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Maor-Landaw K, Avidor I, Rostowsky N, Salti B, Smirnov M, Ofek-Lalzar M, Levin L, Brekhman V, Lotan T. The Molecular Mechanisms Employed by the Parasite Myxobolus bejeranoi (Cnidaria: Myxozoa) from Invasion through Sporulation for Successful Proliferation in Its Fish Host. Int J Mol Sci 2023; 24:12824. [PMID: 37629003 PMCID: PMC10454682 DOI: 10.3390/ijms241612824] [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: 07/22/2023] [Revised: 08/08/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
Myxozoa is a unique group of obligate endoparasites in the phylum Cnidaria that can cause emerging diseases in wild and cultured fish populations. Recently, we identified a new myxozoan species, Myxobolus bejeranoi, which infects the gills of cultured tilapia while suppressing host immunity. To uncover the molecular mechanisms underlying this successful parasitic strategy, we conducted transcriptomics analysis of M. bejeranoi throughout the infection. Our results show that histones, which are essential for accelerated cell division, are highly expressed even one day after invasion. As the infection progressed, conserved parasitic genes that are known to modulate the host immune reaction in different parasitic taxa were upregulated. These genes included energy-related glycolytic enzymes, as well as calreticulin, proteases, and miRNA biogenesis proteins. Interestingly, myxozoan calreticulin formed a distinct phylogenetic clade apart from other cnidarians, suggesting a possible function in parasite pathogenesis. Sporogenesis was in its final stages 20 days post-exposure, as spore-specific markers were highly expressed. Lastly, we provide the first catalog of transcription factors in a Myxozoa species, which is minimized compared to free-living cnidarians and is dominated by homeodomain types. Overall, these molecular insights into myxozoan infection support the concept that parasitic strategies are a result of convergent evolution.
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Affiliation(s)
- Keren Maor-Landaw
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3103301, Israel; (K.M.-L.); (I.A.); (N.R.); (B.S.); (V.B.)
| | - Itamar Avidor
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3103301, Israel; (K.M.-L.); (I.A.); (N.R.); (B.S.); (V.B.)
| | - Nadav Rostowsky
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3103301, Israel; (K.M.-L.); (I.A.); (N.R.); (B.S.); (V.B.)
| | - Barbara Salti
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3103301, Israel; (K.M.-L.); (I.A.); (N.R.); (B.S.); (V.B.)
| | - Margarita Smirnov
- Central Fish Health Laboratory, Department of Fisheries and Aquaculture, Ministry of Agriculture and Rural Development, Nir David 1080300, Israel;
| | - Maya Ofek-Lalzar
- Bioinformatic Unit, University of Haifa, Mt. Carmel, Haifa 3498838, Israel;
| | - Liron Levin
- Bioinformatics Core Facility, llse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel;
| | - Vera Brekhman
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3103301, Israel; (K.M.-L.); (I.A.); (N.R.); (B.S.); (V.B.)
| | - Tamar Lotan
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, Haifa 3103301, Israel; (K.M.-L.); (I.A.); (N.R.); (B.S.); (V.B.)
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Baxa DV, Nehring RB. Effect of substrate on the proliferation of Myxobolus cerebralis in the mitochondrial lineages of the Tubifex tubifex host. Parasitol Res 2022; 121:2503-2516. [PMID: 35895112 PMCID: PMC9378325 DOI: 10.1007/s00436-022-07587-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 06/24/2022] [Indexed: 10/31/2022]
Abstract
The study goal was to examine the effects of sand and mud on the propagation of Myxobolus cerebralis, the whirling disease agent, in four mitochondrial 16S ribosomal DNA lineages (I, III, V, VI) of its oligochaete host, Tubifex tubifex (Tt). In all the lineage groups held continuously in either substrate (non-shifted) or transferred from sand to mud (shifted), substrate influenced parasite proliferation only in lineage III. Sporogenesis and release of triactinomyxon spores (TAMs) were more prevalent in lineage III Tt in mud compared to sand. Low-infection prevalence and lack of parasite development in lineage I is associated with the greater number of resistant worms and were not affected by substrate type. Substrate did not impact Tt from lineages V and VI that failed to develop any parasite stages in either substrate even after shifting from sand to mud. The relationship between the microbial community in the substrate and parasite proliferation in lineage III was described but not analyzed due to small sample size. Substrate-associated bacteria were hypothesized as essential dietary source for the oligochaete host feeding selectively on fine (mud)-microflora. Progeny was produced by all lineage groups shifted to mud with disparate survival profiles in lineage V and VI and high mortalities in lineage III. Our study demonstrates that substrate type can alter parasite proliferation in lineage III. Conversely, parasite development and infectivity were not altered in lineage V and VI that are refractory to the parasite nor among the more resistant phenotypes (I), regardless of substrate type.
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Affiliation(s)
- Dolores V Baxa
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA. .,Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA.
| | - R Barry Nehring
- Colorado Division of Parks and Wildlife, 2300 South Townsend Avenue, Montrose, CO, 81401, USA
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Sindeaux-Neto JL, Velasco M, Silva DTD, Matos P, Silva MFD, Gonçalves EC, Matos E. Myxobolus freitasi n. sp. (Myxozoa: Bivalvulida), a parasite of the brain of the electric knifefish in the Brazilian Amazon region. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA = BRAZILIAN JOURNAL OF VETERINARY PARASITOLOGY : ORGAO OFICIAL DO COLEGIO BRASILEIRO DE PARASITOLOGIA VETERINARIA 2021; 30:e020920. [PMID: 33729315 DOI: 10.1590/s1984-296120201081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
A total of 30 specimens of the Amazonian electric knifefish, Brachyhypopomus beebei Schultz, 1944 (Gymnotiformes: Hypopomidae), were collected from the Peixe-Boi River in the state of Pará, Brazil (1°06'59" S; 47°18'26" W). Fragments of the brain tissue were extracted for analysis via optical microscopy, and 18 specimens (60%) presented microparasites of the genus Myxobolus, with unequal capsules. The spores were 18.6 µm (17.7-19.8 µm) long and 8.6 µm (8.4-9.0 µm) wide; the largest polar capsule was 13.0 µm (12.4-13.4 µm) long and 5.6 µm (5.3-6.0 µm) wide, and the smallest capsule was 5.0 µm (4.5-5.3 µm) long and 2.5 µm (2.3-2.6 µm) wide. Infected brain fragments were extracted for histological processing and staining with hematoxylin-eosin and Ziehl-Neelsen. Some fragments were conserved in ethanol for molecular genetics analysis. A partial sequence of the 18S DNA gene was obtained from the spores, which did not correspond to any other sequences deposited in GenBank, although it did form a clade with other Myxobolus parasites of the nervous system. The morphological data, together with molecular phylogeny, supported the designation of a new species Myxobolus freitasi n. sp.
