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Huang J, Ma K, Zhang J, Zhou J, Yi J, Qi W, Liao M. Pathogenicity and transmission of novel highly pathogenic H7N2 variants originating from H7N9 avian influenza viruses in chickens. Virology 2024; 597:110121. [PMID: 38917688 DOI: 10.1016/j.virol.2024.110121] [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] [Received: 03/06/2024] [Revised: 05/01/2024] [Accepted: 05/21/2024] [Indexed: 06/27/2024]
Abstract
The H7 subtype avian influenza viruses are circulating widely worldwide, causing significant economic losses to the poultry industry and posing a serious threat to human health. In 2019, H7N2 and H7N9 co-circulated in Chinese poultry, yet the risk of H7N2 remained unclear. We isolated and sequenced four H7N2 viruses from chickens, revealing them as novel reassortants with H7N9-derived HA, M, NS genes and H9N2-derived PB2, PB1, PA,NP, NA genes. To further explore the key segment of pathogenicity, H7N2-H7N9NA and H7N2-H9N2HA single-substitution were constructed. Pathogenicity study showed H7N2 isolates to be highly pathogenic in chickens, with H7N2-H7N9NA slightly weaker than H7N2-Wild type. Transcriptomic analysis suggested that H7N9-derived HA genes primarily drove the high pathogenicity of H7N2 isolates, eliciting a strong inflammatory response. These findings underscored the increased threat posed by reassorted H7N2 viruses to chickens, emphasizing the necessity of long-term monitoring of H7 subtype avian influenza viruses.
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Affiliation(s)
- Jinyu Huang
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China; National Avian Influenza Para-Reference Laboratory, Guangzhou, 510642, China; Key Laboratory of Zoonoses, Ministry of Agriculture and Rural Affairs, Guangzhou, 510642, China; National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, Guangzhou, 510642, China
| | - Kaixiong Ma
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China; National Avian Influenza Para-Reference Laboratory, Guangzhou, 510642, China; Key Laboratory of Zoonoses, Ministry of Agriculture and Rural Affairs, Guangzhou, 510642, China
| | - Jiahao Zhang
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China; National Avian Influenza Para-Reference Laboratory, Guangzhou, 510642, China; Key Laboratory of Zoonoses, Ministry of Agriculture and Rural Affairs, Guangzhou, 510642, China
| | - Jiangtao Zhou
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China; National Avian Influenza Para-Reference Laboratory, Guangzhou, 510642, China; Key Laboratory of Zoonoses, Ministry of Agriculture and Rural Affairs, Guangzhou, 510642, China; National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, Guangzhou, 510642, China
| | - Jiahui Yi
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China; National Avian Influenza Para-Reference Laboratory, Guangzhou, 510642, China; Key Laboratory of Zoonoses, Ministry of Agriculture and Rural Affairs, Guangzhou, 510642, China; National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, Guangzhou, 510642, China
| | - Wenbao Qi
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China; National Avian Influenza Para-Reference Laboratory, Guangzhou, 510642, China; Key Laboratory of Zoonoses, Ministry of Agriculture and Rural Affairs, Guangzhou, 510642, China; National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, Guangzhou, 510642, China; Key Laboratory of Zoonoses Prevention and Control of Guangdong Province, Guangzhou, 510642, China.
| | - Ming Liao
- State Key Laboratory for Animal Disease Control and Prevention, South China Agricultural University, Guangzhou, 510642, China; National Avian Influenza Para-Reference Laboratory, Guangzhou, 510642, China; Key Laboratory of Zoonoses, Ministry of Agriculture and Rural Affairs, Guangzhou, 510642, China; National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, Guangzhou, 510642, China; College of Animal Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.
