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Heider A, Wedde M, Weinheimer V, Döllinger S, Monazahian M, Dürrwald R, Wolff T, Schweiger B. Characteristics of two zoonotic swine influenza A(H1N1) viruses isolated in Germany from diseased patients. Int J Med Microbiol 2024; 314:151609. [PMID: 38286065 DOI: 10.1016/j.ijmm.2024.151609] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 01/31/2024] Open
Abstract
Interspecies transmission of influenza A viruses (IAV) from pigs to humans is a concerning event as porcine IAV represent a reservoir of potentially pandemic IAV. We conducted a comprehensive analysis of two porcine A(H1N1)v viruses isolated from human cases by evaluating their genetic, antigenic and virological characteristics. The HA genes of those human isolates belonged to clades 1C.2.1 and 1C.2.2, respectively, of the A(H1N1) Eurasian avian-like swine influenza lineage. Antigenic profiling revealed substantial cross-reactivity between the two zoonotic H1N1 viruses and human A(H1N1)pdm09 virus and some swine viruses, but did not reveal cross-reactivity to H1N2 and earlier human seasonal A(H1N1) viruses. The solid-phase direct receptor binding assay analysis of both A(H1N1)v showed a predominant binding to α2-6-sialylated glycans similar to human-adapted IAV. Investigation of the replicative potential revealed that both A(H1N1)v viruses grow in human bronchial epithelial cells to similar high titers as the human A(H1N1)pdm09 virus. Cytokine induction was studied in human alveolar epithelial cells A549 and showed that both swine viruses isolated from human cases induced higher amounts of type I and type III IFN, as well as IL6 compared to a seasonal A(H1N1) or a A(H1N1)pdm09 virus. In summary, we demonstrate a remarkable adaptation of both zoonotic viruses to propagate in human cells. Our data emphasize the needs for continuous monitoring of people and regions at increased risk of such trans-species transmissions, as well as systematic studies to quantify the frequency of these events and to identify viral molecular determinants enhancing the zoonotic potential of porcine IAV.
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Affiliation(s)
- Alla Heider
- Division of Influenza Viruses and Other Respiratory Viruses, National Reference Centre for Influenza, Robert Koch-Institute, Seestrasse 10, Berlin 13353, Germany.
| | - Marianne Wedde
- Division of Influenza Viruses and Other Respiratory Viruses, National Reference Centre for Influenza, Robert Koch-Institute, Seestrasse 10, Berlin 13353, Germany
| | - Viola Weinheimer
- Division of Influenza Viruses and Other Respiratory Viruses, National Reference Centre for Influenza, Robert Koch-Institute, Seestrasse 10, Berlin 13353, Germany
| | - Stephanie Döllinger
- Division of Influenza Viruses and Other Respiratory Viruses, National Reference Centre for Influenza, Robert Koch-Institute, Seestrasse 10, Berlin 13353, Germany
| | | | - Ralf Dürrwald
- Division of Influenza Viruses and Other Respiratory Viruses, National Reference Centre for Influenza, Robert Koch-Institute, Seestrasse 10, Berlin 13353, Germany
| | - Thorsten Wolff
- Division of Influenza Viruses and Other Respiratory Viruses, National Reference Centre for Influenza, Robert Koch-Institute, Seestrasse 10, Berlin 13353, Germany
| | - Brunhilde Schweiger
- Division of Influenza Viruses and Other Respiratory Viruses, National Reference Centre for Influenza, Robert Koch-Institute, Seestrasse 10, Berlin 13353, Germany
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Rabalski L, Kosinski M, Cybulski P, Stadejek T, Lepek K. Genetic Diversity of Type A Influenza Viruses Found in Swine Herds in Northwestern Poland from 2017 to 2019: The One Health Perspective. Viruses 2023; 15:1893. [PMID: 37766299 PMCID: PMC10536349 DOI: 10.3390/v15091893] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Influenza A viruses (IAV) are still a cause of concern for public health and veterinary services worldwide. With (-) RNA-segmented genome architecture, influenza viruses are prone to reassortment and can generate a great variety of strains, some capable of crossing interspecies barriers. Seasonal IAV strains continuously spread from humans to pigs, leading to multiple reassortation events with strains endemic to swine. Due to its high adaptability to humans, a reassortant strain based on "human-like" genes could potentially be a carrier of avian origin segments responsible for high virulence, and hence become the next pandemic strain with unseen pathogenicity. The rapid evolution of sequencing methods has provided a fast and cost-efficient way to assess the genetic diversity of IAV. In this study, we investigated the genetic diversity of swine influenza viruses (swIAVs) collected from Polish farms. A total of 376 samples were collected from 11 farms. The infection was confirmed in 112 cases. The isolates were subjected to next-generation sequencing (NGS), resulting in 93 full genome sequences. Phylogenetic analysis classified 59 isolates as genotype T (H1avN2g) and 34 isolates as genotype P (H1pdmN1pdm), all of which had an internal gene cassette (IGC) derived from the H1N1pdm09-like strain. These data are consistent with evolutionary trends in European swIAVs. The applied methodology proved to be useful in monitoring the genetic diversity of IAV at the human-animal interface.