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Affiliation(s)
- José Ledamir Sindeaux-Neto
- Universidade da Amazônia - UNAMA, Belém, PA, Brasil
- Laboratório de Pesquisa Carlos Azevedo - LPCA, Universidade Federal Rural da Amazônia - UFRA, Belém, PA, Brasil
| | - Michele Velasco
- Universidade Federal Rural da Amazônia - UFRA, Paragominas, PA, Brasil
| | - Diehgo Tuloza da Silva
- Programa de Pós-graduação em Biologia de Agentes Infecciosos e Parasitários - BAIP, Universidade Federal do Pará - UFPA, Belém, PA, Brasil
| | - Patrícia Matos
- Programa de Pós-graduação em Biologia de Agentes Infecciosos e Parasitários - BAIP, Universidade Federal do Pará - UFPA, Belém, PA, Brasil
| | - Marcelo Francisco da Silva
- Programa de Pós-graduação em Biologia de Agentes Infecciosos e Parasitários - BAIP, Universidade Federal do Pará - UFPA, Belém, PA, Brasil
- Universidade Estadual da Região Tocantina do Maranhão - UEMASUL, Imperatriz, Maranhão, Brasil
| | - Evonnildo Costa Gonçalves
- Laboratório de Tecnologia Biomolecular - LTB, Universidade Federal do Pará - UFPA, Belém, PA, Brasil
| | - Edilson Matos
- Laboratório de Pesquisa Carlos Azevedo - LPCA, Universidade Federal Rural da Amazônia - UFRA, Belém, PA, Brasil
- Programa de Pós-graduação em Biologia de Agentes Infecciosos e Parasitários - BAIP, Universidade Federal do Pará - UFPA, Belém, PA, Brasil
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Nehring RB, Alves J, Nehring JB, Felt B. Elimination of Myxobolus cerebralis in Placer Creek, a Native Cutthroat Trout Stream in Colorado. JOURNAL OF AQUATIC ANIMAL HEALTH 2018; 30:264-279. [PMID: 30133011 DOI: 10.1002/aah.10039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
Placer Creek, a tributary of Sangre de Cristo Creek in Colorado's San Luis Valley, supported an allopatric core conservation population of native Rio Grande Cutthroat Trout Oncorhynchus clarkii virginalis during much of the 20th century. After the failure of gabion barriers in the late 1990s, Brook Trout Salvelinus fontinalis infected with Myxobolus cerebralis invaded from Sangre de Cristo Creek. By 2005, whirling disease (WD) and competition from Brook Trout reduced Rio Grande Cutthroat Trout numbers to less than 10% of the total trout population. New barriers were constructed in 2006 and the stream was treated with rotenone in 2007 and 2009 to eliminate all fish prior to the reintroduction of Rio Grande Cutthroat Trout. Results of WD research studies in Montana, California, and Colorado indicated it might be possible to break the life cycle of the parasite in some situations. Our management interventions included (1) reducing the fish population in the stream to zero for approximately 14 months, (2) introducing lineage V and VI Tubifex tubifex worms, which are not susceptible to M. cerebralis, and (3) eliminating a small off-channel pond that provided optimal habitat that sustained a localized high-density population of lineage III T. tubifex, the oligochaete host susceptible to M. cerebralis. Electrofishing during the fall of 2009 and spring of 2010 indicated the drainage was devoid of fish. Fry, juvenile, and adult Rio Grande Cutthroat Trout were stocked in September and October of 2010 and 2011. Approximately 975,000 lineage V and VI T. tubifex were introduced into Placer Creek between 2010 and 2012 as possible oligochaete competitors for the lineage III worms. The off-channel pond was filled in, and the surface was reseeded in April 2012. No evidence of M. cerebralis infection was detected among more than 280 Rio Grande Cutthroat Trout tested between July 2012 and July 2016, indicating the parasite had been eradicated from the Placer Creek basin upstream of the barriers.
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Affiliation(s)
- R Barry Nehring
- Colorado Division of Parks and Wildlife, 2300 South Townsend Avenue, Montrose, Colorado, 81401, USA
| | - John Alves
- Colorado Division of Parks and Wildlife, 151 East 16th Street, Durango, Colorado, 81301, USA
| | - Joshua B Nehring
- Colorado Division of Parks and Wildlife, 4255 Sinton Road, Colorado Springs, Colorado, 80907, USA
| | - Benjamin Felt
- Colorado Parks and Wildlife, 711 Independent Avenue, Grand Junction, Colorado, 80501, USA
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Abrunhosa J, Sindeaux-Neto JL, Santos ÂKD, Hamoy I, Matos E. Myxobolus marajoensis sp. n. (Myxosporea: Myxobolidae), parasite of the freshwater catfish Rhamdia quelen from the Brazilian Amazon region. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA 2017; 26:465-471. [DOI: 10.1590/s1984-29612017067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 10/24/2017] [Indexed: 11/22/2022]
Abstract
Abstract This study provides morphological and molecular data of a new parasite species found in the muscle layer of the intestinal tract of the South American silver catfish, Rhamdia quelen from Marajó Island region (Pará State, Brazil), an important fishery resource with recognized potential for fish farming. The morphology of these parasites was reanalyzed and phylogenetic analyses were run on their 18S rDNA gene sequences. The spores were morphologically distinct from those of other Myxobolus species described previously. The obtained partial sequence of the 18S rDNA gene sequences of the new species were compared to those of 24 other Myxobolus and Henneguya species available in GenBank. The results of morphological and molecular analyses indicated clearly the existence of a new species, Myxobolus marajoensis sp. n.
