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Parys A, Vandoorn E, Chiers K, Van Reeth K. Alternating 3 different influenza vaccines for swine in Europe for a broader antibody response and protection. Vet Res 2022; 53:44. [PMID: 35705993 PMCID: PMC9202218 DOI: 10.1186/s13567-022-01060-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/16/2022] [Indexed: 11/10/2022] Open
Abstract
Heterologous prime-boost vaccination with experimental or commercial influenza vaccines has been successful in various animal species. In this study, we have examined the efficacy of alternating 3 different European commercial swine influenza A virus (swIAV) vaccines: the trivalent Respiporc® FLU3 (TIV), the bivalent GRIPORK® (BIV) and the monovalent Respiporc® FLUpan H1N1 (MOV). Five groups of 6 pigs each received 3 vaccinations at 4-6 week intervals in a homologous or heterologous prime-boost regimen. A sixth group served as a mock-vaccinated challenge control. Four weeks after the last vaccination, pigs were challenged intranasally with a European avian-like H1N1 (1C.2.1) swIAV, which was antigenically distinct from the vaccine strains. One heterologous prime-boost group (TIV-BIV-MOV) had higher hemagglutination inhibition (HI) and neuraminidase inhibition antibody responses against a panel of antigenically distinct H1N1, H1N2 and H3N2 IAVs than the other heterologous prime-boost group (BIV-TIV-MOV) and the homologous prime-boost groups (3xTIV; 3xBIV; 3xMOV). Group TIV-BIV-MOV had seroprotective HI titers (≥ 40) against 56% of the tested viruses compared to 33% in group BIV-TIV-MOV and 22-39% in the homologous prime-boost groups. Post-challenge, group TIV-BIV-MOV was the single group with significantly reduced virus titers in all respiratory samples compared to the challenge control group. Our results suggest that the use of different commercial swIAV vaccines for successive vaccinations may result in broader antibody responses and protection than the traditional, homologous prime-boost vaccination regimens. In addition, the order in which the different vaccines are administered seems to affect the breadth of the antibody response and protection.
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Affiliation(s)
- Anna Parys
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Elien Vandoorn
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Koen Chiers
- Laboratory of Veterinary Pathology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Kristien Van Reeth
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium.
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Genetic and antigenic evolution of H1 swine influenza A viruses isolated in Belgium and the Netherlands from 2014 through 2019. Sci Rep 2021; 11:11276. [PMID: 34050216 PMCID: PMC8163766 DOI: 10.1038/s41598-021-90512-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/06/2021] [Indexed: 12/17/2022] Open
Abstract
Surveillance of swine influenza A viruses (swIAV) allows timely detection and identification of new variants with potential zoonotic risks. In this study, we aimed to identify swIAV subtypes that circulated in pigs in Belgium and the Netherlands between 2014 and 2019, and characterize their genetic and antigenic evolution. We subtyped all isolates and analyzed hemagglutinin sequences and hemagglutination inhibition assay data for H1 swIAV, which were the dominant HA subtype. We also analyzed whole genome sequences (WGS) of selected isolates. Out of 200 samples, 89 tested positive for swIAV. swIAV of H1N1, H1N2 and H3N2 subtypes were detected. Analysis of WGS of 18 H1 swIAV isolates revealed three newly emerged genotypes. The European avian-like H1 swIAV (lineage 1C) were predominant and accounted for 47.2% of the total isolates. They were shown to evolve faster than the European human-like H1 (1B lineage) swIAV, which represented 27% of the isolates. The 2009 pandemic H1 swIAV (lineage 1A) accounted for only 5.6% of the isolates and showed divergence from their precursor virus. These results point to the increasing divergence of swIAV and stress the need for continuous surveillance of swIAV.
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Lorbach JN, Fitzgerald T, Nolan C, Nolting JM, Treanor JJ, Topham DJ, Bowman AS. Gaps in Serologic Immunity against Contemporary Swine-Origin Influenza A Viruses among Healthy Individuals in the United States. Viruses 2021; 13:v13010127. [PMID: 33477472 PMCID: PMC7830885 DOI: 10.3390/v13010127] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/12/2021] [Accepted: 01/12/2021] [Indexed: 11/16/2022] Open
Abstract
Influenza A Viruses (IAV) in domestic swine (IAV-S) are associated with sporadic zoonotic transmission at the human–animal interface. Previous pandemic IAVs originated from animals, which emphasizes the importance of characterizing human immunity against the increasingly diverse IAV-S. We analyzed serum samples from healthy human donors (n = 153) using hemagglutination-inhibition (HAI) assay to assess existing serologic protection against a panel of contemporary IAV-S isolated from swine in the United States (n = 11). Age-specific seroprotection rates (SPR), which are the proportion of individuals with HAI ≥ 1:40, corresponded with lower or moderate pandemic risk classifications for the multiple IAV-S examined (one H1-δ1, one H1-δ2, three H3-IVA, one H3-IVB, one H3-IVF). Individuals born between 2004 and 2013 had SPRs of 0% for the five classified H3 subtype IAV-S, indicating youth may be particularly predisposed to infection with these viruses. Expansion of existing immunologic gaps over time could increase likelihood of future IAV-S spillover to humans and facilitate subsequent sustained human-to-human transmission resulting in disease outbreaks with pandemic potential.
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Affiliation(s)
- Joshua N. Lorbach
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.N.L.); (J.M.N.)
| | - Theresa Fitzgerald
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14627, USA; (T.F.); (C.N.); (D.J.T.)
| | - Carolyn Nolan
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14627, USA; (T.F.); (C.N.); (D.J.T.)
| | - Jacqueline M. Nolting
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.N.L.); (J.M.N.)
| | - John J. Treanor
- Department of Medicine, University of Rochester Medical Center, Rochester, NY 14627, USA;
| | - David J. Topham
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14627, USA; (T.F.); (C.N.); (D.J.T.)
| | - Andrew S. Bowman
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.N.L.); (J.M.N.)
- Correspondence:
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4
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Swine influenza virus: Current status and challenge. Virus Res 2020; 288:198118. [PMID: 32798539 DOI: 10.1016/j.virusres.2020.198118] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/19/2022]
Abstract
Since swine influenza virus was first isolated in 1930, it has become endemic in pigs worldwide. Although large amount of swine influenza vaccines has been used in swine industry, swine influenza still cannot be efficiently controlled and has been an important economic disease for swine industry. The high diversity and varied distribution of different subtypes and genotypes of swine influenza viruses circulating in pigs globally is a major challenge to produce broadly effective vaccines and control disease. Importantly, swine influenza virus is able to cross species barrier to infect humans and even caused influenza pandemic in 2009. Herein, current status and challenge of swine influenza viruses is reviewed and discussed.
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Abstract
Influenza A viruses (IAVs) of the Orthomyxoviridae virus family cause one of the most important respiratory diseases in pigs and humans. Repeated outbreaks and rapid spread of genetically and antigenically distinct IAVs represent a considerable challenge for animal production and public health. Bidirection transmission of IAV between pigs and people has altered the evolutionary dynamics of IAV, and a "One Health" approach is required to ameliorate morbidity and mortality in both hosts and improve control strategies. Although only subtypes of H1N1, H1N2, and H3N2 are endemic in swine around the world, considerable diversity can be found not only in the hemagglutinin (HA) and neuraminidase (NA) genes but in the remaining six genes as well. Human and swine IAVs have demonstrated a particular propensity for interspecies transmission, leading to regular and sometimes sustained incursions from man to pig and vice versa. The diversity of IAVs in swine remains a critical challenge in the diagnosis and control of this important pathogen for swine health and in turn contributes to a significant public health risk.
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Affiliation(s)
- Amy L Vincent
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA.
| | - Tavis K Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
| | - Kelly M Lager
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
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Hewitt JS, Karuppannan AK, Tan S, Gauger P, Halbur PG, Gerber PF, De Groot AS, Moise L, Opriessnig T. A prime-boost concept using a T-cell epitope-driven DNA vaccine followed by a whole virus vaccine effectively protected pigs in the pandemic H1N1 pig challenge model. Vaccine 2019; 37:4302-4309. [PMID: 31248687 DOI: 10.1016/j.vaccine.2019.06.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 01/08/2023]
Abstract
Influenza A virus (IAV) vaccines in pigs generally provide homosubtypic protection but fail to prevent heterologous infections. In this pilot study, the efficacy of an intradermal pDNA vaccine composed of conserved SLA class I and class II T cell epitopes (EPITOPE) against a homosubtypic challenge was compared to an intramuscular commercial inactivated whole virus vaccine (INACT) and a heterologous prime boost approach using both vaccines. Thirty-nine IAV-free, 3-week-old pigs were randomly assigned to one of five groups including NEG-CONTROL (unvaccinated, sham-challenged), INACT-INACT-IAV (vaccinated with FluSure XP® at 4 and 7 weeks, pH1N1 challenged), EPITOPE-INACT-IAV (vaccinated with PigMatrix EDV at 4 and FluSure XP® at 7 weeks, pH1N1 challenged), EPITOPE-EPITOPE-IAV (vaccinated with PigMatrix EDV at 4 and 7 weeks, pH1N1 challenged), and a POS-CONTROL group (unvaccinated, pH1N1 challenged). The challenge was done at 9 weeks of age and pigs were necropsied at day post challenge (dpc) 5. At the time of challenge, all INACT-INACT-IAV pigs, and by dpc 5 all EPITOPE-INACT-IAV pigs were IAV seropositive. IFNγ secreting cells, recognizing vaccine epitope-specific peptides and pH1N1 challenge virus were highest in the EPITOPE-INACT-IAV pigs at challenge. Macroscopic lung lesion scores were reduced in all EPITOPE-INACT-IAV pigs while INACT-INACT-IAV pigs exhibited a bimodal distribution of low and high scores akin to naïve challenged animals. No IAV antigen in lung tissues was detected at necropsy in the EPITOPE-INACT-IAV group, which was similar to naïve unchallenged pigs and different from all other challenged groups. Results suggest that the heterologous prime boost approach using an epitope-driven DNA vaccine followed by an inactivated vaccine was effective against a homosubtypic challenge, and further exploration of this vaccine approach as a practical control measure against heterosubtypic IAV infections is warranted.