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Halwe NJ, Hamberger L, Sehl-Ewert J, Mache C, Schön J, Ulrich L, Calvelage S, Tönnies M, Fuchs J, Bandawane P, Loganathan M, Abbad A, Carreño JM, Bermúdez-González MC, Simon V, Kandeil A, El-Shesheny R, Ali MA, Kayali G, Budt M, Hippenstiel S, Hocke AC, Krammer F, Wolff T, Schwemmle M, Ciminski K, Hoffmann D, Beer M. Bat-borne H9N2 influenza virus evades MxA restriction and exhibits efficient replication and transmission in ferrets. Nat Commun 2024; 15:3450. [PMID: 38664395 PMCID: PMC11045726 DOI: 10.1038/s41467-024-47455-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Influenza A viruses (IAVs) of subtype H9N2 have reached an endemic stage in poultry farms in the Middle East and Asia. As a result, human infections with avian H9N2 viruses have been increasingly reported. In 2017, an H9N2 virus was isolated for the first time from Egyptian fruit bats (Rousettus aegyptiacus). Phylogenetic analyses revealed that bat H9N2 is descended from a common ancestor dating back centuries ago. However, the H9 and N2 sequences appear to be genetically similar to current avian IAVs, suggesting recent reassortment events. These observations raise the question of the zoonotic potential of the mammal-adapted bat H9N2. Here, we investigate the infection and transmission potential of bat H9N2 in vitro and in vivo, the ability to overcome the antiviral activity of the human MxA protein, and the presence of N2-specific cross-reactive antibodies in human sera. We show that bat H9N2 has high replication and transmission potential in ferrets, efficiently infects human lung explant cultures, and is able to evade antiviral inhibition by MxA in transgenic B6 mice. Together with its low antigenic similarity to the N2 of seasonal human strains, bat H9N2 fulfils key criteria for pre-pandemic IAVs.
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Affiliation(s)
- Nico Joel Halwe
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493, Greifswald, Insel Riems, Germany
| | - Lea Hamberger
- Institute of Virology, Medical Center-University of Freiburg, 79104, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Julia Sehl-Ewert
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, 17493, Greifswald, Insel Riems, Germany
| | - Christin Mache
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353, Berlin, Germany
| | - Jacob Schön
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493, Greifswald, Insel Riems, Germany
| | - Lorenz Ulrich
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493, Greifswald, Insel Riems, Germany
| | - Sten Calvelage
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493, Greifswald, Insel Riems, Germany
| | - Mario Tönnies
- HELIOS Clinic Emil von Behring, Department of Pneumology and Department of Thoracic Surgery, Chest Hospital Heckeshorn, Berlin, Germany
| | - Jonas Fuchs
- Institute of Virology, Medical Center-University of Freiburg, 79104, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Pooja Bandawane
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Madhumathi Loganathan
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Anass Abbad
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Juan Manuel Carreño
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Maria C Bermúdez-González
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Viviana Simon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pathology, Molecular and Cell Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- The Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ahmed Kandeil
- Center of Scientific Excellence for Influenza Virus, Institute of Environmental Research and Climate Changes, National Research Centre, Giza, Egypt
- Human Link DMCC, Dubai, United Arab Emirates
| | - Rabeh El-Shesheny
- Center of Scientific Excellence for Influenza Virus, Institute of Environmental Research and Climate Changes, National Research Centre, Giza, Egypt
- Human Link DMCC, Dubai, United Arab Emirates
| | - Mohamed A Ali
- Center of Scientific Excellence for Influenza Virus, Institute of Environmental Research and Climate Changes, National Research Centre, Giza, Egypt
| | - Ghazi Kayali
- Center of Scientific Excellence for Influenza Virus, Institute of Environmental Research and Climate Changes, National Research Centre, Giza, Egypt
- Human Link DMCC, Dubai, United Arab Emirates
| | - Matthias Budt
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353, Berlin, Germany
| | - Stefan Hippenstiel
- Department of Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Andreas C Hocke
- Department of Infectious Diseases and Respiratory Medicine, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Florian Krammer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pathology, Molecular and Cell Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Thorsten Wolff
- Unit 17, Influenza and Other Respiratory Viruses, Robert Koch-Institut, Seestraße 10, 13353, Berlin, Germany
| | - Martin Schwemmle
- Institute of Virology, Medical Center-University of Freiburg, 79104, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Kevin Ciminski
- Institute of Virology, Medical Center-University of Freiburg, 79104, Freiburg, Germany.
- Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.
| | - Donata Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493, Greifswald, Insel Riems, Germany.
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493, Greifswald, Insel Riems, Germany.
