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Stilwell JM, Griffin MJ, Leary JH, Khoo LH, Camus AC. Massive branchial henneguyosis of catfish: A distinct, myxozoan-induced gill disease caused by severe interlamellar Henneguya exilis infection in catfish aquaculture. Vet Pathol 2024:3009858241259181. [PMID: 38864294 DOI: 10.1177/03009858241259181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Proliferative gill disease (PGD), caused by the myxozoan Henneguya ictaluri, has been the most notorious parasitic gill disease in the US catfish aquaculture industry. In 2019, an unusual gill disease caused by massive burdens of another myxozoan, Henneguya exilis, was described in channel (Ictalurus punctatus) × blue (Ictalurus furcatus) hybrid catfish. Targeted metagenomic sequencing and in situ hybridization (ISH) were used to differentiate these conditions by comparing myxozoan communities involved in lesion development and disease pathogenesis between massive H. exilis infections and PGD cases. Thirty ethanol-fixed gill holobranchs from 7 cases of massive H. exilis infection in hybrid catfish were subjected to targeted amplicon sequencing of the 18S rRNA gene and compared to a targeted metagenomic data set previously generated from clinical PGD case submissions. Furthermore, serial sections of 14 formalin-fixed gill holobranchs (2 per case) were analyzed by RNAscope duplex chromogenic ISH assays targeting 8 different myxozoan species. Targeted metagenomic and ISH data were concordant, indicating myxozoan community compositions significantly differ between PGD and massive branchial henneguyosis. Although PGD cases often consist of mixed species infections, massive branchial henneguyosis consisted of nearly pure H. exilis infections. Still, H. ictaluri was identified by ISH in association with infrequent PGD lesions, suggesting coinfections occur, and some cases of massive branchial henneguyosis may contain concurrent PGD lesions contributing to morbidity. These findings establish a case definition for a putative emerging, myxozoan-induced gill disease of farm-raised catfish with a proposed condition name of massive branchial henneguyosis of catfish (MBHC).
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Affiliation(s)
- Justin M Stilwell
- University of Georgia, Athens, GA
- Mississippi State University, Mississippi State, MS
| | - Matt J Griffin
- Mississippi State University, Mississippi State, MS
- Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS
| | | | - Lester H Khoo
- Mississippi State University, Mississippi State, MS
- Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS
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McAllister CT, Cloutman DG, Leis EM, Camus AC, Robison HW. A new Myxobolus (Cnidaria: Myxosporea: Myxobolidae) from the gills of the southern striped shiner, Luxilus chrysocephalus isolepis (Cypriniformes: Leuciscidae), from southwestern Arkansas, USA. Syst Parasitol 2023; 100:215-229. [PMID: 36656427 DOI: 10.1007/s11230-023-10082-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/03/2023] [Indexed: 01/20/2023]
Abstract
The southern striped shiner, Luxilus chrysocephalus isolepis (Hubbs & Brown) is a relatively large minnow belonging to the true minnow family Leuciscidae Bonaparte. Between May 2020 and January 2022, 55 L. c. isolepis were collected from watersheds in Montgomery (n = 6), Polk (n = 17) and Sevier (n = 32) counties, Arkansas, USA, and their gills, gallbladders, urinary bladders, fins, integument, other major organs, and musculature were examined for myxozoans. Gills of 11 (34%) individual southern striped shiners from Sevier County were infected with a new myxozoan, Myxobolus carlhubbsi n. sp. A qualitative and quantitative morphological description was based on formalin-fixed preserved myxospores, and molecular data consisted of a 1,970 base pair sequence of the partial small subunit rRNA gene from ethanol-preserved specimens. Histologically, plasmodia filled and expanded interlamellar troughs. Hyperplastic epithelial and goblet cells filled interlamellar troughs adjacent to plasmodia, but inflammatory response was limited to scattered lymphocytes. Phylogenetic analysis revealed that M. carlhubbsi n. sp. is a member of a clade of species with pyriform myxospores parasitizing North American Pogonichthyinae Girard and North American and Eurasian Leuciscinae Bonaparte. This is the first report of a myxozoan from L. c. isolepis. This article was registered in the Official Register of Zoological Nomenclature (ZooBank) as urn:lsid:zoobank.org:pub:D10D71C2-2C75-4A1C-80ED-B98FF36CB509.
