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Vanhee M, Floré K, Vanthourenhout S, Hellemans J, Muyldermans A, Reynders M. Implementation of full-length 16S nanopore sequencing for bacterial identification in a clinical diagnostic setting. Diagn Microbiol Infect Dis 2024; 108:116156. [PMID: 38061217 DOI: 10.1016/j.diagmicrobio.2023.116156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/29/2023] [Accepted: 12/03/2023] [Indexed: 01/22/2024]
Abstract
This study describes the implementation of 16S nanopore sequencing in a diagnostic lab for pathogen identification without prior enrichment. First, the universality of the test and taxonomic resolution was evaluated for 78 clinically relevant bacteria (69 known and 9 unknown bacterial cultures). Next, the diagnostic value of the test was evaluated based on clinical samples. It was shown that 16S sequencing can be used both for identification of unknown cultures and to find bacteria directly in the clinical sample without cultivation. All culture-positive samples (n=11) tested positive with 16S sequencing directly performed on the sample, but bacteria were found as well in 15/30 culture-negative samples. Pathogenic bacteria were found in a background of commensal flora, and even complex polymicrobial infections could be unraveled. This study demonstrates the feasibility of implementing 16S nanopore sequencing in a clinical diagnostic setting and demonstrates its value for the diagnosis of culture-negative and polymicrobial infections.
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Affiliation(s)
- Merijn Vanhee
- Department of Laboratory Medicine, General Hospital Sint-Jan Brugge, Ruddershove 10, 8000, Brugge, Belgium.
| | - Katelijne Floré
- Department of Laboratory Medicine, General Hospital Sint-Jan Brugge, Ruddershove 10, 8000, Brugge, Belgium
| | - Sanne Vanthourenhout
- Department of Laboratory Medicine, General Hospital Sint-Jan Brugge, Ruddershove 10, 8000, Brugge, Belgium
| | - Jorn Hellemans
- Department of Laboratory Medicine, General Hospital Sint-Jan Brugge, Ruddershove 10, 8000, Brugge, Belgium
| | - Astrid Muyldermans
- Department of Laboratory Medicine, General Hospital Sint-Jan Brugge, Ruddershove 10, 8000, Brugge, Belgium
| | - Marijke Reynders
- Department of Laboratory Medicine, General Hospital Sint-Jan Brugge, Ruddershove 10, 8000, Brugge, Belgium
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Nevejan L, Ombelet S, Laenen L, Keyaerts E, Demuyser T, Seyler L, Soetens O, Van Nedervelde E, Naesens R, Geysels D, Verstrepen W, Cattoir L, Martens S, Michel C, Mathieu E, Reynders M, Evenepoel A, Hellemans J, Vanhee M, Magerman K, Maes J, Matheeussen V, Boogaerts H, Lagrou K, Cuypers L, André E. Severity of COVID-19 among Hospitalized Patients: Omicron Remains a Severe Threat for Immunocompromised Hosts. Viruses 2022; 14:v14122736. [PMID: 36560741 PMCID: PMC9783877 DOI: 10.3390/v14122736] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in the general population in the context of a relatively high immunity gained through the early waves of coronavirus disease 19 (COVID-19), and vaccination campaigns. Despite this context, a significant number of patients were hospitalized, and identifying the risk factors associated with severe disease in the Omicron era is critical for targeting further preventive, and curative interventions. We retrospectively analyzed the individual medical records of 1501 SARS-CoV-2 positive hospitalized patients between 13 December 2021, and 13 February 2022, in Belgium, of which 187 (12.5%) were infected with Delta, and 1036 (69.0%) with Omicron. Unvaccinated adults showed an increased risk of moderate/severe/critical/fatal COVID-19 (crude OR 1.54; 95% CI 1.09-2.16) compared to vaccinated patients, whether infected with Omicron or Delta. In adults infected with Omicron and moderate/severe/critical/fatal COVID-19 (n = 323), immunocompromised patients showed an increased risk of in-hospital mortality related to COVID-19 (adjusted OR 2.42; 95% CI 1.39-4.22), compared to non-immunocompromised patients. The upcoming impact of the pandemic will be defined by evolving viral variants, and the immune system status of the population. The observations support that, in the context of an intrinsically less virulent variant, vaccination and underlying patient immunity remain the main drivers of severe disease.
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Affiliation(s)
- Louis Nevejan
- Department of Laboratory Medicine, National Reference Center for Respiratory Pathogens, UZ Leuven—University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
- Correspondence: (L.N.); (L.C.); (E.A.)
| | - Sien Ombelet
- Department of Laboratory Medicine, National Reference Center for Respiratory Pathogens, UZ Leuven—University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Microbiology, 3000 Leuven, Belgium
| | - Lies Laenen
- Department of Laboratory Medicine, National Reference Center for Respiratory Pathogens, UZ Leuven—University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Microbiology, 3000 Leuven, Belgium
| | - Els Keyaerts
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Microbiology, 3000 Leuven, Belgium
| | - Thomas Demuyser
- Department of Microbiology and Infection Control, Vrije Universiteit Brussel (VUB), UZ Brussel—University Hospitals Brussels, 1090 Brussels, Belgium
- Center for Neurosciences, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel (VUB), 1090 Brussels, Belgium
| | - Lucie Seyler
- Department of Internal Medicine and Infectious Diseases, Vrije Universiteit Brussel (VUB), UZ Brussel—University Hospitals Brussels, 1090 Brussels, Belgium
| | - Oriane Soetens
- Department of Microbiology and Infection Control, Vrije Universiteit Brussel (VUB), UZ Brussel—University Hospitals Brussels, 1090 Brussels, Belgium
| | - Els Van Nedervelde
- Department of Internal Medicine and Infectious Diseases, Vrije Universiteit Brussel (VUB), UZ Brussel—University Hospitals Brussels, 1090 Brussels, Belgium
| | - Reinout Naesens
- Department of Medical Microbiology, Department of infection prevention and control, ZNA Middelheim, 2020 Antwerp, Belgium
| | - Dieter Geysels
- Department of Medical Microbiology, Department of infection prevention and control, ZNA Middelheim, 2020 Antwerp, Belgium
| | - Walter Verstrepen
- Department of Medical Microbiology, Department of infection prevention and control, ZNA Middelheim, 2020 Antwerp, Belgium
| | - Lien Cattoir
- Clinical Laboratory of Microbiology, OLV Hospital, 9300 Aalst, Belgium
| | - Steven Martens
- Clinical Laboratory of Microbiology, OLV Hospital, 9300 Aalst, Belgium
| | - Charlotte Michel
- Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles, Université Libre de Bruxelles, 1000 Brussels, Belgium
| | - Elise Mathieu
- Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles, Université Libre de Bruxelles, 1000 Brussels, Belgium
| | - Marijke Reynders
- Department of Laboratory Medicine—Medical Microbiology, AZ Sint Jan Brugge-Oostende, 8000 Brugge, Belgium
| | - Anton Evenepoel
- Department of Laboratory Medicine—Medical Microbiology, AZ Sint Jan Brugge-Oostende, 8000 Brugge, Belgium
| | - Jorn Hellemans
- Department of Laboratory Medicine—Medical Microbiology, AZ Sint Jan Brugge-Oostende, 8000 Brugge, Belgium
| | - Merijn Vanhee
- Department of Laboratory Medicine—Medical Microbiology, AZ Sint Jan Brugge-Oostende, 8000 Brugge, Belgium
| | - Koen Magerman
- Clinical Laboratory, Jessa Hospital, 3500 Hasselt, Belgium
| | - Justine Maes
- Clinical Laboratory, Jessa Hospital, 3500 Hasselt, Belgium
| | - Veerle Matheeussen
- Department of Microbiology, University Hospital Antwerp, 2650 Antwerp, Belgium
| | - Hélène Boogaerts
- Department of Microbiology, University Hospital Antwerp, 2650 Antwerp, Belgium
| | - Katrien Lagrou
- Department of Laboratory Medicine, National Reference Center for Respiratory Pathogens, UZ Leuven—University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Microbiology, 3000 Leuven, Belgium
| | - Lize Cuypers
- Department of Laboratory Medicine, National Reference Center for Respiratory Pathogens, UZ Leuven—University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Microbiology, 3000 Leuven, Belgium
- Correspondence: (L.N.); (L.C.); (E.A.)
| | - Emmanuel André
- Department of Laboratory Medicine, National Reference Center for Respiratory Pathogens, UZ Leuven—University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Microbiology, 3000 Leuven, Belgium
- Correspondence: (L.N.); (L.C.); (E.A.)