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Affiliation(s)
- Jacqueline Abrunhosa
- Universidade Federal do Pará, Brasil; Universidade Federal Rural da Amazônia, Brasil
| | | | | | - Igor Hamoy
- Universidade Federal Rural da Amazônia, Brasil
| | - Edilson Matos
- Universidade Federal do Pará, Brasil; Universidade Federal Rural da Amazônia, Brasil
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Fontes I, Hartikainen H, Williams C, Okamura B. Persistence, impacts and environmental drivers of covert infections in invertebrate hosts. Parasit Vectors 2017; 10:542. [PMID: 29096700 PMCID: PMC5668978 DOI: 10.1186/s13071-017-2495-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 10/23/2017] [Indexed: 11/10/2022] Open
Abstract
Background Persistent covert infections of the myxozoan, Tetracapsuloides bryosalmonae, in primary invertebrate hosts (the freshwater bryozoan, Fredericella sultana) have been proposed to represent a reservoir for proliferative kidney disease in secondary fish hosts. However, we have limited understanding of how covert infections persist and vary in bryozoan populations over time and space and how they may impact these populations. In addition, previous studies have likely underestimated covert infection prevalence. To improve our understanding of the dynamics, impacts and implications of covert infections we employed a highly sensitive polymerase chain reaction (PCR) assay and undertook the first investigation of covert infections in the field over an annual period by sampling bryozoans every 45 days from three populations within each of three rivers. Results Covert infections persisted throughout the year and prevalence varied within and between rivers, but were often > 50%. Variation in temperature and water chemistry were linked with changes in prevalence in a manner consistent with the maintenance of covert infections during periods of low productivity and thus poor growth conditions for both bryozoans and T. bryosalmonae. The presence and increased severity of covert infections reduced host growth but only when bryozoans were also investing in the production of overwintering propagules (statoblasts). However, because statoblast production is transitory, this effect is unlikely to greatly impact the capacity of bryozoan populations to act as persistent sources of infections and hence potential disease outbreaks in farmed and wild fish populations. Conclusions We demonstrate that covert infections are widespread and persist over space and time in bryozoan populations. To our knowledge, this is the first long-term study of covert infections in a field setting. Review of the results of this and previous studies enables us to identify key questions related to the ecology and evolution of covert infection strategies and associated host-parasite interactions. Electronic supplementary material The online version of this article (10.1186/s13071-017-2495-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Inês Fontes
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.,Scottish Fish Immunology Research Centre, Aberdeen University, Aberdeen, AB24 2TZ, UK
| | - Hanna Hartikainen
- EAWAG, Department of Aquatic Ecology, Überlandstrasse 133, CH-8600, Dübendorf, Switzerland.,ETH Zürich, Institute of Integrative Biology (IBZ), Zürich, Switzerland
| | - Chris Williams
- Environment Agency, National Fisheries Laboratory, Brampton, Cambridgeshire, PE28 4NE, UK
| | - Beth Okamura
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
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Sarker S, Menanteau-Ledouble S, Kotob MH, El-Matbouli M. A RNAi-based therapeutic proof of concept targets salmonid whirling disease in vivo. PLoS One 2017; 12:e0178687. [PMID: 28575083 PMCID: PMC5456292 DOI: 10.1371/journal.pone.0178687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/17/2017] [Indexed: 11/29/2022] Open
Abstract
Myxobolus cerebralis is a cnidarian-myxozoan parasite that causes salmonid whirling disease. M. cerebralis alternates between two hosts: (1) a vertebrate salmonid and (2) an invertebrate oligochaete, Tubifex tubifex. There is no successful treatment for salmonid whirling disease. MyxSP-1 is a M. cerebralis serine protease implicated in whirling disease pathogenesis. We hypothesized that short-interfering RNA (siRNA)-induced RNA interference (RNAi) can silence MyxSP-1 in the invertebrate host and abrogate the M. cerebralis life cycle. This would preclude whirling disease infection in the salmonid host. To test this hypothesis, we first developed a siRNA delivery protocol in T. tubifex. Second, we determined the effective dose for siRNA treatment of M. cerebralis-infected T. tubifex. M. cerebralis-infected T. tubifex were treated with different concentrations of MyxSP-1 or negative control siRNAs (1μM, 2μM, 5μM or 7μM) at 15°C for 24h, 48h, 72h and 96h, respectively. We monitored MyxSP-1 knockdown using real-time quantitative PCR (qPCR). siRNA treatment with MyxSP-1 siRNA at 2μM concentration for 24h at 15°C showed maximum significant MyxSP-1 knockdown in T. tubifex. Third, we determined the time points in the M. cerebralis life cycle in T. tubifex at which siRNA treatment was most effective. M. cerebralis-infected T. tubifex were treated with MyxSP-1 or negative control siRNAs (2μM concentration for 24h at 15°C) at 24 hours post-infection (24hpi), 48hpi, 72hpi, 96hpi, 1 month post-infection (1mpi), 2mpi and 3mpi, respectively. We observed that siRNA treatment of T. tubifex was most effective at 1mpi, 2mpi and 3mpi. Fourth, we immersed specific-pathogen-free rainbow trout fry in water inhabited by MyxSP-1 siRNA-treated T. tubifex (at 1mpi, 2mpi and 3mpi). The salmonids did not develop whirling disease and showed significant MyxSP-1 knockdown. We also observed long-term RNAi in T. tubifex. Together these results demonstrate a novel RNAi-based therapeutic proof of concept in vivo against salmonid whirling disease.