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Affiliation(s)
- Chris T McAllister
- Science and Mathematics Division, Eastern Oklahoma State College, Idabel, OK, 74745, USA.
| | | | - Eric M Leis
- La Crosse Fish Health Center-Midwest Fisheries Center, U. S. Fish and Wildlife Service, Onalaska, WI, 54650, USA
| | - Alvin C Camus
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, 30677, USA
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Stilwell JM, Griffin MJ, Waldbieser GC, Stanton JB, Leary JH, Khoo LH, Steadman JM, Ware C, Wise DJ, Camus AC. Myxozoan Community Composition and Diversity in Clinical Cases of Proliferative Gill Disease in Mississippi Catfish Aquaculture. J Parasitol 2022; 108:132-140. [DOI: 10.1645/21-57] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Justin M. Stilwell
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 D. W. Brooks Drive, Athens, Georgia 30602
| | - Matt J. Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776
| | - Geoffrey C. Waldbieser
- USDA-ARS, Warmwater Aquaculture Research Unit, 141 Experiment Station Road, Stoneville, Mississippi 38776
| | - James B. Stanton
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 D. W. Brooks Drive, Athens, Georgia 30602
| | - John H. Leary
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 D. W. Brooks Drive, Athens, Georgia 30602
| | - Lester H. Khoo
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776
| | - James M. Steadman
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776
| | - Cynthia Ware
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776
| | - David J. Wise
- Thad Cochran National Warmwater Aquaculture Center, Delta Research and Extension Center, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776
| | - Alvin C. Camus
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 D. W. Brooks Drive, Athens, Georgia 30602
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Dinh-Hung N, Dong HT, Soontara C, Rodkhum C, Nimitkul S, Srisapoome P, Kayansamruaj P, Chatchaiphan S. Co-infection of Candidatus Piscichlamydia Trichopodus (Order Chlamydiales) and Henneguya sp. (Myxosporea, Myxobolidae) in Snakeskin Gourami Trichopodus pectoralis (Regan 1910). Front Vet Sci 2022; 9:847977. [PMID: 35359670 PMCID: PMC8961658 DOI: 10.3389/fvets.2022.847977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/03/2022] [Indexed: 11/20/2022] Open
Abstract
The present study describes a simultaneous infection of a novel Chlamydia-like organism (CLO) with a Myxozoa parasite, Henneguya sp. in snakeskin gourami Trichopodus pectoralis in Thailand. A new CLO is proposed “Candidatus Piscichlamydia trichopodus” (CPT) based on 16S rRNA phylogenetic analysis. Systemic intracellular CPT infection was confirmed by histological examination, in situ hybridization, PCR assay, and sequencing of 16S rRNA. This novel pathogen belongs to the order Chlamydiales but differs in certain aspects from other species. The histopathological changes associated with CPT infection were different from the typical pathological lesions of epitheliocystis caused by previously known CLO. Unlike other CLO, CPT localized in the connective tissue rather than in the epithelial cells and formed smaller clumps of intracellular bacteria that stained dark blue with hematoxylin. On the other hand, typical myxospores of the genus Henneguya with tails were observed in the gill sections. Infection with Henneguya sp. resulted in extensive destruction of the gill filaments, most likely leading to respiratory distress. Due to the frequency of co-infections and the unavailability of culture methods for CLO and Henneguya sp., it was difficult to determine which pathogens were directly responsible for the associated mortality. However, co-infections may increase the negative impact on the host and the severity of the disease. Given the commercial importance of the snakeskin gourami and its significant aquaculture potential, the findings of this study are important for further studies on disease prevention.