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3
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Cuypers L, Bode J, Beuselinck K, Laenen L, Dewaele K, Janssen R, Capron A, Lafort Y, Paridaens H, Bearzatto B, Cauchie M, Huwart A, Degosserie J, Fagnart O, Overmeire Y, Rouffiange A, Vandecandelaere I, Deffontaine M, Pilate T, Yin N, Micalessi I, Roisin S, Moons V, Reynders M, Steyaert S, Henin C, Lazarova E, Obbels D, Dufrasne FE, Pirenne H, Schepers R, Collin A, Verhasselt B, Gillet L, Jonckheere S, Van Lint P, Van den Poel B, Van der Beken Y, Stojkovic V, Garrino MG, Segers H, Vos K, Godefroid M, Pede V, Nollet F, Claes V, Verschraegen I, Bogaerts P, Van Gysel M, Leurs J, Saegeman V, Soetens O, Vanhee M, Schiettekatte G, Huyghe E, Martens S, Lemmens A, Nailis H, Laffineur K, Steensels D, Vanlaere E, Gras J, Roussel G, Gijbels K, Boudewijns M, Sion C, Achtergael W, Maurissen W, Iliano L, Chantrenne M, Vanheule G, Flies R, Hougardy N, Berth M, Verbeke V, Morent R, Vankeerberghen A, Bontems S, Kehoe K, Schallier A, Ho G, Bafort K, Raymaekers M, Pypen Y, Heinrichs A, Schuermans W, Cuigniez D, Lali SE, Drieghe S, Ory D, Le Mercier M, Van Laethem K, Thoelen I, Vandamme S, Mansoor I, Vael C, De Sloovere M, Declerck K, Dequeker E, Desmet S, Maes P, Lagrou K, André E. Nationwide Harmonization Effort for Semi-Quantitative Reporting of SARS-CoV-2 PCR Test Results in Belgium. Viruses 2022; 14:1294. [PMID: 35746765 PMCID: PMC9230955 DOI: 10.3390/v14061294] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 02/05/2023] Open
Abstract
From early 2020, a high demand for SARS-CoV-2 tests was driven by several testing indications, including asymptomatic cases, resulting in the massive roll-out of PCR assays to combat the pandemic. Considering the dynamic of viral shedding during the course of infection, the demand to report cycle threshold (Ct) values rapidly emerged. As Ct values can be affected by a number of factors, we considered that harmonization of semi-quantitative PCR results across laboratories would avoid potential divergent interpretations, particularly in the absence of clinical or serological information. A proposal to harmonize reporting of test results was drafted by the National Reference Centre (NRC) UZ/KU Leuven, distinguishing four categories of positivity based on RNA copies/mL. Pre-quantified control material was shipped to 124 laboratories with instructions to setup a standard curve to define thresholds per assay. For each assay, the mean Ct value and corresponding standard deviation was calculated per target gene, for the three concentrations (107, 105 and 103 copies/mL) that determine the classification. The results of 17 assays are summarized. This harmonization effort allowed to ensure that all Belgian laboratories would report positive PCR results in the same semi-quantitative manner to clinicians and to the national database which feeds contact tracing interventions.
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Affiliation(s)
- Lize Cuypers
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
| | - Jannes Bode
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
| | - Kurt Beuselinck
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
| | - Lies Laenen
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
| | - Klaas Dewaele
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
| | - Reile Janssen
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
| | - Arnaud Capron
- Epidemiology of Infectious Diseases and Quality Service Unit, Scientific Directorate of Epidemiology and Public Health, Sciensano, 1000 Brussels, Belgium; (A.C.); (Y.L.)
| | - Yves Lafort
- Epidemiology of Infectious Diseases and Quality Service Unit, Scientific Directorate of Epidemiology and Public Health, Sciensano, 1000 Brussels, Belgium; (A.C.); (Y.L.)
| | - Henry Paridaens
- Clinical Laboratory, Centre Hospitalier Régional de la Citadelle, 4000 Liège, Belgium;
| | - Bertrand Bearzatto
- Federal Testing Platform COVID-19, Centre des Technologies Moléculaires Appliquées (CTMA), Institute of Experimental and Clinical Research (IREC), Cliniques Universitaires Saint-Luc and Université Catholique de Louvain (UCLouvain), 1200 Brussels, Belgium;
| | | | | | - Jonathan Degosserie
- Federal Testing Platform COVID-19, Department of Laboratory Medicine, CHU UCL Namur, 5530 Yvoir, Belgium;
| | - Olivier Fagnart
- Saint-Jean Hospital Laboratory, Cebiodi, 1000 Brussels, Belgium;
| | - Yarah Overmeire
- Microbiology, Labo Nuytinck, Anacura, 9940 Evergem, Belgium;
| | | | | | - Marine Deffontaine
- Laboratory of Clinical Biology, Centre Hopsitalier de Mouscron, 7700 Mouscron, Belgium;
| | - Thomas Pilate
- Clinical Laboratory, Laboratory Medicine, AZ Diest, 3290 Diest, Belgium;
| | - Nicolas Yin
- Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles—Universitair Laboratorium Brussel (LHUB-ULB), Université de Bruxelles (ULB), 1000 Brussels, Belgium;
| | - Isabel Micalessi
- Clinical Reference Laboratory, Department of Clinical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
| | - Sandrine Roisin
- Microbiology, Centre Hospitalier Universitaire de Tivoli, 7100 La Louvière, Belgium;
| | - Veronique Moons
- Microbiology, LKO-LMC Medical Laboratory, 3800 Sint-Truiden, Belgium;
| | - Marijke Reynders
- Laboratory Medicine, AZ Sint-Jan Brugge-Oostende AV, 8000 Brugge, Belgium;
| | - Sophia Steyaert
- Clinical Laboratory, AZ Maria Middelares, 9000 Gent, Belgium;
| | - Coralie Henin
- Federal Testing Platform COVID-19, Université Libre de Bruxelles, 1070 Brussels, Belgium;
| | - Elena Lazarova
- Centre Hospitalier Régional de la Haute Senne, Department of Clinical Biology, 7060 Soignies, Belgium;
| | - Dagmar Obbels
- Imelda, Clinical Laboratory, 2820 Bonheiden, Belgium;
| | | | - Hendri Pirenne
- Synlab Belgium, Synlab Laboratory Collard, 4020 Liège, Belgium;
| | - Raf Schepers
- Synlab Belgium, Synlab Laboratory Heppignies, 6220 Heppignies, Belgium;
| | | | - Bruno Verhasselt
- Federal Testing Platform COVID-19, Department of Laboratory Medicine, Ghent University and Ghent University Hospital, 9000 Gent, Belgium;
| | - Laurent Gillet
- Federal Testing Platform COVID-19, University of Liège, 4000 Liège, Belgium;
| | - Stijn Jonckheere
- Jan Yperman Hospital, Laboratory of Clinical Biology, 8900 Ieper, Belgium;
| | | | - Bea Van den Poel
- Clinical Laboratory, General Hospital Jan Portaels, 1800 Vilvoorde, Belgium;
| | - Yolien Van der Beken
- Military Medicine Lab Capacity, Military Hospital Queen Astrid, 1120 Brussels, Belgium;
| | - Violeta Stojkovic
- Centre Hospitalier Bois de l’Abbaye, Laboratory Service, 4100 Seraing, Belgium;
| | | | | | - Kevin Vos
- RZ Heilig Hart Tienen, Clinical Biology, 3300 Tienen, Belgium;
| | | | - Valerie Pede