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Sun X, Belser JA, Pulit-Penaloza JA, Brock N, Kieran TJ, Zeng H, Pappas C, Tumpey TM, Maines TR. A naturally occurring HA-stabilizing amino acid (HA1-Y17) in an A(H9N2) low-pathogenic influenza virus contributes to airborne transmission. mBio 2024; 15:e0295723. [PMID: 38112470 PMCID: PMC10790695 DOI: 10.1128/mbio.02957-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 11/14/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Despite the accumulation of evidence showing that airborne transmissible influenza A virus (IAV) typically has a lower pH threshold for hemagglutinin (HA) fusion activation, the underlying mechanism for such a link remains unclear. In our study, by using a pair of isogenic recombinant A(H9N2) viruses with a phenotypical difference in virus airborne transmission in a ferret model due to an acid-destabilizing mutation (HA1-Y17H) in the HA, we demonstrate that an acid-stable A(H9N2) virus possesses a multitude of advantages over its less stable counterpart, including better fitness in the ferret respiratory tract, more effective aerosol emission from infected animals, and improved host susceptibility. Our study provides supporting evidence for the requirement of acid stability in efficient airborne transmission of IAV and sheds light on fundamental mechanisms for virus airborne transmission.
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Affiliation(s)
- Xiangjie Sun
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jessica A. Belser
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Joanna A. Pulit-Penaloza
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Nicole Brock
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Troy J. Kieran
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Hui Zeng
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Claudia Pappas
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Terrence M. Tumpey
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Taronna R. Maines
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Zhang N, Quan K, Chen Z, Hu Q, Nie M, Xu N, Gao R, Wang X, Qin T, Chen S, Peng D, Liu X. The emergence of new antigen branches of H9N2 avian influenza virus in China due to antigenic drift on hemagglutinin through antibody escape at immunodominant sites. Emerg Microbes Infect 2023; 12:2246582. [PMID: 37550992 PMCID: PMC10444018 DOI: 10.1080/22221751.2023.2246582] [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] [Received: 04/11/2023] [Revised: 07/13/2023] [Accepted: 08/06/2023] [Indexed: 08/09/2023]
Abstract
Vaccination is a crucial prevention and control measure against H9N2 avian influenza viruses (AIVs) that threaten poultry production and public health. However, H9N2 AIVs in China undergo continuous antigenic drift of hemagglutinin (HA) under antibody pressure, leading to the emergence of immune escape variants. In this study, we investigated the molecular basis of the current widespread antigenic drift of H9N2 AIVs. Specifically, the most prevalent h9.4.2.5-lineage in China was divided into two antigenic branches based on monoclonal antibody (mAb) hemagglutination inhibition (HI) profiling analysis, and 12 antibody escape residues were identified as molecular markers of these two branches. The 12 escape residues were mapped to antigenic sites A, B, and E (H3 was used as the reference). Among these, eight residues primarily increased 3`SLN preference and contributed to antigenicity drift, and four of the eight residues at sites A and B were positively selected. Moreover, the analysis of H9N2 strains over time and space has revealed the emergence of a new antigenic branch in China since 2015, which has replaced the previous branch. However, the old antigenic branch recirculated to several regions after 2018. Collectively, this study provides a theoretical basis for understanding the molecular mechanisms of antigenic drift and for developing vaccine candidates that contest with the current antigenicity of H9N2 AIVs.
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Affiliation(s)
- Nan Zhang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Keji Quan
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Zixuan Chen
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Qun Hu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Maoshun Nie
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Nuo Xu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Ruyi Gao
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Xiaoquan Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Tao Qin
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Sujuan Chen
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Daxin Peng
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, People’s Republic of China
- The International Joint Laboratory for Cooperation in Agriculture and Agricultural Product Safety, Ministry of Education, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, Yangzhou, People’s Republic of China