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Affiliation(s)
- Joshua S Hewitt
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Anbu K Karuppannan
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Swan Tan
- Institute for Immunology and Informatics, Department of Cell and Molecular Biology, University of Rhode Island, Providence, RI, USA
| | - Phillip Gauger
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Patrick G Halbur
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Priscilla F Gerber
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, Australia
| | - Anne S De Groot
- Institute for Immunology and Informatics, Department of Cell and Molecular Biology, University of Rhode Island, Providence, RI, USA; EpiVax Inc., Providence, RI, USA
| | - Leonard Moise
- Institute for Immunology and Informatics, Department of Cell and Molecular Biology, University of Rhode Island, Providence, RI, USA; EpiVax Inc., Providence, RI, USA
| | - Tanja Opriessnig
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA; The Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK.
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7
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Zeller MA, Anderson TK, Walia RW, Vincent AL, Gauger PC. ISU FLUture: a veterinary diagnostic laboratory web-based platform to monitor the temporal genetic patterns of Influenza A virus in swine. BMC Bioinformatics 2018; 19:397. [PMID: 30382842 PMCID: PMC6211438 DOI: 10.1186/s12859-018-2408-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 10/03/2018] [Indexed: 01/25/2023] Open
Abstract
Background Influenza A Virus (IAV) causes respiratory disease in swine and is a zoonotic pathogen. Uncontrolled IAV in swine herds not only affects animal health, it also impacts production through increased costs associated with treatment and prevention efforts. The Iowa State University Veterinary Diagnostic Laboratory (ISU VDL) diagnoses influenza respiratory disease in swine and provides epidemiological analyses on samples submitted by veterinarians. Description To assess the incidence of IAV in swine and inform stakeholders, the ISU FLUture website was developed as an interactive visualization tool that allows the exploration of the ISU VDL swine IAV aggregate data in the clinical diagnostic database. The information associated with diagnostic cases has varying levels of completeness and is anonymous, but minimally contains: sample collection date, specimen type, and IAV subtype. Many IAV positive samples are sequenced, and in these cases, the hemagglutinin (HA) sequence and genetic classification are completed. These data are collected and presented on ISU FLUture in near real-time, and more than 6,000 IAV positive diagnostic cases and their epidemiological and evolutionary information since 2003 are presented to date. The database and web interface provides rapid and unique insight into the trends of IAV derived from both large- and small-scale swine farms across the United States of America. Conclusion ISU FLUture provides a suite of web-based tools to allow stakeholders to search for trends and correlations in IAV case metadata in swine from the ISU VDL. Since the database infrastructure is updated in near real-time and is integrated within a high-volume veterinary diagnostic laboratory, earlier detection is now possible for emerging IAV in swine that subsequently cause vaccination and control challenges. The access to real-time swine IAV data provides a link with the national USDA swine IAV surveillance system and allows veterinarians to make objective decisions regarding the management and control of IAV in swine. The website is publicly accessible at http://influenza.cvm.iastate.edu. Electronic supplementary material The online version of this article (10.1186/s12859-018-2408-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael A Zeller
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA, USA.,Department of Veterinary Microbiology & Preventive Medicine, Iowa State University, Ames, IA, USA
| | - Tavis K Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
| | - Rasna W Walia
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
| | - Amy L Vincent
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
| | - Phillip C Gauger
- Department of Veterinary Diagnostic & Production Animal Medicine, Iowa State University, 1575 Vet Med, 1850 Christensen Dr, Ames, IA, 50011-1134, USA.
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Rajao DS, Anderson TK, Kitikoon P, Stratton J, Lewis NS, Vincent AL. Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States. Virology 2018; 518:45-54. [PMID: 29453058 PMCID: PMC8608352 DOI: 10.1016/j.virol.2018.02.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/03/2018] [Accepted: 02/05/2018] [Indexed: 01/02/2023]
Abstract
Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evolution. Here, we characterized the genetic and antigenic evolution of contemporary swine H1N1 and H1N2 viruses representing clusters H1-α (1A.1), H1-β (1A.2), H1pdm (1A.3.3.2), H1-γ (1A.3.3.3), H1-δ1 (1B.2.2), and H1-δ2 (1B.2.1) currently circulating in pigs in the United States. The δ1-viruses diversified into two new genetic clades, H1-δ1a (1B.2.2.1) and H1-δ1b (1B.2.2.2), which were also antigenically distinct from the earlier H1-δ1-viruses. Further characterization revealed that a few key amino acid changes were associated with antigenic divergence in these groups. The continued genetic and antigenic evolution of contemporary H1 viruses might lead to loss of vaccine cross-protection that could lead to significant economic impact to the swine industry, and represents a challenge to public health initiatives that attempt to minimize swine-to-human IAV transmission.
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Affiliation(s)
- Daniela S Rajao
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Avenue, PO Box 70, Ames, IA 50010, USA
| | - Tavis K Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Avenue, PO Box 70, Ames, IA 50010, USA
| | - Pravina Kitikoon
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Avenue, PO Box 70, Ames, IA 50010, USA
| | - Jered Stratton
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Avenue, PO Box 70, Ames, IA 50010, USA
| | - Nicola S Lewis
- Department of Zoology, University of Cambridge, Downing St, Cambridge CB2 3EJ, UK
| | - Amy L Vincent
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Avenue, PO Box 70, Ames, IA 50010, USA.
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Rajão DS, Walia RR, Campbell B, Gauger PC, Janas-Martindale A, Killian ML, Vincent AL. Reassortment between Swine H3N2 and 2009 Pandemic H1N1 in the United States Resulted in Influenza A Viruses with Diverse Genetic Constellations with Variable Virulence in Pigs. J Virol 2017; 91:e01763-16. [PMID: 27928015 PMCID: PMC5286888 DOI: 10.1128/jvi.01763-16] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 12/01/2016] [Indexed: 11/20/2022] Open
Abstract
Repeated spillovers of the H1N1 pandemic virus (H1N1pdm09) from humans to pigs resulted in substantial evolution of influenza A viruses infecting swine, contributing to the genetic and antigenic diversity of influenza A viruses (IAV) currently circulating in swine. The reassortment with endemic swine viruses and maintenance of some of the H1N1pdm09 internal genes resulted in the circulation of different genomic constellations in pigs. Here, we performed a whole-genome phylogenetic analysis of 368 IAV circulating in swine from 2009 to 2016 in the United States. We identified 44 different genotypes, with the most common genotype (32.33%) containing a clade IV-A HA gene, a 2002-lineage NA gene, an M-pdm09 gene, and remaining gene segments of triple reassortant internal gene (TRIG) origin. To understand how different genetic constellations may relate to viral fitness, we compared the pathogenesis and transmission in pigs of six representative genotypes. Although all six genotypes efficiently infected pigs, they resulted in different degrees of pathology and viral shedding. These results highlight the vast H3N2 genetic diversity circulating in U.S. swine after 2009. This diversity has important implications in the control of this disease by the swine industry, as well as a potential risk for public health if swine-adapted viruses with H1N1pdm09 genes have an increased risk to humans, as occurred in the 2011-2012 and 2016 human variant H3N2v cases associated with exhibition swine. IMPORTANCE People continue to spread the 2009 H1N1 pandemic (H1N1pdm09) IAV to pigs, allowing H1N1pdm09 to reassort with endemic swine IAV. In this study, we determined the 8 gene combinations of swine H3N2 IAV detected from 2009 to 2016. We identified 44 different genotypes of H3N2, the majority of which contained at least one H1N1pdm09 gene segment. We compared six representative genotypes of H3N2 in pigs. All six genotypes efficiently infected pigs, but they resulted in different degrees of lung damage and viral shedding. These results highlight the vast genetic diversity of H3N2 circulating in U.S. swine after 2009, with important implications for the control of IAV for the swine industry. Because H1N1pdm09 is also highly adapted to humans, these swine viruses pose a potential risk to public health if swine-adapted viruses with H1N1pdm09 genes also have an increased risk for human infection.
