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Kelly AM, Renukdas N, Barnett LM, Beck BH, Abdelrahman HA, Roy LA. The Use of Kaolin as a Prophylactic Treatment to Prevent Columnaris Disease ( Flavobacterium covae) in Commercial Baitfish and Sportfish Species. Vet Sci 2023; 10:441. [PMID: 37505846 PMCID: PMC10385048 DOI: 10.3390/vetsci10070441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 07/01/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023] Open
Abstract
Aquaculture farms in Arkansas, USA routinely battle columnaris disease caused by Flavobacterium covae. Columnaris is prevalent during stressful events such as feed training and when fish are stocked at high densities in holding vats before sale. Kaolin clay was effective in laboratory trials as a treatment for columnaris in catfish. As a result, fish farmers are interested in applying kaolin products but were hesitant as they feared that the high doses of kaolin clay in vats might negatively affect the gills and overall health of fish. Therefore, we evaluated potential clay concentrations that might be used to prophylactically treat fish in vats. The effects of low to excessively high doses (0, 1, 2, 4, or 8 g/L) of kaolin clay (AkuaProTM, Imerys, GA, USA) were evaluated using a 72 h bioassay conducted in static tanks using Micropterus salmoides, Pomoxis nigromaculatus, Lepomis macrochirus, Ictalurus punctatus, Notemigonus crysoleucas, and Pimephales promelas. Results of these trials revealed a 100% survival rate across all six fish species exposed to kaolin clay at concentrations of up to 8 g/L for 48 h (followed by a 24 h recovery period in clean water) with no adverse effects to eyes, skin, gastrointestinal tract, or liver histology noted at any treatment. In addition, Micropterus salmoides analyzed for heavy metals due to exposure to the clay indicated that concentrations did not differ from control fish.
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Affiliation(s)
- Anita M Kelly
- Alabama Fish Farming Center, School of Fisheries, Aquaculture & Aquatic Sciences, Auburn University, 529 Centreville Street, Greensboro, AL 36744, USA
| | - Nilima Renukdas
- UAPB Fish Health Services, University of Arkansas at Pine Bluff, 2001 Hwy 70 East, Lonoke, AR 72086, USA
| | - Louis Matthew Barnett
- Stuttgart National Aquaculture Research Center, USDA-Agricultural Research Service, 2955 Hwy 130 East, Stuttgart, AR 72160, USA
| | - Benjamin H Beck
- Aquatic Animal Health Research Unit, USDA-Agricultural Research Service, 990 Wire Road, Auburn, AL 36832, USA
| | - Hisham A Abdelrahman
- Alabama Fish Farming Center, School of Fisheries, Aquaculture & Aquatic Sciences, Auburn University, 529 Centreville Street, Greensboro, AL 36744, USA
- Department of Veterinary Hygiene and Management, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt
| | - Luke A Roy
- Alabama Fish Farming Center, School of Fisheries, Aquaculture & Aquatic Sciences, Auburn University, 529 Centreville Street, Greensboro, AL 36744, USA
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Jin Y, Bergmann SM, Mai Q, Yang Y, Liu W, Sun D, Chen Y, Yu Y, Liu Y, Cai W, Dong H, Li H, Yu H, Wu Y, Lai M, Zeng W. Simultaneous Isolation and Identification of Largemouth Bass Virus and Rhabdovirus from Moribund Largemouth Bass ( Micropterus salmoides). Viruses 2022; 14:v14081643. [PMID: 36016264 PMCID: PMC9415833 DOI: 10.3390/v14081643] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 02/04/2023] Open
Abstract
Largemouth bass is an important commercially farmed fish in China, but the rapid expansion of its breeding has resulted in increased incidence of diseases caused by bacteria, viruses and parasites. In this study, moribund largemouth bass containing ulcer foci on body surfaces indicated the most likely pathogens were iridovirus and rhabdovirus members and this was confirmed using a combination of immunohistochemistry, cell culture, electron microscopy and conserved gene sequence analysis. We identified that these fish had been co-infected with these viruses. We observed bullet-shaped virions (100−140 nm long and 50−100 nm in diameter) along with hexagonal virions with 140 nm diameters in cell culture inoculated with tissue homogenates. The viruses were plaque purified and a comparison of the highly conserved regions of the genome of these viruses indicated that they are most similar to largemouth bass virus (LMBV) and hybrid snakehead rhabdovirus (HSHRV), respectively. Regression infection experiments indicated fish mortalities for LMBV-FS2021 and HSHRV-MS2021 were 86.7 and 11.1%, respectively. While co-infection resulted in 93.3% mortality that was significantly (p < 0.05) higher than the single infections even though the viral loads differed by >100-fold. Overall, we simultaneously isolated and identified LMBV and a HSHRV-like virus from diseased largemouth bass, and our results can provide novel ideas for the prevention and treatment of combined virus infection especially in largemouth bass.