| | - Xiufan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
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Arbani O, Ducatez MF, Mahmoudi S, Salamat F, Khayi S, Mouahid M, Selim KM, Kichou F, Ouchhour I, El Houadfi M, Fellahi S. Low Pathogenic Avian Influenza H9N2 Viruses in Morocco: Antigenic and Molecular Evolution from 2021 to 2023. Viruses 2023; 15:2355. [PMID: 38140596 PMCID: PMC10747644 DOI: 10.3390/v15122355] [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] [Received: 10/06/2023] [Revised: 11/03/2023] [Accepted: 11/09/2023] [Indexed: 12/24/2023] Open
Abstract
Avian influenza viruses pose significant threats to both the poultry industry and public health worldwide. Among them, the H9N2 subtype has gained substantial attention due to its high prevalence, especially in Asia, the Middle East, and Africa; its ability to reassort with other influenza viruses; and its potential to infect humans. This study presents a comprehensive phylogenetic and molecular analysis of H9N2 avian influenza viruses circulating in Morocco from 2021 to 2023. Through an active epidemiological survey, a total of 1140 samples (trachea and lungs) and oropharyngeal swabs pooled into 283 pools, collected from 205 farms located in 7 regions of Morocco known for having a high density of poultry farms, were analyzed. Various poultry farms were investigated (159 broiler farms, 24 layer farms, 10 breeder farms, and 12 turkey breeder farms). A total of 21 AI H9N2 strains were isolated, and in order to understand the molecular evolution of the H9N2 avian influenza virus, their genetic sequences were determined using the Sanger sequencing technique. Phylogenetic analysis was performed using a dataset comprising global H9N2 sequences to determine the genetic relatedness and evolutionary dynamics of the Moroccan strains. The results revealed the continued circulation and diversification of H9N2 avian influenza viruses in Morocco during the study period. Real-time RT-PCR showed a positivity rate of 35.6% (73/205), with cycle threshold values ranging from 19.2 to 34.9. The phylogenetic analysis indicated that all Moroccan strains belonged to a G1-like lineage and regrouped into two distinct clusters. Our newly detected isolates aggregated distinctly from the genotypes previously isolated in Morocco, North and West Africa, and the Middle East. This indicats the potential of virus evolution resulting from both national circulation and cross-border transmission. A high genetic diversity at both nucleotide and amino-acid levels was observed among all the strains isolated in this study, as compared to H9N2 strains isolated in Morocco since 2016, which suggests the co-circulation of genetically diverse H9N2 variants. Newly discovered mutations were detected in hemagglutinin positions 226, 227, and 193 (H3 numbering), which highlights the genetic evolution of the H9N2 AIVs. These findings contribute to our understanding of the evolution and epidemiology of H9N2 in the region and provide valuable insights for the development of effective prevention and control strategies against this emerging avian influenza subtype.
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Affiliation(s)
- Oumayma Arbani
- Department of Veterinary Pathology and Public Health, Institut Agronomique et Vétérinaire Hassan II, Rabat 10000, Morocco; (F.S.); (F.K.); (I.O.); (M.E.H.)
| | - Mariette F. Ducatez
- Laboratoire Interactions Hôtes-Agents Pathogènes (IHAP), Toulouse University, INRAE, ENVT, 31300 Toulouse, France;
| | - Salma Mahmoudi
- Laboratory of Microbiology and Molecular Biology, Department of Biology, Faculty of Sciences, Mohamed V University in Rabat, 4 Avenue Ibn Battouta, Rabat 10106, Morocco;
| | - Faiçal Salamat
- Department of Veterinary Pathology and Public Health, Institut Agronomique et Vétérinaire Hassan II, Rabat 10000, Morocco; (F.S.); (F.K.); (I.O.); (M.E.H.)
| | - Slimane Khayi
- Biotechnology Research Unit, CRRA-Rabat, National Institute of Agricultural Research, Rabat 10101, Morocco;
| | | | - Karim M. Selim
- Reference Laboratory for Veterinary Quality Control on Poultry Production, Agriculture Research Center, Animal Health Research Institute, Giza 12618, Egypt;
| | - Faouzi Kichou
- Department of Veterinary Pathology and Public Health, Institut Agronomique et Vétérinaire Hassan II, Rabat 10000, Morocco; (F.S.); (F.K.); (I.O.); (M.E.H.)
| | - Ikram Ouchhour
- Department of Veterinary Pathology and Public Health, Institut Agronomique et Vétérinaire Hassan II, Rabat 10000, Morocco; (F.S.); (F.K.); (I.O.); (M.E.H.)
| | - Mohammed El Houadfi
- Department of Veterinary Pathology and Public Health, Institut Agronomique et Vétérinaire Hassan II, Rabat 10000, Morocco; (F.S.); (F.K.); (I.O.); (M.E.H.)
| | - Siham Fellahi
- Department of Veterinary Pathology and Public Health, Institut Agronomique et Vétérinaire Hassan II, Rabat 10000, Morocco; (F.S.); (F.K.); (I.O.); (M.E.H.)