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Affiliation(s)
- Subhodeep Sarker
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- Discipline of Pharmacology, School of Medical Sciences, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
- * E-mail: (SS); (ME-M)
| | - Simon Menanteau-Ledouble
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Mohamed H. Kotob
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Asyut, Egypt
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- * E-mail: (SS); (ME-M)
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Nehring RB, Schisler GJ, Chiaramonte L, Horton A, Poole B. Accelerated deactivation of Myxobolus cerebralis myxospores by susceptible and non-susceptible Tubifex tubifex. DISEASES OF AQUATIC ORGANISMS 2016; 121:37-47. [PMID: 27596858 DOI: 10.3354/dao03025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In the 1990s, the Tubifex tubifex aquatic oligochaete species complex was parsed into 6 separate lineages differing in susceptibility to Myxobolus cerebralis, the myxozoan parasite that can cause whirling disease (WD). Lineage III T. tubifex oligochaetes are highly susceptible to M. cerebralis infection. Lineage I, IV, V and VI oligochaetes are highly resistant or refractory to infection and may function as biological filters by deactivating M. cerebralis myxospores. We designed a 2-phased laboratory experiment using triactinomyxon (TAM) production as the response variable to test that hypothesis. A separate study conducted concurrently demonstrated that M. cerebralis myxospores held in sand and water at temperatures ≤15°C degrade rapidly, becoming almost completely non-viable after 180 d. Those results provided the baseline to assess deactivation of M. cerebralis myxospores by replicates of mixed lineage (I, III, V and VI) and refractory lineage (V and VI) oligochaetes. TAM production was zero among 7 of 8 Lineage V and Lineage VI T. tubifex oligochaete groups exposed to 12500 M. cerebralis myxospores for 15, 45, 90 and 135 d. Among 4 mixed lineage exposure groups, TAM production averaged 14641 compared with 2202495 among 12 groups of Lineage III oligochaetes. Among the 6 unexposed Lineage III experimental groups seeded into original Phase 1 substrates for the 45, 90 and 135 d treatments during the Phase 2 portion of the study, TAM production was reduced by 98.9, 99.9 and 99.9%, respectively, compared with the average for the 15 d exposure groups. These results are congruent with the hypothesis that Lineage V and Lineage VI T. tubifex oligochaetes can deactivate and destroy M. cerebralis myxospores.
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Affiliation(s)
- R Barry Nehring
- Colorado Division of Parks and Wildlife, 2300 South Townsend Avenue, Montrose, Colorado 81401, USA
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Lovy J, Hutcheson JM. Myxobolus mauriensisn. sp. Infecting Rib Cartilage of Young-of-the-Year River Herring in New Jersey: Notes on Pathology, Prevalence, and Genetics. J Parasitol 2016; 102:419-28. [DOI: 10.1645/15-939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Jan Lovy
- Office of Fish and Wildlife Health and Forensics, New Jersey Division of Fish and Wildlife, 605 Pequest Road, Oxford, New Jersey 07863
| | - Josette M. Hutcheson
- Office of Fish and Wildlife Health and Forensics, New Jersey Division of Fish and Wildlife, 605 Pequest Road, Oxford, New Jersey 07863
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Sindeaux Neto JL, Velasco M, Silva JMVD, Santos PDFSD, Sanches O, Matos P, Matos E. Lymphocytic meningoencephalomyelitis associated with Myxobolus sp. (Bivalvulidae: Myxozoa) infection in the Amazonian fish Eigenmannia sp. (Sternopygidae: Gymnotiformes). REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA 2016; 25:158-62. [DOI: 10.1590/s1984-29612016023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/13/2016] [Indexed: 11/22/2022]
Abstract
Abstract The genus Myxobolus, parasites that infect fishes, which cause myxobolosis, includes spore organisms belonging to the phylum Myxozoa and represents approximately 36% of all species described for the entire phylum. This study describes lymphocytic meningoencephalomyelitis associated with Myxobolus sp. infection in the brain and spinal cord (the central nervous system, CNS) of Eigenmannia sp., from the Amazon estuary region, in the Administrative District of Outeiro (DAOUT), Belém, Pará, Brazil. In May and June 2015, 40 Eigenmannia sp. specimens were captured from this region and examined. The fish were anesthetized, slaughtered and dissected for sexing (gonad evaluation) and studying parasites and cysts; after diagnosing the presence of the myxozoans using a light microscope, small fragments of the brain and spinal cord were removed for histological processing and Hematoxylin-Eosin and Ziehl-Neelsen staining. Histopathological analysis of the brain and spinal cord, based on histological sections stained with Hematoxylin-Eosin, pronounced and diffuse edema in these tissues, and congestion, degeneration, and focal necrosis of the cerebral cortex. The present study describes lymphocytic meningoencephalomyelitis associated with infection by Myxobolus sp. in the central nervous system of Eigenmannia sp.
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Sarker S, Kallert DM, Hedrick RP, El-Matbouli M. Whirling disease revisited: pathogenesis, parasite biology and disease intervention. DISEASES OF AQUATIC ORGANISMS 2015; 114:155-175. [PMID: 25993890 DOI: 10.3354/dao02856] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Whirling disease (WD) is an ecologically and economically debilitating disease of rainbow trout Oncorhynchus mykiss caused by the actinosporean spores of the parasite Myxobolus cerebralis. M. cerebralis has a complex, 2-host life cycle alternating between salmonid fish and the oligochaete host Tubifex tubifex. The parasite alternates between 2 spore forms as transmission stages: an actinosporean triactinomyxon spore that is produced in the oligochaete host and a myxosporean spore that develops in the salmonid host. Waterborne triactinomyxon spores released from infected T. tubifex oligochaetes attach to the salmonid host by polar filament extrusion elicited by chemical (nucleoside) and mechanical (thigmotropy) stimuli-a process which is rapidly followed by active penetration of the sporoplasms into the fish epidermis. Upon penetration, sporoplasms multiply and migrate via peripheral nerves and the central nervous system to reach the cartilage where they form trophozoites which undergo further multiplication and subsequent sporogenesis. M. cerebralis myxospores are released into the aquatic environment when infected fish die and autolyse, or when they are consumed and excreted by predators. Myxospores released into the water are ingested by susceptible T. tubifex where they develop intercellularly in the intestine over a period of 3 mo through 4 developmental stages to give rise to mature actinospores. In this article, we review our current understanding of WD-the parasite and its alternate hosts, life cycle and development of the parasite in either host, disease distribution, susceptibility and resistance mechanisms in salmonid host and strategies involved in diagnosis, prevention and control of WD.