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Affiliation(s)
- Lukasz Rabalski
- Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
- Biological Threats Identification and Countermeasure Center of the General Karol Kaczkowski Military Institute of Hygiene and Epidemiology, Lubelska 4 St, 24-100 Pulawy, Poland
| | - Maciej Kosinski
- Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Piotr Cybulski
- Goodvalley Agro S.A., Dworcowa 25, 77-320 Przechlewo, Poland
| | - Tomasz Stadejek
- Department of Pathology and Veterinary Diagnostic, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, 02-776 Warsaw, Poland
| | - Krzysztof Lepek
- Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
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van Diemen PM, Byrne AMP, Ramsay AM, Watson S, Nunez A, V Moreno A, Chiapponi C, Foni E, Brown IH, Brookes SM, Everett HE. Interspecies Transmission of Swine Influenza A Viruses and Human Seasonal Vaccine-Mediated Protection Investigated in Ferret Model. Emerg Infect Dis 2023; 29:1798-1807. [PMID: 37610158 PMCID: PMC10461666 DOI: 10.3201/eid2909.230066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023] Open
Abstract
We investigated the infection dynamics of 2 influenza A(H1N1) virus isolates from the swine 1A.3.3.2 (pandemic 2009) and 1C (Eurasian, avian-like) lineages. The 1C-lineage virus, A/Pavia/65/2016, although phylogenetically related to swine-origin viruses, was isolated from a human clinical case. This strain infected ferrets, a human influenza model species, and could be transmitted by direct contact and, less efficiently, by airborne exposure. Infecting ferrets and pigs (the natural host) resulted in mild or inapparent clinical signs comparable to those observed with 1A.3.3.2-lineage swine-origin viruses. Both H1N1 viruses could infect pigs and were transmitted to cohoused ferrets. Ferrets vaccinated with a human 2016-17 seasonal influenza vaccine were protected against infection with the antigenically matched 1A pandemic 2009 virus but not against the swine-lineage 1C virus. Our results reaffirm the need for continuous influenza A virus surveillance in pigs and identification of candidate human vaccine viruses.
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Hufnagel DE, Young KM, Arendsee ZW, Gay LC, Caceres CJ, Rajão DS, Perez DR, Vincent Baker AL, Anderson TK. Characterizing a century of genetic diversity and contemporary antigenic diversity of N1 neuraminidase in influenza A virus from North American swine. Virus Evol 2023; 9:vead015. [PMID: 36993794 PMCID: PMC10041950 DOI: 10.1093/ve/vead015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/08/2023] [Accepted: 02/27/2023] [Indexed: 03/29/2023] Open
Abstract
Influenza A viruses (IAVs) of the H1N1 classical swine lineage became endemic in North American swine following the 1918 pandemic. Additional human-to-swine transmission events after 1918, and a spillover of H1 viruses from wild birds in Europe, potentiated a rapid increase in genomic diversity via reassortment between introductions and the endemic classical swine lineage. To determine mechanisms affecting reassortment and evolution, we conducted a phylogenetic analysis of N1 and paired HA swine IAV genes in North America between 1930 and 2020. We described fourteen N1 clades within the N1 Eurasian avian lineage (including the N1 pandemic clade), the N1 classical swine lineage, and the N1 human seasonal lineage. Seven N1 genetic clades had evidence for contemporary circulation. To assess antigenic drift associated with N1 genetic diversity, we generated a panel of representative swine N1 antisera and quantified the antigenic distance between wild-type viruses using enzyme-linked lectin assays and antigenic cartography. Within the N1 genes, the antigenic similarity was variable and reflected shared evolutionary history. Sustained circulation and evolution of N1 genes in swine had resulted in a significant antigenic distance between the N1 pandemic clade and the classical swine lineage. Between 2010 and 2020, N1 clades and N1-HA pairings fluctuated in detection frequency across North America, with hotspots of diversity generally appearing and disappearing within 2 years. We also identified frequent N1-HA reassortment events (n = 36), which were rarely sustained (n = 6) and sometimes also concomitant with the emergence of new N1 genetic clades (n = 3). These data form a baseline from which we can identify N1 clades that expand in range or genetic diversity that may impact viral phenotypes or vaccine immunity and subsequently the health of North American swine.