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6
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Wasberg A, Faria IR, Bergholm J, Petric PP, Mostafa A, Pleschka S, Schwemmle M, Lundkvist Å, Ellström P, Naguib MM. Assessing compatibility and viral fitness between poultry-adapted H9N2 and wild bird-derived neuraminidases. Sci Rep 2023; 13:4476. [PMID: 36934147 PMCID: PMC10024770 DOI: 10.1038/s41598-023-31653-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
Exchange of viral segments between one or more influenza virus subtypes can contribute to a shift in virulence and adaptation to new hosts. Among several influenza subtypes, H9N2 is widely circulating in poultry populations worldwide and has the ability to infect humans. Here, we studied the reassortant compatibility between chicken H9N2 with N1-N9 gene segments of wild bird origin, either with an intact or truncated stalk. Naturally occurring amino acid deletions in the NA stalk of the influenza virus can lead to increased virulence in both mallard ducks and chickens. Our findings show extended genetic compatibility between chicken H9Nx gene segments and the wild-bird NA with and without 20 amino acid stalk deletion. Replication kinetics in avian, mammalian and human cell lines revealed that parental chH9N2 and rH9N6 viruses with intact NA-stalk replicated significantly better in avian DF1 cells compared to human A549 cells. After introducing a stalk deletion, an enhanced preference for replication in mammalian and human cell lines could be observed for rH9N2Δ(H6), rH9N6Δ and rH9N9Δ compared to the parental chH9N2 virus. This highlights the potential emergence of novel viruses with variable phenotypic traits, warranting the continuous monitoring of H9N2 and co-circulating subtypes in avian hosts.
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Affiliation(s)
- Anishia Wasberg
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Inês R Faria
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Julia Bergholm
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Box 7028, 750 07, Uppsala, Sweden
| | - Philipp P Petric
- Institute of Virology, Medical Center, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ahmed Mostafa
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza, Egypt
| | - Stephan Pleschka
- Institute of Medical Virology, Justus Liebig University Giessen, Giessen, Germany
- German Center for Infection Research (DZIF),partner site Giessen-Marburg-Langen, Giessen, Germany
| | - Martin Schwemmle
- Institute of Virology, Medical Center, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Åke Lundkvist
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Patrik Ellström
- Zoonosis Science Center, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Mahmoud M Naguib
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
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7
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Pulit-Penaloza JA, Brock N, Belser JA, Sun X, Pappas C, Tumpey TM, Maines TR. Kinetics and magnitude of viral RNA shedding as indicators for Influenza A virus transmissibility in ferrets. Commun Biol 2023; 6:90. [PMID: 36690690 PMCID: PMC9871019 DOI: 10.1038/s42003-023-04459-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/10/2023] [Indexed: 01/24/2023] Open
Abstract
The ferret transmission model is routinely used to evaluate the pandemic potential of newly emerging influenza A viruses. However, concurrent measurement of viral load in the air is typically not a component of such studies. To address this knowledge gap, we measured the levels of virus in ferret nasal washes as well as viral RNA emitted into the air for 14 diverse influenza viruses, encompassing human-, swine-, and avian-origin strains. Here we show that transmissible viruses display robust replication and fast release into the air. In contrast, poorly- and non-transmissible viruses show significantly reduced or delayed replication along with lower detection of airborne viral RNA at early time points post inoculation. These findings indicate that efficient ferret-to-ferret transmission via the air is directly associated with fast emission of virus-laden particles; as such, quantification of viral RNA in the air represents a useful addition to established assessments of new influenza virus strains.
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Affiliation(s)
- Joanna A Pulit-Penaloza
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Nicole Brock
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jessica A Belser
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Xiangjie Sun
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Claudia Pappas
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Terrence M Tumpey
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Taronna R Maines
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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8
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Zhao C, Pu J. Influence of Host Sialic Acid Receptors Structure on the Host Specificity of Influenza Viruses. Viruses 2022; 14:v14102141. [PMID: 36298694 PMCID: PMC9608321 DOI: 10.3390/v14102141] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/23/2022] Open
Abstract
Influenza viruses need to use sialic acid receptors to invade host cells, and the α-2,3 and α-2,6 sialic acids glycosidic bonds linking the terminal sialic acids are generally considered to be the most important factors influencing the cross-species transmission of the influenza viruses. The development of methods to detect the binding of influenza virus HA proteins to sialic acid receptors, as well as the development of glycobiological techniques, has led to a richer understanding of the structure of the sialylated glycan in influenza virus hosts. It was found that, in addition to the sialic acid glycosidic bond, sialic acid variants, length of the sialylated glycan, Gal-GlcNAc-linked glycosidic bond within the sialylated glycan, and sulfation/fucosylation of the GlcNAc within the sialylated glycan all affect the binding properties of influenza viruses to the sialic acid receptors, thus indirectly affecting the host specificity of influenza viruses. This paper will review the sialic acid variants, internal structural differences of sialylated glycan molecules that affect the host specificity of influenza viruses, and distribution characteristics of sialic acid receptors in influenza virus hosts, in order to provide a more reliable theoretical basis for the in-depth investigation of cross-species transmission of influenza viruses and the development of new antiviral drugs.