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Affiliation(s)
- Subhodeep Sarker
- Clinical Division of Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
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Rangel LF, Rocha S, Castro R, Severino R, Casal G, Azevedo C, Cavaleiro F, Santos MJ. The life cycle of Ortholinea auratae (Myxozoa: Ortholineidae) involves an actinospore of the triactinomyxon morphotype infecting a marine oligochaete. Parasitol Res 2015; 114:2671-8. [DOI: 10.1007/s00436-015-4472-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/07/2015] [Indexed: 12/01/2022]
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Turner KG, Smith MJ, Ridenhour BJ. Whirling disease dynamics: an analysis of intervention strategies. Prev Vet Med 2013; 113:457-68. [PMID: 24439792 DOI: 10.1016/j.prevetmed.2013.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 12/10/2013] [Accepted: 12/18/2013] [Indexed: 11/26/2022]
Abstract
Whirling disease (WD), a severe and widespread disease of salmonids, is caused by the myxosporean parasite Myxobolus cerebralis. It is further characterized by a unique two-host life cycle, utilizing the oligochaete Tubifex tubifex as an intermediate host. M. cerebralis is an invasive species that has been affecting populations in the United States including epidemics that killed in excess of 90% of populations in Colorado and Montana streams within the past 20 years. Currently, there is no known cure for WD, and the accepted method of control is removal of infected fish from the population. We have created a compartmental model of the WD system in order to assess more efficient means of control and management of the disease. Using data gathered from the literature, we used Bayesian model fitting to estimate model parameters and estimated that R0≈1.51 (95% CI: 1.39, 1.72), a value which implies that WD can be controlled using available strategies. To this end, we posit several parameters that we expect to be most influential to WD propagation, namely: release of triactinomyxons by T. tubifex, release of spores by salmonids, and infectious particle loads in each respective host. Based on currently available control strategies, approaches targeting the infectious particles and the oligochaete host appear the most effective alternative strategies for management and control of WD.
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Affiliation(s)
- Kimbra G Turner
- Eck Institute for Global Health, University of Notre Dame, Department of Biological Sciences, Notre Dame, IN 46556, USA.
| | - Matthew J Smith
- Eck Institute for Global Health, University of Notre Dame, Department of Biological Sciences, Notre Dame, IN 46556, USA
| | - Benjamin J Ridenhour
- Eck Institute for Global Health, University of Notre Dame, Department of Biological Sciences, Notre Dame, IN 46556, USA.
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Re-isolating Batrachochytrium dendrobatidis from an amphibian host increases pathogenicity in a subsequent exposure. PLoS One 2013; 8:e61260. [PMID: 23671564 PMCID: PMC3646005 DOI: 10.1371/journal.pone.0061260] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 03/12/2013] [Indexed: 11/19/2022] Open
Abstract
Controlled exposure experiments can be very informative, however, they are based on the assumption that pathogens maintained on artificial media under long-term storage retain the infective and pathogenic properties of the reproducing pathogen as it occurs in a host. We observed that JEL284, an in vitro cultured and maintained isolate of Batrachochytrium dendrobatidis (Bd), was becoming less infectious with successive uses. We hypothesized that passing an isolate propagated on artificial media through an amphibian host would make the isolate more infectious and pathogenic in subsequent exposures. To test our hypothesis, we used two discreet steps, a reisolation step (step 1) and a comparative exposure step (step 2). In step 1, we exposed eastern spadefoot toads, Scaphiopus holbrooki, to JEL284 and JEL197, another isolate that had been maintained in vitro for over six years. We then re-isolated JEL284 only from a successful infection and named this new isolate JEL284(FMBa). JEL197 did not infect any amphibians and, thus, did not proceed to step 2. In step 2, we compared infectivity and pathogenicity (mortality and survival time) of JEL284 and JEL284(FMBa) by exposing 54 naïve S. holbrooki to three treatments (JEL284, JEL284(FMBa), and negative control) with 18 individuals per group. We found that JEL284(FMBa) caused higher mortality and decreased survival time in infected individuals when compared to JEL284 and negative controls. Thus, our data show that pathogenicity of Bd can decrease when cultured successively in media only and can be partially restored by passage through an amphibian host. Therefore, we have demonstrated that pathogenicity shifts can occur rapidly in this pathogen. Given the potential for shifts in pathogenicity demonstrated here, we suspect Bd to have similar potential in natural populations. We suggest that, when possible, the use of freshly isolated or cryopreserved Bd would improve the quality of controlled exposure experiments using this pathogen.
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Lodh N, Kerans BL, Stevens L. The Parasite that Causes Whirling Disease, Myxobolus cerebralis, is Genetically Variable Within and Across Spatial Scales. J Eukaryot Microbiol 2011; 59:80-7. [DOI: 10.1111/j.1550-7408.2011.00596.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 10/24/2011] [Indexed: 11/29/2022]
Affiliation(s)
- Nilanjan Lodh
- Department of Biology; The University of Vermont; 109 Carrigan Drive; 120A MLS; Burlington; Vermont; 05405
| | - Billie L. Kerans
- Department of Ecology; Montana State University; 310 Lewis Hall; Bozeman; Montana; 59717
| | - Lori Stevens
- Department of Biology; The University of Vermont; 109 Carrigan Drive; 120A MLS; Burlington; Vermont; 05405
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Lodh N, Stevens L, Kerans B. Prevalence of Myxobolus cerebralis Infections Among Genetic Lineages of Tubifex tubifex at Three Locations in the Madison River, Montana. J Parasitol 2011; 97:531-4. [DOI: 10.1645/ge-2497.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Grimmett SG, Chalmers HJ, Wolf JC, Bowser PR. Spinal deformity in triploid grass carp Ctenopharyngodon idella (Valenciennes). JOURNAL OF FISH DISEASES 2011; 34:217-225. [PMID: 21306588 DOI: 10.1111/j.1365-2761.2010.01229.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
From mid-2004 to mid-2005, several grass carp, Ctenophayngodon idella (Valenciennes), showing evidence of spinal deformity were presented to the Aquatic Animal Health Program, Cornell University. The carp were from three separate locations in New York State. The first case involved several fish from a natural body of water in the Catskill Mountain region of south-eastern New York State. The second was a single affected individual from a private pond in the Fingerlakes region of Central New York State. The third was a single individual from the Cold Springs Harbor Fish Hatchery, Cold Springs Harbor, Long Island. All fish were at least 7 years of age. Radiographs and computed tomography (CT) scans revealed the deformities to be of bony origin. The spinal deformities were characterized by variable amounts of kyphosis, scoliosis and rotation. While it is not possible to determine the specific cause(s) of the lesions, we consider a genetic component as a likely contributor to the observed pathology.
