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Sheehy A, Shahin K, Camus A, Francis-Floyd R, Yanong R, Fogelson S, Soto E. Diagnosis of piscine francisellosis in Largemouth Bass from a public display exhibit in north-central Florida, USA. JOURNAL OF AQUATIC ANIMAL HEALTH 2023; 35:201-210. [PMID: 37965692 DOI: 10.1002/aah.10197] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/19/2023] [Accepted: 07/31/2023] [Indexed: 11/16/2023]
Abstract
OBJECTIVE The Largemouth Bass Micropterus salmoides is an important freshwater fish that is native to the southeastern United States and is cultured for conservation, food, and for the sports fishing industry. Francisella orientalis is a globally distributed bacterial pathogen of warmwater fish species and is associated with granulomatous inflammation and high mortalities. Outbreaks of piscine francisellosis in the United States have been reported in only a few fish species. This study describes three case presentations of francisellosis in Largemouth Bass from a public display system in north-central Florida. Additionally, laboratory-controlled immersion challenges using an F. orientalis isolate from tilapia Oreochromis spp. evaluate susceptibility of Largemouth Bass fingerlings to F. orientalis infection and mortality through this exposure route. METHODS Necropsy, histologic examination, immunohistochemistry, bacterial recovery and culture, and quantitative polymerase chain reaction were used as diagnostic tools to evaluate both the affected display fish and the immersion-challenged fingerlings. RESULT Although the display fish and immersion-challenged fingerlings presented with nonspecific clinical signs, gross and histological changes were indicative of granulomatous disease. Immunohistochemical and molecular testing methods confirmed F. orientalis infection in affected fish. CONCLUSION The three case presentations described here mark the first reporting of naturally occurring piscine francisellosis in Largemouth Bass that were held in a public display exhibit. Additionally, causality was proven in the Largemouth Bass fingerlings through the immersion challenges. These findings demonstrate susceptibility through immersion-based exposure and assert that francisellosis should be considered among the list of differential diagnoses for Largemouth Bass with granulomatous disease.
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Affiliation(s)
- Amanda Sheehy
- Aquatic Animal Health Program, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Khalid Shahin
- Aquatic Animal Diseases Laboratory, National Institute of Oceanography and Fisheries, Cairo, Egypt
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, USA
| | - Alvin Camus
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Ruth Francis-Floyd
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Roy Yanong
- Tropical Aquaculture Laboratory, Program in Fisheries and Aquatic Sciences, School of Forest, Fisheries, and Geomatics Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, Florida, USA
| | | | - Esteban Soto
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, USA
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A panoptic review of techniques for finfish disease diagnosis: The status quo and future perspectives. J Microbiol Methods 2022; 196:106477. [DOI: 10.1016/j.mimet.2022.106477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/21/2022] [Accepted: 04/21/2022] [Indexed: 12/27/2022]
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3
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Chang CT, Benedict S, Whipps CM. Transmission of Mycobacterium chelonae and Mycobacterium marinum in laboratory zebrafish through live feeds. JOURNAL OF FISH DISEASES 2019; 36:681-4. [PMID: 31418901 DOI: 10.1111/jfd.12071] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 11/14/2012] [Indexed: 05/04/2023]
Abstract
The zebrafish (Danio rerio) is a popular vertebrate model organism used in a wide range of research fields. Mycobacteriosis, caused by Mycobacterium species, is particularly concerning because it is a common disease associated with chronic infections in these fish. Infections are also a source of uncontrolled experimental variance that may influence research results. Live feeds for zebrafish are common and include paramecia (Paramecium caudatum), brine shrimp (Artemia franciscana) and rotifers (Branchionus spp.). Although nutritionally beneficial, live feeds may pose a biosecurity risk. In this study, we investigate transmission of Mycobacterium chelonae and Mycobacterium marinum through these three live feeds. We show that all three live feeds ingest both M. marinum and M. chelonae and can transmit mycobacterial infections to zebrafish. This observation emphasizes the need for live feeds to be included in the consideration of potential biosecurity risks. This study is of importance to other beyond the zebrafish community, including those of additional aquatic models and those using live feeds for other types of aquaculture.