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Affiliation(s)
- Yuqi Jin
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Sven M. Bergmann
- Institute of Infectology, Friedrich-Loffler-Institut (FLI), Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-InselRiems, Germany;
| | - Qianyi Mai
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Ying Yang
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Weiqiang Liu
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Dongli Sun
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Yanfeng Chen
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Yingying Yu
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Yuhong Liu
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Wenlong Cai
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong 999077, China;
| | - Hanxu Dong
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Hua Li
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Hui Yu
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
| | - Yali Wu
- Foshan Institute of Agricultural Sciences, Guangdong, Foshan 528145, China; (Y.W.); (M.L.)
| | - Mingjian Lai
- Foshan Institute of Agricultural Sciences, Guangdong, Foshan 528145, China; (Y.W.); (M.L.)
| | - Weiwei Zeng
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528231, China; (Y.J.); (Q.M.); (Y.Y.); (W.L.); (D.S.); (Y.C.); (Y.Y.); (Y.L.); (H.D.); (H.L.); (H.Y.)
- Correspondence: ; Tel.: +86-(0757)-83962672
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LaFrentz BR, Králová S, Burbick CR, Alexander TL, Phillips CW, Griffin MJ, Waldbieser GC, García JC, de Alexandre Sebastião F, Soto E, Loch TP, Liles MR, Snekvik KR. The fish pathogen Flavobacterium columnare represents four distinct species: Flavobacterium columnare, Flavobacterium covae sp. nov., Flavobacterium davisii sp. nov. and Flavobacterium oreochromis sp. nov., and emended description of Flavobacterium columnare. Syst Appl Microbiol 2021; 45:126293. [PMID: 35026686 DOI: 10.1016/j.syapm.2021.126293] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/03/2021] [Accepted: 12/17/2021] [Indexed: 01/09/2023]
Abstract
Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish and four discrete genetic groups exist within the species, suggesting that the species designation requires revision. The present study determined the taxonomic status of the four genetic groups of F. columnare using polyphasic and phylogenomic approaches and included five representative isolates from each genetic group (including type strain ATCC 23463T; genetic group 1). 16S rRNA gene sequence analysis revealed genetic group 2 isolate AL-02-36T, genetic group 3 isolate 90-106T, and genetic group 4 isolate Costa Rica 04-02-TNT shared less than <98.8 % sequence identity to F. columnare ATCC 23463T. Phylogenetic analyses of 16S rRNA and gyrB genes using different methodologies demonstrated the four genetic groups formed well-supported and distinct clades within the genus Flavobacterium. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (GGDC) values between F. columnare ATCC 23463T, genetic group 2 isolate AL-02-36T, genetic group 3 isolate 90-106T, and genetic group 4 isolate Costa Rica 04-02-TNT were less than 90.84% and 42.7%, respectively. Biochemical and physiological characteristics were similar among the four genetic groups; however, quantitative differences in fatty acid profiles were detected and MALDI-TOF analyses demonstrated numerous distinguishing peaks unique to each genetic group. Chemotaxonomic, MALDI-TOF characterization and ANI/GGDC calculations afforded differentiation between the genetic groups, indicating each group is a discrete species. Herein, the names F. covae sp. nov. (AL-02-36T), F. davisii sp. nov. (90-106T), and F. oreochromis sp. nov. (Costa Rica 04-02-TNT) are proposed to represent genetic groups 2, 3, and 4, respectively.