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Affiliation(s)
- S G Grimmett
- Aquatic Animal Health Program, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401, USA
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Arsan* EL, Bartholomew JL. Potential Dispersal of the Non-Native ParasiteMyxobolus cerebralisin the Willamette River Basin, Oregon: A Qualitative Analysis of Risk. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/10641260802013726] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Myxobolus cerebralis(Myxozoa), the causative agent of whirling disease, reduces fecundity and feeding activity ofTubifex tubifex(Oligochaeta). Parasitology 2009; 136:603-13. [DOI: 10.1017/s0031182009005721] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYMyxobolus cerebralisis the causative agent of whirling disease that has significant economical and ecological impacts on trout populations. Although intensive studies have been conducted to understand its effects on and interactions with its fish host, only limited information is available about how and to what extentM. cerebralisaffects its oligochaete host,Tubifex tubifex. We investigated the effects ofM. cerebralison survival, growth, reproduction, and feeding activity ofT. tubifex. Mature, immature and juvenile worms were exposed to myxospores and their infection prevalence, mortality, sexual development, reproduction and spore production were compared with unexposed worms. The parasite affected neither survival nor growth but inhibited clitellar development and reduced cocoon production by over 80%. Numbers of actinospores released from mature worms were nearly 9-fold higher than that of immature worms. When non-clitellated infected worms were kept at 30°C for 4 days, spore release ceased and they re-developed a clitellum. These results suggest parasite-induced castration. Comparative monitoring of defecation rate revealed thatM. cerebralisreduced feeding activity ofT. tubifexby approximately 40%. Low energy intake and impaired energetic allocation may be the underlying mechanism behind reduced fecundity of infectedT. tubifex.
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Arsan EL, Bartholomew JL. Potential for dissemination of the nonnative salmonid parasite Myxobolus cerebralis in Alaska. JOURNAL OF AQUATIC ANIMAL HEALTH 2008; 20:136-149. [PMID: 18942590 DOI: 10.1577/h07-016.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Myxobolus cerebralis, the myxozoan parasite responsible for whirling disease in salmonids, was first introduced into the United States in 1958 and has since spread across the country, causing severe declines in wild trout populations in the intermountain western United States. The recent detection of the parasite in Alaska is further evidence of the species' capability to invade and colonize new habitat. This study qualitatively assesses the risk of further spread and establishment of M. cerebralis in Alaska. We examine four potential routes of dissemination: human movement of fish, natural dispersal by salmonid predators and straying salmon, recreational activities, and commercial seafood processing. Potential for establishment was evaluated by examining water temperatures, spatial and temporal overlap of hosts, and the distribution and genetic composition of the oligochaete host, Tubifex tubifex. The most likely pathway of M. cerebralis transport in Alaska is human movement of fish by stocking. The extent of M. cerebralis infection in Alaskan salmonid populations is unknown, but if the parasite becomes dispersed, conditions are appropriate for establishment and propagation of the parasite life cycle in areas of south-central Alaska. The probability of further establishment is greatest in Ship Creek, where the abundance of susceptible T. tubifex, the presence of susceptible rainbow trout Oncorhynchus mykiss, and the proximity of this system to the known area of infection make conditions particularly suitable for spread of the parasite.
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Affiliation(s)
- E Leyla Arsan
- Center for Fish Disease Research, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon 97331-3652, USA
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Discovery of genes implicated in whirling disease infection and resistance in rainbow trout using genome-wide expression profiling. BMC Genomics 2008; 9:37. [PMID: 18218127 PMCID: PMC2257940 DOI: 10.1186/1471-2164-9-37] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 01/24/2008] [Indexed: 12/03/2022] Open
Abstract
Background Whirling disease, caused by the pathogen Myxobolus cerebralis, afflicts several salmonid species. Rainbow trout are particularly susceptible and may suffer high mortality rates. The disease is persistent and spreading in hatcheries and natural waters of several countries, including the U.S.A., and the economic losses attributed to whirling disease are substantial. In this study, genome-wide expression profiling using cDNA microarrays was conducted for resistant Hofer and susceptible Trout Lodge rainbow trout strains following pathogen exposure with the primary objective of identifying specific genes implicated in whirling disease resistance. Results Several genes were significantly up-regulated in skin following pathogen exposure for both the resistant and susceptible rainbow trout strains. For both strains, response to infection appears to be linked with the interferon system. Expression profiles for three genes identified with microarrays were confirmed with qRT-PCR. Ubiquitin-like protein 1 was up-regulated over 100 fold and interferon regulating factor 1 was up-regulated over 15 fold following pathogen exposure for both strains. Expression of metallothionein B, which has known roles in inflammation and immune response, was up-regulated over 5 fold in the resistant Hofer strain but was unchanged in the susceptible Trout Lodge strain following pathogen exposure. Conclusion The present study has provided an initial view into the genetic basis underlying immune response and resistance of rainbow trout to the whirling disease parasite. The identified genes have allowed us to gain insight into the molecular mechanisms implicated in salmonid immune response and resistance to whirling disease infection.