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Affiliation(s)
- Carolyn T Chang
- Department of Environment and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, New York
| | - Samuel Benedict
- Department of Environment and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, New York
| | - Christopher M Whipps
- Department of Environment and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, New York
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Pereira FL, Tavares GC, de Carvalho AF, Rosa JCC, Rezende CP, Leal CAG, Figueiredo HCP. Effects of temperature changes in the transcriptional profile of the emerging fish pathogen Francisella noatunensis subsp. orientalis. Microb Pathog 2019; 133:103548. [PMID: 31112771 DOI: 10.1016/j.micpath.2019.103548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 01/05/2023]
Abstract
One of the major challenges in Nile tilapia (Oreochromis niloticus L.) farming is the occurrence of bacterial infections, and the Francisella noatunensis subsp. orientalis (FNO) is an important pathogen that has emerged in last decades. Francisellosis outbreaks have been reported in the literature as occurring seasonally when water temperature is below 24 °C. The aim of this study was to quantify the median lethal doses (LD50) of FNO in experimental challenges at 28 °C and 22 °C, and to investigate the impact of temperature changes in whole genome expression using microarray technology. The LD50 for Nile tilapia at 28 °C was ∼105.7, whereas at 22 °C, the LD50 was ∼102.2, showing that the decrease in temperature enhanced disease outcome. Out of 1917 genes screened, a total of 31 and 19 genes were down- and up-regulated at 22 °C, respectively. These genes were grouped by orthology into functional categories of: amino acid, inorganic ion, and carbohydrate transport and metabolism; transcription; and posttranslational modification, protein turnover, and chaperones. Expression of genes related to metabolism, oxidative stress, and thermal shock were regulated by temperature changes, reflecting an ability of FNO to adapt to the environment. Expression of virulence genes usually required for the Francisella genus was not changed between tested temperatures, including that of genes located on the Francisella Pathogenicity Island.
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Affiliation(s)
- Felipe Luiz Pereira
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Guilherme Campos Tavares
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Alex Fiorini de Carvalho
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Júlio César Camara Rosa
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Cristiana Perdigão Rezende
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Carlos Augusto Gomes Leal
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil.
| | - Henrique César Pereira Figueiredo
- AQUACEN, National Reference Laboratory for Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Federal University of Minas Gerais, Brazil. http://www.vet.ufmg.br/
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Shahin K, Gustavo Ramirez-Paredes J, Harold G, Lopez-Jimena B, Adams A, Weidmann M. Development of a recombinase polymerase amplification assay for rapid detection of Francisella noatunensis subsp. orientalis. PLoS One 2018; 13:e0192979. [PMID: 29444148 PMCID: PMC5812721 DOI: 10.1371/journal.pone.0192979] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/01/2018] [Indexed: 11/18/2022] Open
Abstract
Francisella noatunensis subsp. orientalis (Fno) is the causative agent of piscine francisellosis in warm water fish including tilapia. The disease induces chronic granulomatous inflammation with high morbidity and can result in high mortality. Early and accurate detection of Fno is crucial to set appropriate outbreak control measures in tilapia farms. Laboratory detection of Fno mainly depends on bacterial culture and molecular techniques. Recombinase polymerase amplification (RPA) is a novel isothermal technology that has been widely used for the molecular diagnosis of various infectious diseases. In this study, a recombinase polymerase amplification (RPA) assay for rapid detection of Fno was developed and validated. The RPA reaction was performed at a constant temperature of 42°C for 20 min. The RPA assay was performed using a quantitative plasmid standard containing a unique Fno gene sequence. Validation of the assay was performed not only by using DNA from Fno, closely related Francisella species and other common bacterial pathogens in tilapia farms, but also by screening 78 Nile tilapia and 5 water samples. All results were compared with those obtained by previously established real-time qPCR. The developed RPA showed high specificity in detection of Fno with no cross-detection of either the closely related Francisella spp. or the other tested bacteria. The Fno-RPA performance was highly comparable to the published qPCR with detection limits at 15 and 11 DNA molecules detected, respectively. The RPA gave quicker results in approximately 6 min in contrast to the qPCR that needed about 90 min to reach the same detection limit, taking only 2.7–3 min to determine Fno in clinical samples. Moreover, RPA was more tolerant to reaction inhibitors than qPCR when tested with field samples. The fast reaction, simplicity, cost-effectiveness, sensitivity and specificity make the RPA an attractive diagnostic tool that will contribute to controlling the infection through prompt on-site detection of Fno.