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Affiliation(s)
- Daniela S Rajão
- Virus and Prion Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa, USA
| | - Rasna R Walia
- Virus and Prion Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa, USA
| | - Brian Campbell
- Virus and Prion Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa, USA
| | - Phillip C Gauger
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Alicia Janas-Martindale
- Diagnostic Virology Laboratory, National Veterinary Services Laboratories, Science, Technology and Analysis Services, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, Ames, Iowa, USA
| | - Mary Lea Killian
- Diagnostic Virology Laboratory, National Veterinary Services Laboratories, Science, Technology and Analysis Services, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, Ames, Iowa, USA
| | - Amy L Vincent
- Virus and Prion Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa, USA
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Anderson TK, Macken CA, Lewis NS, Scheuermann RH, Van Reeth K, Brown IH, Swenson SL, Simon G, Saito T, Berhane Y, Ciacci-Zanella J, Pereda A, Davis CT, Donis RO, Webby RJ, Vincent AL. A Phylogeny-Based Global Nomenclature System and Automated Annotation Tool for H1 Hemagglutinin Genes from Swine Influenza A Viruses. mSphere 2016; 1:e00275-16. [PMID: 27981236 PMCID: PMC5156671 DOI: 10.1128/msphere.00275-16] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/10/2016] [Indexed: 12/30/2022] Open
Abstract
The H1 subtype of influenza A viruses (IAVs) has been circulating in swine since the 1918 human influenza pandemic. Over time, and aided by further introductions from nonswine hosts, swine H1 viruses have diversified into three genetic lineages. Due to limited global data, these H1 lineages were named based on colloquial context, leading to a proliferation of inconsistent regional naming conventions. In this study, we propose rigorous phylogenetic criteria to establish a globally consistent nomenclature of swine H1 virus hemagglutinin (HA) evolution. These criteria applied to a data set of 7,070 H1 HA sequences led to 28 distinct clades as the basis for the nomenclature. We developed and implemented a web-accessible annotation tool that can assign these biologically informative categories to new sequence data. The annotation tool assigned the combined data set of 7,070 H1 sequences to the correct clade more than 99% of the time. Our analyses indicated that 87% of the swine H1 viruses from 2010 to the present had HAs that belonged to 7 contemporary cocirculating clades. Our nomenclature and web-accessible classification tool provide an accurate method for researchers, diagnosticians, and health officials to assign clade designations to HA sequences. The tool can be updated readily to track evolving nomenclature as new clades emerge, ensuring continued relevance. A common global nomenclature facilitates comparisons of IAVs infecting humans and pigs, within and between regions, and can provide insight into the diversity of swine H1 influenza virus and its impact on vaccine strain selection, diagnostic reagents, and test performance, thereby simplifying communication of such data. IMPORTANCE A fundamental goal in the biological sciences is the definition of groups of organisms based on evolutionary history and the naming of those groups. For influenza A viruses (IAVs) in swine, understanding the hemagglutinin (HA) genetic lineage of a circulating strain aids in vaccine antigen selection and allows for inferences about vaccine efficacy. Previous reporting of H1 virus HA in swine relied on colloquial names, frequently with incriminating and stigmatizing geographic toponyms, making comparisons between studies challenging. To overcome this, we developed an adaptable nomenclature using measurable criteria for historical and contemporary evolutionary patterns of H1 global swine IAVs. We also developed a web-accessible tool that classifies viruses according to this nomenclature. This classification system will aid agricultural production and pandemic preparedness through the identification of important changes in swine IAVs and provides terminology enabling discussion of swine IAVs in a common context among animal and human health initiatives.
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Affiliation(s)
- Tavis K. Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa, USA
| | | | - Nicola S. Lewis
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Richard H. Scheuermann
- J. Craig Venter Institute, La Jolla, California, USA
- Department of Pathology, University of California, San Diego, California, USA
| | - Kristien Van Reeth
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Ian H. Brown
- Animal and Plant Health Agency, Weybridge, United Kingdom
| | | | - Gaëlle Simon
- ANSES, Ploufragan-Plouzané Laboratory, Swine Virology Immunology Unit, Ploufragan, France
| | - Takehiko Saito
- Division of Transboundary Animal Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Ibaraki, Japan
| | - Yohannes Berhane
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, Manitoba, Canada
| | - Janice Ciacci-Zanella
- Embrapa Swine and Poultry, Animal Health and Genetic Laboratory, Concórdia, SC, Brazil
| | - Ariel Pereda
- Instituto de Patobiología, CICVyA INTA, Hurlingham, Buenos Aires, Argentina
| | - C. Todd Davis
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ruben O. Donis
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Richard J. Webby
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Amy L. Vincent
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, Iowa, USA
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11
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De Vleeschauwer A, Qiu Y, Van Reeth K. Vaccination-challenge studies with a Port Chalmers/73 (H3N2)-based swine influenza virus vaccine: Reflections on vaccine strain updates and on the vaccine potency test. Vaccine 2015; 33:2360-6. [PMID: 25804707 DOI: 10.1016/j.vaccine.2015.03.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/18/2015] [Accepted: 03/11/2015] [Indexed: 11/30/2022]
Abstract
The human A/Port Chalmers/1/73 (H3N2) influenza virus strain, the supposed ancestor of European H3N2 swine influenza viruses (SIVs), was used in most commercial SIV vaccines in Europe until recently. If manufacturers want to update vaccine strains, they have to perform laborious intratracheal (IT) challenge experiments and demonstrate reduced virus titres in the lungs of vaccinated pigs. We aimed to examine (a) the ability of a Port Chalmers/73-based commercial vaccine to induce cross-protection against a contemporary European H3N2 SIV and serologic cross-reaction against H3N2 SIVs from Europe and North America and (b) the validity of intranasal (IN) challenge and virus titrations of nasal swabs as alternatives for IT challenge and titrations of lung tissue in vaccine potency tests. Pigs were vaccinated with Suvaxyn Flu(®) and challenged by the IT or IN route with sw/Gent/172/08. Post-vaccination sera were examined in haemagglutination-inhibition assays against vaccine and challenge strains and additional H3N2 SIVs from Europe and North America, including an H3N2 variant virus. Tissues of the respiratory tract and nasal swabs were collected 3 days post challenge (DPCh) and from 0-7 DPCh, respectively, and examined by virus titration. Two vaccinations consistently induced cross-reactive antibodies against European H3N2 SIVs from 1998-2012, but minimal or undetectable antibody titres against North American viruses. Challenge virus titres in the lungs, trachea and nasal mucosa of the vaccinated pigs were significantly reduced after both IT and IN challenge. Yet the reduction of virus titres and nasal shedding was greater after IT challenge. The Port Chalmers/73-based vaccine still offered protection against a European H3N2 SIV isolated 35 years later and with only 86.9% amino acid homology in its HA1, but it is unlikely to protect against H3N2 SIVs that are endemic in North America. We use our data to reflect on vaccine strain updates and on the vaccine potency test.
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Affiliation(s)
- Annebel De Vleeschauwer
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Yu Qiu
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Kristien Van Reeth
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
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12
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European surveillance network for influenza in pigs: surveillance programs, diagnostic tools and Swine influenza virus subtypes identified in 14 European countries from 2010 to 2013. PLoS One 2014; 9:e115815. [PMID: 25542013 PMCID: PMC4277368 DOI: 10.1371/journal.pone.0115815] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 11/26/2014] [Indexed: 12/02/2022] Open
Abstract
Swine influenza causes concern for global veterinary and public health officials. In continuing two previous networks that initiated the surveillance of swine influenza viruses (SIVs) circulating in European pigs between 2001 and 2008, a third European Surveillance Network for Influenza in Pigs (ESNIP3, 2010–2013) aimed to expand widely the knowledge of the epidemiology of European SIVs. ESNIP3 stimulated programs of harmonized SIV surveillance in European countries and supported the coordination of appropriate diagnostic tools and subtyping methods. Thus, an extensive virological monitoring, mainly conducted through passive surveillance programs, resulted in the examination of more than 9 000 herds in 17 countries. Influenza A viruses were detected in 31% of herds examined from which 1887 viruses were preliminary characterized. The dominating subtypes were the three European enzootic SIVs: avian-like swine H1N1 (53.6%), human-like reassortant swine H1N2 (13%) and human-like reassortant swine H3N2 (9.1%), as well as pandemic A/H1N1 2009 (H1N1pdm) virus (10.3%). Viruses from these four lineages co-circulated in several countries but with very different relative levels of incidence. For instance, the H3N2 subtype was not detected at all in some geographic areas whereas it was still prevalent in other parts of Europe. Interestingly, H3N2-free areas were those that exhibited highest frequencies of circulating H1N2 viruses. H1N1pdm viruses were isolated at an increasing incidence in some countries from 2010 to 2013, indicating that this subtype has become established in the European pig population. Finally, 13.9% of the viruses represented reassortants between these four lineages, especially between previous enzootic SIVs and H1N1pdm. These novel viruses were detected at the same time in several countries, with increasing prevalence. Some of them might become established in pig herds, causing implications for zoonotic infections.