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Affiliation(s)
- Nguyen Dinh-Hung
- The International Graduate Program of Veterinary Science and Technology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence in Fish Infectious Diseases, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Ha Thanh Dong
- Department of Food, Agriculture and Bioresources, Aquaculture and Aquatic Resources Management Program, Asian Institute of Technology, School of Environment, Klong Luang, Thailand
| | - Chayanit Soontara
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - Channarong Rodkhum
- The International Graduate Program of Veterinary Science and Technology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence in Fish Infectious Diseases, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Sukkrit Nimitkul
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - Prapansak Srisapoome
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - Pattanapon Kayansamruaj
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
- *Correspondence: Pattanapon Kayansamruaj
| | - Satid Chatchaiphan
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
- Satid Chatchaiphan
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Vieira DHMD, Narciso RB, de Azevedo RK, da Silva RJ. Description of Two Novel Henneguya (Cnidaria: Myxosporea) Infecting Curimatid Fish, Using Morphological, Histological, and Molecular Analyses. Acta Parasitol 2022; 67:233-243. [PMID: 34273054 DOI: 10.1007/s11686-021-00454-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/06/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE We describe two new Henneguya spp. (Myxobolidae) found parasitizing Cyphocharax modestus from Pardo river, Paraná river basin, municipality of Botucatu, São Paulo State, Brazil: Henneguya fastigata n. sp. from gill lamellae and Henneguya pardensis n. sp. from gill arches. We based the descriptions on myxospore morphology, histology, and small subunit ribosomal DNA sequences. METHODS In this investigation, 50 specimens of Cyphocharax modestus were examined between July and December 2020 for myxozoan infections. Morphological characterization was based on the mature myxospores. The small subunit ribosomal DNA sequences were used for molecular and phylogenetic study. RESULTS Phylogenetic analysis provided the evolutionary position of these new species with other myxobolids species. Myxospores of the two species had similar morphology and morphometrics, but differed in spore body width and length, and ssrDNA sequences differed by 7.2%. These data supported the diagnosis of the parasites as distinct and novel species. The phylogenetic analysis showed a well-supported subclade formed by species that parasitize curimatid fishes, with Henneguya gilbert as a sister species of Henneguya fastigata n. sp., and Henneguya pardensis n. sp. as a sister species of both species. CONCLUSION Our analysis was consistent with previous studies suggesting that orders and families of the hosts are strongly correlated with phylogenetic signals in the Myxobolidae. These are the first species of myxozoans described in the Pardo river.
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Affiliation(s)
- Diego Henrique Mirandola Dias Vieira
- Laboratory of Parasitology of Wild Animals, Division of Parasitology, Institute of Biosciences, Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), R. Prof. Dr. Antônio Celso Wagner Zanin, 250, Rubião Junior, CEP 18618-689, Botucatu, SP, Brazil.
| | - Rodrigo Bravin Narciso
- Laboratory of Parasitology of Wild Animals, Division of Parasitology, Institute of Biosciences, Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), R. Prof. Dr. Antônio Celso Wagner Zanin, 250, Rubião Junior, CEP 18618-689, Botucatu, SP, Brazil
| | | | - Reinaldo José da Silva
- Laboratory of Parasitology of Wild Animals, Division of Parasitology, Institute of Biosciences, Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), R. Prof. Dr. Antônio Celso Wagner Zanin, 250, Rubião Junior, CEP 18618-689, Botucatu, SP, Brazil
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Woodyard ET, Rosser TG, Stilwell JM, Camus AC, Khoo LH, Waldbieser G, Lorenz WW, Griffin MJ. New data on Henneguya postexilis Minchew, 1977, a parasite of channel catfish Ictalurus punctatus, with notes on resolution of molecular markers for myxozoan phylogeny. Syst Parasitol 2022; 99:41-62. [PMID: 35028798 DOI: 10.1007/s11230-021-10015-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/15/2021] [Indexed: 11/27/2022]
Abstract
Previous morphological and histological data are supplemented with molecular and ultrastructural data for a Henneguya sp. isolated from farm-raised channel catfish Ictalurus punctatus in Mississippi, USA. Myxospores were cryptic, encapsulated within a thin layer of epithelium in the gill lamellae with spore measurements consistent with the original description of Henneguya postexilis Minchew, 1977. Myxospores were 42.7-49.1 µm in total length with spore bodies 12.1-17.2 × 3.6-4.8 × 2.9-3 µm. Polar capsules were of unequal length, with the longer capsule being 4.4-6.7 × 1.1-1.6 µm and the shorter capsule being 4.4-6.4 × 1.1-1.6 µm. Polar tubules had 6-8 turns. Caudal processes were 25.7-38.1 µm in length. Spores were encapsulated in a thin layer of epithelium in the gill lamellae. Molecular data from the most commonly used markers for myxozoan identification and phylogeny, partial 18S small subunit ribosomal gene (SSU), partial 28S large subunit ribosomal gene (LSU), and elongation factor 2 (EF2) were generated for H. postexilis. Additionally, novel data for LSU and EF2 were generated for archived myxozoan specimens from farm-raised catfish (H. mississippiensis, H. ictaluri, H. exilis, H. adiposa, H. sutherlandi, H. bulbosus, Unicauda fimbrethilae), as well as archived specimens from wild fish (H. laseeae [from Pylodictis olivaris], Hennegoides flockae [from Aphredoderus sayanus], Myxobolus cloutmani [from Cycleptus elongatus]. These include the first EF2 sequence data for the genera Hennegoides and Unicauda. Phylogenetic analyses using these data placed H. postexilis in well supported clades with other ictalurid-infecting Henneguya species. Phylogenetic signal assessments on these analyses suggest that while SSU provided the greatest phylogenetic signal, LSU yielded comparable signal, supporting previous work implying this region may be underutilised in reconstructing myxobolid phylogenies.