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Affiliation(s)
- Khalid Shahin
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
- Aquatic Animal Diseases Lab, Division of Aquaculture, National Institute of Oceanography and Fisheries, Suez, Egypt
- * E-mail:
| | - Jose Gustavo Ramirez-Paredes
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Graham Harold
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Benjamin Lopez-Jimena
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Alexandra Adams
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
| | - Manfred Weidmann
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, United Kingdom
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Sebastião FA, Pilarski F, Kearney MT, Soto E. Molecular detection of Francisella noatunensis subsp. orientalis in cultured Nile tilapia (Oreochromis niloticus L.) in three Brazilian states. JOURNAL OF FISH DISEASES 2017; 40:1731-1735. [PMID: 28449216 DOI: 10.1111/jfd.12636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/21/2017] [Accepted: 02/22/2017] [Indexed: 06/07/2023]
Affiliation(s)
- F A Sebastião
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA
- Centro de Aquicultura da UNESP, Univ Estadual Paulista, Jaboticabal, SP, Brazil
| | - F Pilarski
- Centro de Aquicultura da UNESP, Univ Estadual Paulista, Jaboticabal, SP, Brazil
| | - M T Kearney
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - E Soto
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA
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Assis GBN, de Oliveira TF, Gardner IA, Figueiredo HCP, Leal CAG. Sensitivity and specificity of real-time PCR and bacteriological culture for francisellosis in farm-raised Nile tilapia (Oreochromis niloticus L.). JOURNAL OF FISH DISEASES 2017; 40:785-795. [PMID: 27670740 DOI: 10.1111/jfd.12559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 06/06/2023]
Abstract
Despite the worldwide occurrence of Francisella noatunensis subsp. orientalis (Fno) infection in farmed tilapia, sensitivity and specificity estimates of commonly used diagnostic tests have not been reported. This study aimed to estimate the sensitivity and specificity of bacteriological culture and qPCR to detect Fno infection. We tested 559 fish, sampled from four farms with different epidemiological scenarios: (i) healthy fish in a hatchery free of Fno; (ii) targeted sampling of diseased fish with suggestive external clinical signs of francisellosis during an outbreak; (iii) convenience sampling of diseased and clinically healthy fish during an outbreak; and (iv) sampling of healthy fish in a cage farm without a history of outbreaks, but with francisellosis reported in other farms in the same reservoir. The qPCR had higher median sensitivity (range, 48.8-99.5%) than culture (range, 1.6-74.4%). Culture had a substantially lower median sensitivity (1.6%) than qPCR (48.8%) to detect Fno in carrier tilapia (farm 4). Median specificity estimates for both tests were >99.2%. The qPCR is the superior test for use in surveillance and monitoring programmes for francisellosis in farmed Nile tilapia, but both tests have high sensitivity and specificity which make them fit for use in the diagnosis of Fno outbreaks.