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Affiliation(s)
- David E Hufnagel
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Ave, Ames, IA 50010, USA
| | - Katharine M Young
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Ave, Ames, IA 50010, USA
| | - Zebulun W Arendsee
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Ave, Ames, IA 50010, USA
| | - L Claire Gay
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Rd, Athens, GA 30602, USA
| | - C Joaquin Caceres
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Rd, Athens, GA 30602, USA
| | - Daniela S Rajão
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Rd, Athens, GA 30602, USA
| | - Daniel R Perez
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Rd, Athens, GA 30602, USA
| | - Amy L Vincent Baker
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Ave, Ames, IA 50010, USA
| | - Tavis K Anderson
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, 1920 Dayton Ave, Ames, IA 50010, USA
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Peñarrubia L, Rao SN, Porco R, Varo M, Muñoz-Torrero P, Ortiz-Martinez F, Pareja J, López-Fontanals M, Manissero D. Detecting zoonotic Influenza A using QIAstat-Dx Respiratory SARS-CoV-2 panel for pandemic preparedness. Sci Rep 2023; 13:2833. [PMID: 36807577 PMCID: PMC9936110 DOI: 10.1038/s41598-023-29838-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 02/10/2023] [Indexed: 02/19/2023] Open
Abstract
Recent reports from the World Health Organization regarding Influenza A cases of zoonotic origin in humans (H1v and H9N2) and publications describing emergence swine Influenza A cases in humans together with "G4" Eurasian avian-like H1N1 Influenza A virus have drawn global attention to Influenza A pandemic threat. Additionally, the current COVID-19 epidemic has stressed the importance of surveillance and preparedness to prevent potential outbreaks. One feature of the QIAstat-Dx Respiratory SARS-CoV-2 panel is the double target approach for Influenza A detection of seasonal strains affecting humans using a generic Influenza A assay plus the three specific human subtype assays. This work explores the potential use of this double target approach in the QIAstat-Dx Respiratory SARS-Co-V-2 Panel as a tool to detect zoonotic Influenza A strains. A set of recently recorded H9 and H1 spillover strains and the G4 EA Influenza A strains as example of recent zoonotic Flu A strains were subjected to detection prediction with QIAstat-Dx Respiratory SARS-CoV-2 Panel using commercial synthetic dsDNA sequences. In addition, a large set of available commercial human and non-human influenza A strains were also tested using QIAstat-Dx Respiratory SARS-CoV-2 Panel for a better understanding of detection and discrimination of Influenza A strains. Results show that QIAstat-Dx Respiratory SARS-CoV-2 Panel generic Influenza A assay detects all the recently recorded H9, H5 and H1 zoonotic spillover strains and all the G4 EA Influenza A strains. Additionally, these strains yielded negative results for the three-human seasonal IAV (H1, H3 and H1N1 pandemic) assays. Additional non-human strains corroborated those results of Flu A detection with no subtype discrimination, whereas human Influenza strains were positively discriminated. These results indicate that QIAstat-Dx Respiratory SARS-CoV-2 Panel could be a useful tool to diagnose zoonotic Influenza A strains and differentiate them from the seasonal strains commonly affecting humans.
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Affiliation(s)
- Luis Peñarrubia
- STAT-Dx Life S.L. (A QIAGEN Company), Baldiri Reixac, 4, 08028, Barcelona, Spain.
| | - Sonia N. Rao
- grid.421680.90000 0004 0404 0296QIAGEN Inc., 19300 Germantown Road, Germantown, MD 20874 USA
| | - Roberto Porco
- STAT-Dx Life S.L. (A QIAGEN Company), Baldiri Reixac, 4, 08028 Barcelona, Spain
| | - Marta Varo
- STAT-Dx Life S.L. (A QIAGEN Company), Baldiri Reixac, 4, 08028 Barcelona, Spain
| | | | | | - Josep Pareja
- STAT-Dx Life S.L. (A QIAGEN Company), Baldiri Reixac, 4, 08028 Barcelona, Spain
| | | | - Davide Manissero
- grid.474454.20000 0004 0451 3823QIAGEN Manchester Ltd, Skelton House, Lloyd Street North, Manchester, M15 6SH UK
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6
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Strohmeier S, Amanat F, Carreño JM, Krammer F. Monoclonal antibodies targeting the influenza virus N6 neuraminidase. Front Immunol 2022; 13:944907. [PMID: 35967389 PMCID: PMC9363587 DOI: 10.3389/fimmu.2022.944907] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Influenza A viruses are a diverse species that include 16 true hemagglutinin (HA) subtypes and 9 true neuraminidase (NA) subtypes. While the antigenicity of many HA subtypes is reasonably well studied, less is known about NA antigenicity, especially when it comes to non-human subtypes that only circulate in animal reservoirs. The N6 subtype NAs are mostly found in viruses infecting birds. However, they have also been identified in viruses that infect mammals, such as swine and seals. More recently, highly pathogenic H5N6 subtype viruses have caused rare infections and mortality in humans. Here, we generated murine mAbs to the N6 NA, characterized their breadth and antiviral properties in vitro and in vivo and mapped their epitopes by generating escape mutant viruses. We found that the antibodies had broad reactivity across the American and Eurasian N6 lineages, but relatively little binding to the H5N6 NA. Several of the antibodies exhibited strong NA inhibition activity and some also showed activity in the antibody dependent cellular cytotoxicity reporter assay and neutralization assay. In addition, we generated escape mutant viruses for six monoclonal antibodies and found mutations on the lateral ridge of the NA. Lastly, we observed variable protection in H4N6 mouse challenge models when the antibodies were given prophylactically.
