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Lin Q, Goldberg EE, Leitner T, Molina-París C, King AA, Romero-Severson EO. The Number and Pattern of Viral Genomic Reassortments are not Necessarily Identifiable from Segment Trees. Mol Biol Evol 2024; 41:msae078. [PMID: 38648521 PMCID: PMC11152448 DOI: 10.1093/molbev/msae078] [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: 09/20/2023] [Revised: 02/23/2024] [Accepted: 04/09/2024] [Indexed: 04/25/2024] Open
Abstract
Reassortment is an evolutionary process common in viruses with segmented genomes. These viruses can swap whole genomic segments during cellular co-infection, giving rise to novel progeny formed from the mixture of parental segments. Since large-scale genome rearrangements have the potential to generate new phenotypes, reassortment is important to both evolutionary biology and public health research. However, statistical inference of the pattern of reassortment events from phylogenetic data is exceptionally difficult, potentially involving inference of general graphs in which individual segment trees are embedded. In this paper, we argue that, in general, the number and pattern of reassortment events are not identifiable from segment trees alone, even with theoretically ideal data. We call this fact the fundamental problem of reassortment, which we illustrate using the concept of the "first-infection tree," a potentially counterfactual genealogy that would have been observed in the segment trees had no reassortment occurred. Further, we illustrate four additional problems that can arise logically in the inference of reassortment events and show, using simulated data, that these problems are not rare and can potentially distort our observation of reassortment even in small data sets. Finally, we discuss how existing methods can be augmented or adapted to account for not only the fundamental problem of reassortment, but also the four additional situations that can complicate the inference of reassortment.
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Affiliation(s)
- Qianying Lin
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Emma E Goldberg
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Thomas Leitner
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Carmen Molina-París
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Aaron A King
- Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Mathematics, University of Michigan, Ann Arbor, MI, USA
- Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI, USA
- Santa Fe Institute, Santa Fe, NM, USA
| | - Ethan O Romero-Severson
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
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Lin Q, Goldberg EE, Leitner T, Molina-París C, King AA, Romero-Severson EO. Modeling the evolution of segment trees reveals deficiencies in current inferential methods for genomic reassortment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.558687. [PMID: 37790507 PMCID: PMC10542121 DOI: 10.1101/2023.09.20.558687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Reassortment is an evolutionary process common in viruses with segmented genomes. These viruses can swap whole genomic segments during cellular co-infection, giving rise to new viral variants. Large-scale genome rearrangements, such as reassortment, have the potential to quickly generate new phenotypes, making the understanding of viral reassortment important to both evolutionary biology and public health research. In this paper, we argue that reassortment cannot be reliably inferred from incongruities between segment phylogenies using the established remove-and-rejoin or coalescent approaches. We instead show that reassortment must be considered in the context of a broader population process that includes the dynamics of the infected hosts. Using illustrative examples and simulation we identify four types of evolutionary events that are difficult or impossible to reconstruct with incongruence-based methods. Further, we show that these specific situations are very common and will likely occur even in small samples. Finally, we argue that existing methods can be augmented or modified to account for all the problematic situations that we identify in this paper. Robust assessment of the role of reassortment in viral evolution is difficult, and we hope to provide conceptual clarity on some important methodological issues that can arise in the development of the next generation of tools for studying reassortment.
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Wille M, Tolf C, Latorre-Margalef N, Fouchier RAM, Halpin RA, Wentworth DE, Ragwani J, Pybus OG, Olsen B, Waldenström J. Evolutionary features of a prolific subtype of avian influenza A virus in European waterfowl. Virus Evol 2022; 8:veac074. [PMID: 36128050 PMCID: PMC9477075 DOI: 10.1093/ve/veac074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 06/12/2022] [Accepted: 08/25/2022] [Indexed: 11/26/2022] Open
Abstract
Avian influenza A virus (AIV) is ubiquitous in waterfowl and is detected annually at high prevalence in waterfowl during the Northern Hemisphere autumn. Some AIV subtypes are globally common in waterfowl, such as H3N8, H4N6, and H6N2, and are detected in the same populations at a high frequency, annually. In order to investigate genetic features associated to the long-term maintenance of common subtypes in migratory ducks, we sequenced 248 H4 viruses isolated across 8 years (2002-9) from mallards (Anas platyrhynchos) sampled in southeast Sweden. Phylogenetic analyses showed that both H4 and N6 sequences fell into three distinct lineages, structured by year of isolation. Specifically, across the 8 years of the study, we observed lineage replacement, whereby a different HA lineage circulated in the population each year. Analysis of deduced amino acid sequences of the HA lineages illustrated key differences in regions of the globular head of hemagglutinin that overlap with established antigenic sites in homologous hemagglutinin H3, suggesting the possibility of antigenic differences among these HA lineages. Beyond HA, lineage replacement was common to all segments, such that novel genome constellations were detected across years. A dominant genome constellation would rapidly amplify in the duck population, followed by unlinking of gene segments as a result of reassortment within 2-3 weeks following introduction. These data help reveal the evolutionary dynamics exhibited by AIV on both annual and decadal scales in an important reservoir host.