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Affiliation(s)
- G B N Assis
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - T F de Oliveira
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - I A Gardner
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - H C P Figueiredo
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - C A G Leal
- AQUAVET, Laboratory of Aquatic Animal Diseases, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
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Lewisch E, Menanteau-Ledouble S, Tichy A, El-Matbouli M. Susceptibility of common carp and sunfish to a strain of Francisella noatunensis subsp. orientalis in a challenge experiment. DISEASES OF AQUATIC ORGANISMS 2016; 121:161-166. [PMID: 27667813 DOI: 10.3354/dao03044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Francisellosis, an emerging disease in many fish species, can cause high mortality in affected populations. Here we investigated the susceptibility of common carp Cyprinus carpio and sunfish Lepomis gibbosus to Francisella noatunensis subsp. orientalis (Fno), and possible transmission of the bacteria between the 2 fish species. In a challenge experiment, 3 groups of each species were injected intraperitoneally (IP) with 3 different doses of an Fno strain no. 9449 of the Norwegian Veterinary Institute, recovered from naturally infected ornamental Malawi cichlids. Infected carp were cohabitated with sunfish and vice versa. Control groups were injected with 0.9M phosphate-buffered saline and cohabitated accordingly. Fish were sampled at different time points. Mortality of challenged sunfish was observed during the first 96 h and reached 56.1%. In the control sunfish, 4 of 16 fish (25%) died within 48 h. In carp, no mortalities or clinical signs were observed during the experiment. General clinical and patho-anatomical disease signs of affected sunfish were observed. We detected granulomas in 2 cohabitated sunfish and 1 challenged carp, but could not re-isolate Fno from these fish. Fno was successfully cultured from 6 sunfish and 3 carp specimens until 35 d post injection. PCR of spleen and kidney with 16S rDNA Francisella-like bacterium primers 180f and 485r yielded amplicons in 68.3% of challenged sunfish and only 12.2% of challenged carp. We demonstrated that sunfish were susceptible to Fno infection while the carp were not. Horizontal transmission of the agent between the 2 fish species could not be demonstrated.
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Affiliation(s)
- E Lewisch
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210 Vienna, Austria
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Dong HT, Gangnonngiw W, Phiwsaiya K, Charoensapsri W, Nguyen VV, Nilsen P, Pradeep PJ, Withyachumnarnkul B, Senapin S, Rodkhum C. Duplex PCR assay and in situ hybridization for detection of Francisella spp. and Francisella noatunensis subsp. orientalis in red tilapia. DISEASES OF AQUATIC ORGANISMS 2016; 120:39-47. [PMID: 27304869 DOI: 10.3354/dao03021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Conventional isolation and identification based on phenotypic characteristics is challenging with the highly fastidious, intracellular bacterium Francisella noatunensis subsp. orientalis (Fno). Here, we developed a duplex PCR method for simultaneous detection of the Francisella genus and Fno in one PCR reaction and an in situ hybridization method for paraffin section based diagnosis of Fno. The PCR results showed genus- and species-specific bands (1140 and 203 bp) from Fno but only one genus-specific band (1140 bp) from F. noatunensis subsp. noatunensis. Sensitivity of the duplex PCR assay revealed a detection limit of 20 to 200 fg genomic DNA (~10 to 100 genome equivalents) depending on DNA template extraction methods. The newly developed duplex PCR assay could be used to detect Fno from clinically sick fish exhibiting signs of visceral granulomas and would also be able to detect Fno infection in naturally diseased fish without symptoms of francisellosis, indicating potential application for diagnosis of field samples. The in situ hybridization assay using Fno species-specific probe revealed positive signals in multiple organs including the spleen, liver, kidney, gills and intestine of infected fish.
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Affiliation(s)
- Ha T Dong
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
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Gonçalves LA, de Castro Soares S, Pereira FL, Dorella FA, de Carvalho AF, de Freitas Almeida GM, Leal CAG, Azevedo V, Figueiredo HCP. Complete genome sequences of Francisella noatunensis subsp. orientalis strains FNO12, FNO24 and FNO190: a fish pathogen with genomic clonal behavior. Stand Genomic Sci 2016; 11:30. [PMID: 27073591 PMCID: PMC4828924 DOI: 10.1186/s40793-016-0151-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 04/05/2016] [Indexed: 11/10/2022] Open
Abstract
The genus Francisella is composed of Gram-negative, pleomorphic, strictly aerobic and non-motile bacteria, which are capable of infecting a variety of terrestrial and aquatic animals, among which Francisella noatunensis subsp. orientalis stands out as the causative agent of pyogranulomatous and granulomatous infections in fish. Accordingly, F. noatunensis subsp. orientalis is responsible for high mortality rates in freshwater fish, especially Nile Tilapia. In the current study, we present the genome sequences of F. noatunensis subsp. orientalis strains FNO12, FNO24 and FNO190. The genomes include one circular chromosome of 1,859,720 bp, consisting of 32 % GC content, 1538 coded proteins and 363 pseudogenes for FNO12; one circular chromosome of 1,862,322 bp, consisting of 32 % GC content, 1537 coded proteins and 365 pseudogenes for FNO24; and one circular chromosome of 1,859,595 bp, consisting of 32 % GC content, 1539 coded proteins and 362 pseudogenes for FNO190. All genomes have similar genetic content, implicating a clonal-like behavior for this species.