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Affiliation(s)
- Ethan T Woodyard
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39759, USA.
| | - Thomas G Rosser
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39759, USA
| | - Justin M Stilwell
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Alvin C Camus
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, 30602, USA
| | - Lester H Khoo
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39759, USA
| | - Geoffrey Waldbieser
- USDA-ARS Warmwater Aquaculture Research Unit, Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS, 38776, USA
| | - W Walter Lorenz
- Georgia Genomics and Bioinformatics Core, University of Georgia, Athens, GA, 30602, USA
| | - Matt J Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39759, USA
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Truong TN, Bullard SA. Susceptibility of Channel Catfish (Ictalurus punctatus), Blue Catfish (Ictalurus furcatus), and Their Commercially Cultured Hybrid to Metazoan Parasite Infection in Earthen Pond Aquaculture. COMP PARASITOL 2021. [DOI: 10.1654/1525-2647-88.1.93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Triet N. Truong
- Aquatic Parasitology Laboratory, School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, Alabama 36849, U.S.A. (e-mail: , )
| | - Stephen A. Bullard
- Aquatic Parasitology Laboratory, School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, Alabama 36849, U.S.A. (e-mail: , )
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Rosser TG, Loch TP, Faisal M, Baumgartner WA, Griffin MJ. Henneguya michiganensis n. sp. (Cnidaria: Myxosporea) from the gills of muskellunge Esox masquinongy Mitchill(Esociformes: Esocidae). Syst Parasitol 2021; 98:119-130. [PMID: 33687653 DOI: 10.1007/s11230-021-09965-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 09/15/2020] [Indexed: 11/29/2022]
Abstract
Henneguya Thélohan, 1892 is the second most species rich genus of myxozoans, with reports from freshwater and marine fish worldwide. In the Great Lakes region of North America, muskellunge Esox masquinongy is an important game fish species that serves as an apex predator in the ecosystems of many inland lakes. The myxozoan fauna of esocid fish, especially muskellunge, remains largely understudied. During fish health assessments, muskellunge were examined for parasitic infections and myxozoan pseudocysts were observed on gill clip wet mounts. When ruptured under pressure, the intralamellar pseudocysts released thousands of myxospores consistent with those of the genus Henneguya. The myxospores were 67.3-96.6 (79.1 ± 5.9) µm in total length. The spore body was 18.6-22.6 (20.9 ± 1.0) µm × 5.4-6.9 (6.3 ± 0.4) µm in valvular view and 3.5-4.0 (3.8 ± 0.3) µm wide in sutural view. The two pyriform polar capsules positioned at the anterior of the spore body were 6.4-7.7 (7.0 ± 0.4) µm × 1.8-2.1 (2.0 ± 0.1) µm and each contained a tightly coiled polar filament with 9-10 turns. Two tapering caudal processes extended from the posterior of the spore body and were 47.3-75.6 (58.3 ± 5.8) µm in length. Histologically, large intralamellar polysporic plasmodia were surrounded by plump pillar cells and a distinct layer of plasma. Mild inflammation was present peripherally, with small numbers of necrotic germinative cells and intraplasmodial phagocytes internally. Ribosomal 18S rRNA gene sequence data were obtained from three gill pseudocysts. The three ~2000-bp sequences were identical, but shared no significant similarity with any publicly available sequence data. Phylogenetic analyses demonstrated sequence data from this Henneguya fell within a well-supported clade of Henneguya spp. reported from northern pike Esox lucius in Europe. Based on the distinct morphological, histological and molecular data, this species is designated as Henneguya michiganensis n. sp. from muskellunge in Michigan, USA.