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Abstract
Myxobolus cerebralis, the myxozoan parasite responsible for whirling disease in salmonid fishes, has a complex life-cycle involving an invertebrate host and 2 spore stages. Water flow rate is an environmental variable thought to affect the establishment and propagation of M. cerebralis; however, experimental data that separates flow effects from those of other variables are scarce. To compare how this parameter affected parasite infection dynamics and the invertebrate and vertebrate hosts, dead, infected fish were introduced into a naive habitat with susceptible hosts under 2 experimental flow regimes: slow (0 x 02 cm/s) and fast (2 x 0 cm/s). Throughout the 1-year study, uninfected fry were held in both systems, the outflows were screened weekly for spores and the annelid populations were monitored. We found clear differences in prevalence of infection in the worms, prevalence and severity of infection in the fish, and host survival. Both flows provided environments in which M. cerebralis could complete its life-cycle; however, both the parasite and its invertebrate host proliferated to a greater extent in the slow flow environment over the 1-year study period. This finding is of significance for aquatic systems where the flow rate can be manipulated, and should be incorporated into risk analysis assessments.
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Arsan EL, Hallett SL, Bartholomew JL. TUBIFEX TUBIFEX FROM ALASKA AND THEIR SUSCEPTIBILITY TO MYXOBOLUS CEREBRALIS. J Parasitol 2007; 93:1332-42. [DOI: 10.1645/ge-1117.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Baxa DV, Kelley GO, Mukkatira KS, Beauchamp KA, Rasmussen C, Hedrick RP. Arrested development of the myxozoan parasite, Myxobolus cerebralis, in certain populations of mitochondrial 16S lineage III Tubifex tubifex. Parasitol Res 2007; 102:219-28. [PMID: 17891544 DOI: 10.1007/s00436-007-0750-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 08/30/2007] [Indexed: 10/22/2022]
Abstract
Laboratory populations of Tubifex tubifex from mitochondrial (mt)16S ribosomal DNA (rDNA) lineage III were generated from single cocoons of adult worms releasing the triactinomyxon stages (TAMs) of the myxozoan parasite, Myxobolus cerebralis. Subsequent worm populations from these cocoons, referred to as clonal lines, were tested for susceptibility to infection with the myxospore stages of M. cerebralis. Development and release of TAMs occurred in five clonal lines, while four clonal lines showed immature parasitic forms that were not expelled from the worm (non-TAM producers). Oligochaetes from TAM- and non-TAM-producing clonal lines were confirmed as lineage III based on mt16S rDNA and internal transcribed spacer region 1 (ITS1) sequences, but these genes did not differentiate these phenotypes. In contrast, random amplified polymorphic DNA analyses of genomic DNA demonstrated unique banding patterns that distinguished the phenotypes. Cohabitation of parasite-exposed TAM- and non-TAM-producing phenotypes showed an overall decrease in expected TAM production compared to the same exposure dose of the TAM-producing phenotype without cohabitation. These studies suggest that differences in susceptibility to parasite infection can occur in genetically similar T. tubifex populations, and their coexistence may affect overall M. cerebralis production, a factor that may influence the severity of whirling disease in wild trout populations.
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Affiliation(s)
- D V Baxa
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, CA, 95616, USA.
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Bartholomew JL, Kerans BL, Hedrick RP, Macdiarmid SC, Winton JR. A Risk Assessment Based Approach for the Management of Whirling Disease. ACTA ACUST UNITED AC 2007. [DOI: 10.1080/10641260500326842] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Beauchamp KA, El-Matbouli M, Gay M, Georgiadis MP, Nehring RB, Hedrick RP. The effect of cohabitation of Tubifex tubifex (Oligochaeta: Tubificidae) populations on infections to Myxobolus cerebralis (Myxozoa: Myxobolidae). J Invertebr Pathol 2006; 91:1-8. [PMID: 16321396 DOI: 10.1016/j.jip.2005.08.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Revised: 07/29/2005] [Accepted: 08/08/2005] [Indexed: 11/16/2022]
Abstract
The competitive interactions between susceptible and resistant Tubifex tubifex (Oligochaeta: Tubificidae) exposed to Myxobolus cerebralis (Myxozoa: Myxobolidae) infections were investigated in two laboratory trials. Competition was assessed by the total parasite production over the course of the trials in mixed and pure cultures of M. cerebralis exposed worms, and by the genetic analyses of worms from the control and experimental groups at the beginning and end of the experiments. Mixed cultures of resistant and susceptible worms showed a 70% reduction in production of parasites released when compared with pure cultures of susceptible worms. In studies with laboratory and field-collected oligochaetes the mixed cultures at the end of the cohabitation experiments were dominated by resistant Tubifex from lineage V (HB strain) this strain of Tubifex has a competitive advantage over worms from other lineages. The results of this study suggest that certain species of Tubifex may be dead-end hosts to M. cerebralis by absorbing or inactivating the parasite and may also show greater survival compared to susceptible oligochaetes in certain whirling disease enzootic habitats.
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Affiliation(s)
- Katherine A Beauchamp
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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Beauchamp KA, Kelley GO, Nehring RB, Hedrick RP. THE SEVERITY OF WHIRLING DISEASE AMONG WILD TROUT CORRESPONDS TO THE DIFFERENCES IN GENETIC COMPOSITION OF TUBIFEX TUBIFEX POPULATIONS IN CENTRAL COLORADO. J Parasitol 2005; 91:53-60. [PMID: 15856872 DOI: 10.1645/ge-327r] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We analyzed the geographic distribution of Tubifex tubifex from various river drainages in central Colorado by genetic screening with specific mitochondrial 16S ribosomal DNA (mt 16S rDNA) markers. Four distinct mt 16S rDNA lineages are evident. The sites varied with respect to land- and water-use practices. All sites represented habitats presumed capable of supporting oligochaetes. At the locations where whirling disease has had the greatest impact on resident rainbow trout, T. tubifex, representing lineages I and III (genotypes known to be susceptible to Mxyobolus cerebralis), were most commonly found. In contrast, at sites less affected by whirling disease, T. tubifex of lineages V and VI that are more resistant to M. cerebralis infections were more abundant. The predominance of resistant T. tubifex worms (lineages V and VI) at low-impact sites supports the conclusion that when these genotypes are in greater abundance, the potential for more severe effects of whirling disease on wild rainbow trout populations may be diminished.