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13
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Monger VR, Stegeman JA, Koop G, Dukpa K, Tenzin T, Loeffen WLA. Seroprevalence and associated risk factors of important pig viral diseases in Bhutan. Prev Vet Med 2014; 117:222-32. [PMID: 25081946 DOI: 10.1016/j.prevetmed.2014.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 07/04/2014] [Accepted: 07/05/2014] [Indexed: 10/25/2022]
Abstract
A cross-sectional serological study was conducted in Bhutan between October 2011 and February 2012 to determine the prevalence of antibodies to classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), swine influenza virus (SIV) subtype H1N1 and Aujeszky's disease virus (ADV). Furthermore, risk factors for the seropositive status were investigated. Antibodies to SIV, subtype H1N1 (likely pandemic H1N1 2009) were detected in 49% of the pigs in the government farms, and 8% of the village backyard pigs. For PCV2, these percentages were 73% and 37% respectively. For CSFV, the percentages were closer together, with 62% and 52% respectively. It should be taken into consideration that vaccination of piglets is routine in the government herds, and that piglets distributed to backyard farms are also vaccinated. No direct evidence of CSFV infections was found, either by clinical signs or virus isolation. Antibodies to PRRSV and Aujeszky's disease, on the other hand, were not found at all. Risk factors found are mainly related to practices of swill feeding and other biosecurity measures. For CSFV, these were swill feeding (OR=2.25, 95% CI: 1.01-4.99) and contact with neighbour's pigs (OR=0.31, 95% CI: 0.13-0.75). For PCV2 this was lending of boars for local breeding purposes (OR=3.30, 95% CI: 1.43-7.59). The results of this study showed that PCV2 and SIV infections are important in pigs in Bhutan and thus appropriate control strategies need to be designed and applied which could involve strict regulation on the import of live pigs and vaccination against these diseases.
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Affiliation(s)
- V R Monger
- Central Veterinary Institute of Wageningen UR, Department of Virology, P.O. Box 65, 8200 AB Lelystad, The Netherlands; National Centre for Animal Health, Department of Livestock, Ministry of Agriculture and Forests, Thimphu, Bhutan.
| | - J A Stegeman
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL Utrecht, The Netherlands
| | - G Koop
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL Utrecht, The Netherlands
| | - K Dukpa
- National Centre for Animal Health, Department of Livestock, Ministry of Agriculture and Forests, Thimphu, Bhutan
| | - T Tenzin
- National Centre for Animal Health, Department of Livestock, Ministry of Agriculture and Forests, Thimphu, Bhutan
| | - W L A Loeffen
- Central Veterinary Institute of Wageningen UR, Department of Virology, P.O. Box 65, 8200 AB Lelystad, The Netherlands
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Anderson TK, Nelson MI, Kitikoon P, Swenson SL, Korslund JA, Vincent AL. Population dynamics of cocirculating swine influenza A viruses in the United States from 2009 to 2012. Influenza Other Respir Viruses 2014; 7 Suppl 4:42-51. [PMID: 24224819 DOI: 10.1111/irv.12193] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Understanding the ecology and evolution of influenza A viruses (IAV) in mammalian hosts is critical to reduce disease burden in production animals and lower zoonotic infection risk in humans. Recent advances in influenza surveillance in US swine populations allow for timely epidemiological, phylogenetic, and virological analyses that monitor emergence of novel viruses and assess changes in viral population dynamics. METHODS To better understand IAV in the North American swine population, we undertook a phylogenetic analysis of 1075 HA, 1049 NA, and 1040 M sequences of IAV isolated from US swine during 2009-2012 through voluntary and anonymous submissions to the US Department of Agriculture IAV swine surveillance system. RESULTS Analyses revealed changes in population dynamics among multiple clades of A/H1N1, A/H3N2, and A/H1N2 cocirculating in US swine populations during 2009-2012. Viral isolates were categorized into one of seven genetically and antigenically distinct hemagglutinin lineages: H1α, H1β, H1γ, H1δ1, H1δ2, H1pdm09, and H3 cluster IV. There was an increase in occurrence of H1δ1 in samples submitted, with a concurrent decrease in H1pdm09. H3 cluster IV exhibited increasing diversification, warranting a re-evaluation of phylogenetic nomenclature criteria. Although H3N2 represented 25% of identified viruses, this subtype was reported in increasing proportion of sequenced isolates since late 2011. CONCLUSIONS Surveillance and reporting of IAV in US swine have increased since 2009, and we demonstrate a period of expanded viral diversity. These data may be used to inform intervention strategies of vaccine and diagnostic updates and changes in swine health management.
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Affiliation(s)
- Tavis K Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA
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15
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Abstract
Influenza A viruses (IAV) of the Orthomyxoviridae virus family cause one of the most important respiratory diseases in pigs as well as humans. Repeated outbreaks and rapid spread of genetically and antigenically distinct IAVs represent a considerable challenge for animal production and public health. This overlap between human and animal health is a prime example of the "One Health" concept. Although only subtypes of H1N1, H1N2, and H3N2 are endemic in swine around the world, considerable diversity can be found not only in the hemagglutinin (HA) and neuraminidase (NA) genes, but in the other 6 genes as well. Human and swine IAV have demonstrated a particular propensity for interspecies transmission in the past century, leading to regular and sometimes sustained, incursions from man to pig and vice versa. The diversity of IAV in swine remains one of the critical challenges in diagnosis and control of this important pathogen for swine health, and in turn contributes to a significant public health risk.
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16
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Abstract
Swine influenza is an acute respiratory disease of pigs caused by influenza A virus (IAV) and characterized by fever followed by lethargy, anorexia, and serous nasal discharge. The disease progresses rapidly and may be complicated when associated with other respiratory pathogens. IAV is one of the most prevalent respiratory pathogens of swine, resulting in substantial economic burden to pork producers. In the past 10-15 years, a dramatic evolution of the IAV in U.S. swine has occurred, resulting in the co-circulation of many antigenically distinct IAV strains, derived from 13 phylogenetically distinct hemagglutinin clusters of H1 and H3 viruses. Vaccination is the most common strategy to prevent influenza in pigs, however, the current diverse IAV epidemiology poses a challenge for the production of efficacious and protective vaccines. A concern regarding the use of traditional inactivated vaccines is the possibility of inducing vaccine-associated enhanced respiratory disease (VAERD) when vaccine virus strains are mismatched with the infecting strain. In this review, we discuss the current epidemiology and pathogenesis of swine influenza in the United States, different vaccines platforms with potential to control influenza in pigs, and the factors associated with vaccine-associated disease enhancement.
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Meng F, Punyadarsaniya D, Uhlenbruck S, Hennig-Pauka I, Schwegmann-Wessels C, Ren X, Dürrwald R, Herrler G. Replication characteristics of swine influenza viruses in precision-cut lung slices reflect the virulence properties of the viruses. Vet Res 2013; 44:110. [PMID: 24225030 PMCID: PMC3840634 DOI: 10.1186/1297-9716-44-110] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 10/29/2013] [Indexed: 12/30/2022] Open
Abstract
Precision-cut lung slices of pigs were infected with five swine influenza A viruses of different subtypes (A/sw/Potsdam/15/1981 H1N1, A/sw/Bad Griesbach/IDT5604/2006 H1N1, A/sw/Bakum/1832/2000 H1N2, A/sw/Damme/IDT5673/2006 H3N2, A/sw/Herford/IDT5932/2007 H3N2). The viruses were able to infect ciliated and mucus-producing cells. The infection of well-differentiated respiratory epithelial cells by swine influenza A viruses was analyzed with respect to the kinetics of virus release into the supernatant. The highest titres were determined for H3N2/2006 and H3N2/2007 viruses. H1N1/1981 and H1N2/2000 viruses replicated somewhat slower than the H3N2 viruses whereas a H1N1 strain from 2006 multiplied at significantly lower titres than the other strains. Regarding their ability to induce a ciliostatic effect, the two H3N2 strains were found to be most virulent. H1N1/1981 and H1N2/2000 were somewhat less virulent with respect to their effect on ciliary activity. The lowest ciliostatic effect was observed with H1N1/2006. In order to investigate whether this finding is associated with a corresponding virulence in the host, pigs were infected experimentally with H3N2/2006, H1N2/2000, H1N1/1981 and H1N1/2006 viruses. The H1N1/2006 virus was significantly less virulent than the other viruses in pigs which was in agreement with the results obtained by the in vitro-studies. These findings offer the possibility to develop an ex vivo-system that is able to assess virulence of swine influenza A viruses.
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Affiliation(s)
| | | | | | | | | | | | | | - Georg Herrler
- Institute of Virology University of Veterinary Medicine, Hannover, Germany.