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Affiliation(s)
- Thomas G Rosser
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi, MS, 39762, USA
| | - Thomas P Loch
- Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, 48824, USA.
| | - Mohamed Faisal
- Department of Fisheries and Wildlife, College of Agriculture and Natural Resources, Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Wes A Baumgartner
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Illinois, Urbana, IL, 61802, USA
| | - Matt J Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Stoneville, MS, 38776, USA
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Stilwell JM, Stilwell NK, Camus AC, Ware C, Rosser TG, Griffin MJ. Necroulcerative dermatitis associated with Myxobolus dermatoulcerans n. sp. (Cnidaria: Myxobolidae) in red-bellied piranha, Pygocentrus nattereri Kner (Characiformes: Serrasalmidae), from Peru. Syst Parasitol 2020; 97:649-659. [PMID: 32951165 DOI: 10.1007/s11230-020-09936-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/30/2020] [Indexed: 11/28/2022]
Abstract
A group of red-bellied piranha, Pygocentrus nattereri Kner, recently imported from Peru exhibited multifocal, cutaneous ulcerations with exposure of the underlying musculature. Skin scrapes yielded moderate numbers of myxospores morphologically consistent with Myxobolus Bütschli, 1882. Myxospores from these fish were morphologically and molecularly distinct from other myxobolids infecting piranha. Myxospores are pyriform to capsular with a rounded posterior and slightly rounded to tapering anterior aspect in valvular view. Myxospore bodies are 14.3-17.8 (mean 16.1) µm long and 7.6-10.3 (mean 8.9) µm wide. Polar capsules are symmetrical, slender, elongate, and measure 7.4-10.2 (mean 9.2) µm long and 2.1-3.7 (mean 3.0) µm wide. Sequence generated for the 18S rRNA gene had no direct matches to any sequence available on GenBank but demonstrated less than 89% nucleotide similarity to various published and unpublished Myxobolus spp. from Piaractus brachypomus (Cuvier) and Colossoma macropomum (Cuvier). This paper provides the morphological and molecular characterisation of Myxobolus dermatoulcerans n. sp. from red-bellied piranha and describes associated pathological lesions.
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Affiliation(s)
- Justin M Stilwell
- Department of Pathology, University of Georgia, Athens, Georgia, 30602, USA.
| | - Natalie K Stilwell
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, University of Georgia, Athens, Georgia, 30602, USA
| | - Alvin C Camus
- Department of Pathology, University of Georgia, Athens, Georgia, 30602, USA
| | - Cyndi Ware
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Thomas G Rosser
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
| | - Matt J Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi, 39762, USA
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Stilwell JM, Griffin MJ, Rosser TG, Mohammed HH, Sidor IF, Camus AC. Insights into myxozoan composition and physiology revealed by histochemical properties of myxospores. JOURNAL OF FISH DISEASES 2020; 43:583-597. [PMID: 32202327 DOI: 10.1111/jfd.13152] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/19/2020] [Accepted: 02/21/2020] [Indexed: 06/10/2023]
Abstract
Myxozoa (phylum Cnidaria) are a diverse group of metazoan parasites that predominately infect fish. Little is known regarding the composition and physiology of their myxospore life stage. The objective of this work was to investigate the composition of myxospores and extrasporogonic stages of nine myxozoan species infecting various teleost fish using histochemical staining techniques. Thirty histochemical stains were applied to formalin-fixed, paraffin-embedded tissues processed routinely for light microscopic evaluation. The polar capsules were the most consistent stain target across the taxa examined. Polar capsule staining with Alizarin red, von Kossa and methyl green-pyronin suggests the presence of intracapsular calcium and phosphate, which may contribute to polar filament discharge or pathogenesis of host invasion. The shell valves and suture lines of most myxozoans were stained with Luna and phosphotungstic acid haematoxylin stains, consistent with the presence of chitin and microfibrils, respectively. Vacuoles were consistently highlighted by diastase-susceptible periodic acid-Schiff and Grocott's methenamine silver staining, indicating glycogen. Other histochemical stains exhibited inconsistent staining across the taxa, suggesting differences in myxospore composition potentially reflective of physiologic variations and tissue tropisms. This work provides some information on conserved features and taxa-associated composition of myxospores and lends insight into myxozoan physiology and host-parasite interactions.