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Affiliation(s)
- Michelle Wille
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Universitetsplatsen 1, Kalmar SE-39231, Sweden
| | - Conny Tolf
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Universitetsplatsen 1, Kalmar SE-39231, Sweden
| | - Neus Latorre-Margalef
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Universitetsplatsen 1, Kalmar SE-39231, Sweden
| | - Ron A M Fouchier
- Department of Virology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | | | | | - Jayna Ragwani
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
| | - Oliver G Pybus
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, London AL9 7TA, UK
| | - Björn Olsen
- Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala SE751 85, Sweden
| | - Jonas Waldenström
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Universitetsplatsen 1, Kalmar SE-39231, Sweden
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Ganti K, Bagga A, DaSilva J, Shepard SS, Barnes JR, Shriner S, Koelle K, Lowen AC. Avian Influenza A Viruses Reassort and Diversify Differently in Mallards and Mammals. Viruses 2021; 13:v13030509. [PMID: 33808674 PMCID: PMC8003500 DOI: 10.3390/v13030509] [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: 02/06/2021] [Revised: 03/10/2021] [Accepted: 03/16/2021] [Indexed: 12/18/2022] Open
Abstract
Reassortment among co-infecting influenza A viruses (IAVs) is an important source of viral diversity and can facilitate expansion into novel host species. Indeed, reassortment played a key role in the evolution of the last three pandemic IAVs. Observed patterns of reassortment within a coinfected host are likely to be shaped by several factors, including viral load, the extent of viral mixing within the host and the stringency of selection. These factors in turn are expected to vary among the diverse host species that IAV infects. To investigate host differences in IAV reassortment, here we examined reassortment of two distinct avian IAVs within their natural host (mallards) and a mammalian model system (guinea pigs). Animals were co-inoculated with A/wildbird/California/187718-36/2008 (H3N8) and A/mallard/Colorado/P66F1-5/2008 (H4N6) viruses. Longitudinal samples were collected from the cloaca of mallards or the nasal tract of guinea pigs and viral genetic exchange was monitored by genotyping clonal isolates from these samples. Relative to those in guinea pigs, viral populations in mallards showed higher frequencies of reassortant genotypes and were characterized by higher genotype richness and diversity. In line with these observations, analysis of pairwise segment combinations revealed lower linkage disequilibrium in mallards as compared to guinea pigs. No clear longitudinal patterns in richness, diversity or linkage disequilibrium were present in either host. Our results reveal mallards to be a highly permissive host for IAV reassortment and suggest that reduced viral mixing limits avian IAV reassortment in a mammalian host.
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Affiliation(s)
- Ketaki Ganti
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Anish Bagga
- Emory College of Arts and Sciences, Emory University, Atlanta, GA 30322, USA;
| | - Juliana DaSilva
- Center for Disease Control and Prevention, Influenza Division, Atlanta, GA 30322, USA; (J.D.); (S.S.S.); (J.R.B.)
| | - Samuel S. Shepard
- Center for Disease Control and Prevention, Influenza Division, Atlanta, GA 30322, USA; (J.D.); (S.S.S.); (J.R.B.)
| | - John R. Barnes
- Center for Disease Control and Prevention, Influenza Division, Atlanta, GA 30322, USA; (J.D.); (S.S.S.); (J.R.B.)
| | - Susan Shriner
- National Wildlife Research Center, US Department of Agriculture-Animal and Plant Health Inspection Service, Fort Collins, CO 80521, USA;
| | - Katia Koelle
- Department of Biology, Emory University, Atlanta, GA 30322, USA
- Emory-UGA Center of Excellence for Influenza Research and Surveillance (CEIRS), Atlanta, GA 30322, USA
- Correspondence: (K.K.); , (A.C.L.)
| | - Anice C. Lowen
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA;
- Emory-UGA Center of Excellence for Influenza Research and Surveillance (CEIRS), Atlanta, GA 30322, USA
- Correspondence: (K.K.); , (A.C.L.)