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Affiliation(s)
- Shirin Strohmeier
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Fatima Amanat
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Juan Manuel Carreño
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Vaccine Research and Pandemic Preparedness (C-VARPP), Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Florian Krammer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Center for Vaccine Research and Pandemic Preparedness (C-VARPP), Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Department of Pathology, Molecular and Cell Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- *Correspondence: Florian Krammer,
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7
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Hennig C, Graaf A, Petric PP, Graf L, Schwemmle M, Beer M, Harder T. Are pigs overestimated as a source of zoonotic influenza viruses? Porcine Health Manag 2022; 8:30. [PMID: 35773676 PMCID: PMC9244577 DOI: 10.1186/s40813-022-00274-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/20/2022] [Indexed: 11/23/2022] Open
Abstract
Background Swine influenza caused by influenza A viruses (IAV) directly affects respiratory health and indirectly impairs reproduction rates in pigs causing production losses. In Europe, and elsewhere, production systems have intensified featuring fewer holdings but, in turn, increased breeding herd and litter sizes. This seems to foster swine IAV (swIAV) infections with respect to the entrenchment within and spread between holdings. Disease management of swine influenza is difficult and relies on biosecurity and vaccination measures. Recently discovered and widely proliferating forms of self-sustaining modes of swIAV infections in large swine holdings challenge these preventive concepts by generating vaccine-escape mutants in rolling circles of infection. Main body The most recent human IAV pandemic of 2009 rooted at least partly in IAV of porcine origin highlighting the zoonotic potential of swIAV. Pigs constitute a mixing vessel of IAV from different species including avian and human hosts. However, other host species such as turkey and quail but also humans themselves may also act in this way; thus, pigs are not essentially required for the generation of IAV reassortants with a multispecies origin. Since 1918, all human pandemic influenza viruses except the H2N2 virus of 1958 have been transmitted in a reverse zoonotic mode from human into swine populations. Swine populations act as long-term reservoirs of these viruses. Human-derived IAV constitute a major driver of swIAV epidemiology in pigs. Swine-to-human IAV transmissions occurred rarely and mainly sporadically as compared to avian-to-human spill-over events of avian IAV. Yet, new swIAV variants that harbor zoonotic components continue to be detected. This increases the risk that such components might eventually reassort into viruses with pandemic potential. Conclusions Domestic pig populations should not be globally stigmatized as the only or most important reservoir of potentially zoonotic IAV. The likely emergence from swine of the most recent human IAV pandemic in 2009, however, emphasized the principal risks of swine populations in which IAV circulate unimpededly. Implementation of regular and close-meshed IAV surveillance of domestic swine populations to follow the dynamics of swIAV evolution is clearly demanded. Improved algorithms for directly inferring zoonotic potential from whole IAV genome sequences as well as improved vaccines are still being sought.
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Affiliation(s)
- Christin Hennig
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Annika Graaf
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Philipp P Petric
- Institute of Virology, Medical Center, University of Freiburg, 79104, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Laura Graf
- Institute of Virology, Medical Center, University of Freiburg, 79104, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Martin Schwemmle
- Institute of Virology, Medical Center, University of Freiburg, 79104, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Timm Harder
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany.
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Effect of serial in vivo passages on the adaptation of H1N1 avian influenza virus to pigs. J Vet Res 2022; 66:9-19. [PMID: 35582490 PMCID: PMC8959685 DOI: 10.2478/jvetres-2022-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/02/2022] [Indexed: 11/26/2022] Open
Abstract
Introduction The lack of proofreading activity of the viral polymerase and the segmented nature of the influenza A virus (IAV) genome are responsible for the genetic diversity of IAVs and for their ability to adapt to a new host. We tried to adapt avian IAV (avIAV) to the pig by serial passages in vivo and assessed the occurrence of point mutations and their influence on viral fitness in the pig’s body. Material and Methods A total of 25 in vivo avIAV passages of the A/duck/Bavaria/77 strain were performed by inoculation of 50 piglets, and after predetermined numbers of passages 20 uninoculated piglets were exposed to the virus through contact with inoculated animals. Clinical signs of swine influenza were assessed daily. Nasal swabs and lung tissue were used to detect IAV RNA by real-time RT-PCR and isolates from selected passages were sequenced. Results Apart from a rise in rectal temperature and a sporadic cough, no typical clinical signs were observed in infected pigs. The original strain required 20 passages to improve its replication ability noticeably. A total of 29 amino-acid substitutions were identified. Eighteen of them were detected in the first sequenced isolate, of which 16 were also in all other analysed strains. Additional mutations were detected with more passages. One substitution, threonine (T) 135 to serine (S) in neuraminidase (NA), was only detected in an IAV isolate from a contact-exposed piglet. Conclusion Passaging 25 times allowed us to obtain a partially swine-adapted IAV. The improvement in isolate replication ability was most likely related to S654 to glycine (G) substitution in the basic protein (PB) 1 as well as to aspartic acid (D) 701 to asparagine (N) and arginine (R) 477 to G in PB2, glutamic acid (E) 204 to D and G239E in haemagglutinin and T135S in NA.