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9
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Yang F, Dong D, Wu D, Zhu L, Liu F, Yao H, Wu N, Ye C, Wu H. A multiplex real-time RT-PCR method for detecting H5, H7 and H9 subtype avian influenza viruses in field and clinical samples. Virus Res 2021; 309:198669. [PMID: 34954007 DOI: 10.1016/j.virusres.2021.198669] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 11/16/2022]
Abstract
In recent years, H5 and H7 subtypes of highly pathogenic avian influenza viruses (HPAIVs) have been identified in poultry worldwide, resulting in large economic losses to poultry production. Furthermore, H9N2 low pathogenic AIVs are reported to provide internal genes for generating novel reassortant AIVs, leading to potential pandemic risks. To establish an accurate, sensitive and convenient diagnostic method for H5, H7 and H9 subtype AIVs in Eurasian lineage, four groups of specific primers and probes were designed based on the conserved fragments of M, H5, H7 and H9 genes, and a multiplex real-time RT-PCR (RRT-PCR) method was established. High sensitivity was achieved for the multiplex RRT-PCR approach, with a detection limit of 1-10 copies (plasmid DNA) per reaction. The specificity of the method was evaluated using diverse subtypes of AIVs and other avian respiratory viruses isolated in eastern China over the last 9 years. Compared with virus isolation, a higher consistency was achieved when assessing 135 field samples and 126 clinical samples. The results showed that the multiplex RRT-PCR method is a fast, convenient and practical method for AIV clinical detection and epidemiological analysis.
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Affiliation(s)
- Fan Yang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, and National Clinical Research Center for Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Dalu Dong
- Hangzhou Biotest Biotech Co.,Ltd., 17 Futai Road, Zhongtai Street, Yuhang District, Hangzhou 311121, Zhejiang, China
| | - Danna Wu
- Hangzhou Biotest Biotech Co.,Ltd., 17 Futai Road, Zhongtai Street, Yuhang District, Hangzhou 311121, Zhejiang, China
| | - Linwei Zhu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, and National Clinical Research Center for Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Fumin Liu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, and National Clinical Research Center for Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Hangping Yao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, and National Clinical Research Center for Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Nanping Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, and National Clinical Research Center for Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Chunsheng Ye
- Hangzhou Biotest Biotech Co.,Ltd., 17 Futai Road, Zhongtai Street, Yuhang District, Hangzhou 311121, Zhejiang, China.
| | - Haibo Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, and National Clinical Research Center for Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China.
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10
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Fusade-Boyer M, Djegui F, Batawui K, Byuragaba DK, Jones JC, Wabwire-Mangeni F, Erima B, Atim G, Ukuli QA, Tugume T, Dogno K, Adjabli K, Nzuzi M, Adjin R, Jeevan T, Rubrum A, Go-Maro W, Kayali G, McKenzie P, Webby RJ, Ducatez MF. Antigenic and molecular characterization of low pathogenic avian influenza A(H9N2) viruses in sub-Saharan Africa from 2017 through 2019. Emerg Microbes Infect 2021; 10:753-761. [PMID: 33754959 PMCID: PMC8057090 DOI: 10.1080/22221751.2021.1908097] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/25/2021] [Accepted: 03/20/2021] [Indexed: 12/13/2022]
Abstract
Sub-Saharan Africa was historically considered an animal influenza cold spot, with only sporadic highly pathogenic H5 outbreaks detected over the last 20 years. However, in 2017, low pathogenic avian influenza A(H9N2) viruses were detected in poultry in Sub-Saharan Africa. Molecular, phylogenetic, and antigenic characterization of isolates from Benin, Togo, and Uganda showed that they belonged to the G1 lineage. Isolates from Benin and Togo clustered with viruses previously described in Western Africa, whereas viruses from Uganda were genetically distant and clustered with viruses from the Middle East. Viruses from Benin exhibited decreased cross-reactivity with those from Togo and Uganda, suggesting antigenic drift associated with reduced replication in Calu-3 cells. The viruses exhibited mammalian adaptation markers similar to those of the human strain A/Senegal/0243/2019 (H9N2). Therefore, viral genetic and antigenic surveillance in Africa is of paramount importance to detect further evolution or emergence of new zoonotic strains.