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Affiliation(s)
- Justin M Stilwell
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - Matt J Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Stoneville, MS, USA
| | - Thomas G Rosser
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Stoneville, MS, USA
| | - Haitham H Mohammed
- School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, USA
| | - Inga F Sidor
- New Hampshire Veterinary Diagnostic Laboratory, Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
| | - Alvin C Camus
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
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Characterisation of Myxobolus stellatus n. sp. (Cnidaria: Myxobolidae) infecting the cranial nerves and ganglia of the spotfin hatchetfish Thoracocharax stellatus (Kner) (Characiformes: Gasteropelecidae) from Colombia. Syst Parasitol 2020; 97:305-314. [PMID: 32253575 DOI: 10.1007/s11230-020-09911-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/27/2020] [Indexed: 10/24/2022]
Abstract
A previously undescribed Myxobolus sp. was isolated from the cranial nerves and ganglia of the spotfin hatchetfish Thoracocharax stellatus (Kner) that exhibited neurologic signs following importation from Colombia. Associated plasmodia formed space-occupying masses within nerves, compressing neuronal cell bodies and causing axonal degeneration. Myxospores from these fish were morphologically and molecularly distinct from other myxobolids infecting the central nervous system of characins. In valvular view, spores are pyriform with a rounded posterior and tapering anterior aspect. Myxospore bodies are 17.0-19.4 (mean 18.4) µm long and 8.2-9.3 (mean 8.8) µm wide. Polar capsules are asymmetrical and pyriform with a neck-like projection at the apical end. The small polar capsule measures 4.3-5.9 × 2.2-3.1 (mean 5.0 × 2.6) µm, while the large polar capsule measures 9.1-10.7 × 4.9-6.3 (mean 9.9 × 5.4) µm wide. The sequence generated for the small subunit rRNA (18S) gene did not directly match any sequences available on GenBank, but demonstrated 92% nucleotide similarity to Myxobolus axelrodi Camus, Dill, Rosser, Pote & Griffin, 2017 infecting Paracheirodon axelrodi (Schultz). This study provides the first morphological, histological and molecular characterisation of Myxobolus stellatus n. sp. from the spotfin hatchetfish.
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Stilwell JM, Stilwell NK, Camus AC, Griffin MJ, Rosser TG. A morphological, molecular, and histopathological redescription of Henneguya nyongensis Fomena & Bouix, 1996 (Cnidaria: Myxobolidae) infecting the gills of Peter's elephantnose fish, Gnathonemus petersii (Günther) (Osteoglossiformes: Mormyridae), imported from Nigeria. Syst Parasitol 2019; 96:767-776. [PMID: 31721045 DOI: 10.1007/s11230-019-09887-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/24/2019] [Indexed: 11/26/2022]
Abstract
A Henneguya sp., morphologically resembling Henneguya nyongensis Fomena & Bouix, 1996, was isolated from the gills of Peter's elephantnose fish, Gnathonemus petersii Günther, imported from Nigeria. Plasmodia were located between lamellae and within the gill epithelium, often leading to lamellar fusion. Although slightly smaller, the myxospores from these fish were morphologically consistent with H. nyongensis. In valvular view, spores are elongate, pyriform with a rounded posterior and tapering caudal processes. Myxospore bodies are 9.6-12.3 (mean 11.2) µm long and 4.0-4.7 (mean 4.3) µm wide. Polar capsules are pyriform, elongate, 4.5-5.2 (4.7) µm long and 1.3-1.6 (1.4) µm wide, with a characteristic neck-like structure at the apical end. Sequence generated for the 18S small subunit rRNA gene did not directly match any sequences available on GenBank, but demonstrated 91% nucleotide similarity to an unpublished Henneguya sp. infecting Mormyrus kannume Forsskål. Herein, the description of H. nyongensis is supplemented with new data on histopathology, molecular characterisation, and expanded host and geographical range.
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Affiliation(s)
- Justin M Stilwell
- Department of Pathology, University of Georgia, Athens, GA, 30602, USA.
| | - Natalie K Stilwell
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, University of Georgia, Athens, GA, 30602, USA
| | - Alvin C Camus
- Department of Pathology, University of Georgia, Athens, GA, 30602, USA
| | - Matt J Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Thomas G Rosser
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA
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