- AZ Sint-Elisabeth Zottegem, Laboratory of Clinical Biology, 9600 Zottegem, Belgium;
| | - Friedel Nollet
- Biogazelle NV, Diagnostic Testing, 9052 Zwijnaarde, Belgium;
| | - Vincent Claes
- Institute of Clinical Biology ULB-IBC, 1170 Brussels, Belgium;
| | | | - Pierre Bogaerts
- CHU UCL Namur, Department of Laboratory Medicine, Molecular Diagnostics Center, 5530 Yvoir, Belgium;
| | | | | | | | - Oriane Soetens
- Department of Microbiology and Infection Control, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, 1090 Brussels, Belgium;
| | - Merijn Vanhee
- Clinical Laboratory, Laboratory Medicine, AZ Delta, 8800 Roeselare, Belgium;
| | | | - Evelyne Huyghe
- ZNA Middelheim, Clinical Laboratory, 2020 Antwerp, Belgium;
| | | | - Ann Lemmens
- AZ Sint-Maarten, Laboratory of Clinical Biology, 2800 Mechelen, Belgium;
| | | | | | - Deborah Steensels
- Clinical Laboratory, Campus Sint-Jan, Hospital Oost-Limburg, 3600 Genk, Belgium;
| | - Elke Vanlaere
- Clinical Laboratory, AZ Sint-Lucas Hospital, 9000 Gent, Belgium;
| | - Jérémie Gras
- Institute of Pathology and Genetics, 6041 Gosselies, Belgium;
| | - Gatien Roussel
- Clinique Saint Pierre, Laboratory, 1340 Ottignies, Belgium;
| | | | - Michael Boudewijns
- Clinical Laboratory, Campus Kennedylaan, AZ Groeninge, 8500 Kortrijk, Belgium;
| | - Catherine Sion
- Grand Hôpital de Charleroi, Clinical Biology and Microbiology, 6060 Gilly, Belgium;
| | - Wim Achtergael
- Clinical Laboratory, Algemeen Stedelijk Ziekenhuis Aalst, 9300 Aalst, Belgium;
| | | | - Luc Iliano
- Laboratory for Medical Biology Iliano, 9070 Destelbergen, Belgium;
| | | | | | | | - Nicolas Hougardy
- Clinical Biology Unit, Vivalia Clinique du Sud-Luxembourg, 6700 Arlon, Belgium;
| | - Mario Berth
- Clinical Laboratory, AZ Alma, 9900 Eeklo, Belgium;
| | | | - Robin Morent
- Department of Laboratory Medicine, Campus Henri Serruys, AZ Sint-Jan Brugge, 8400 Oostende, Belgium;
| | - Anne Vankeerberghen
- Laboratory of Molecular Biology, Campus Aalst-Asse-Ninove, Onze-Lieve-Vrouwziekenhuis, 9300 Aalst, Belgium;
| | - Sébastien Bontems
- Clinical Laboratory, Unit of Clinical Microbiology, CHU Liège, 4000 Liège, Belgium;
| | - Kaat Kehoe
- Microbiology, Algemeen Medisch Laboratorium, 2020 Antwerp, Belgium;
| | | | - Giang Ho
- Laboratory, Clinique du MontLégia, Groupe Santé CHC, 4000 Liège, Belgium;
| | - Kristof Bafort
- Clinical Laboratory, Mariaziekenhuis Noorderhart, 3900 Pelt, Belgium;
| | - Marijke Raymaekers
- Laboratory for Molecular Diagnostics, Jessa Hospital, 3500 Hasselt, Belgium;
| | - Yolande Pypen
- Microbiology, Laboratory Somedi, 2220 Heist-op-den-Berg, Belgium;
| | - Amelie Heinrichs
- Laboratory of Clinical Biology, Hospital Arlon—Vivalia, 6700 Arlon, Belgium;
| | - Wim Schuermans
- Clinical Laboratory, Ziekenhuis Geel, 2440 Geel, Belgium;
| | | | | | - Stefanie Drieghe
- Microbiology, Algemeen Medisch Laboratorium West, 8850 Ardooie, Belgium;
| | - Dieter Ory
- Clinical Laboratory, Heilig Hart Ziekenhuis Mol, 2400 Mol, Belgium;
| | - Marie Le Mercier
- Federal Testing Platform COVID-19, University Hospitals Antwerp, 2650 Edegem, Belgium;
| | - Kristel Van Laethem
- Federal Testing Platform COVID-19, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium;
- Laboratory of Clinical and Epidemiological Virology, Department of Microbiology, Rega Institute for Medical Research, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium;
| | - Inge Thoelen
- Clinical Laboratory, AZ Vesalius Tongeren, 3700 Tongeren, Belgium;
| | - Sarah Vandamme
- Microbiology Laboratory, University Hospitals Antwerp, 2650 Edegem, Belgium;
| | - Iqbal Mansoor
- Clinical Laboratory, Hospital Hornu Epicura, 7301 Boussu, Belgium;
| | - Carl Vael
- Clinical Laboratory, AZ Klina, 2930 Brasschaat, Belgium;
| | | | | | - Elisabeth Dequeker
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
| | - Stefanie Desmet
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
- Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Piet Maes
- Laboratory of Clinical and Epidemiological Virology, Department of Microbiology, Rega Institute for Medical Research, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium;
| | - Katrien Lagrou
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
- Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Emmanuel André
- National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium; (J.B.); (K.B.); (L.L.); (K.D.); (R.J.); (E.D.); (S.D.); (K.L.); (E.A.)
- Federal Testing Platform COVID-19, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium;
- Laboratory of Clinical Microbiology, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
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Cottone E, Van Hoecke F, Martens GA, De Laere E, De Smedt R, Vervaeke S, Vanhee M, De Smet D. Pitfalls of SARS-CoV-2 antigen testing at emergency department. Infect Dis (Lond) 2022; 54:731-737. [PMID: 35638185 DOI: 10.1080/23744235.2022.2083226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Current method for diagnosis of SARS-CoV-2 infection is an RT-PCR test on the nasopharyngeal or oropharyngeal swab. Rapid diagnosis is essential for containing viral spread and triage of symptomatic patients presenting to hospital ER departments. As a faster alternative to RT-PCR, we evaluated a SARS-Cov-2 Rapid Antigen test in symptomatic patients presenting to hospital ER departments. METHODS We evaluated the diagnostic performance of the Roche SARS-CoV-2 Rapid Antigen test (SD Biosensor) for detection of SARS-CoV-2 compared to RT-PCR. RESULTS Our study showed inferior performance of the SARS-CoV-2 Rapid Antigen test for detection of SARS-CoV-2. Firstly, because of the lack of specificity, which is potentially life-threatening due to the association of nosocomial-acquired SARS-CoV-2 infection. Secondly, with a sensitivity of 45.5%, it is impossible to rule out SARS-CoV-2 infection, resulting in reflex PCR-testing. Comparison of viral load in RT-PCR positive samples with corresponding antigen results showed a significant difference between antigen positive and negative samples. COVID-19 infection will not be detected in patients admitted to the hospital in an early or late phase, typically associated with low viral loads. Sensitivity increases when testing within 5-7 symptomatic days, but the implementation of this cut-off is impractical in ER settings. However, diagnostic performance is better to detect high viral load (> = 5 log10 copies/mL) linked with contagiousness. CONCLUSION Our study showed inferior performance of the Roche SARS-CoV-2 Rapid Antigen test (SD Biosensor) for detection of SARS-CoV-2 which limits its use as a diagnostic gatekeeper in ER departments, but is able to differentiate contagious individuals.