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18
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Vincent A, Awada L, Brown I, Chen H, Claes F, Dauphin G, Donis R, Culhane M, Hamilton K, Lewis N, Mumford E, Nguyen T, Parchariyanon S, Pasick J, Pavade G, Pereda A, Peiris M, Saito T, Swenson S, Van Reeth K, Webby R, Wong F, Ciacci-Zanella J. Review of Influenza A Virus in Swine Worldwide: A Call for Increased Surveillance and Research. Zoonoses Public Health 2013; 61:4-17. [DOI: 10.1111/zph.12049] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Indexed: 11/30/2022]
Affiliation(s)
- A. Vincent
- Virus and Prion Research Unit; USDA-ARS NADC; Ames IA USA
| | - L. Awada
- World Organization for Animal Health (OIE); Paris France
| | - I. Brown
- Animal Health and Veterinary Laboratories Agency; Weybridge UK
| | - H. Chen
- Harbin Veterinary Research Institute; Harbin China
| | - F. Claes
- Food and Agriculture Organization of the United Nations (FAO); Rome Italy
| | - G. Dauphin
- Food and Agriculture Organization of the United Nations (FAO); Rome Italy
| | | | - M. Culhane
- University of Minnesota Veterinary Diagnostic Lab; St. Paul MN USA
| | - K. Hamilton
- World Organization for Animal Health (OIE); Paris France
| | - N. Lewis
- Department of Zoology; University of Cambridge; Cambridge UK
| | - E. Mumford
- World Health Organization (WHO); Geneva Switzerland
| | - T. Nguyen
- Department of Animal Health; National Centre for Veterinary Diagnostics; Hanoi Vietnam
| | | | - J. Pasick
- Canadian Food Inspection Agency; Winnepeg Canada
| | - G. Pavade
- World Organization for Animal Health (OIE); Paris France
| | - A. Pereda
- Instituto de Virología - INTA; Buenos Aires Argentina
| | - M. Peiris
- Hong Kong University; Hong Kong City Hong Kong
| | - T. Saito
- National Institute of Animal Health; Ibaraki Japan
| | | | | | - R. Webby
- St. Jude Children's Research Hospital; Memphis TN USA
| | - F. Wong
- Australian Animal Health Laboratory; CSIRO Livestock Industries; Geelong Vic. Australia
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Qiu Y, van der Meulen K, Van Reeth K. Prior infection of pigs with a recent human H3N2 influenza virus confers minimal cross-protection against a European swine H3N2 virus. Influenza Other Respir Viruses 2013; 7:1260-8. [PMID: 23551882 PMCID: PMC4634290 DOI: 10.1111/irv.12105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2013] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND H3N2 influenza viruses circulating in humans and European pigs originate from the pandemic A/Hong Kong/68 virus. Because of slower antigenic drift in swine, the antigenic divergence between swine and human viruses has been increasing. It remains unknown to what extent this results in a reduced cross-protection between recent human and swine H3N2 influenza viruses. OBJECTIVES We examined whether prior infection of pigs with an old [A/Victoria/3/75 (A/Vic/75)] or a more recent [A/Wisconsin/67/05 (A/Wis/05)] human H3N2 virus protected against a European swine H3N2 virus [sw/Gent/172/08 (sw/Gent/08)]. Genetic and antigenic relationships between sw/Gent/08 and a selection of human H3N2 viruses were also assessed. RESULTS After challenge with sw/Gent/08, all challenge controls had high virus titers in the entire respiratory tract at 3 days post-challenge and nasal virus excretion for 5-6 days. Prior infection with sw/Gent/08 or A/Vic/75 offered complete virological protection against challenge. Pigs previously inoculated with A/Wis/05 showed similar virus titers in the respiratory tract as challenge controls, but the mean duration of nasal shedding was 1·3 days shorter. Unlike sw/Gent/08- and A/Vic/75-inoculated pigs, A/Wis/05-inoculated pigs lacked cross-reactive neutralizing antibodies against sw/Gent/08 before challenge, but they showed a more rapid antibody response to sw/Gent/08 than challenge controls after challenge. Cross-protection and serological responses correlated with genetic and antigenic differences. CONCLUSIONS Infection immunity to a recent human H3N2 virus confers minimal cross-protection against a European swine H3N2 virus. We discuss our findings with regard to the recent zoonotic infections of humans in the United States with a swine-origin H3N2 variant virus.
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Affiliation(s)
- Yu Qiu
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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20
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Antigenic variation of H1N1, H1N2 and H3N2 swine influenza viruses in Japan and Vietnam. Arch Virol 2013; 158:859-76. [PMID: 23435952 DOI: 10.1007/s00705-013-1616-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 12/13/2012] [Indexed: 10/27/2022]
Abstract
The antigenicity of the influenza A virus hemagglutinin is responsible for vaccine efficacy in protecting pigs against swine influenza virus (SIV) infection. However, the antigenicity of SIV strains currently circulating in Japan and Vietnam has not been well characterized. We examined the antigenicity of classical H1 SIVs, pandemic A(H1N1)2009 (A(H1N1)pdm09) viruses, and seasonal human-lineage SIVs isolated in Japan and Vietnam. A hemagglutination inhibition (HI) assay was used to determine antigenic differences that differentiate the recent Japanese H1N2 and H3N2 SIVs from the H1N1 and H3N2 domestic vaccine strains. Minor antigenic variation between pig A(H1N1)pdm09 viruses was evident by HI assay using 13 mAbs raised against homologous virus. A Vietnamese H1N2 SIV, whose H1 gene originated from a human strain in the mid-2000s, reacted poorly with post-infection ferret serum against human vaccine strains from 2000-2010. These results provide useful information for selection of optimal strains for SIV vaccine production.
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21
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Abstract
Avian-like H1N1 and reassortant H3N2 and H1N2 influenza A viruses with a human-like haemagglutinin have been co-circulating in swine in Europe for more than a decade. We aimed to examine the infection dynamics of the three swine influenza virus (SIV) lineages at the farm level, and to identify possible regional and seasonal variations in their circulation. Sera were collected from six successive generations of fattening pigs (2006-2008) in a total 80 farrow-to-finish herds in Belgium, Italy, France and Spain and examined for antibodies against the three SIVs in haemagglutination inhibition tests. Overall, in all regions and periods, 9.7% of all farms were negative for SIV, 49% were infected with one subtype, 38% with two subtypes and 3.9% with all three SIVs. We found serological evidence for the circulation of all three subtypes in Belgium, Italy and Spain, while only infections with H1N1 and H1N2 SIVs were detected in France. Despite temporary changes in the circulation of H1N2 in Belgium and in Spain, there was no true seasonal variation. The exact combination of subtypes on the same farm differed in each of the sampling periods. On the other hand, 21 farms were found to be consistently infected with the same SIV subtype throughout the study. This can either be explained by the persistence of the virus in a farm, or by the periodical re-introduction of SIVs of the same subtype.
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22
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Feng E, Ye D, Li J, Zhang D, Wang J, Zhao F, Hilgenfeld R, Zheng M, Jiang H, Liu H. Recent advances in neuraminidase inhibitor development as anti-influenza drugs. ChemMedChem 2012; 7:1527-36. [PMID: 22807317 DOI: 10.1002/cmdc.201200155] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 06/13/2012] [Indexed: 11/06/2022]
Abstract
The recent emergence of the highly pathogenic H5N1 subtype of avian influenza virus (AIV) and of the new type of human influenza A (H1N1) have emphasized the need for the development of effective anti-influenza drugs. Presently, neuraminidase (NA) inhibitors are widely used in the treatment and prophylaxis of human influenza virus infection, and tremendous efforts have been made to develop more potent NA inhibitors to combat resistance and new influenza viruses. In this review, we discuss the structural characteristics of NA catalytic domains and the recent developments of new NA inhibitors using structure-based drug design strategies. These drugs include analogues of zanamivir, analogues of oseltamivir, analogues of peramivir, and analogues of aromatic carboxylic acid and present promising options for therapeutics or leads for further development of NA inhibitors that may be useful in the event of a future influenza pandemic.
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Affiliation(s)
- Enguang Feng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Graduate School of the Chinese Academy of Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai, 201203, China
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23
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Abstract
In Europe, swine influenza is considered one of the most important primary pathogens of swine respiratory disease and infection is primarily with H1N1, H1N2 and H3N2 influenza A viruses. The antigenetic characteristics of these viruses distinguish them from others circulating at a global level in pigs. These viruses have remained endemic in European pig populations but significant differences in the circulation of these strains occur at a regional level across Europe. The dynamic of co-circulation of viruses, impact of prior immunity, husbandry practices and other local factors all contribute to the complex epidemiology. Surveillance programmes in European pigs did not reveal the presence of pandemic H1N1 virus prior to its detection in humans in 2009 but there is evidence that the virus can be maintained in European pigs even when there are relatively good levels of herd immunity to other H1 viruses. Evidence for the pig as a 'mixing vessel' of influenza viruses of non-swine-origin has been demonstrated in Europe on several occasions. Furthermore significant and highly variable genetic diversity occurs at the whole genome level for all virus subtypes and this has contributed to changing patterns of virus epidemiology over time.