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Affiliation(s)
| | | | | | | | - Jeremy C. Jones
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | | | - Bernard Erima
- Makerere University Walter Reed Project, Kampala, Uganda
| | - Gladys Atim
- Makerere University Walter Reed Project, Kampala, Uganda
| | | | - Titus Tugume
- Makerere University Walter Reed Project, Kampala, Uganda
| | - Koffi Dogno
- Laboratoire Central Vétérinaire de Lomé, Lomé, Togo
| | | | - Mvibudulu Nzuzi
- IHAP, UMR1225, Université de Toulouse, INRAe, ENVT, Toulouse, France
| | | | - Trushar Jeevan
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Adam Rubrum
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | | | - Ghazi Kayali
- Human Link, Hazmieh, Lebanon
- University of Texas Health Sciences Center, Houston, Texas, USA
| | - Pamela McKenzie
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Richard J. Webby
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
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11
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Cáceres CJ, Rajao DS, Perez DR. Airborne Transmission of Avian Origin H9N2 Influenza A Viruses in Mammals. Viruses 2021; 13:v13101919. [PMID: 34696349 PMCID: PMC8540072 DOI: 10.3390/v13101919] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 12/17/2022] Open
Abstract
Influenza A viruses (IAV) are widespread viruses affecting avian and mammalian species worldwide. IAVs from avian species can be transmitted to mammals including humans and, thus, they are of inherent pandemic concern. Most of the efforts to understand the pathogenicity and transmission of avian origin IAVs have been focused on H5 and H7 subtypes due to their highly pathogenic phenotype in poultry. However, IAV of the H9 subtype, which circulate endemically in poultry flocks in some regions of the world, have also been associated with cases of zoonotic infections. In this review, we discuss the mammalian transmission of H9N2 and the molecular factors that are thought relevant for this spillover, focusing on the HA segment. Additionally, we discuss factors that have been associated with the ability of these viruses to transmit through the respiratory route in mammalian species. The summarized information shows that minimal amino acid changes in the HA and/or the combination of H9N2 surface genes with internal genes of human influenza viruses are enough for the generation of H9N2 viruses with the ability to transmit via aerosol.
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12
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Elgendy EM, Arai Y, Kawashita N, Isobe A, Daidoji T, Ibrahim MS, Ono T, Takagi T, Nakaya T, Matsumoto K, Watanabe Y. Double mutations in the H9N2 avian influenza virus PB2 gene act cooperatively to increase viral host adaptation and replication for human infections. J Gen Virol 2021; 102. [PMID: 34061017 DOI: 10.1099/jgv.0.001612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Avian H9N2 influenza viruses in East Asia are genetically diversified and multiple genotypes (A-W) have been established in poultry. Genotype S strains are currently the most prevalent strains, have caused many human infections and pose a public health threat. In this study, human adaptation mutations in the PB2 polymerase in genotype S strains were identified by database screening. Several PB2 double mutations were identified that acted cooperatively to produce higher genotype S virus polymerase activity and replication in human cells than in avian cells and to increase viral growth and virulence in mice. These mutations were chronologically and phylogenetically clustered in a new group within genotype S viruses. Most of the relevant human virus isolates carry the PB2-A588V mutation together with another PB2 mutation (i.e. K526R, E627V or E627K), indicating a host adaptation advantage for these double mutations. The prevalence of PB2 double mutations in human H9N2 virus isolates has also been found in genetically related human H7N9 and H10N8 viruses. These results suggested that PB2 double mutations in viruses in the field acted cooperatively to increase human adaptation of the currently prevalent H9N2 genotype S strains. This may have contributed to the recent surge of H9N2 infections and may be applicable to the human adaptation of several other avian influenza viruses. Our study provides a better understanding of the human adaptation pathways of genetically related H9N2, H7N9 and H10N8 viruses in nature.