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Affiliation(s)
- Eleonora Cottone
- AZ Delta Medical Laboratories, AZ Delta General Hospital, Roeselare, Belgium
| | - Frederik Van Hoecke
- AZ Delta Medical Laboratories, AZ Delta General Hospital, Roeselare, Belgium
| | - Geert Antoine Martens
- AZ Delta Medical Laboratories, AZ Delta General Hospital, Roeselare, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Emmanuel De Laere
- AZ Delta Medical Laboratories, AZ Delta General Hospital, Roeselare, Belgium
| | - Roos De Smedt
- AZ Delta Medical Laboratories, AZ Delta General Hospital, Roeselare, Belgium
| | - Steven Vervaeke
- AZ Delta Medical Laboratories, AZ Delta General Hospital, Roeselare, Belgium
| | - Merijn Vanhee
- Department of Laboratory Medicine, AZ Sint-Jan AV, Brugge, Belgium
| | - Dieter De Smet
- AZ Delta Medical Laboratories, AZ Delta General Hospital, Roeselare, Belgium
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5
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De Smet D, Vanhee M, Maes B, Swaerts K, De Jaeger P, Maelegheer K, Van Hoecke F, Martens GA. Cycle Threshold Probability Score for Immediate and Sensitive Detection of B.1.351 SARS-CoV-2 Lineage. Am J Clin Pathol 2022; 157:731-741. [PMID: 34724038 DOI: 10.1093/ajcp/aqab186] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/21/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern associated with immune escape is important to safeguard vaccination efficacy. We describe the potential of delayed N gene amplification in the Allplex SARS-CoV-2 Assay (Seegene) for screening of the B.1.351 (20H/501.V2, variant of concern 2 [VOC.V2], South African SARS-CoV-2 variant) lineage. METHODS In a study cohort of 397 consecutive polymerase chain reaction-positive samples genotyped by whole-genome sequencing, amplification curves of E/N/S-RdRP targets indicated delayedN vs E gene amplification characteristic of B.1.351. Logistic regression was used to calculate a VOC.V2 probability score that was evaluated as a separate screening test in an independent validation cohort vs sequencing. RESULTS B.1.351 showed a proportionally delayed amplification of the N vs E gene. In logistic regression, only N and E gene cycle thresholds independently contributed to B.1.351 prediction, allowing calculation of a VOC.V2 probability score with an area under the curve of 0.94. At an optimal dichotomous cutoff point of 0.12, the VOC.V2 probability score achieved 98.7% sensitivity at 79.9% specificity, resulting in a negative predictive value (NPV) of 99.6% and a positive predictive value of 54.6%. The probability of B.1.351 increased with an increasing VOC.V2 probability score, achieving a likelihood ratio of 12.01 above 0.5. A near-maximal NPV was confirmed in 153 consecutive validation samples. CONCLUSIONS Delayed N vs E gene amplification in the Allplex SARS-CoV-2 Assay can be used for fast and highly sensitive screening of B.1.351.
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Affiliation(s)
- Dieter De Smet
- Department of Laboratory Medicine, AZ Delta General Hospital, Roeselare, Belgium
| | - Merijn Vanhee
- Department of Laboratory Medicine, AZ Delta General Hospital, Roeselare, Belgium
| | - Brigitte Maes
- Department of Clinical Biology, Jessa Hospital, Hasselt, Belgium
| | - Koen Swaerts
- Department of Laboratory Medicine, AZ Delta General Hospital, Roeselare, Belgium
| | - Peter De Jaeger
- Department of Laboratory Medicine, AZ Delta General Hospital, Roeselare, Belgium
| | - Karel Maelegheer
- Department of Clinical Biology, AZ Sint-Lucas Hospital, Bruges, Belgium
| | - Frederik Van Hoecke
- Department of Laboratory Medicine, AZ Delta General Hospital, Roeselare, Belgium
| | - Geert Antoine Martens
- Department of Laboratory Medicine, AZ Delta General Hospital, Roeselare, Belgium
- Department of Biomolecular Medicine, Ghent University, Gent, Belgium
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Vanderheijden N, Stevaert A, Xie J, Ren X, Barbezange C, Noppen S, Desombere I, Verhasselt B, Geldhof P, Vereecke N, Stroobants V, Oh D, Vanhee M, Naesens LMJ, Nauwynck HJ. Functional Analysis of Human and Feline Coronavirus Cross-Reactive Antibodies Directed Against the SARS-CoV-2 Fusion Peptide. Front Immunol 2022; 12:790415. [PMID: 35069571 PMCID: PMC8766817 DOI: 10.3389/fimmu.2021.790415] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022] Open
Abstract
To face the continuous emergence of SARS-CoV-2 variants, broadly protective therapeutic antibodies are highly needed. We here focused on the fusion peptide (FP) region of the viral spike antigen since it is highly conserved among alpha- and betacoronaviruses. First, we found that coronavirus cross-reactive antibodies are commonly formed during infection, being omnipresent in sera from COVID-19 patients, in ~50% of pre-pandemic human sera (rich in antibodies against endemic human coronaviruses), and even in feline coronavirus-infected cats. Pepscan analyses demonstrated that a confined N-terminal region of the FP is strongly immunogenic across diverse coronaviruses. Peptide-purified human antibodies targeting this conserved FP epitope exhibited broad binding of alpha- and betacoronaviruses, besides weak and transient SARS-CoV-2 neutralizing activity. Being frequently elicited by coronavirus infection, these FP-binding antibodies might potentially exhibit Fc-mediated effector functions and influence the kinetics or severity of coronavirus infection and disease.