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Abstract
Influenza is a highly contagious respiratory pathogen that continues to evolve and threaten both veterinary and human public health. Influenza A viruses are continually undergoing molecular changes through mutations, reassortment, and, in rare instances, recombination. While they generally cause benign enteric infection in their natural reservoir of wild aquatic birds, they can cause catastrophic and potentially lethal disease outbreaks in humans, domestic poultry, and pigs when they cross the host species barrier. The continuing circulation of highly pathogenic (HP) H5N1 influenza viruses in domestic poultry in parts of Eurasia and the emergence and global spread of pandemic H1N1 2009 are current examples of influenza evolution. The spread of both HP H5N1 and pandemic H1N1 to multiple hosts emphasizes the potential for continued evolution. In this review, we discuss the current understanding of influenza A virus structure and strategies of variation, with a specific focus on the HP H5N1 and pandemic H1N1 influenza viruses. Additionally, we attempt to identify the gaps in our knowledge of H5N1 and pandemic H1N1 influenza viruses. These gaps include (i) an understanding of the molecular determinants of influenza virus and the host that permit efficient transmissibility and pandemic potential, (ii) the urgent need for prospective surveillance in apparently healthy swine, (iii) the molecular determinants of high pathogenicity in poultry, pigs, and people, (iv) the genetic basis of host susceptibility, (v) antigenic variability, (vi) the use of vaccine to control influenza, (vii) the role of wild birds as the reservoir of highly pathogenic avian influenza, (viii) the problems with vaccines, (ix) seasonality, (x) co-infections, and (xi) anti-influenza drug resistance. Our failure to eradicate HP H5N1 globally and to explain why H5N1 does not transmit efficiently in humans while an H1N1 pandemic virus of swine origin spread globally in months are key examples that emphasize the critical need to bridge these knowledge gaps. Future directions in influenza research that will help us resolve each of the above-mentioned knowledge gaps include complete genomic and proteomic analysis of both the virus and the host with the prospect of designing new control strategies and the development of genetically resistant hosts.
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Kitikoon P, Vincent AL, Janke BH, Erickson B, Strait EL, Yu S, Gramer MR, Thacker EL. Swine influenza matrix 2 (M2) protein contributes to protection against infection with different H1 swine influenza virus (SIV) isolates. Vaccine 2009; 28:523-31. [PMID: 19837089 DOI: 10.1016/j.vaccine.2009.09.130] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 09/18/2009] [Accepted: 09/30/2009] [Indexed: 11/25/2022]
Abstract
A swine influenza virus (SIV) vaccine-challenge pig model was used to study the potential of a conserved matrix 2 (M2) protein vaccine alone or in combination with an inactivated H1N1-vaccine to protect against H1N1 and H1N2 viruses. The H1N1-vaccine and heterologous H1N2-challenge virus model has previously been shown to prolong fever and increase SIV-associated pneumonic lesions. The M2 vaccine in combination with the H1N1-vaccine reduced the H1N2 induced fever but not virus shedding. The M2 vaccine alone reduced respiratory signs and pneumonic lesions to levels similar to the negative control pigs following H1N2 infection. This study found that the M2 protein has potential as a vaccine for SIV-associated disease prevention. However, development of an immune response towards the major envelope HA protein was required to reduce SIV shedding.
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Affiliation(s)
- Pravina Kitikoon
- College of Veterinary Medicine, Iowa State University, Ames, IA, USA
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26
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Kuntz-Simon G, Madec F. Genetic and Antigenic Evolution of Swine Influenza Viruses in Europe and Evaluation of Their Zoonotic Potential. Zoonoses Public Health 2009; 56:310-25. [DOI: 10.1111/j.1863-2378.2009.01236.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Cheng C, Dong J, Yao L, Chen A, Jia R, Huan L, Guo J, Shu Y, Zhang Z. Potent inhibition of human influenza H5N1 virus by oligonucleotides derived by SELEX. Biochem Biophys Res Commun 2007; 366:670-4. [PMID: 18078808 DOI: 10.1016/j.bbrc.2007.11.183] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 11/28/2007] [Indexed: 11/30/2022]
Abstract
New therapeutics are urgently needed for the treatment of pandemic influenza caused by H5N1 influenza virus mutants. Aptamer was a promising candidate for treatment and prophylaxis of influenza virus infections. In this study, systemic evolution of ligands through exponential enrichment (SELEX) was used to screen DNA aptamers targeted to recombinant HA1 proteins of the H5N1 influenza virus. After 11 rounds of selection, DNA aptamers that bind to the HA1 protein were isolated and shown to have different binding capacities. Among them, aptamer 10 had the strongest binding to the HA1 protein, and had an inhibitory effect on H5N1 influenza virus, as shown by the hemagglutinin and MTT assays. These results should aid the development of new drugs for the prevention and control of influenza virus infections.
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Affiliation(s)
- Congsheng Cheng
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 100 Yingxin Jie, Xuanwu District, 100052 Beijing, China
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28
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Bauer K, Schrader C, Suess J, Wutzler P, Schmidtke M. Neuraminidase inhibitor susceptibility of porcine H3N2 influenza A viruses isolated in Germany between 1982 and 1999. Antiviral Res 2007; 75:219-26. [PMID: 17445913 DOI: 10.1016/j.antiviral.2007.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 02/12/2007] [Accepted: 03/14/2007] [Indexed: 11/26/2022]
Abstract
As an intermediate host of avian and human influenza A viruses (FLUAV) pigs may play a potential role in interspecies virus transmission and reassortment of viral genes including those conferring antiviral drug resistance. Porcine FLUAV isolated in Germany between 1989 and 2001 contains mutations in the M2 gene inducing amantadine resistance. No data exist on neuraminidase inhibitor (NAI) susceptibility of these porcine FLUAV. We studied the antiviral activity of NAI against seven selected H3N2 FLUAV isolated from pigs in Germany between 1982 and 1999. All isolates were susceptible towards oseltamivir and zanamivir in neuraminidase enzyme-inhibition assays. Both compounds inhibited virus spreading and reduced the virus yields and plaque size at low concentrations. Higher concentrations were necessary to reduce the plaque number. Two isolates that differed in glycosylation pattern of viral hemagglutinin (HA) showed markedly reduced drug susceptibility in cell culture-based assays.
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Affiliation(s)
- Katja Bauer
- Institute of Virology and Antiviral Therapy, Medical Centre of the Friedrich Schiller University Jena, Hans Knoell Str. 2, PF, D-07740 Jena, Germany
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29
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Evolution and variation of the H3 gene of influenza A virus and interaction among hosts. Intervirology 2007; 50:287-95. [PMID: 17622733 DOI: 10.1159/000104788] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Accepted: 02/05/2007] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Continual mutations to the hemagglutinin (HA) gene of influenza A virus generate novel antigenic strains that cause annual epidemics. The aim of this study was to evaluate evolution tendency of the H3 gene in a long period of time. METHODS 1842 H3 HA1 nucleotide strains of different hosts were collected for analysis. A two-step clustering method was used to divide strains into groups, and then a phylogenetic tree was constructed based on cluster results. Evolution rate in lineages were future estimated. RESULTS Tree structure showed three lineages: horse/canine, human/swine and avian. As a single trunk, the human/swine lineage was mainly composed of human strains, and more big branches appeared in recent years. Tree topology showed no evidence that swine affected the main evolution tendency of human H3 strains. The evolution rate of H3 strains varied between lineages. We observed that the rate in the human lineage decreased from 3.2 substitutions/year before 1980 to 1.8 after 1997. CONCLUSION We concluded that the variation of human H3 gene was associated with swine strains but independent of others, including bird strains. The evolution rate of human H3 strains seems to have decreased in recent years, while the reasons for the rate change need to be further explored.
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30
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de Jong JC, Smith DJ, Lapedes AS, Donatelli I, Campitelli L, Barigazzi G, Van Reeth K, Jones TC, Rimmelzwaan GF, Osterhaus ADME, Fouchier RAM. Antigenic and genetic evolution of swine influenza A (H3N2) viruses in Europe. J Virol 2007; 81:4315-22. [PMID: 17287258 PMCID: PMC1866135 DOI: 10.1128/jvi.02458-06] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the early 1970s, a human influenza A/Port Chalmers/1/73 (H3N2)-like virus colonized the European swine population. Analyses of swine influenza A (H3N2) viruses isolated in The Netherlands and Belgium revealed that in the early 1990s, antigenic drift had occurred, away from A/Port Chalmers/1/73, the strain commonly used in influenza vaccines for pigs. Here we show that Italian swine influenza A (H3N2) viruses displayed antigenic and genetic changes similar to those observed in Northern European viruses in the same period. We used antigenic cartography methods for quantitative analyses of the antigenic evolution of European swine H3N2 viruses and observed a clustered virus evolution as seen for human viruses. Although the antigenic drift of swine and human H3N2 viruses has followed distinct evolutionary paths, potential cluster-differentiating amino acid substitutions in the influenza virus surface protein hemagglutinin (HA) were in part the same. The antigenic evolution of swine viruses occurred at a rate approximately six times slower than the rate in human viruses, even though the rates of genetic evolution of the HA at the nucleotide and amino acid level were similar for human and swine H3N2 viruses. Continuous monitoring of antigenic changes is recommended to give a first indication as to whether vaccine strains may need updating. Our data suggest that humoral immunity in the population plays a smaller role in the evolutionary selection processes of swine H3N2 viruses than in human H3N2 viruses.