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Affiliation(s)
- Katherine A Beauchamp
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, California 95616, USA.
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Rácz OZ, Székely C, Molnár K. Intraoligochaete development of Myxobolus intimus (Myxosporea: Myxobolidae), a gill myxosporean of the roach (Rutilus rutilus). Folia Parasitol (Praha) 2004. [DOI: 10.14411/fp.2004.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Gilbert MA, Granath WO. Whirling disease of salmonid fish: life cycle, biology, and disease. J Parasitol 2003; 89:658-67. [PMID: 14533670 DOI: 10.1645/ge-82r] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Myxobolus cerebralis is the myxozoan parasite responsible for causing whirling disease in salmonid fish. Although the parasite was first described nearly 100 yr ago, it received relatively little attention until the discovery of its 2-host life cycle in the mid 1980s. This was the first, complete, myxozoan life cycle to be described, and it was greeted with some skepticism because it united 2 stages of M. cerebralis that were previously classified in 2 separate taxa. In the last decade, there has been a renewed interest in this parasite because whirling disease has been implicated in the decline of wild trout populations in several western states in the United States. Subsequent research efforts have dramatically increased the understanding of the biology of M. cerebralis and the numerous factors that affect the severity of whirling disease in salmonid hosts. These efforts also have provided a great deal of new information concerning interactions between M. cerebralis and its aquatic oligochaete host Tubifex tubifex. This review examines the current state of M. cerebralis in relation to 3 categories: the life cycle, the salmonid hosts, and the oligochaete host.
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Affiliation(s)
- Michael A Gilbert
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA.
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Koprivnikar J, Desser SS. A new form of raabeia-type actinosporean (Myxozoa) from the oligochaete Uncinais uncinata. Folia Parasitol (Praha) 2003; 49:89-92. [PMID: 12194494 DOI: 10.14411/fp.2002.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In a study of the oligochaete fauna and their actinosporean parasites in three lakes in Algonquin Park, Canada, a novel form of raabeia-type actinosporean was observed in a single specimen of Uncinais uncinata (Øersted) (Naididae). This form differs from those previously described in its small size, and by having caudal processes that gradually widen and terminate with a single prominent branch.
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Affiliation(s)
- Janet Koprivnikar
- Department of Zoology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 3G5, Canada
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Blazer VS, Waldrop TB, Schill WB, Densmore CL, Smith D. Effects of water temperature and substrate type on spore production and release in eastern Tubifex tubifex worms infected with Myxobolus cerebralis. J Parasitol 2003; 89:21-6. [PMID: 12659298 DOI: 10.1645/0022-3395(2003)089[0021:eowtas]2.0.co;2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Eastern Tubifex tubifex worms were exposed to Myxobolus cerebralis spores at 9, 13, 17, and 20 C in 1-L jars that contained sand, mud, or leaf litter as substrata. Beginning 60 days after exposure, water from each jar was filtered daily and examined for the presence of waterborne triactinomyxon spores (TAMs). On discovering a single TAM from an experimental jar, 48 T. tubifex worms from that jar were placed individually into 24-well plates. Spores released from individual infected T. tubifex worms were quantified to determine the first day of TAM release from infected worms, the infection rate, the total number of TAMs released per worm, and the duration of release. No TAMs were found in any of the jars incubated at 20 C or in uninfected, control worms at any temperature. The total number of TAMs released by infected worms in mud and sand was highest at 13 C compared with other temperatures. Infection rates among individual worms increased with temperature between 9 and 17 C. Higher temperatures (up to 17 C) induced earlier TAM releases among infected worms, and substratum did not influence this production parameter. The average duration of TAM release decreased as the temperature increased from 9 to 17 C, and there was a significant effect of substratum in the groups maintained at 13 and 17 C. In all temperature treatments between 9 and 17 C, the duration of release was least in the worms maintained in leaf litter, as was the total number of TAMs released during the experimental period and the median number of TAMs per production day.
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Affiliation(s)
- Vicki S Blazer
- U.S. Geological Survey, National Fish Health Research Laboratory, Leetown Science Center, 11700 Leetown Road, Kearneysville, West Virginia 25430, USA.
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Oumouna M, Hallett SL, Hoffmann RW, El-Matbouli M. Early developmental stages of two actinosporeans, Raabeia and Aurantiactinomyxon (Myxozoa), as detected by light and electron microscopy. J Invertebr Pathol 2002; 79:17-26. [PMID: 12054783 DOI: 10.1016/s0022-2011(02)00007-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The development of actinosporeans in their oligochaete host proceeding pansporocyst formation is relatively well documented, however, phases preceding it are not as well known. The initial stages in the development of two actinosporeans, Raabeia type 1 of Oumouna et al. [Parasitol. Res. 2002] and Aurantiactinomyxon pavinsis (Ormières, 1968) Marquès [Languedoc, Universite des Sciences et Techniques, Dissertation, 1984] from schizogony to gametogony and sporogony are described. Both actinosporeans begin their development as multinucleate stages near the basal lamina of the oligochaete intestine. Proximal to these stages and between the host epithelium cells are uninucleate cells whose nuclei divide to produce binucleate cells. These divide mitotically to produce cells with four nuclei which then undergo plasmotomy to yield a tetracellular stage and the first phase in pansporocyst formation. From the uninucleate stage to the tetranucleate stage, the cell membrane of the parasite is associated closely via finger-like projections with the intestinal epithelial and glandular cells of the host.
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Affiliation(s)
- M Oumouna
- Institute for Zoology Fish Biology and Fish Diseases, Kaulbachstrasse 37, 80539 Munich, Germany
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