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Affiliation(s)
- Nathalie Vanderheijden
- Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Annelies Stevaert
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven – University of Leuven, Leuven, Belgium
| | - Jiexiong Xie
- Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Xiaolei Ren
- Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Cyril Barbezange
- National Influenza Centre and Epidemiology of Infectious Diseases, Sciensano, Brussels, Belgium
| | - Sam Noppen
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven – University of Leuven, Leuven, Belgium
| | | | - Bruno Verhasselt
- Laboratory for Medical Microbiology, Ghent University Hospital, Ghent, Belgium
| | - Peter Geldhof
- Laboratory of Parasitology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Nick Vereecke
- Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- PathoSense BV, Lier, Belgium
| | - Veerle Stroobants
- Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Dayoung Oh
- Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Merijn Vanhee
- Department of Laboratory Medicine, AZ Sint-Jan Brugge-Oostende, Bruges, Belgium
| | - Lieve M. J. Naesens
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, KU Leuven – University of Leuven, Leuven, Belgium
| | - Hans J. Nauwynck
- Laboratory of Virology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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7
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Yona CM, Vanhee M, Simulundu E, Makange M, Nauwynck HJ, Misinzo G. Persistent domestic circulation of African swine fever virus in Tanzania, 2015-2017. BMC Vet Res 2020; 16:369. [PMID: 33004025 PMCID: PMC7528248 DOI: 10.1186/s12917-020-02588-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 09/23/2020] [Indexed: 11/12/2022] Open
Abstract
Background African swine fever (ASF) is a highly fatal viral hemorrhagic disease of domestic pigs that threatens livelihoods and food security. In Africa, ASF virus (ASFV) circulates in sylvatic (transmission between warthogs and soft argasid ticks) and domestic (transmission between domestic pigs) cycles, with outbreaks resulting from ASFV spill-over from sylvatic cycle. A number of outbreaks were reported in different parts of Tanzania between 2015 and 2017. The present study investigated ASFV transmission patterns through viral DNA sequencing and phylogenetic analysis. A total of 3120 tissue samples were collected from 2396 domestic pigs during outbreaks at different locations in Tanzania between 2015 and 2017. Partial sequencing of the B646L (p72) gene was conducted for diagnostic confirmation and molecular characterization of ASFV. Phylogenetic analysis to study the relatedness of current ASFV with those that caused previous outbreaks in Tanzania and representatives of all known 24 ASFV was performed using the Maximum Composite Likelihood model with 1000 bootstrap replications in MEGA 6.0. Results ASFV was confirmed to cause disease in sampled domestic pigs. ASFV genotypes II, IX, and X were detected from reported outbreaks in 2015–2017. The current ASFV isolates were similar to those recently documented in the previous studies in Tanzania. The similarities of these isolates suggests for continuous circulation of ASFV with virus maintenance within the domestic pigs. Conclusions Genetic analysis confirmed the circulation of ASFV genotypes II, IX, and X by partial B646L (p72) gene sequencing. The similarities of current isolates to previously isolated Tanzanian isolates and pattern of disease spread suggest for continuous circulation of ASF with virus’ maintenance in the domestic pigs. Although certain viral genotypes seem to be geographically restricted into certain zones within Tanzania, genotype II seems to expand its geographical range northwards with the likelihood of spreading to other states of the East African Community. The spread of ASFV is due to breach of quarantine and transportation of infected pigs via major highways. Appropriate control measures including zoosanitary measures and quarantine enforcement are recommended to prevent ASF domestic circulation in Tanzania.
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Affiliation(s)
- Clara M Yona
- SACIDS Foundation for One Health, SACIDS Africa Centre of Excellence for Infectious Diseases, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Biosciences, Solomon Mahlangu College of Science and Education, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Merijn Vanhee
- Department of Biotechnology, VIVES University College, Roeselare, Belgium
| | - Edgar Simulundu
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Mariam Makange
- Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Hans J Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, University of Gent, Merelbeke, Belgium
| | - Gerald Misinzo
- SACIDS Foundation for One Health, SACIDS Africa Centre of Excellence for Infectious Diseases, Sokoine University of Agriculture, Morogoro, Tanzania. .,Department of Veterinary Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania.
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Vanhee M, Dalemans AC, Viaene J, Depuydt L, Claerebout E. Toxocara in sandpits of public playgrounds and kindergartens in Flanders (Belgium). Vet Parasitol Reg Stud Reports 2016; 1-2:51-54. [PMID: 31018409 DOI: 10.1016/j.vprsr.2016.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/11/2016] [Accepted: 03/16/2016] [Indexed: 10/22/2022]
Abstract
Belgium counts more than a million dogs and at least two million cats, of which many are carrying zoonotic nematodes of the genus Toxocara. Environmental contamination with worm eggs is considered the key transmission route from animals to humans, and mainly young children are at risk. Contamination of soil with Toxocara eggs has been reported from all over the world, but data are lacking for Belgium. In this study, faecal contamination and the presence of Toxocara eggs in sand were investigated in sandpits of public playgrounds and kindergartens in Flanders (Northern Belgium). Faeces, of which 85% originated from cats, were found in about one third of the public playgrounds and one fifth of the kindergartens. Toxocara eggs were found in 12% of the faecal samples, in 14% of the public sandpits, and in 2% of the sandpits of kindergartens. These data indicate that environmental contamination with Toxocara exists in urban areas in Belgium, and that cats are most likely the main source.
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Affiliation(s)
- Merijn Vanhee
- Department of Biotechnology, Vives University College, Wilgenstraat 32, 8800 Roeselare, Belgium.
| | | | - Jasmine Viaene
- Department of Biotechnology, Vives University College, Wilgenstraat 32, 8800 Roeselare, Belgium.
| | - Lies Depuydt
- Department of Biotechnology, Vives University College, Wilgenstraat 32, 8800 Roeselare, Belgium.
| | - Edwin Claerebout
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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Saha D, Karniychuk UU, Huang L, Geldhof M, Vanhee M, Lefebvre DJ, Meerts P, Ducatelle R, Doorsselaere JV, Nauwynck HJ. Unusual outcome of in utero infection and subsequent postnatal super-infection with different PCV2b strains. Virol Sin 2014; 29:176-82. [PMID: 24950783 DOI: 10.1007/s12250-014-3431-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022] Open
Abstract
VC2002, isolated from postweaning multisystemic wasting syndrome (PMWS)-affected pig, is a mixture of two porcine circovirus genotype 2b (PCV2b) viruses, K2 and K39. Preliminary experiments disclosed short-term adverse effects of K39, but not K2, on porcine foetuses. These findings led to the hypothesis that infection of immuno-incompetent foetuses with K2 confers a status of immunotolerance, and postnatal super-infection with K39 triggers PMWS. To explore this hypothesis, nine 55-day-old foetuses were inoculated in utero (three with K2-10(4.3)TCID50, three with K39-10(4.3)TCID50 and three with medium), and foeto-pathogenicity examined. At 21 days post-inoculation (dpi), K2 did not induce pathology, whereas pathological effects of K39 were evident. Twenty-four 45-day-old foetuses were subsequently inoculated to examine the long-term effect of K2, including six with K2-high dose-10(4.3)TCID50, six with K2-low dose-10(2.3)TCID50 and 12 mock-inoculated controls. Both doses resulted in five mummified foetuses and one live-born piglet each (69dpi). K2 was recovered from all mummies. K2 and K2-specific antibodies were not detected in serum of the two live-born piglets at birth, indicating full control of K2 infection. The K2-low dose-infected piglet was immunostimulated at day 2, but not the K2-high dose-infected piglet. Both non-stimulated and stimulated K2-infected piglets were super-inoculated with K39 at day 6 or 8 (taken as 0 days post super-inoculation). Low viral replication was observed in the non-stimulated K2-K39 piglet (up to 10(3.3)TCID50/g; identified as K39). In contrast, viral replication was extremely high in the stimulated K2-K39 piglet (up to 10(5.6)TCID50/g) and identified as K2, indicating that K2 infection is controlled during foetal life, but emerges after birth upon immunostimulation. However, none of the piglets showed any signs of PMWS.
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Affiliation(s)
- Dipongkor Saha
- Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
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10
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Badaoui B, Rutigliano T, Anselmo A, Vanhee M, Nauwynck H, Giuffra E, Botti S. RNA-sequence analysis of primary alveolar macrophages after in vitro infection with porcine reproductive and respiratory syndrome virus strains of differing virulence. PLoS One 2014; 9:e91918. [PMID: 24643046 PMCID: PMC3958415 DOI: 10.1371/journal.pone.0091918] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 02/18/2014] [Indexed: 12/03/2022] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) mainly infects porcine alveolar macrophages (PAMs), resulting in porcine reproductive and respiratory syndrome (PRRS) in pigs. Most of the transcriptomic studies on PAMs infected with PRRSV conducted thus far have made use of microarray technology. Here, we investigated the transcriptome of PAMs in vitro at 12 h post-infection with two European PRRSV strains characterized by low (Lelystad, LV) and high (Lena) virulence through RNA-Seq. The expression levels of genes, isoforms, alternative transcription start sites (TSS) and differential promoter usage revealed a complex pattern of transcriptional and post-transcriptional gene regulation upon infection with the two strains. Gene ontology analysis confirmed that infection of PAMs with both the Lena and LV strains affected signaling pathways directly linked to the innate immune response, including interferon regulatory factors (IRF), RIG1-like receptors, TLRs and PKR pathways. The results confirmed that interferon signaling is crucial for transcriptional regulation during PAM infection. IFN-β1 and IFN-αω, but not IFN-α, were up-regulated following infection with either the LV or Lena strain. The down-regulation of canonical pathways, such as the interplay between the innate and adaptive immune responses, cell death and TLR3/TLR7 signaling, was observed for both strains, but Lena triggered a stronger down-regulation than LV. This analysis contributes to a better understanding of the interactions between PRRSV and PAMs and outlines the differences in the responses of PAMs to strains with different levels of virulence, which may lead to the development of new PRRSV control strategies.