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Affiliation(s)
- Benjamin R LaFrentz
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service (USDA-ARS), Auburn, AL, United States.
| | - Stanislava Králová
- Department of Experimental Biology, Czech Collection of Microorganisms, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic; Department of Biological Sciences, Auburn University, Auburn, AL, United States
| | - Claire R Burbick
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
| | - Trevor L Alexander
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States
| | - Conner W Phillips
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States
| | - Matt J Griffin
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Stoneville, MS, United States
| | - Geoffrey C Waldbieser
- Warmwater Aquaculture Research Unit, USDA-ARS, Thad Cochran National Warmwater Aquaculture Center, Stoneville, MS, United States
| | - Julio C García
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service (USDA-ARS), Auburn, AL, United States
| | | | - Esteban Soto
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, United States
| | - 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, United States
| | - Mark R Liles
- Department of Biological Sciences, Auburn University, Auburn, AL, United States
| | - Kevin R Snekvik
- Washington Animal Disease Diagnostic Laboratory, Pullman, WA, United States; Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
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Sebastião FD, Shahin K, Heckman TI, LaFrentz BR, Griffin MJ, Loch TP, Mukkatira K, Veek T, Richey C, Adkison M, Holt RA, Soto E. Genetic characterization of Flavobacterium columnare isolates from the Pacific Northwest, USA. DISEASES OF AQUATIC ORGANISMS 2021; 144:151-158. [PMID: 33955853 DOI: 10.3354/dao03588] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Flavobacterium columnare is the causative agent of columnaris disease. Previous work has demonstrated a high degree of genetic variability among F. columnare isolates, identifying 4 genetic groups (GGs) with some host associations. Herein, a total of 49 F. columnare isolates were characterized, the majority of which were collected from 15 different locations throughout the US Pacific Northwest. Most isolates were collected from 2015-2018 and originated from disease outbreaks in salmonid hatcheries and rearing ponds, sturgeon hatcheries and ornamental fish. Other isolates were part of collections recovered from 1980-2018. Initial identification was confirmed by F. columnare species-specific qPCR. Study isolates were further characterized using a multiplex PCR that differentiates between the 4 currently recognized F. columnare GGs. Multiplex PCR results were supported by repetitive sequence-mediated PCR fingerprinting and gyrB sequence analysis. F. columnare GG1 was the most prevalent (83.7%, n = 41/49), represented by isolates from salmonids (n = 32), white sturgeon (n = 2), channel catfish (n = 1), ornamental goldfish (n = 1), koi (n = 3), wild sunfish (n = 1) and 1 unknown host. Six isolates (12.2%, n = 6/49) were identified as GG3, which were cultured from rainbow trout (n = 3) and steelhead trout (n = 3). Two isolates were identified as GG2 (4.1%, n = 2/49) and were from ornamental fish. No GG4 isolates were cultured in this study. The biological significance of this genetic variability remains unclear, but this variation could have significant implications for fish health management. The results from this study provide baseline data for future work developing strategies to ameliorate columnaris-related losses in the US Pacific Northwest.