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Affiliation(s)
- J C de Jong
- National Influenza Center, Department of Virology, Erasmus Medical Center, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
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31
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Kitikoon P, Nilubol D, Erickson BJ, Janke BH, Hoover TC, Sornsen SA, Thacker EL. The immune response and maternal antibody interference to a heterologous H1N1 swine influenza virus infection following vaccination. Vet Immunol Immunopathol 2006; 112:117-28. [PMID: 16621020 DOI: 10.1016/j.vetimm.2006.02.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 01/30/2006] [Accepted: 02/13/2006] [Indexed: 10/24/2022]
Abstract
This study investigated the efficacy of a bivalent swine influenza virus (SIV) vaccine in piglets challenged with a heterologous H1N1 SIV isolate. The ability of maternally derived antibodies (MDA) to provide protection against a heterologous challenge and the impact MDA have on vaccine efficacy were also evaluated. Forty-eight MDA(+) pigs and 48 MDA(-) pigs were assigned to 8 different groups. Vaccinated pigs received two doses of a bivalent SIV vaccine at 3 and 5 weeks of age. The infected pigs were challenged at 7 weeks of age with an H1N1 SIV strain heterologous to the H1N1 vaccine strain. Clinical signs, rectal temperature, macroscopic and microscopic lesions, virus excretion, serum and local antibody responses, and influenza-specific T-cell responses were measured. The bivalent SIV vaccine induced a high serum hemagglutination-inhibition (HI) antibody titer against the vaccine virus, but antibodies cross-reacted at a lower level to the challenge virus. This study determined that low serum HI antibodies to a challenge virus induced by vaccination with a heterologous virus provided protection demonstrated by clinical protection and reduced pneumonia and viral excretion. The vaccine was able to prime the local SIV-specific antibody response in the lower respiratory tract as well as inducing a systemic SIV-specific memory T-cell response. MDA alone were capable of suppressing fever subsequent to infection, but other parameters showed reduced protection against infection compared to vaccination. The presence of MDA at vaccination negatively impacted vaccine efficacy as fever and clinical signs were prolonged, and unexpectedly, SIV-induced pneumonia was increased compared to pigs vaccinated in the absence of MDA. MDA also suppressed the serum antibody response and the induction of SIV-specific memory T-cells following vaccination. The results of this study question the effectiveness of the current practice of generating increased MDA levels through sow vaccination in protecting piglets against disease.
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Affiliation(s)
- Pravina Kitikoon
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
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32
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Webby RJ, Rossow K, Erickson G, Sims Y, Webster R. Multiple lineages of antigenically and genetically diverse influenza A virus co-circulate in the United States swine population. Virus Res 2004; 103:67-73. [PMID: 15163491 DOI: 10.1016/j.virusres.2004.02.015] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Before the isolation of H3N2 viruses in 1998, swine influenza in the United States was an endemic disease caused exclusively by classical-swine H1N1 viruses. In this study we determined the antigenic and phylogenetic composition of a selection of currently circulating strains and revealed that, in contrast to the situation pre-1998, the swine population in the United States is now a dynamic viral reservoir containing multiple viral lineages. H3N2 viruses still circulate and representatives of each of two previously identified phylogenetic groups were isolated. H1N1 and H1N2 viruses were also identified. In addition to the genotypic diversity present, there was also considerable antigenic diversity seen. At least three antigenic profiles of H1 viruses were noted and all of the recent H3N2 viruses reacted poorly, if at all, to the index A/swine/Texas/4199-2/98 H3N2 antiserum in hemagglutination inhibition assays. The influenza reservoir in the United States swine population has thus gone from a stable single viral lineage to one where genetically and antigenically heterogenic viruses co-circulate. The growing complexity of influenza at this animal-human interface and the presence of viruses with a seemingly high affinity for reassortment makes the United States swine population an increasingly important reservoir of viruses with human pandemic potential.
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Affiliation(s)
- R J Webby
- Division of Virology, Department of Infectious Diseases, MS#330, St. Jude Children's Research Hospital, 332 N Lauderdale, Memphis, TN 38105, USA.
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33
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Van Reeth K, Van Gucht S, Pensaert M. Investigations of the efficacy of European H1N1- and H3N2-based swine influenza vaccines against the novel H1N2 subtype. Vet Rec 2003; 153:9-13. [PMID: 12877210 DOI: 10.1136/vr.153.1.9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The efficacy of a commercial swine influenza vaccine based on A/New Jersey/8/76 (H1N1) and A/Port Chalmers/1/73 (H3N2) strains was tested against challenge with an H1N2 swine influenza virus. Influenza virus-seronegative pigs were vaccinated twice with the vaccine when they were four and eight weeks old, or with the same vaccine supplemented with an H1N2 component. Control pigs were left unvaccinated. Three weeks after the second vaccination, all the pigs were challenged intratracheally with the swine influenza strain Sw/Gent/7625/99 (H1N2). The commercial vaccine induced cross-reactive antibodies to H1N2, as detected by the virus neutralisation (VN) assay, but VN antibody titres were 18 times lower than in the pigs vaccinated with the H1N2-supplemented vaccine. The challenge produced severe respiratory signs in nine of 10 unvaccinated control pigs, which developed high H1N2 virus titres in the lungs 24 and 72 hours after the challenge. Vaccination with the commercial vaccine resulted in milder respiratory signs, but H1N2 virus replication was not prevented. Mean virus titres in the pigs vaccinated with the commercial vaccine were 1-5 log10 lower than in the controls at 24 hours but no different at 72 hours. In contrast, the H1N2-supplemented vaccine prevented respiratory disease in most pigs. There was a 4-5 log10 reduction in the mean virus titre at 24 hours in the pigs vaccinated with this vaccine, and no detectable virus replication at 72 hours. These data indicate that the commercial swine influenza vaccine did not confer adequate protection against the H1N2 subtype.
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Affiliation(s)
- K Van Reeth
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
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34
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Loeffen WLA, Heinen PP, Bianchi ATJ, Hunneman WA, Verheijden JHM. Effect of maternally derived antibodies on the clinical signs and immune response in pigs after primary and secondary infection with an influenza H1N1 virus. Vet Immunol Immunopathol 2003; 92:23-35. [PMID: 12628761 DOI: 10.1016/s0165-2427(03)00019-9] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of this study was to determine the role of maternally derived antibodies (MDA) against an influenza H1N1 virus in the clinical protection of piglets and especially their effect on the development of the active immunity after an infection with a homologous influenza H1N1 virus. Twenty piglets with MDA and 10 piglets without MDA were housed together and inoculated twice with influenza H1N1 virus, at 7 and 15 weeks of age. Nine piglets without MDA were added to these groups at 12 weeks of age to be inoculated at 15 weeks of age only. Clinical signs, body temperature, growth performance, virus excretion, antibody responses, and influenza-specific T-cell response were monitored. It was shown that MDA protect piglets against the clinical consequences of a primary influenza infection, but that this protection is not complete. A short but significant rise in body temperature was observed and growth seemed to be inhibited due to the infection. Piglets with MDA shed virus for a longer period after an infection than piglets without MDA. Piglets with and without MDA were protected against the clinical consequences of a secondary infection. However, both after primary and secondary infection significant differences in immune responses were observed that indicated that pigs with MDA developed a weaker immunity than pigs without MDA. Furthermore, overall growth performances from weaning to slaughter show a trend in favour of pigs without maternal antibodies, compared to pigs with maternal antibodies, mainly caused by a significant better performance in the second half of the finishing period. The results of this study provide us insight in the role of MDA in clinical protection and their influence on active immunity after an influenza virus infection of pigs. Furthermore, it leads us to the discussion about the profitability of massive sow herd vaccinations in an attempt to increase MDA levels in piglets, taking into account the overall performance of these piglets and the possible effects on antigenic drift.
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Affiliation(s)
- W L A Loeffen
- Department of Swine Health, Animal Health Service, P.O. Box 9, 7400AA Deventer, The Netherlands.
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35
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Abstract
Since 1997, novel viruses of three different subtypes and five different genotypes have emerged as agents of influenza among pigs in North America. The appearance of these viruses is remarkable because there were no substantial changes in the overall epidemiology of swine influenza in the United States and Canada for over 60 years prior to this time. Viruses of the classical H1N1 lineage were virtually the exclusive cause of swine influenza from the time of their initial isolation in 1930 through 1998. Antigenic drift variants of these H1N1 viruses were isolated in 1991-1998, but a much more dramatic antigenic shift occurred with the emergence of H3N2 viruses in 1997-1998. In particular, H3N2 viruses with genes derived from human, swine and avian viruses have become a major cause of swine influenza in North America. In addition, H1N2 viruses that resulted from reassortment between the triple reassortant H3N2 viruses and classical H1N1 swine viruses have been isolated subsequently from pigs in at least six states. Finally, avian H4N6 viruses crossed the species barrier to infect pigs in Canada in 1999. Fortunately, these H4N6 viruses have not been isolated beyond their initial farm of origin. If these viruses spread more widely, they will represent another antigenic shift for our swine population, and could pose a threat to the world's human population. Research on these novel viruses may offer important clues to the genetic basis for interspecies transmission of influenza viruses.
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Affiliation(s)
- Christopher W Olsen
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, USA.