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9
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A SYBR Green-based real-time RT-PCR assay to differentiate the H1N1 influenza virus lineages. J Virol Methods 2021; 300:114387. [PMID: 34848281 DOI: 10.1016/j.jviromet.2021.114387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/19/2021] [Accepted: 11/25/2021] [Indexed: 12/15/2022]
Abstract
The H1N1 subtype influenza viruses (H1N1) have been causing persistent epidemics in human, swine and poultry populations since 1918. This subtype has evolved into four relatively stable genetic lineages, including classical swine influenza virus lineage, seasonal human influenza virus lineage, avian influenza virus lineage and Eurasian avian-like swine influenza virus lineage. In this study, four pairs of primers, based on the relatively conserved HA nucleotide regions of each H1N1 genetic lineage, were designed to establish a SYBR Green-based real-time quantitative RT-PCR (qPCR) assay to differentiate between the H1N1 genetic lineages. The results of qPCR assay showed that the lineage-specific primers designed for each H1N1 lineage were intra-lineage-specific, without mismatch of inter-lineage or inter-subtype and there appeared specific amplification curves when the concentrations of H1N1 plasmids were greater than or equal to 1.0 × 101 copies/reaction. Thus, this qPCR assay can specifically differentiate between the four lineages of H1N1 with a good specificity and sensitivity, which would assist in recognizing the infection and epidemic status of different H1N1 genetic lineages.
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10
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Ancestral sequence reconstruction pinpoints adaptations that enable avian influenza virus transmission in pigs. Nat Microbiol 2021; 6:1455-1465. [PMID: 34702977 PMCID: PMC8557130 DOI: 10.1038/s41564-021-00976-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 09/07/2021] [Indexed: 12/22/2022]
Abstract
Understanding the evolutionary adaptations that enable avian influenza viruses to transmit in mammalian hosts could allow better detection of zoonotic viruses with pandemic potential. We applied ancestral sequence reconstruction to gain viruses representing different adaptive stages of the European avian-like (EA) H1N1 swine influenza virus as it transitioned from avian to swine hosts since 1979. Ancestral viruses representing the avian-like precursor virus and EA swine viruses from 1979–1983, 1984–1987, and 1988–1992 were reconstructed and characterized. Glycan array analyses showed stepwise changes in the hemagglutinin receptor binding specificity from recognizing both alpha2,3- and alpha2,6-sialosides to alpha2,6-sialosides; however, efficient transmission in piglets was enabled by adaptive changes in the viral polymerase protein and nucleoprotein that have been fixed after 1983. PB1-Q621R and NP-R351K increased viral replication and transmission in piglets when introduced into the 1979–1983 ancestral virus that lacked efficient transmissibility. The stepwise adaptation of an avian influenza virus to a mammalian host suggests that there may be opportunities to intervene and prevent interspecies jump through strategic coordination of surveillance and risk assessment activities.
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11
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Cocirculation of Swine H1N1 Influenza A Virus Lineages in Germany. Viruses 2020; 12:v12070762. [PMID: 32679903 PMCID: PMC7411773 DOI: 10.3390/v12070762] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/16/2022] Open
Abstract
The genome analysis of 328 H1N1 swine influenza virus isolates collected in a 13-year long-term swine influenza surveillance in Germany is reported. Viral genomes were sequenced with the Illumina next-generation sequencing technique and conventional Sanger methods. Phylogenetic analyses were conducted with Bayesian tree inference. The results indicate continued prevalence of Eurasian avian swine H1N1 but also emergence of a novel H1N1 reassortant, named Schneiderkrug/2013-like swine H1N1, with human-like hemagglutinin and avian-like neuraminidase and internal genes. Additionally, the evolution of an antigenic drift variant of A (H1N1) pdm09 was observed, named Wachtum/2014-like swine H1N1. Both variants were first isolated in northwest Germany, spread to neighboring German states and reached greater proportions of the H1N1 isolates of 2014 and 2015. The upsurge of Wachtum/2014-like swine H1N1 is of interest as this is the first documented persistent swine-to-swine spread of A (H1N1) pdm09 in Germany associated with antigenic variation. Present enzootic swine influenza viruses in Germany now include two or more co-circulating, antigenically variant viruses of each of the subtypes, H1N1 and H1N2.
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12
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Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection. Proc Natl Acad Sci U S A 2020; 117:17204-17210. [PMID: 32601207 DOI: 10.1073/pnas.1921186117] [Citation(s) in RCA: 183] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pigs are considered as important hosts or "mixing vessels" for the generation of pandemic influenza viruses. Systematic surveillance of influenza viruses in pigs is essential for early warning and preparedness for the next potential pandemic. Here, we report on an influenza virus surveillance of pigs from 2011 to 2018 in China, and identify a recently emerged genotype 4 (G4) reassortant Eurasian avian-like (EA) H1N1 virus, which bears 2009 pandemic (pdm/09) and triple-reassortant (TR)-derived internal genes and has been predominant in swine populations since 2016. Similar to pdm/09 virus, G4 viruses bind to human-type receptors, produce much higher progeny virus in human airway epithelial cells, and show efficient infectivity and aerosol transmission in ferrets. Moreover, low antigenic cross-reactivity of human influenza vaccine strains with G4 reassortant EA H1N1 virus indicates that preexisting population immunity does not provide protection against G4 viruses. Further serological surveillance among occupational exposure population showed that 10.4% (35/338) of swine workers were positive for G4 EA H1N1 virus, especially for participants 18 y to 35 y old, who had 20.5% (9/44) seropositive rates, indicating that the predominant G4 EA H1N1 virus has acquired increased human infectivity. Such infectivity greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses.