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Affiliation(s)
- Fernanda de Sebastião
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, California 95616, USA
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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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Lavrinenko IV, Shulga LV, Peredera OO, Zhernosik IA. Analysis of the treatment regimen efficacy for columnaris disease in Pterophyllum scalare. REGULATORY MECHANISMS IN BIOSYSTEMS 2020. [DOI: 10.15421/022033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The article presents the results of studies on the treatment scheme efficacy for columnaris in Pterophyllum scalare, common under private aquarium husbandry conditions. To establish the diagnosis, the clinical features of the diseased fish, pathological and anatomical changes and the results of microscopic and microbiological studies were taken into account. Separate chemical and microbiological parameters of aquarium water were also studied. It was established that fish disease developed against the background of adverse changes in the chemical composition and microbiocenosis of aquarium water. High alkalinity and excess of phosphates compared to the norm provoked accumulation of opportunistic microbiota, resulting in a balance disorder in the parasite-host system and development of clinical manifestation of the fish disease. During the disease outbreak, bacteriological indices of water indicated a high level of organic contamination and a low intensity of water self-purification processes. Clinically, the disease was manifested in P. scalare by decrease in appetite and motor activity, onset of ulcerative lesions of various shapes and sizes on the surface of the body and on the gill covers. Selected pure cultures of Flavobacterium columnare showed sensitivity to enrofloxacin (growth retardation zone 31.3 ± 1.0 mm); moderate resistance was found to tylosin. The microorganisms were resistant to amoxicillin, doxycycline, benzylpenicillin and tetracycline. Microscopic studies of intestinal specimens of dead P. scalare revealed numerous motile flagellates. It has been shown that an effective treatment regimen that provides recovery for 70% of diseased P. scalare is the use of enroxil 10% solution for five days, metronidazole three times a day, and “API MelaFix” for seven days. It is proved that the following measures are effective to restore the disrupted hydro-balance: periodic water replacement in the amount of 20% of the total volume, providing the aquarium with active aeration systems, planting slow-growing plants and reducing the amount of fish food provided. The measures developed were efficient, they led to elimination of the outbreak of columnaris in the P. scalare and to restoration of biological equilibrium in a closed aquatic ecosystem.
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LaFrentz BR, García JC, Shelley JP. Multiplex PCR for genotyping Flavobacterium columnare. JOURNAL OF FISH DISEASES 2019; 42:1531-1542. [PMID: 31469439 DOI: 10.1111/jfd.13068] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 06/10/2023]
Abstract
Recent research has identified four distinct genetic groups among isolates of Flavobacterium columnare through multilocus phylogenetic analyses; however, there are no quick methods to determine the genotype of an isolate. The objective of this research was to develop a multiplex PCR to rapidly genotype F. columnare to genetic group. Comparative bacterial genomics was used to identify regions in the genomes unique to each genetic group, and primers were designed to specifically amplify different sized amplicons for each genetic group. The optimized assay was demonstrated to be specific for each genetic group and F. columnare, and no specific amplicons were generated using gDNA from a panel of other Flavobacterium spp. and bacterial fish pathogens. The analytical sensitivity of the assay ranged from 209 to 883 genome equivalents depending on the genetic group. The multiplex PCR was evaluated by genotyping a panel of 22 unknown F. columnare isolates and performing DNA sequencing of the dnaK gene in parallel. The results demonstrated 100% accordance between multiplex PCR results and assignment to genetic group via phylogenetic analysis. The multiplex PCR provides a useful tool for assigning an unknown isolate to genetic group and may be used to determine which genetic groups of F. columnare are circulating and most predominant in different aquaculture industries.