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Affiliation(s)
- Bouabid Badaoui
- Parco Tecnologico Padano, Via Einstein, Lodi, Italy
- * E-mail:
| | | | - Anna Anselmo
- Parco Tecnologico Padano, Via Einstein, Lodi, Italy
| | - Merijn Vanhee
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Hans Nauwynck
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | | | - Sara Botti
- Parco Tecnologico Padano, Via Einstein, Lodi, Italy
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Geldhof MF, Van Breedam W, De Jong E, Lopez Rodriguez A, Karniychuk UU, Vanhee M, Van Doorsselaere J, Maes D, Nauwynck HJ. Antibody response and maternal immunity upon boosting PRRSV-immune sows with experimental farm-specific and commercial PRRSV vaccines. Vet Microbiol 2013; 167:260-71. [PMID: 24041768 DOI: 10.1016/j.vetmic.2013.08.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 08/14/2013] [Accepted: 08/19/2013] [Indexed: 11/17/2022]
Abstract
The porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive failure in sows and respiratory disease in pigs of all ages. Despite the frequent use of vaccines to maintain PRRSV immunity in sows, little is known on how the currently used vaccines affect the immunity against currently circulating and genetically divergent PRRSV variants in PRRSV-immune sows, i.e. sows that have a pre-existing PRRSV-specific immunity due to previous infection with or vaccination against the virus. Therefore, this study aimed to assess the capacity of commercially available attenuated/inactivated PRRSV vaccines and autogenous inactivated PRRSV vaccines - prepared according to a previously optimized in-house protocol - to boost the antibody immunity against currently circulating PRRSV variants in PRRSV-immune sows. PRRSV isolates were obtained from 3 different swine herds experiencing PRRSV-related problems, despite regular vaccination of gilts and sows against the virus. In a first part of the study, the PRRSV-specific antibody response upon booster vaccination with commercial PRRSV vaccines and inactivated farm-specific PRRSV vaccines was evaluated in PRRSV-immune, non-pregnant replacement sows from the 3 herds. A boost in virus-neutralizing antibodies against the farm-specific isolate was observed in all sow groups vaccinated with the corresponding farm-specific inactivated vaccines. Use of the commercial attenuated EU type vaccine boosted neutralizing antibodies against the farm-specific isolate in sows derived from 2 farms, while use of the commercial attenuated NA type vaccine did not boost farm-specific virus-neutralizing antibodies in any of the sow groups. Interestingly, the commercial inactivated EU type vaccine boosted farm-specific virus-neutralizing antibodies in sows from 1 farm. In the second part of the study, a field trial was performed at one of the farms to evaluate the booster effect of an inactivated farm-specific vaccine and a commercial attenuated EU-type vaccine in immune sows at 60 days of gestation. The impact of this vaccination on maternal immunity and on the PRRSV infection pattern in piglets during their first weeks of life was evaluated. Upon vaccination with the farm-specific inactivated vaccine, a significant increase in farm-specific virus-neutralizing antibodies was detected in all sows. Virus-neutralizing antibodies were also transferred to the piglets via colostrum and were detectable in the serum of these animals until 5 weeks after parturition. In contrast, not all sows vaccinated with the commercial attenuated vaccine showed an increase in farm-specific virus-neutralizing antibodies and the piglets of this group generally had lower virus-neutralizing antibody titers. Interestingly, the number of viremic animals (i.e. animals that have infectious virus in their bloodstream) was significantly lower among piglets of both vaccinated groups than among piglets of mock-vaccinated sows and this at least until 9 weeks after parturition. The results of this study indicate that inactivated farm-specific PRRSV vaccines and commercial attenuated vaccines can be useful tools to boost PRRSV-specific (humoral) immunity in sows and reduce viremia in weaned piglets.
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Affiliation(s)
- Marc F Geldhof
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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12
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Karniychuk UU, Saha D, Vanhee M, Geldhof M, Cornillie P, Caij AB, De Regge N, Nauwynck HJ. Impact of a novel inactivated PRRS virus vaccine on virus replication and virus-induced pathology in fetal implantation sites and fetuses upon challenge. Theriogenology 2013; 78:1527-37. [PMID: 22980086 DOI: 10.1016/j.theriogenology.2012.06.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 06/05/2012] [Accepted: 06/10/2012] [Indexed: 12/25/2022]
Abstract
Preventing congenital infection is important for the control of porcine reproductive and respiratory syndrome (PRRS). Recently, in our laboratory, an inactivated porcine reproductive and respiratory syndrome virus (PRRSV) vaccine has been developed. Promising results in young pigs encouraged us to test the vaccine potency to prevent congenital infection. In the present study, the performance of this experimental inactivated vaccine was investigated in pregnant gilts. An advanced protocol was used to test the PRRSV vaccine efficacy. This protocol is based on recent insights in the pathogenesis of congenital PRRSV infections. Three gilts were vaccinated with an experimental PRRSV 07V63 inactivated vaccine at 27, 55, and 83 days of gestation. Three unvaccinated gilts were included as controls. At 90 days of gestation, all animals were intranasally inoculated with 10(5) tissue culture infectious dose 50 (TCID(50)) of PRRSV 07V63. Twenty days postchallenge animals were euthanized and sampled. The vaccinated gilts quickly developed virus neutralizing (VN) antibodies starting from 3 to 7 days postchallenge (1.0 to 5.0 log2). In contrast, the unvaccinated gilts remained negative for VN antibodies after challenge. The vaccinated gilts had shorter viremia than the control gilts. Gross pathology (mummification) was observed in 8% of the fetuses from vaccinated gilts and in 15% of the fetuses from unvaccinated gilts. The number of fetuses with severe microscopic lesions in the fetal implantation sites (a focal detachment of the trophoblast from the uterine epithelium; a focal, multifocal, or full degeneration of the fetal placenta) was lower in the vaccinated (19%) versus unvaccinated (45%) gilts (P < 0.05). The number of PRRS-positive cells in the fetal placentae was higher in unvaccinated versus vaccinated gilts (P < 0.05). In contrast, the number of PRRS-positive cells in the myometrium/endometrium was higher in vaccinated versus unvaccinated gilts (P < 0.05). Fifty-seven percent of the fetuses from the vaccinated gilts and 75% of the fetuses from the unvaccinated gilts were PRRSV-positive. In conclusion, implementation of the novel experimental inactivated PRRSV vaccine primed the VN antibody response and slightly reduced the duration of viremia in gilts. It also reduced the number of virus-positive fetuses and improved the fetal survival, but was not able to fully prevent congenital PRRSV infection. The reduction of fetal infection and pathology is most probably attributable to the vaccine-mediated decrease of PRRSV transfer from the endometrium to the fetal placenta.