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Yin R, Zhou X, Rashid S, Kwoh CK. HopPER: an adaptive model for probability estimation of influenza reassortment through host prediction. BMC Med Genomics 2020; 13:9. [PMID: 31973709 PMCID: PMC6979075 DOI: 10.1186/s12920-019-0656-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 12/26/2019] [Indexed: 12/29/2022] Open
Abstract
Background Influenza reassortment, a mechanism where influenza viruses exchange their RNA segments by co-infecting a single cell, has been implicated in several major pandemics since 19th century. Owing to the significant impact on public health and social stability, great attention has been received on the identification of influenza reassortment. Methods We proposed a novel computational method named HopPER (Host-prediction-based Probability Estimation of Reassortment), that sturdily estimates reassortment probabilities through host tropism prediction using 147 new features generated from seven physicochemical properties of amino acids. We conducted the experiments on a range of real and synthetic datasets and compared HopPER with several state-of-the-art methods. Results It is shown that 280 out of 318 candidate reassortants have been successfully identified. Additionally, not only can HopPER be applied to complete genomes but its effectiveness on incomplete genomes is also demonstrated. The analysis of evolutionary success of avian, human and swine viruses generated through reassortment across different years using HopPER further revealed the reassortment history of the influenza viruses. Conclusions Our study presents a novel method for the prediction of influenza reassortment. We hope this method could facilitate rapid reassortment detection and provide novel insights into the evolutionary patterns of influenza viruses.
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Affiliation(s)
- Rui Yin
- School of Computer Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
| | - Xinrui Zhou
- School of Computer Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Shamima Rashid
- School of Computer Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Chee Keong Kwoh
- School of Computer Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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Pepin KM, Hopken MW, Shriner SA, Spackman E, Abdo Z, Parrish C, Riley S, Lloyd-Smith JO, Piaggio AJ. Improving risk assessment of the emergence of novel influenza A viruses by incorporating environmental surveillance. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180346. [PMID: 31401963 PMCID: PMC6711309 DOI: 10.1098/rstb.2018.0346] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Reassortment is an evolutionary mechanism by which influenza A viruses (IAV) generate genetic novelty. Reassortment is an important driver of host jumps and is widespread according to retrospective surveillance studies. However, predicting the epidemiological risk of reassortant emergence in novel hosts from surveillance data remains challenging. IAV strains persist and co-occur in the environment, promoting co-infection during environmental transmission. These conditions offer opportunity to understand reassortant emergence in reservoir and spillover hosts. Specifically, environmental RNA could provide rich information for understanding the evolutionary ecology of segmented viruses, and transform our ability to quantify epidemiological risk to spillover hosts. However, significant challenges with recovering and interpreting genomic RNA from the environment have impeded progress towards predicting reassortant emergence from environmental surveillance data. We discuss how the fields of genomics, experimental ecology and epidemiological modelling are well positioned to address these challenges. Coupling quantitative disease models and natural transmission studies with new molecular technologies, such as deep-mutational scanning and single-virus sequencing of environmental samples, should dramatically improve our understanding of viral co-occurrence and reassortment. We define observable risk metrics for emerging molecular technologies and propose a conceptual research framework for improving accuracy and efficiency of risk prediction. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
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Affiliation(s)
- Kim M. Pepin
- National Wildlife Research Center, USDA-APHIS, Fort Collins, CO 80521, USA
- e-mail:
| | - Matthew W. Hopken
- National Wildlife Research Center, USDA-APHIS, Fort Collins, CO 80521, USA
- Colorado State University, Fort Collins, CO 80523, USA
| | - Susan A. Shriner
- National Wildlife Research Center, USDA-APHIS, Fort Collins, CO 80521, USA
| | - Erica Spackman
- Exotic and Emerging Avian Viral Diseases Research, USDA-ARS, Athens, GA 30605, USA
| | - Zaid Abdo
- Colorado State University, Fort Collins, CO 80523, USA
| | - Colin Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
| | - Steven Riley
- MRC Centre for Global Infectious Disease Analysis, Imperial College, London, SW7 2AZ, UK
| | - James O. Lloyd-Smith
- UCLA, Los Angeles, CA 90095, USA
- Department of Ecology and Evolutionary Biology, Fogarty International Center, National Institutes of Health, Bethesda MD 20892, USA
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Bergervoet SA, Pritz-Verschuren SBE, Gonzales JL, Bossers A, Poen MJ, Dutta J, Khan Z, Kriti D, van Bakel H, Bouwstra R, Fouchier RAM, Beerens N. Circulation of low pathogenic avian influenza (LPAI) viruses in wild birds and poultry in the Netherlands, 2006-2016. Sci Rep 2019; 9:13681. [PMID: 31548582 PMCID: PMC6757041 DOI: 10.1038/s41598-019-50170-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 08/27/2019] [Indexed: 01/01/2023] Open
Abstract
In this study, we explore the circulation of low pathogenic avian influenza (LPAI) viruses in wild birds and poultry in the Netherlands. Surveillance data collected between 2006 and 2016 was used to evaluate subtype diversity, spatiotemporal distribution and genetic relationships between wild bird and poultry viruses. We observed close species-dependent associations among hemagglutinin and neuraminidase subtypes. Not all subtypes detected in wild birds were found in poultry, suggesting transmission to poultry is selective and likely depends on viral factors that determine host range restriction. Subtypes commonly detected in poultry were in wild birds most frequently detected in mallards and geese. Different temporal patterns in virus prevalence were observed between wild bird species. Virus detections in domestic ducks coincided with the prevalence peak in wild ducks, whereas virus detections in other poultry types were made throughout the year. Genetic analysis of the surface genes demonstrated that most poultry viruses were related to locally circulating wild bird viruses, but no direct spatiotemporal link was observed. Results indicate prolonged undetected virus circulation and frequent reassortment events with local and newly introduced viruses within the wild bird population. Increased knowledge on LPAI virus circulation can be used to improve surveillance strategies.
