAL OF FISH DISEASES 2012; 35:725-732. [PMID: 22808922 DOI: 10.1111/j.1365-2761.2012.01407.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 06/01/2023]
Abstract
Ceratomyxa shasta is a myxozoan parasite of salmonid fish. In natural communities, distinct genotypes of the parasite are associated with different salmonid hosts. To test the hypothesis that genotypes of C. shasta cause differential mortality, the polychaete host was experimentally infected with different parasite genotypes. Genotype I was obtained from Chinook salmon, Oncorhynchus tshawytscha, and genotype II from either coho salmon, O. kisutch, or rainbow trout, O. mykiss, We then challenged four salmonid strains: Chinook and coho salmon that occur in sympatry with the parasite and allopatric Chinook salmon and rainbow trout. Parasite genotype I caused mortality only in Chinook strains, although mortality in the allopatric strain also occurred from exposure to genotype II. A second experiment demonstrated that genotype II could be separated into two biotypes based on differential mortality in rainbow trout and coho salmon. These differential patterns of mortality as a result of infection by certain genotypes of C. shasta support field observations and suggest a co-evolutionary relationship between these parasites and their hosts.
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Affiliation(s)
- C N Hurst
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
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Ray RA, Holt RA, Bartholomew JL. Relationship between temperature and Ceratomyxa shasta -induced mortality in Klamath River salmonids. J Parasitol 2012; 98:520-6. [PMID: 22746389 DOI: 10.1645/jp-ge-2737.1] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Water temperature influences almost every biological and physiological process of salmon, including disease resistance. In the Klamath River (California), current thermal conditions are considered sub-optimal for juvenile salmon. In addition to borderline temperatures, these fish must contend with the myxozoan parasite Ceratomyxa shasta , a significant cause of juvenile salmonid mortality in this system. This paper presents 2 studies, conducted from 2007 to 2010, that examine thermal effects on C. shasta -induced mortality in native Klamath River Chinook ( Oncorhynchus tshawytscha ) and coho ( Oncorhynchus kisutch ) salmon. In each study, fish were exposed to C. shasta in the Klamath River for 72 hr and then reared in the laboratory under temperature-controlled conditions. The first study analyzed data collected from a multi-year monitoring project to asses the influence of elevated temperatures on parasite-induced mortality during the spring/summer migration period. The second study compared disease progression in both species at 4 temperatures (13, 15, 18, and 21 C) representative of spring/summer migration conditions. Both studies demonstrated that elevated water temperatures consistently resulted in higher mortality and faster mean days to death. However, analysis of data from the multi-year monitoring showed that the magnitude of this effect varied among years and was more closely associated with parasite density than with temperature. Also, there was a difference in the timing of peak mortality between species; Chinook incurred high mortalities in 2008 and 2009, whereas coho was greatest in 2007 and 2008. As neither temperature nor parasite density can be easily manipulated, management strategies should focus on disrupting the overlap of this parasite and its obligate hosts to improve emigration success and survival of juvenile salmon in the Klamath River.
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Affiliation(s)
- R Adam Ray
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon 97331, USA
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Density of the waterborne parasite Ceratomyxa shasta and its biological effects on salmon. Appl Environ Microbiol 2012; 78:3724-31. [PMID: 22407689 DOI: 10.1128/aem.07801-11] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The myxozoan parasite Ceratomyxa shasta is a significant pathogen of juvenile salmonids in the Pacific Northwest of North America and is limiting recovery of Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon populations in the Klamath River. We conducted a 5-year monitoring program that comprised concurrent sentinel fish exposures and water sampling across 212 river kilometers of the Klamath River. We used percent mortality and degree-days to death to measure disease severity in fish. We analyzed water samples using quantitative PCR and Sanger sequencing, to determine total parasite density and relative abundance of C. shasta genotypes, which differ in their pathogenicity to salmonids. We detected the parasite throughout the study zone, but parasite density and genetic composition fluctuated spatially and temporally. Chinook and coho mortality increased with density of their specific parasite genotype, but mortality-density thresholds and time to death differed. A lethality threshold of 40% mortality was reached with 10 spores liter(-1) for Chinook but only 5 spores liter(-1) for coho. Parasite density did not affect degree-days to death for Chinook but was negatively correlated for coho, and there was wider variation among coho individuals. These differences likely reflect the different life histories and genetic heterogeneity of the salmon populations. Direct quantification of the density of host-specific parasite genotypes in water samples offers a management tool for predicting host population-level impacts.
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Geographical and host distribution patterns of Parvicapsula minibicornis (Myxozoa) small subunit ribosomal RNA genetic types. Parasitology 2011; 138:969-77. [DOI: 10.1017/s0031182011000734] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYParvicapsula minibicornis is a myxozoan parasite implicated in mortalities of both juvenile and pre-spawning adult salmon in the Pacific Northwest of North America. Disease severity and presentation varies between salmon species and geographical localities. To better characterize population structure of the parasite, we sought genetic markers in the P. minibicornis ribosomal RNA gene. We compared samples from California with the type specimen from British Columbia, identified sequence variations, and then sequenced 197 samples from fish, river water and the parasite's polychaete worm host. Although DNA sequences of the parasite were >98·9% similar, there was enough variation to define 15 genotypes. All genotypes were detected in fish samples, although not in all species. A single genotype only was found in sockeye and pink salmon in the Fraser River Basin, but was not detected in sockeye from the adjacent Columbia River Basin. All coho salmon, irrespective of river basin, were infected with a unique mix of 2 genotypes. These data indicated that the P. minibicornis population exhibited strong signals of structuring by both geography and salmonid host species. Particular genotypes may correlate with disease differences seen in salmon populations in the Pacific Northwest.
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Ray RA, Rossignol PA, Bartholomew JL. Mortality threshold for juvenile Chinook salmon Oncorhynchus tshawytscha in an epidemiological model of Ceratomyxa shasta. DISEASES OF AQUATIC ORGANISMS 2010; 93:63-70. [PMID: 21290897 DOI: 10.3354/dao02281] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The myxozoan parasite Ceratomyxa shasta is a significant pathogen of juvenile Chinook salmon Oncorhynchus tshawytscha in the Klamath River, California, USA. This parasite requires 2 hosts to complete its life cycle: a freshwater polychaete (Manayunkia speciosa) and a salmonid. The complex life cycle and large geographic area where infection occurs make it difficult to monitor and manage ceratomyxosis. We present a model for ceratomyxosis-induced mortality in O. tshawytscha, from which parameters important to the persistence of C. shasta are identified. We also experimentally quantify specific parameters from the model and identify a mortality threshold (a critical parameter), by naturally exposing native O. tshawytscha to C. shasta in the Klamath River. The average percent mortality that resulted from these experimental challenges ranged from 2.5 to 98.5% over an exposure dose of 4.4 to 612 x 10(6) parasites. This experiment identified a non-linear mortality threshold of 7.7 +/- 2.1 x 10(4) actinospores fish(-1) for Chinook salmon from the Iron Gate Hatchery on the Klamath River. Below this threshold no mortality occurred and above it mortality increased dramatically, thus providing a target by which to reduce parasitism in emigrating juvenile O. tshawytscha.
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Affiliation(s)
- R Adam Ray
- Department of Fisheries and Wildlife, Nash Hall, Oregon State University, Corvallis, Oregon 97331, USA
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