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36
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Heinen PP, de Boer-Luijtze EA, Bianchi ATJ. Respiratory and systemic humoral and cellular immune responses of pigs to a heterosubtypic influenza A virus infection. J Gen Virol 2001; 82:2697-2707. [PMID: 11602782 DOI: 10.1099/0022-1317-82-11-2697] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The level of heterosubtypic immunity (Het-I) and the immune mechanisms stimulated by a heterosubtypic influenza virus infection were investigated in pigs. Pigs are natural hosts for influenza virus and, like humans, they host both subtypes H1N1 and H3N2. Marked Het-I was observed when pigs were infected with H1N1 and subsequently challenged with H3N2. After challenge with H3N2, pigs infected earlier with H1N1 did not develop fever and showed reduced virus excretion compared with non-immune control pigs. In addition, virus transmission to unchallenged group-mates could be shown by virus isolation in the non-immune control group but not in the group infected previously with H1N1. Pigs infected previously with homologous H3N2 virus were protected completely. After challenge with H3N2, pigs infected previously with H1N1 showed a considerable increase in serum IgG titre to the conserved extracellular domain of M2 but not to the conserved nucleoprotein. These results suggest that antibodies against external conserved epitopes can have an important role in broad-spectrum immunity. After primary infection with both H1N1 and H3N2, a long-lived increase was observed in the percentage of CD8(+) T cells in the lungs and in the lymphoproliferation response in the blood. Upon challenge with H3N2, pigs infected previously with H1N1 again showed an increase in the percentage of CD8(+) T cells in the lungs, whereas pigs infected previously with H3N2 did not, suggesting that CD8(+) T cells also have a role in Het-I. To confer broad-spectrum immunity, future vaccines should induce antibodies and CD8(+) T cells against conserved antigens.
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Affiliation(s)
- Paul P Heinen
- Department of Mammalian Virology, Institute for Animal Science and Health (ID-Lelystad BV), PO Box 65, 8200 AB Lelystad, The Netherlands1
| | - Els A de Boer-Luijtze
- Department of Mammalian Virology, Institute for Animal Science and Health (ID-Lelystad BV), PO Box 65, 8200 AB Lelystad, The Netherlands1
| | - Andre T J Bianchi
- Department of Mammalian Virology, Institute for Animal Science and Health (ID-Lelystad BV), PO Box 65, 8200 AB Lelystad, The Netherlands1
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37
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Heinen PP, van Nieuwstadt AP, de Boer-Luijtze EA, Bianchi AT. Analysis of the quality of protection induced by a porcine influenza A vaccine to challenge with an H3N2 virus. Vet Immunol Immunopathol 2001; 82:39-56. [PMID: 11557293 DOI: 10.1016/s0165-2427(01)00342-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Antigenic drift of swine influenza A (H3N2) viruses away from the human A/Port Chalmers/1/73 (H3N2) strain, used in current commercial swine influenza vaccines, has been demonstrated in The Netherlands and Belgium. Therefore, replacement of this human strain by a more recent swine H3N2 isolate has to be considered. In this study, the efficacy of a current commercial swine influenza vaccine to protect pigs against a recent Dutch field strain (A/Sw/Oedenrode/96) was assessed. To evaluate the level of protection induced by the vaccine it was compared with the optimal protection induced by a previous homologous infection. Development of fever, virus excretion, and viral transmission to unchallenged group mates were determined to evaluate protection. The vaccine appeared efficacious in the experiment because it was able to prevent fever and virus transmission to the unchallenged group mates. Nevertheless, the protection conferred by the vaccine was sub-optimal because vaccinated pigs excreted influenza virus for a short period of time after challenge, whereas naturally immune pigs appeared completely protected. The immune response was monitored, to investigate why the vaccine conferred a sub-optimal protection. The haemagglutination inhibiting and virus neutralising antibody responses in sera, the nucleoprotein-specific IgM, IgG, and IgA antibody responses in sera and nasal secretions and the influenza-specific lymphoproliferation responses in the blood were studied. Vaccinated pigs developed the same or higher serum haemagglutination inhibiting, virus neutralising, and nucleoprotein-specific IgG antibody titres as infected pigs but lower nasal IgA titres and lymphoproliferation responses. The lower mucosal and cell-mediated immune responses may explain why protection after vaccination was sub-optimal.
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Affiliation(s)
- P P Heinen
- Department of Mammalian Virology, Institute for Animal Science and Health (ID-Lelystad BV), P.O. Box 65, 8200 AB, Lelystad, The Netherlands.
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38
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de Jong JC, Heinen PP, Loeffen WL, van Nieuwstadt AP, Claas EC, Bestebroer TM, Bijlsma K, Verweij C, Osterhaus AD, Rimmelzwaan GF, Fouchier RA, Kimman TG. Antigenic and molecular heterogeneity in recent swine influenza A(H1N1) virus isolates with possible implications for vaccination policy. Vaccine 2001; 19:4452-64. [PMID: 11483271 DOI: 10.1016/s0264-410x(01)00190-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In order to explore the occurrence of antigenic drift in swine influenza A(H1N1) viruses and the match between epidemic and vaccine strains, 26 virus isolates from outbreaks of respiratory disease among finishing pigs in the Netherlands in the 1995/1996 season and reference strains from earlier outbreaks were examined using serological and molecular methods. In contrast to swine H3N2 viruses, no significant antigenic drift was observed in swine H1N1 viruses isolated from the late 1980s up to 1996 inclusive. However, a marked antigenic and genetic heterogeneity in haemagglutination inhibition tests and nucleotide sequence analyses was detected among the 26 recent swine H1N1 virus strains. Interestingly, the observed antigenic and molecular variants were not randomly distributed over the farms. This finding indicates independent introductions of different swine H1N1 virus variants at the various farms of the study and points to a marked difference between the epidemiologies of human and swine influenza viruses. The observed heterogeneity may hamper the control of swine influenza by vaccination and indicates that the efficacy of current swine influenza vaccines requires re-evaluation and that the antigenic reactivity of swine influenza viruses should be monitored on a regular basis.
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Affiliation(s)
- J C de Jong
- Research Laboratory of Infectious Diseases, National Institute of Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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Webby RJ, Swenson SL, Krauss SL, Gerrish PJ, Goyal SM, Webster RG. Evolution of swine H3N2 influenza viruses in the United States. J Virol 2000; 74:8243-51. [PMID: 10954521 PMCID: PMC116332 DOI: 10.1128/jvi.74.18.8243-8251.2000] [Citation(s) in RCA: 271] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During 1998, severe outbreaks of influenza were observed in four swine herds in the United States. This event was unique because the causative agents, H3N2 influenza viruses, are infrequently isolated from swine in North America. Two antigenically distinct reassortant viruses (H3N2) were isolated from infected animals: a double-reassortant virus containing genes similar to those of human and swine viruses, and a triple-reassortant virus containing genes similar to those of human, swine, and avian influenza viruses (N. N. Zhou, D. A. Senne, J. S. Landgraf, S. L. Swenson, G. Erickson, K. Rossow, L. Liu, K.-J. Yoon, S. Krauss, and R. G. Webster, J. Virol. 73:8851-8856, 1999). Because the U.S. pig population was essentially naive in regard to H3N2 viruses, it was important to determine the extent of viral spread. Hemagglutination inhibition (HI) assays of 4, 382 serum samples from swine in 23 states indicated that 28.3% of these animals had been exposed to classical swine-like H1N1 viruses and 20.5% had been exposed to the triple-reassortant-like H3N2 viruses. The HI data suggested that viruses antigenically related to the double-reassortant H3N2 virus have not become widespread in the U.S. swine population. The seroreactivity levels in swine serum samples and the nucleotide sequences of six additional 1999 isolates, all of which were of the triple-reassortant genotype, suggested that H3N2 viruses containing avian PA and PB2 genes had spread throughout much of the country. These avian-like genes cluster with genes from North American avian viruses. The worldwide predominance of swine viruses containing an avian-like internal gene component suggests that these genes may confer a selective advantage in pigs. Analysis of the 1999 swine H3N2 isolates showed that the internal gene complex of the triple-reassortant viruses was associated with three recent phylogenetically distinct human-like hemagglutinin (HA) molecules. Acquisition of HA genes from the human virus reservoir will significantly affect the efficacy of the current swine H3N2 vaccines. This finding supports continued surveillance of U.S. swine populations for influenza virus activity.
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Affiliation(s)
- R J Webby
- Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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Abstract
Pigs serve as major reservoirs of H1N1 and H3N2 influenza viruses which are endemic in pig populations world-wide and are responsible for one of the most prevalent respiratory diseases in pigs. The maintenance of these viruses in pigs and the frequent exchange of viruses between pigs and other species is facilitated directly by swine husbandry practices, which provide for a continual supply of susceptible pigs and regular contact with other species, particularly humans. The pig has been a contender for the role of intermediate host for reassortment of influenza A viruses of avian and human origin since it is the only domesticated mammalian species which is reared in abundance and is susceptible to, and allows productive replication, of avian and human influenza viruses. This can lead to the generation of new strains of influenza, some of which may be transmitted to other species including humans. This concept is supported by the detection of human-avian reassortant viruses in European pigs with some evidence for subsequent transmission to the human population. Following interspecies transmission to pigs, some influenza viruses may be extremely unstable genetically, giving rise to variants which could be conducive to the species barrier being breached a second time. Eventually, a stable lineage derived from the dominant variant may become established in pigs. Genetic drift occurs particularly in the genes encoding the external glycoproteins, but does not usually result in the same antigenic variability that occurs in the prevailing strains in the human population. Adaptation of a 'newly' transmitted influenza virus to pigs can take many years. Both human H3N2 and avian H1N1 were detected in pigs many years before they acquired the ability to spread rapidly and become associated with disease epidemics in pigs.
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Affiliation(s)
- I H Brown
- Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, UK.
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