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Affiliation(s)
- Saskia A Bergervoet
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands.,Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | | | - Jose L Gonzales
- Department of Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Alex Bossers
- Department of Infection Biology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Marjolein J Poen
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Jayeeta Dutta
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Zenab Khan
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Divya Kriti
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, USA.,Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, USA
| | | | - Ron A M Fouchier
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Nancy Beerens
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands.
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8
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Diversity and distribution of type A influenza viruses: an updated panorama analysis based on protein sequences. Virol J 2019; 16:85. [PMID: 31242907 PMCID: PMC6595669 DOI: 10.1186/s12985-019-1188-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/31/2019] [Indexed: 01/09/2023] Open
Abstract
Background Type A influenza viruses (IAVs) cause significant infections in humans and multiple species of animals including pigs, horses, birds, dogs and some marine animals. They are of complicated phylogenetic diversity and distribution, and analysis of their phylogenetic diversity and distribution from a panorama view has not been updated for multiple years. Methods 139,872 protein sequences of IAVs from GenBank were selected, and they were aligned and phylogenetically analyzed using the software tool MEGA 7.0. Lineages and subordinate lineages were classified according to the topology of the phylogenetic trees and the host, temporal and spatial distribution of the viruses, and designated using a novel universal nomenclature system. Results Large phylogenetic trees of the two external viral genes (HA and NA) and six internal genes (PB2, PB1, PA, NP, MP and NS) were constructed, and the diversity and the host, temporal and spatial distribution of these genes were calculated and statistically analyzed. Various features regarding the diversity and distribution of IAVs were confirmed, revised or added through this study, as compared with previous reports. Lineages and subordinate lineages were classified and designated for each of the genes based on the updated panorama views. Conclusions The panorama views of phylogenetic diversity and distribution of IAVs and their nomenclature system were updated and assumed to be of significance for studies and communication of IAVs. Electronic supplementary material The online version of this article (10.1186/s12985-019-1188-7) contains supplementary material, which is available to authorized users.
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9
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Bergervoet SA, Heutink R, Bouwstra R, Fouchier RAM, Beerens N. Genetic analysis identifies potential transmission of low pathogenic avian influenza viruses between poultry farms. Transbound Emerg Dis 2019; 66:1653-1664. [PMID: 30964232 PMCID: PMC6850361 DOI: 10.1111/tbed.13199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/25/2019] [Accepted: 04/02/2019] [Indexed: 12/25/2022]
Abstract
Poultry can become infected with low pathogenic avian influenza (LPAI) viruses via (in)direct contact with infected wild birds or by transmission of the virus between farms. This study combines routinely collected surveillance data with genetic analysis to assess the contribution of between‐farm transmission to the overall incidence of LPAI virus infections in poultry. Over a 10‐year surveillance period, we identified 35 potential cases of between‐farm transmission in the Netherlands, of which 10 formed geographical clusters. A total of 21 LPAI viruses were isolated from nine potential between‐farm transmission cases, which were further studied by genetic and epidemiological analysis. Whole genome sequence analysis identified close genetic links between infected farms in seven cases. The presence of identical deletions in the neuraminidase stalk region and minority variants provided additional indications of between‐farm transmission. Spatiotemporal analysis demonstrated that genetically closely related viruses were detected within a median time interval of 8 days, and the median distance between the infected farms was significantly shorter compared to farms infected with genetically distinct viruses (6.3 versus 69.0 km; p < 0.05). The results further suggest that between‐farm transmission was not restricted to holdings of the same poultry type and not related to the housing system. Although separate introductions from the wild bird reservoir cannot be excluded, our study indicates that between‐farm transmission occurred in seven of nine virologically analysed cases. Based on these findings, it is likely that between‐farm transmission contributes considerably to the incidence of LPAI virus infections in poultry.