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Avian Influenza A Virus Infects Swine Airway Epithelial Cells without Prior Adaptation. Viruses 2020; 12:v12060589. [PMID: 32481674 PMCID: PMC7374723 DOI: 10.3390/v12060589] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 01/15/2023] Open
Abstract
Pigs play an important role in the interspecies transmission of influenza A viruses (IAV). The porcine airway epithelium contains binding sites for both swine/human IAV (α2,6-linked sialic acids) and avian IAV (α2,3-linked sialic acids) and therefore is suited for adaptation of viruses from other species as suggested by the “mixing vessel theory”. Here, we applied well-differentiated swine airway epithelial cells to find out whether efficient infection by avian IAV requires prior adaption. Furthermore, we analyzed the influence of the sialic acid-binding activity and the virus-induced detrimental effects. Surprisingly, an avian IAV H1N1 strain circulating in European poultry and waterfowl shows increased and prolonged viral replication without inducing a strong innate immune response. This virus could infect the lower respiratory tract in our precision cut-lung slice model. Pretreating the cells with poly (I:C) and/or JAK/STAT pathway inhibitors revealed that the interferon-stimulated innate immune response influences the replication of avian IAV in swine airway epitheliums but not that of swine IAV. Further studies indicated that in the infection by IAVs, the binding affinity of sialic acid is not the sole factor affecting the virus infectivity for swine or human airway epithelial cells, whereas it may be crucial in well-differentiated ferret tracheal epithelial cells. Taken together, our results suggest that the role of pigs being the vessel of interspecies transmission should be reconsidered, and the potential of avian H1N1 viruses to infect mammals needs to be characterized in more detail.
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Chen W, Xu Q, Zhong Y, Yu H, Shu J, Ma T, Li Z. Genetic variation and co-evolutionary relationship of RNA polymerase complex segments in influenza A viruses. Virology 2017; 511:193-206. [PMID: 28866238 DOI: 10.1016/j.virol.2017.07.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 11/19/2022]
Abstract
The RNA polymerase complex (RNApc) in influenza A viruses (IVs) is composed of the PB2, PB1 and PA subunits, which are encoded by the three longest genome segments (Seg1-3) and are responsible for the replication of vRNAs and transcription of viral mRNAs. However, the co-evolutionary relationships of the three segments from the known 126 subtypes IVs are unclear. In this study, we performed a detailed analysis based on a total number of 121,191 nucleotide sequences. Three segment sequences were aligned before the repeated, incomplete and mixed sequences were removed for homologous and phylogenetic analyses. Subsequently, the estimated substitution rates and TMRCAs (Times for Most Recent Common Ancestor) were calculated by 175 representative IVs. Tracing the cladistic distribution of three segments from these IVs, co-evolutionary patterns and trajectories could be inferred. The further correlation analysis of six internal protein coding segments reflect the RNApc segments have the closer correlation than others during continuous reassortments. This global approach facilitates the establishment of a fast antiviral strategy and monitoring of viral variation.
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Affiliation(s)
- Wentian Chen
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Qi Xu
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Yaogang Zhong
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Hanjie Yu
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Jian Shu
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Tianran Ma
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Zheng Li
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China.
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Joseph U, Vijaykrishna D, Smith GJD, Su YCF. Adaptive evolution during the establishment of European avian-like H1N1 influenza A virus in swine. Evol Appl 2017; 11:534-546. [PMID: 29636804 PMCID: PMC5891058 DOI: 10.1111/eva.12536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 08/15/2017] [Indexed: 12/23/2022] Open
Abstract
An H1N1 subtype influenza A virus with all eight gene segments derived from wild birds (including mallards), ducks and chickens, caused severe disease outbreaks in swine populations in Europe beginning in 1979 and successfully adapted to form the European avian‐like swine (EA‐swine) influenza lineage. Genes of the EA‐swine lineage that are clearly segregated from its closest avian relatives continue to circulate in swine populations globally and represent a unique opportunity to study the adaptive process of an avian‐to‐mammalian cross‐species transmission. Here, we used a relaxed molecular clock model to test whether the EA‐swine virus originated through the introduction of a single avian ancestor as an entire genome, followed by an analysis of host‐specific selection pressures among different gene segments. Our data indicated independent introduction of gene segments via transmission of avian viruses into swine followed by reassortment events that occurred at least 1–4 years prior to the EA‐swine outbreak. All EA‐swine gene segments exhibit greater selection pressure than avian viruses, reflecting both adaptive pressures and relaxed selective constraints that are associated with host switching. Notably, we identified key amino acid mutations in the viral surface proteins (H1 and N1) that play a role in adaptation to new hosts. Following the establishment of EA‐swine lineage, we observed an increased frequency of intrasubtype reassortment of segments compared to the earlier strains that has been associated with adaptive amino acid replacements, disease severity and vaccine escape. Taken together, our study provides key insights into the adaptive changes in viral genomes following the transmission of avian influenza viruses to swine and the early establishment of the EA‐swine lineage.