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Affiliation(s)
- Benjamin R LaFrentz
- Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA
| | - Julio C García
- Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA
| | - John P Shelley
- Aquatic Animal Health Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Auburn, AL, USA
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LaFrentz BR, García JC, Waldbieser GC, Evenhuis JP, Loch TP, Liles MR, Wong FS, Chang SF. Identification of Four Distinct Phylogenetic Groups in Flavobacterium columnare With Fish Host Associations. Front Microbiol 2018; 9:452. [PMID: 29593693 PMCID: PMC5859164 DOI: 10.3389/fmicb.2018.00452] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/27/2018] [Indexed: 12/04/2022] Open
Abstract
Columnaris disease, caused by the Gram-negative bacterium Flavobacterium columnare, is one of the most prevalent fish diseases worldwide. An exceptionally high level of genetic diversity among isolates of F. columnare has long been recognized, whereby six established genomovars have been described to date. However, little has been done to quantify or characterize this diversity further in a systematic fashion. The objective of this research was to perform phylogenetic analyses of 16S rRNA and housekeeping gene sequences to decipher the genetic diversity of F. columnare. Fifty isolates and/or genomes of F. columnare, originating from diverse years, geographic locations, fish hosts, and representative of the six genomovars were analyzed in this study. A multilocus phylogenetic analysis (MLPA) of the 16S rRNA and six housekeeping genes supported four distinct F. columnare genetic groups. There were associations between genomovar and genetic group, but these relationships were imperfect indicating that genomovar assignment does not accurately reflect F. columnare genetic diversity. To expand the dataset, an additional 90 16S rRNA gene sequences were retrieved from GenBank and a phylogenetic analysis of this larger dataset also supported the establishment of four genetic groups. Examination of isolate historical data indicated biological relevance to the identified genetic diversity, with some genetic groups isolated preferentially from specific fish species or families. It is proposed that F. columnare isolates be assigned to the four genetic groups defined in this study rather than genomovar in order to facilitate a standard nomenclature across the scientific community. An increased understanding of which genetic groups are most prevalent in different regions and/or aquaculture industries may allow for the development of improved targeted control and treatment measures for columnaris disease.
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Affiliation(s)
- Benjamin R LaFrentz
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service, Auburn, AL, United States
| | - Julio C García
- Aquatic Animal Health Research Unit, United States Department of Agriculture - Agricultural Research Service, Auburn, AL, United States
| | - Geoffrey C Waldbieser
- Warmwater Aquaculture Research Unit, Thad Cochran National Warmwater Aquaculture Center, United States Department of Agriculture - Agricultural Research Service, Stoneville, MS, United States
| | - Jason P Evenhuis
- National Center for Cool and Cold Water Aquaculture, United States Department of Agriculture - Agricultural Research Service, Kearneysville, WV, United States
| | - Thomas P Loch
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Mark R Liles
- Department of Biological Sciences, Auburn University, Auburn, AL, United States
| | - Fong S Wong
- MSD Animal Health Innovation Pte. Ltd., Singapore, Singapore
| | - Siow F Chang
- MSD Animal Health Innovation Pte. Ltd., Singapore, Singapore
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Laboratory investigation into the role of largemouth bass virus (Ranavirus, Iridoviridae) in smallmouth bass mortality events in Pennsylvania rivers. BMC Vet Res 2018; 14:62. [PMID: 29499725 PMCID: PMC5834888 DOI: 10.1186/s12917-018-1371-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 02/14/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mortality episodes have affected young-of-year smallmouth bass (Micropterus dolomieu) in several river systems in Pennsylvania since 2005. A series of laboratory experiments were performed to determine the potential role of largemouth bass virus (Ranavirus, Iridoviridae) in causing these events. RESULTS Juvenile smallmouth bass experimentally infected with the largemouth bass virus exhibited internal and external clinical signs and mortality consistent with those observed during die-offs. Microscopically, infected fish developed multifocal necrosis in the mesenteric fat, liver, spleen and kidneys. Fish challenged by immersion also developed severe ulcerative dermatitis and necrotizing myositis and rarely panuveitis and keratitis. Largemouth bass virus-challenged smallmouth bass experienced greater mortality at 28 °C than at 23 or 11 °C. Co-infection with Flavobacterium columnare at 28 °C resulted in significant increase in mortality of smallmouth bass previously infected with largemouth bass virus. Aeromonas salmonicida seems to be very pathogenic to fish at water temperatures < 23 °C. While co-infection of smallmouth bass by both A. salmonicida and largemouth bass virus can be devastating to juvenile smallmouth bass, the optimal temperatures of each pathogen are 7-10 °C apart, making their synergistic effects highly unlikely under field conditions. CONCLUSIONS The sum of our data generated in this study suggests that largemouth bass virus can be the causative agent of young-of-year smallmouth bass mortality episodes observed at relatively high water temperature.
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