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Affiliation(s)
- Saskia A Bergervoet
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands.,Department of Viroscience, Erasmus MC, Rotterdam, The Netherlandss
| | - Rene Heutink
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | | | - Ron A M Fouchier
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlandss
| | - Nancy Beerens
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
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Abstract
Waterbirds are the main reservoir for low pathogenic avian influenza A viruses (LPAIV), from which occasional spillover to poultry occurs. When circulating among poultry, LPAIV may become highly pathogenic avian influenza A viruses (HPAIV). In recent years, the epidemiology of HPAIV viruses has changed drastically. HPAIV H5N1 are currently endemic among poultry in a number of countries. In addition, global spread of HPAIV H5Nx viruses has resulted in major outbreaks among wild birds and poultry worldwide. Using data collected during these outbreaks, the role of migratory birds as a vector became increasingly clear. Here we provide an overview of current data about various aspects of the changing role of wild birds in the epidemiology of avian influenza A viruses.
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11
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Seasonal H3N2 and 2009 Pandemic H1N1 Influenza A Viruses Reassort Efficiently but Produce Attenuated Progeny. J Virol 2017. [PMID: 28637755 DOI: 10.1128/jvi.00830-17] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Reassortment of gene segments between coinfecting influenza A viruses (IAVs) facilitates viral diversification and has a significant epidemiological impact on seasonal and pandemic influenza. Since 1977, human IAVs of H1N1 and H3N2 subtypes have cocirculated with relatively few documented cases of reassortment. We evaluated the potential for viruses of the 2009 pandemic H1N1 (pH1N1) and seasonal H3N2 lineages to reassort under experimental conditions. Results of heterologous coinfections with pH1N1 and H3N2 viruses were compared to those obtained following coinfection with homologous, genetically tagged, pH1N1 viruses as a control. High genotype diversity was observed among progeny of both coinfections; however, diversity was more limited following heterologous coinfection. Pairwise analysis of genotype patterns revealed that homologous reassortment was random while heterologous reassortment was characterized by specific biases. pH1N1/H3N2 reassortant genotypes produced under single-cycle coinfection conditions showed a strong preference for homologous PB2-PA combinations and general preferences for the H3N2 NA, pH1N1 M, and H3N2 PB2 except when paired with the pH1N1 PA or NP. Multicycle coinfection results corroborated these findings and revealed an additional preference for the H3N2 HA. Segment compatibility was further investigated by measuring chimeric polymerase activity and growth of selected reassortants in human tracheobronchial epithelial cells. In guinea pigs inoculated with a mixture of viruses, parental H3N2 viruses dominated but reassortants also infected and transmitted to cage mates. Taken together, our results indicate that strong intrinsic barriers to reassortment between seasonal H3N2 and pH1N1 viruses are few but that the reassortants formed are attenuated relative to parental strains.IMPORTANCE The genome of IAV is relatively simple, comprising eight RNA segments, each of which typically encodes one or two proteins. Each viral protein carries out multiple functions in coordination with other viral components and the machinery of the cell. When two IAVs coinfect a cell, they can exchange genes through reassortment. The resultant progeny viruses often suffer fitness defects due to suboptimal interactions among divergent viral components. The genetic diversity generated through reassortment can facilitate the emergence of novel outbreak strains. Thus, it is important to understand the efficiency of reassortment and the factors that limit its potential. The research described here offers new tools for studying reassortment between two strains of interest and applies those tools to viruses of the 2009 pandemic H1N1 and seasonal H3N2 lineages, which currently cocirculate in humans and therefore have the potential to give rise to novel epidemic strains.
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12
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Genetic characterization of H5N2 influenza viruses isolated from wild birds in Japan suggests multiple reassortment. Arch Virol 2016; 161:3309-3322. [DOI: 10.1007/s00705-016-3023-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/20/2016] [Indexed: 10/21/2022]
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Wellehan • JF, Lierz • M, Phalen • D, Raidal • S, Styles • DK, Crosta • L, Melillo • A, Schnitzer • P, Lennox • A, Lumeij JT. Infectious disease. CURRENT THERAPY IN AVIAN MEDICINE AND SURGERY 2016. [PMCID: PMC7158187 DOI: 10.1016/b978-1-4557-4671-2.00011-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Okuya K, Kawabata T, Nagano K, Tsukiyama-Kohara K, Kusumoto I, Takase K, Ozawa M. Isolation and characterization of influenza A viruses from environmental water at an overwintering site of migratory birds in Japan. Arch Virol 2015; 160:3037-52. [PMID: 26392284 DOI: 10.1007/s00705-015-2610-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 09/10/2015] [Indexed: 10/23/2022]
Abstract
The Izumi plain in Kagoshima prefecture, Japan, is an overwintering site of more than 10,000 cranes. The wet paddy areas are artificially created to provide roosting sites for the cranes every winter. Since wild ducks, known to be a natural reservoir of influenza A viruses, also overwinter in this area, the cranes' roost water likely serves as a source of influenza A virus infection. To assess this potential risk, we collected 126 water samples from the cranes' roost in the 2012/2013 winter season for virus isolation. We isolated six influenza viruses of three subtypes (H3N8, H4N6, and H4N8) from the water samples collected in the months of November and December. Genetic analysis of our isolates indicated that these viruses were genetically similar to the low-pathogenic avian influenza viruses circulating among Eurasian waterfowl. These findings suggest the possibility of the cranes becoming infected with the avian influenza viruses that are present in their roost water.