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Affiliation(s)
- U U Karniychuk
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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13
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Geldhof MF, Vanhee M, Van Breedam W, Van Doorsselaere J, Karniychuk UU, Nauwynck HJ. Comparison of the efficacy of autogenous inactivated Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) vaccines with that of commercial vaccines against homologous and heterologous challenges. BMC Vet Res 2012; 8:182. [PMID: 23031319 PMCID: PMC3514241 DOI: 10.1186/1746-6148-8-182] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 09/23/2012] [Indexed: 11/11/2022] Open
Abstract
Background The porcine reproductive and respiratory syndrome virus (PRRSV) is a rapidly evolving pathogen of swine. At present, there is a high demand for safe and more effective vaccines that can be adapted regularly to emerging virus variants. A recent study showed that, by the use of a controlled inactivation procedure, an experimental BEI-inactivated PRRSV vaccine can be developed that offers partial protection against homologous challenge with the prototype strain LV. At present, it is however not known if this vaccine can be adapted to currently circulating virus variants. In this study, two recent PRRSV field isolates (07 V063 and 08 V194) were used for BEI-inactivated vaccine production. The main objective of this study was to assess the efficacy of these experimental BEI-inactivated vaccines against homologous and heterologous challenge and to compare it with an experimental LV-based BEI-inactivated vaccine and commercial inactivated and attenuated vaccines. In addition, the induction of challenge virus-specific (neutralizing) antibodies by the different vaccines was assessed. Results In a first experiment (challenge with 07 V063), vaccination with the experimental homologous (07 V063) inactivated vaccine shortened the viremic phase upon challenge with approximately 2 weeks compared to the mock-vaccinated control group. Vaccination with the commercial attenuated vaccines reduced the duration of viremia with approximately one week compared to the mock-vaccinated control group. In contrast, the experimental heterologous (LV) inactivated vaccine and the commercial inactivated vaccine did not influence viremia. Interestingly, both the homologous and the heterologous experimental inactivated vaccine induced 07 V063-specific neutralizing antibodies upon vaccination, while the commercial inactivated and attenuated vaccines failed to do so. In the second experiment (challenge with 08 V194), use of the experimental homologous (08 V194) inactivated vaccine shortened viremia upon challenge with approximately 3 weeks compared to the mock-vaccinated control group. Similar results were obtained with the commercial attenuated vaccine. The experimental heterologous (07 V063 and LV) inactivated vaccines did not significantly alter viremia. In this experiment, 08 V194-specific neutralizing antibodies were induced by the experimental homologous and heterologous inactivated vaccines and a faster appearance post challenge was observed with the commercial attenuated vaccine. Conclusions The experimental homologous inactivated vaccines significantly shortened viremia upon challenge. Despite the concerns regarding the efficacy of the commercial attenuated vaccines used on the farms where the field isolates were obtained, use of commercial attenuated vaccines clearly shortened the viremic phase upon challenge. In contrast, the experimental heterologous inactivated vaccines and the commercial inactivated vaccine had no or only a limited influence on viremia. The observation that homologous BEI-inactivated vaccines can provide a more or less standardized, predictable degree of protection against a specific virus variant suggests that such vaccines may prove useful in case virus variants emerge that escape the immunity induced by the attenuated vaccines.
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Affiliation(s)
- Marc F Geldhof
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium.
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Nauwynck HJ, Van Gorp H, Vanhee M, Karniychuk U, Geldhof M, Cao A, Verbeeck M, Van Breedam W. Micro-Dissecting the Pathogenesis and Immune Response of PRRSV Infection Paves the Way for More Efficient PRRSV Vaccines. Transbound Emerg Dis 2012; 59 Suppl 1:50-4. [DOI: 10.1111/j.1865-1682.2011.01292.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Vanhee M, Van Breedam W, Costers S, Geldhof M, Noppe Y, Nauwynck H. Characterization of antigenic regions in the porcine reproductive and respiratory syndrome virus by the use of peptide-specific serum antibodies. Vaccine 2011; 29:4794-804. [PMID: 21554913 DOI: 10.1016/j.vaccine.2011.04.071] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/12/2011] [Accepted: 04/19/2011] [Indexed: 12/22/2022]
Abstract
The porcine reproductive and respiratory syndrome virus (PRRSV) is an RNA virus that causes reproductive failure in sows and boars, and respiratory disease in pigs of all ages. Antibodies against several viral envelope proteins are produced upon infection, and the glycoproteins GP4 and GP5 are known targets for virus neutralization. Still, substantial evidence points to the presence of more, yet unidentified neutralizing antibody targets in the PRRSV envelope proteins. The current study aimed to identify and characterize linear antigenic regions (ARs) within the entire set of envelope proteins of the European prototype PRRSV strain Lelystad virus (LV). Seventeen LV-specific antisera were tested in pepscan analysis on GP2, E, GP3, GP4, GP5 and M, resulting in the identification of twenty-one ARs that are capable of inducing antibodies upon infection in pigs. A considerable number of these ARs correspond to previously described epitopes in different European- and North-American-type PRRSV strains. Remarkably, the largest number of ARs was found in GP3, and two ARs in the GP3 ectodomain consistently induced antibodies in a majority of infected pigs. In contrast, all remaining ARs, except for a highly immunogenic epitope in GP4, were only recognized by one or a few infected animals. Sensitivity to antibody-mediated neutralization was tested for a selected number of ARs by in vitro virus-neutralization tests on alveolar macrophages with peptide-purified antibodies. In addition to the known neutralizing epitope in GP4, two ARs in GP2 and one in GP3 turned out to be targets for virus-neutralizing antibodies. No virus-neutralizing antibody targets were found in E, GP5 or M. Since the neutralizing AR in GP3 induced antibodies in a majority of infected pigs, the immunogenicity of this AR was studied more extensively, and it was demonstrated that the corresponding region in GP3 of virus strains other than LV also induces virus-neutralizing antibodies. This study provides new insights into PRRSV antigenicity, and contributes to the knowledge on protective immunity and immune evasion strategies of the virus.
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Affiliation(s)
- Merijn Vanhee
- Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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Van Breedam W, Costers S, Vanhee M, Gagnon CA, Rodríguez-Gómez IM, Geldhof M, Verbeeck M, Van Doorsselaere J, Karniychuk U, Nauwynck HJ. Porcine reproductive and respiratory syndrome virus (PRRSV)-specific mAbs: supporting diagnostics and providing new insights into the antigenic properties of the virus. Vet Immunol Immunopathol 2011; 141:246-57. [PMID: 21470695 DOI: 10.1016/j.vetimm.2011.03.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 03/02/2011] [Accepted: 03/06/2011] [Indexed: 01/27/2023]
Abstract
The porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important viral pathogens in the swine industry. Despite great efforts of pig holders, veterinarians, researchers and vaccine developers, the virus still causes major production losses. It is clear that efficient and correct monitoring and rational development of vaccines are crucial in the combat against this pathogen. PRRSV-specific monoclonal antibodies (mAbs) are essential tools for both diagnostic and research purposes. This study describes the production of PRRSV GP3-, GP5- and N-specific hybridomas and an extensive characterization of the mAbs. The N-specific mAbs generated in this study appear to be useful tools for diagnostics, as they were found to react with genetically very different PRRSV isolates and may serve to discriminate between European and American type PRRSV isolates. These mAbs also allowed detection of the PRRSV N protein in both formalin-fixed, paraffin-embedded tissue sections and frozen tissue sections of PRRSV-infected lungs, further illustrating their diagnostic value. Different neutralization assays pointed out that none of the GP3- and GP5-specific mAbs tested shows virus-neutralizing capacity. This is noteworthy, as these mAbs recognize epitopes in the predicted ectodomains of their target protein and since the GP5-specific antibodies specifically react with the antigenic region that corresponds to the "major neutralizing epitope" suggested for American type PRRSV. The current findings argue against an important role of the identified antigenic regions in direct antibody-mediated neutralization of European type PRRSV in vivo. However, it is also clear that findings concerning a specific PRRSV epitope cannot always be generalized, as the antigenic determinants and their biological properties may differ radically between different virus isolates.