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Affiliation(s)
- Lucas Amorim Gonçalves
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil ; Laboratory of Cellular and Molecular Genetics (LGCM), Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Siomar de Castro Soares
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Felipe Luiz Pereira
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fernanda Alves Dorella
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Alex Fiorini de Carvalho
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Gabriel Magno de Freitas Almeida
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Carlos Augusto Gomes Leal
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Vasco Azevedo
- Laboratory of Cellular and Molecular Genetics (LGCM), Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Henrique César Pereira Figueiredo
- National Reference Laboratory for Aquatic Animal Diseases (AQUACEN), Ministry of Fisheries and Aquaculture, Federal University of Minas Gerais, Belo Horizonte, Brazil
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Whole-Genome Sequence of Francisella noatunensis subsp. orientalis Strain FNO01 Isolated from Diseased Nile Tilapia in Brazil. GENOME ANNOUNCEMENTS 2016; 4:4/1/e01603-15. [PMID: 26798105 PMCID: PMC4722272 DOI: 10.1128/genomea.01603-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This paper describes the complete genome sequence of Francisella noatunensis subsp. orientalis strain FNO01, which was isolated during the first outbreak of francisellosis in cultured Nile tilapia in Brazil. The genome is composed of a circular chromosome with 1,859,830 bp and a G+C content of ~32%.
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Soto E, McGovern-Hopkins K, Klinger-Bowen R, Fox BK, Brock J, Antonio N, Waal ZVD, Rushton S, Mill A, Tamaru CS. Prevalence of Francisella noatunensis subsp. orientalis in cultured tilapia on the island of Oahu, Hawaii. JOURNAL OF AQUATIC ANIMAL HEALTH 2013; 25:104-109. [PMID: 23639074 DOI: 10.1080/08997659.2013.781554] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Francisellosis is an emergent disease in cultured and wild aquatic animals. The causative agent, Francisella noatunensis subsp. orientalis (Fno), is a gram-negative bacterium recognized as one of the most virulent pathogens of warmwater fish. The main objective of this project was to investigate the prevalence of Fno in cultured tilapia (specifically, Mozambique Tilapia Oreochromis mossambicus, Koilapia [also known as Wami Tilapia] O. hornorum, Blue Tilapia O. aureus, and Nile Tilapia O. niloticus hybrids) on the island of Oahu, Hawaii, using conventional and real-time PCR assays followed by statistical modeling to compare the different diagnostic methods and identify potential risk factors. During 2010 and 2012, 827 fish were collected from different geographical locations throughout the island of Oahu. Upon collection of fish, the water temperature in the rearing system and the length of individual fish were measured. Extraction of DNA from different tissues collected aseptically during necropsy served as a template for molecular diagnosis. High correlation between both molecular methods was observed. Moreover, the bacterium was isolated from infected tilapia on selective media and confirmed to be Fno utilizing a species-specific Taqman-based real-time PCR assay. Although a direct comparison of the prevalence of Fno between the different geographical areas was not possible, the results indicate a high prevalence of Fno DNA in cultured tilapia throughout the farm sites located on Oahu. Of the different tilapia species and hybrids currently cultured in Hawaii, Mozambique Tilapia were more susceptible to infection than Koilapia. Water temperature in the rearing systems and fish size also had a strong effect on the predicted level of infection, with fish held at lower temperatures and smaller fish being more susceptible to piscine francisellosis.
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Affiliation(s)
- Esteban Soto
- Department of Pathobiology, Ross University, Basseterre, St. Kitts, West Indies.
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