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Affiliation(s)
- Kosuke Okuya
- Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan
| | - Toshiko Kawabata
- Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Kiori Nagano
- Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Kyoko Tsukiyama-Kohara
- Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan.,Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Isamu Kusumoto
- Kagoshima Crane Conservation Committee, Izumi, Kagoshima, Japan
| | - Kozo Takase
- Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan.,Laboratory of Animal Microbiology, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Makoto Ozawa
- Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan. .,Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan.
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15
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Vijaykrishna D, Mukerji R, Smith GJD. RNA Virus Reassortment: An Evolutionary Mechanism for Host Jumps and Immune Evasion. PLoS Pathog 2015; 11:e1004902. [PMID: 26158697 PMCID: PMC4497687 DOI: 10.1371/journal.ppat.1004902] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Dhanasekaran Vijaykrishna
- Duke-NUS Graduate Medical School, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Department of Pathology, Singapore General Hospital, SingHealth, Singapore
- * E-mail:
| | | | - Gavin J. D. Smith
- Duke-NUS Graduate Medical School, Singapore
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
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16
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Xiaorong P, Haibo W, Xiuming P, Nanping W. Molecular phylogeny and evolutionary dynamics of matrix gene of avian influenza viruses in China. INFECTION GENETICS AND EVOLUTION 2015; 34:344-51. [PMID: 26044199 DOI: 10.1016/j.meegid.2015.05.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/19/2015] [Accepted: 05/30/2015] [Indexed: 12/12/2022]
Abstract
In China, several subtype avian influenza viruses consistently circulate in poultry. Numerous studies have focused on the evolution of the hemagglutinin gene; however, studies on the evolution of the matrix (M) gene are limited. In this study, a large-scale phylogenetic analysis of M gene sequences of avian influenza viruses isolated in China revealed that the M gene has evolved into six different lineages denoted as I-VI. The majority of lineages I and IV were isolated in terrestrial birds, while the majority of lineages II, III, V and VI were isolated in aquatic birds. Lineage I included 148 H9N2 subtype viruses (72.2%), lineage II comprised of 63 H6 subtype viruses (100%), and lineage IV included 157 H5 subtype viruses (97.5%). The mean substitution rates of different lineages ranged from 1.32×10(-3) (lineage III) to 3.64×10(-3) (lineage IV) substitutions per site per year. According to the most recent common ancestor of all lineages, lineage III was the oldest lineage, formed in 1981 or even earlier. And lineage V was the most recent, established around the year 2000. Selective pressure on M2 was stronger than that on M1. The strongest selection pressure was observed in lineage IV. In addition, site-by-site analyses of each lineage identified 8 positive selection sites, all in M2. Most of the sites (5 out of 8) were located in the extracellular domain, which is an antigen for vaccine development. The positive selection sites (amino acid positions 66, 82 and 97) are likely associated with virus budding. This study enhanced our knowledge of M gene evolution of avian influenza viruses, and is expected to improve the early detection of new viruses and lead to vaccine development.
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Affiliation(s)
- Peng Xiaorong
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, 310003 Hangzhou, China.
| | - Wu Haibo
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, 310003 Hangzhou, China
| | - Peng Xiuming
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, 310003 Hangzhou, China
| | - Wu Nanping
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, 310003 Hangzhou, China.