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Affiliation(s)
- Udayan Joseph
- Programme in Emerging Infectious Diseases Duke-NUS Medical School Singapore
| | - Dhanasekaran Vijaykrishna
- Programme in Emerging Infectious Diseases Duke-NUS Medical School Singapore.,Department of Microbiology Biomedicine Discovery Institute Monash University Melbourne Vic. Australia
| | - Gavin J D Smith
- Programme in Emerging Infectious Diseases Duke-NUS Medical School Singapore.,Duke Global Health Institute Duke University Durham NC USA
| | - Yvonne C F Su
- Programme in Emerging Infectious Diseases Duke-NUS Medical School Singapore
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Henritzi D, Zhao N, Starick E, Simon G, Krog JS, Larsen LE, Reid SM, Brown IH, Chiapponi C, Foni E, Wacheck S, Schmid P, Beer M, Hoffmann B, Harder TC. Rapid detection and subtyping of European swine influenza viruses in porcine clinical samples by haemagglutinin- and neuraminidase-specific tetra- and triplex real-time RT-PCRs. Influenza Other Respir Viruses 2016; 10:504-517. [PMID: 27397600 PMCID: PMC5059951 DOI: 10.1111/irv.12407] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2016] [Indexed: 12/26/2022] Open
Abstract
Background A diversifying pool of mammalian‐adapted influenza A viruses (IAV) with largely unknown zoonotic potential is maintained in domestic swine populations worldwide. The most recent human influenza pandemic in 2009 was caused by a virus with genes originating from IAV isolated from swine. Swine influenza viruses (SIV) are widespread in European domestic pig populations and evolve dynamically. Knowledge regarding occurrence, spread and evolution of potentially zoonotic SIV in Europe is poorly understood. Objectives Efficient SIV surveillance programmes depend on sensitive and specific diagnostic methods which allow for cost‐effective large‐scale analysis. Methods New SIV haemagglutinin (HA) and neuraminidase (NA) subtype‐ and lineage‐specific multiplex real‐time RT‐PCRs (RT‐qPCR) have been developed and validated with reference virus isolates and clinical samples. Results A diagnostic algorithm is proposed for the combined detection in clinical samples and subtyping of SIV strains currently circulating in Europe that is based on a generic, M‐gene‐specific influenza A virus RT‐qPCR. In a second step, positive samples are examined by tetraplex HA‐ and triplex NA‐specific RT‐qPCRs to differentiate the porcine subtypes H1, H3, N1 and N2. Within the HA subtype H1, lineages “av” (European avian‐derived), “hu” (European human‐derived) and “pdm” (human pandemic A/H1N1, 2009) are distinguished by RT‐qPCRs, and within the NA subtype N1, lineage “pdm” is differentiated. An RT‐PCR amplicon Sanger sequencing method of small fragments of the HA and NA genes is also proposed to safeguard against failure of multiplex RT‐qPCR subtyping. Conclusions These new multiplex RT‐qPCR assays provide adequate tools for sustained SIV monitoring programmes in Europe.
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Affiliation(s)
- Dinah Henritzi
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute (FLI), Greifswald-Insel Riems, Germany
| | - Na Zhao
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute (FLI), Greifswald-Insel Riems, Germany
| | - Elke Starick
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute (FLI), Greifswald-Insel Riems, Germany
| | - Gaelle Simon
- Anses, Ploufragan-Plouzané Laboratory, Swine Virology Immunology Unit, Ploufragan, France
| | - Jesper S Krog
- National Veterinary Institute; Technical University of Denmark (DTU), Frederiksberg C, Denmark
| | - Lars Erik Larsen
- National Veterinary Institute; Technical University of Denmark (DTU), Frederiksberg C, Denmark
| | - Scott M Reid
- Department of Virology, Animal and Plant Health Agency-Weybridge, New Haw, Addlestone, Surrey, UK
| | - Ian H Brown
- Department of Virology, Animal and Plant Health Agency-Weybridge, New Haw, Addlestone, Surrey, UK
| | - Chiara Chiapponi
- Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna, Parma, Italy
| | - Emanuela Foni
- Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna, Parma, Italy
| | | | | | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute (FLI), Greifswald-Insel Riems, Germany
| | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute (FLI), Greifswald-Insel Riems, Germany
| | - Timm C Harder
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute (FLI), Greifswald-Insel Riems, Germany.