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Affiliation(s)
- Wander Van Breedam
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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Vanhee M, Costers S, Van Breedam W, Geldhof MF, Van Doorsselaere J, Nauwynck HJ. A variable region in GP4 of European-type porcine reproductive and respiratory syndrome virus induces neutralizing antibodies against homologous but not heterologous virus strains. Viral Immunol 2011; 23:403-13. [PMID: 20712485 DOI: 10.1089/vim.2010.0025] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) can induce severe reproductive failure in sows, and is involved in the porcine respiratory disease complex. The glycoprotein GP4 of the European prototype PRRSV strain Lelystad virus (LV) contains a linear neutralizing epitope that is located in a highly variable region. The current study aimed to evaluate the antibody response against this and other epitopes on GP4 to infection of pigs with European-type PRRSV. It was shown that three virus strains, differing in the region that corresponds to the neutralizing epitope on GP4 of LV, strongly induce antibodies against this area. Antibodies against the epitopes of the different virus strains were purified from polyclonal swine sera, and used in virus-neutralization tests on primary alveolar macrophages. This revealed that antibodies against the variable region in GP4 of different virus strains are able to neutralize infection with homologous but not heterologous virus strains.
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Affiliation(s)
- Merijn Vanhee
- Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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Costers S, Vanhee M, Van Breedam W, Van Doorsselaere J, Geldhof M, Nauwynck HJ. GP4-specific neutralizing antibodies might be a driving force in PRRSV evolution. Virus Res 2010; 154:104-13. [PMID: 20837070 DOI: 10.1016/j.virusres.2010.08.026] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 08/27/2010] [Accepted: 08/27/2010] [Indexed: 12/31/2022]
Abstract
The structural envelope glycoprotein GP4 of European porcine reproductive and respiratory syndrome virus (PRRSV) strains contains a highly variable neutralizing epitope that is susceptible to neutralizing antibody-mediated selective pressure in vitro. In this study, it was analyzed what happens with this neutralizing epitope during infection in vivo in the presence of neutralizing antibodies. A neutralizing antibody-mediated selective pressure was created in 30 pigs by vaccination prior to inoculation with infectious Lelystad virus (LV). Nine viable neutralizing antibody-escape variants were isolated from 9 of these pigs and their neutralizing antibody-escape mutant-identity was confirmed by the acquired resistance to neutralization by autologous neutralizing sera. Six out of 9 neutralizing antibody-escape variants contained aa substitutions in the GP4 neutralizing epitope and had become resistant to neutralization by a monoclonal antibody (mAb) against this epitope. In addition, in all 6 corresponding pigs, antibodies against this epitope were detected early in infection. In contrast to these 6 virus variants, the 3 other antibody-escape variants did not contain aa substitutions in the GP4 neutralizing epitope and were still sensitive to neutralization by the GP4-specific mAb. These antibody-escape variants were isolated from pigs that did not contain antibodies against this epitope early in infection. All these findings together strongly indicate that aa substitutions in the GP4 neutralizing epitope can abrogate antibody recognition, and that neutralizing antibodies might be responsible for the selection of neutralizing antibody-resistant variants with aa substitutions in the neutralizing epitope on GP4. In conclusion, this study indicates that neutralizing antibodies in pigs might be a driving force in the rapid evolution of the neutralizing epitope on GP4 of European PRRSV strains.
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Affiliation(s)
- Sarah Costers
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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Karniychuk UU, Geldhof M, Vanhee M, Van Doorsselaere J, Saveleva TA, Nauwynck HJ. Pathogenesis and antigenic characterization of a new East European subtype 3 porcine reproductive and respiratory syndrome virus isolate. BMC Vet Res 2010; 6:30. [PMID: 20525333 PMCID: PMC2898778 DOI: 10.1186/1746-6148-6-30] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 06/04/2010] [Indexed: 11/18/2022] Open
Abstract
Background Porcine reproductive and respiratory syndrome virus (PRRSV) is divided into a European and North American genotype. East European PRRSV isolates have been found to be of the European genotype, but form different subtypes. In the present study, PRRSV was isolated from a Belarusian farm with reproductive and respiratory failure and designated "Lena". Analyses revealed that Lena is a new East European subtype 3 PRRSV isolate. The main purpose of this investigation was to study the pathogenesis and antigenic characteristics of PRRSV (Lena). Results Obvious clinical and virological differences were observed between the animals inoculated with a recent European subtype 1 PRRSV isolate (Belgium A) and animals inoculated with PRRSV (Lena). Three out of six pigs inoculated with PRRSV (Belgium A) had anorexia and low fever at 3, 4 and 5 days post-inoculation (dpi). High fever, anorexia and depression were prominent signs in most pigs inoculated with PRRSV (Lena) between 2 and 28 dpi. Four pigs out of ten died during the experiment. Arcanobacterium pyogenes was isolated from lungs of one animal that died, and Streptococcus suis was isolated from lungs of one animal that was euthanized. The difference in viral titres in sera from PRRSV (Belgium A) and PRRSV (Lena)-infected pigs was statistically significant (p < 0.05) at 7, 10, 14 and 21 dpi. The highest viral titres in sera ranged from 104.8 to 106.1 TCID50/ml for PRRSV (Lena) whereas they ranged from 103.1 to 104.8 TCID50/ml for PRRSV (Belgium A). The replication of PRRSV (Lena) was further studied in depth. Viral titres ranged from 102.5 TCID50/100 mg to 105.6 TCID50/100 mg in nasal secretions between 3 and 14 dpi and from 102.8 TCID50/100 mg to 104.6 TCID50/100 mg in tonsillar scrapings between 3 and 21 dpi. High viral titres were detected in lungs (102.3-107.7 TCID50/g tissue), tonsils (102.0-106.2 TCID50/g tissue) and inguinal lymph nodes (102.2-106.6 TCID50/g tissue) until 35, 28 and 35 dpi, respectively. To examine the antigenic heterogeneity between the East European subtype 3 isolate Lena, the European subtype 1 strain Lelystad and the North American strain US5, sets of monospecific polyclonal antisera were tested in immunoperoxidase monolayer assays (IPMAs) with homologous and heterologous viral antigens. Heterologous antibody titres were significantly lower than homologous titres (p = 0.01-0.03) for antisera against PRRSV (Lena) at all sampling time points. For antisera against PRRSV (Lelystad) and PRRSV (US5), heterologous antibody titres were significantly lower than homologous titres at 14 and 21 dpi (p = 0.01-0.03) and at 10 and 14 dpi (p = 0.04), respectively. Conclusions Lena is a highly pathogenic East European subtype 3 PRRSV, which differs from European subtype 1 Lelystad and North American US5 strains at both the genetic and antigenic level.
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Affiliation(s)
- Uladzimir U Karniychuk
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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Vanhee M, Delputte PL, Delrue I, Geldhof MF, Nauwynck HJ. Experimental PRRSV vaccine induces virus-neutralising antibodies. Vet Rec 2010. [DOI: 10.1136/vr.b5639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Vanhee M, Delputte PL, Delrue I, Geldhof MF, Nauwynck HJ. Development of an experimental inactivated PRRSV vaccine that induces virus-neutralizing antibodies. Vet Res 2009; 40:63. [DOI: 10.1051/vetres/2009046] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Accepted: 08/11/2009] [Indexed: 11/14/2022] Open
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