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17
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Bui C, Bethmont A, Chughtai AA, Gardner L, Sarkar S, Hassan S, Seale H, MacIntyre CR. A Systematic Review of the Comparative Epidemiology of Avian and Human Influenza A H5N1 and H7N9 - Lessons and Unanswered Questions. Transbound Emerg Dis 2015; 63:602-620. [DOI: 10.1111/tbed.12327] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Indexed: 11/29/2022]
Affiliation(s)
- C. Bui
- School of Public Health and Community Medicine; University of New South Wales; Sydney NSW Australia
| | - A. Bethmont
- School of Public Health and Community Medicine; University of New South Wales; Sydney NSW Australia
| | - A. A. Chughtai
- School of Public Health and Community Medicine; University of New South Wales; Sydney NSW Australia
| | - L. Gardner
- School of Civil and Environmental Engineering; University of New South Wales; Sydney NSW Australia
| | - S. Sarkar
- Section of Integrative Biology; University of Texas at Austin; Austin TX USA
| | - S. Hassan
- School of Public Health and Community Medicine; University of New South Wales; Sydney NSW Australia
| | - H. Seale
- School of Public Health and Community Medicine; University of New South Wales; Sydney NSW Australia
| | - C. R. MacIntyre
- School of Public Health and Community Medicine; University of New South Wales; Sydney NSW Australia
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18
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Plant EP, Ye Z. Chimeric neuraminidase and mutant PB1 gene constellation improves growth and yield of H5N1 vaccine candidate virus. J Gen Virol 2014; 96:752-755. [PMID: 25502649 DOI: 10.1099/jgv.0.000025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We previously showed that a mutated PB1 gene improved the growth kinetics of a H3N2 influenza reassortant. Here, we showed that the same mutations improved the growth kinetics of a virus containing the A/Vietnam/1203/2004 (H5N1) haemagglutinin and neuraminidase (NA). Total protein yield and NA activity were increased when a chimeric NA was included. These increases indicated that the synergistic effect was due to the gene constellation containing both the altered PB1 gene and the chimeric NA gene.
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Affiliation(s)
- Ewan P Plant
- Laboratory of Respiratory Viral Diseases, Division of Viral Products, Office of Vaccine Research and Review, US Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Zhiping Ye
- Laboratory of Respiratory Viral Diseases, Division of Viral Products, Office of Vaccine Research and Review, US Food and Drug Administration, Silver Spring, MD 20993, USA
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19
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Le TH, Nguyen NTB. Evolutionary dynamics of highly pathogenic avian influenza A/H5N1 HA clades and vaccine implementation in Vietnam. Clin Exp Vaccine Res 2014; 3:117-27. [PMID: 25003084 PMCID: PMC4083063 DOI: 10.7774/cevr.2014.3.2.117] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 05/02/2014] [Accepted: 05/11/2014] [Indexed: 01/05/2023] Open
Abstract
Based on hemagglutinin (HA) and neuraminidase (NA), influenza A virus is divided into 18 different HA (H1 to H18) and 11 NA types (N1 to N11), opening the possibility for reassortment between the HA and NA genes to generate new HxNy subtypes (where x could be any HA and y is any NA, possibly). In recent four years, since 2010, highly pathogenic avian influenza (HPAI) viruses of H5N1 subtype (HPAI A/H5N1) have become highly enzootic and dynamically evolved to form multiple H5 HA clades, particularly in China, Vietnam, Indonesia, Egypt, Cambodia, and Bangladesh. So far, after more than 10 years emerged in Vietnam (since late 2003), HPAI A/H5N1 is still posing a potential risk of causing outbreaks in poultry, with high frequency of annual endemics. Intragenic variation (referred to as antigenic drift) in HA (e.g., H5) has given rise to form numerous clades, typically marking the major timelines of the evolutionary status and vaccine application in each period. The dominance of genetically and antigenically diversified clade 2.3.2.1 (of subgroups a, b, c), clade 1.1 (1.1.1/1.1.2) and re-emergence of clade 7.1/7.2 at present, has urged Vietnam to the need for dynamically applied antigenicity-matching vaccines, i.e., the plan of importing Re-6 vaccine for use in 2014, in parallel use of Re-1/Re-5 since 2006. In this review, we summarize evolutionary features of HPAI A/H5N1 viruses and clade formation during recent 10 years (2004-2014). Dynamic of vaccine implementation in Vienam is also remarked.
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Affiliation(s)
- Thanh Hoa Le
- Department of Immunology, Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nga Thi Bich Nguyen
- Department of Immunology, Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
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20
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Sequence and phylogenetic analysis of H2N7 avian influenza viruses isolated from domestic ducks in Zhejiang Province, Eastern China, 2013. Virus Genes 2014; 48:391-6. [PMID: 24442671 DOI: 10.1007/s11262-014-1033-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 01/06/2014] [Indexed: 10/25/2022]
Abstract
Two H2N7 avian influenza viruses (AIVs) were isolated from domestic ducks in live poultry markets in Zhejiang Province, Eastern China, 2013. All viruses were characterized by whole-genome sequencing with subsequent phylogenetic analysis and genetic comparison. Phylogenetic analysis of all eight viral genes showed that the viruses clustered in the Eurasian lineage of AIVs and originated from genes reassortment among different viruses co-circulating in domestic ducks in Eastern China. The hemagglutinin cleavage site of all viruses indicated that the two strains were low-pathogenic avian influenza viruses. Considering the important role of the domestic ducks in the dissemination and reassortment of AIVs, continued surveillance of circulating H2 subtype AIVs in domestic ducks in live poultry markets is needed.