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Transmission and pathogenicity of novel reassortants derived from Eurasian avian-like and 2009 pandemic H1N1 influenza viruses in mice and guinea pigs. Sci Rep 2016; 6:27067. [PMID: 27252023 PMCID: PMC4890009 DOI: 10.1038/srep27067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/20/2016] [Indexed: 11/08/2022] Open
Abstract
Given the present extensive co-circulation in pigs of Eurasian avian-like (EA) swine H1N1 and 2009 pandemic (pdm/09) H1N1 viruses, reassortment between them is highly plausible but largely uncharacterized. Here, experimentally co-infected pigs with a representative EA virus and a pdm/09 virus yielded 55 novel reassortant viruses that could be categorized into 17 genotypes from Gt1 to Gt17 based on segment segregation. Majority of novel reassortants were isolated from the lower respiratory tract. Most of reassortant viruses were more pathogenic and contagious than the parental EA viruses in mice and guinea pigs. The most transmissible reassortant genotypes demonstrated in guinea pigs (Gt2, Gt3, Gt7, Gt10 and Gt13) were also the most lethal in mice. Notably, nearly all these highly virulent reassortants (all except Gt13) were characterized with possession of EA H1 and full complement of pdm/09 ribonucleoprotein genes. Compositionally, we demonstrated that EA H1-222G contributed to virulence by its ability to bind avian-type sialic acid receptors, and that pdm/09 RNP conferred the most robust polymerase activity to reassortants. The present study revealed high reassortment compatibility between EA and pdm/09 viruses in pigs, which could give rise to progeny reassortant viruses with enhanced virulence and transmissibility in mice and guinea pig models.
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H1N1 Swine Influenza Viruses Differ from Avian Precursors by a Higher pH Optimum of Membrane Fusion. J Virol 2015; 90:1569-77. [PMID: 26608319 DOI: 10.1128/jvi.02332-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/19/2015] [Indexed: 02/05/2023] Open
Abstract
UNLABELLED The H1N1 Eurasian avian-like swine (EAsw) influenza viruses originated from an avian H1N1 virus. To characterize potential changes in the membrane fusion activity of the hemagglutinin (HA) during avian-to-swine adaptation of the virus, we studied EAsw viruses isolated in the first years of their circulation in pigs and closely related contemporary H1N1 viruses of wild aquatic birds. Compared to the avian viruses, the swine viruses were less sensitive to neutralization by lysosomotropic agent NH4Cl in MDCK cells, had a higher pH optimum of hemolytic activity, and were less stable at acidic pH. Eight amino acid substitutions in the HA were found to separate the EAsw viruses from their putative avian precursor; four substitutions-T492S, N722D, R752K, and S1132F-were located in the structural regions of the HA2 subunit known to play a role in acid-induced conformational transition of the HA. We also studied low-pH-induced syncytium formation by cell-expressed HA proteins and found that the HAs of the 1918, 1957, 1968, and 2009 pandemic viruses required a lower pH for fusion induction than did the HA of a representative EAsw virus. Our data show that transmission of an avian H1N1 virus to pigs was accompanied by changes in conformational stability and fusion promotion activity of the HA. We conclude that distinctive host-determined fusion characteristics of the HA may represent a barrier for avian-to-swine and swine-to-human transmission of influenza viruses. IMPORTANCE Continuing cases of human infections with zoonotic influenza viruses highlight the necessity to understand which viral properties contribute to interspecies transmission. Efficient binding of the HA to cellular receptors in a new host species is known to be essential for the transmission. Less is known about required adaptive changes in the membrane fusion activity of the HA. Here we show that adaptation of an avian influenza virus to pigs in Europe in 1980s was accompanied by mutations in the HA, which decreased its conformational stability and increased pH optimum of membrane fusion activity. This finding represents the first formal evidence of alteration of the HA fusion activity/stability during interspecies transmission of influenza viruses under natural settings.
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Novel reassortant influenza viruses between pandemic (H1N1) 2009 and other influenza viruses pose a risk to public health. Microb Pathog 2015; 89:62-72. [PMID: 26344393 DOI: 10.1016/j.micpath.2015.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 12/21/2022]
Abstract
Influenza A virus (IAV) is characterized by eight single-stranded, negative sense RNA segments, which allows for gene reassortment among different IAV subtypes when they co-infect a single host cell simultaneously. Genetic reassortment is an important way to favor the evolution of influenza virus. Novel reassortant virus may pose a pandemic among humans. In history, three human pandemic influenza viruses were caused by genetic reassortment between avian, human and swine influenza viruses. Since 2009, pandemic (H1N1) 2009 (pdm/09 H1N1) influenza virus composed of two swine influenza virus genes highlighted the genetic reassortment again. Due to wide host species and high transmission of the pdm/09 H1N1 influenza virus, many different avian, human or swine influenza virus subtypes may reassert with it to generate novel reassortant viruses, which may result in a next pandemic among humans. So, it is necessary to understand the potential threat of current reassortant viruses between the pdm/09 H1N1 and other influenza viruses to public health. This study summarized the status of the reassortant viruses between the pdm/09 H1N1 and other influenza viruses of different species origins in natural and experimental conditions. The aim of this summarization is to facilitate us to further understand the potential threats of novel reassortant influenza viruses to public health and to make effective prevention and control strategies for these pathogens.
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