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Affiliation(s)
- Emad Mohamed Elgendy
- Department of Infectious Diseases, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Yasuha Arai
- Department of Infectious Diseases, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Norihito Kawashita
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.,Faculty of Science and Engineering, Kindai University, Osaka, Japan
| | - Ayana Isobe
- Department of Infectious Diseases, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomo Daidoji
- Department of Infectious Diseases, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Madiha Salah Ibrahim
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Egypt
| | - Takao Ono
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Tatsuya Takagi
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Takaaki Nakaya
- Department of Infectious Diseases, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazuhiko Matsumoto
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Yohei Watanabe
- Department of Infectious Diseases, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, Kyoto, Japan
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13
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Russell CJ. Hemagglutinin Stability and Its Impact on Influenza A Virus Infectivity, Pathogenicity, and Transmissibility in Avians, Mice, Swine, Seals, Ferrets, and Humans. Viruses 2021; 13:746. [PMID: 33923198 PMCID: PMC8145662 DOI: 10.3390/v13050746] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 12/13/2022] Open
Abstract
Genetically diverse influenza A viruses (IAVs) circulate in wild aquatic birds. From this reservoir, IAVs sporadically cause outbreaks, epidemics, and pandemics in wild and domestic avians, wild land and sea mammals, horses, canines, felines, swine, humans, and other species. One molecular trait shown to modulate IAV host range is the stability of the hemagglutinin (HA) surface glycoprotein. The HA protein is the major antigen and during virus entry, this trimeric envelope glycoprotein binds sialic acid-containing receptors before being triggered by endosomal low pH to undergo irreversible structural changes that cause membrane fusion. The HA proteins from different IAV isolates can vary in the pH at which HA protein structural changes are triggered, the protein causes membrane fusion, or outside the cell the virion becomes inactivated. HA activation pH values generally range from pH 4.8 to 6.2. Human-adapted HA proteins tend to have relatively stable HA proteins activated at pH 5.5 or below. Here, studies are reviewed that report HA stability values and investigate the biological impact of variations in HA stability on replication, pathogenicity, and transmissibility in experimental animal models. Overall, a stabilized HA protein appears to be necessary for human pandemic potential and should be considered when assessing human pandemic risk.
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Affiliation(s)
- Charles J Russell
- Department of Infectious Diseases, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105-3678, USA
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14
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Adlhoch C, Fusaro A, Kuiken T, Niqueux É, Staubach C, Terregino C, Muñoz Guajardo I, Baldinelli F. Avian influenza overview May - August 2020. EFSA J 2020; 18:e06270. [PMID: 33281980 PMCID: PMC7525800 DOI: 10.2903/j.efsa.2020.6270] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Between 16 May and 15 August 2020, seven highly pathogenic avian influenza (HPAI) A(H5N8) virus outbreaks were reported in Europe in poultry, with one outbreak reported in Bulgaria(n=1) andsix in Hungary (n=6) and one low pathogenic avian influenza (LPAI) A(H5N3) virus outbreak was reported in poultry in Italy. All six outbreaks detected in Hungary were secondary outbreaks and seem to be the tail end of the HPAI A(H5N8) epidemic that wasobserved in poultry over the winter and spring in central Europe from December 2019 (n=334).Genetic analysis of the HPAI A(H5N8) viruses isolated during this reporting period from Bulgaria and Hungary did not identify any major changes compared tothe viruses collected in the respective countries during the first months of 2020. This suggests a persistence of the virus in the two countries rather than new introductions via infectedwild birds. HPAI A(H5N8) virus has been detected in poultry and wild birds in western Russia within the reporting period, and as of the middle of September also in Kazakhstan. The presence of HPAI virus in western Russiaand in north Kazakhstan,spatially associated with autumnmigration routes of wild waterbirds, is of concern due to the possible spread of the virus via wild birds migrating to the EU.It is highly recommended thatMember States take appropriate measures to promptly detect suspected cases of HPAI, including increasing biosecurity measures. According to past experiences (2005-2006 and 2016-2017 epidemic waves), the northern and eastern European areas might be at higher risk of virus introduction in the coming autumn-winter seasonand should be the key regions where prompt response measures to early detect the virusshould be set up. One human case due to A(H9N2) avian influenza virus infection was reported during the reporting period.
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