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21
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Ling HY, Pelosi A, Walmsley AM. Current status of plant-made vaccines for veterinary purposes. Expert Rev Vaccines 2014; 9:971-82. [DOI: 10.1586/erv.10.87] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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23
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Zhou Z, Deng F, Han N, Wang H, Sun S, Zhang Y, Hu Z, Rayner S. Reassortment and migration analysis of Crimean-Congo haemorrhagic fever virus. J Gen Virol 2013; 94:2536-2548. [PMID: 23939975 DOI: 10.1099/vir.0.056374-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Crimean-Congo haemorrhagic fever virus (CCHFV) is a tick-borne virus with high pathogenicity to humans. CCHFV contains a three-segment [small (S), medium (M) and large (L)] genome and is prone to reassortment. Investigation of identified reassortment events can yield insight into the evolutionary history of the virus, while migration events reflect its geographical dissemination. While many studies have already considered these issues, they have investigated small numbers of isolates and lack statistical support for their findings. Here, we consider a larger set of 30 full genomes to investigate reassortment using recombination methods, as well as two sets of partial S segments comprising 393 isolates, reflecting a broader geographical range, to investigate migration events. Phylogenetic analysis revealed that the S segment showed strong geographical subdivision, but this was less apparent in the M and L segments. A total of 16 reassortment events with 22 isolates were identified with strong statistical support. Migration analysis on the partial S segments identified both long- and short-range migration events that spanned the entire geographical region in which the CCHFV has been isolated, reflecting the complex processes associated with the dissemination of the virus.
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Affiliation(s)
- Zhaorui Zhou
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Fei Deng
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Na Han
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Hualin Wang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Surong Sun
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumuqi, Xinjiang 830046, PR China
| | - Yujiang Zhang
- Center for Disease Control and Prevention of Xinjiang Uygur Autonomous Region, 4 Jianquan First Street, Urumuqi, Xinjiang 830046, PR China
| | - Zhihong Hu
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Simon Rayner
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Chinese Academy of Sciences, Wuhan 430071, PR China
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24
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Complex reassortment of multiple subtypes of avian influenza viruses in domestic ducks at the Dongting Lake Region of China. J Virol 2013; 87:9452-62. [PMID: 23804642 DOI: 10.1128/jvi.00776-13] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To gain insight into the ecology of avian influenza viruses (AIV), we conducted active influenza virus surveillance in domestic ducks on farms located on the flyway of migratory birds in the Dongting Lake region of Hunan Province, China, from winter 2011 until spring 2012. Specimens comprising 3,030 duck swab samples and 1,010 environmental samples were collected from 101 duck farms. We isolated AIV of various HA subtypes, including H3, H4, H5, H6, H9, H10, H11, and H12. We sequenced the entire coding sequences of the genomes of 28 representative isolates constituting 13 specific subtypes. When the phylogenetic relationships among these isolates were examined, we observed that extensive reassortment events had occurred. Among the 28 Dongting Lake viruses, 21 genotypes involving the six internal genes were identified. Furthermore, we identified viruses or viral genes introduced from other countries, viral gene segments of unknown origin, and a novel HA/NA combination. Our findings emphasize the importance of farmed domestic ducks in the Dongting Lake region to the genesis and evolution of AIV and highlight the need for continued surveillance of domestic ducks in this region.
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25
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Synergistic effect of the PDZ and p85β-binding domains of the NS1 protein on virulence of an avian H5N1 influenza A virus. J Virol 2013; 87:4861-71. [PMID: 23408626 DOI: 10.1128/jvi.02608-12] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The influenza A virus NS1 protein affects virulence through several mechanisms, including the host's innate immune response and various signaling pathways. Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype continue to evolve through reassortment and mutations. Our recent phylogenetic analysis identified a group of HPAI H5N1 viruses with two characteristic mutations in NS1: the avian virus-type PDZ domain-binding motif ESEV (which affects virulence) was replaced with ESKV, and NS1-138F (which is highly conserved among all influenza A viruses and may affect the activation of the phosphatidylinositol 3-kinase [PI3K]/Akt signaling pathway) was replaced with NS1-138Y. Here, we show that an HPAI H5N1 virus (A/duck/Hunan/69/2004) encoding NS1-ESKV and NS1-138Y was confined to the respiratory tract of infected mice, whereas a mutant encoding NS1-ESEV and NS1-138F caused systemic infection and killed mice more efficiently. Mutation of either one of these sites had small effects on virulence. In addition, we found that the amino acid at NS1-138 affected not only the induction of the PI3K/Akt pathway but also the interaction of NS1 with cellular PDZ domain proteins. Similarly, the mutation in the PDZ domain-binding motif of NS1 altered its binding to cellular PDZ domain proteins and affected Akt phosphorylation. These findings suggest a functional interplay between the mutations at NS1-138 and NS1-229 that results in a synergistic effect on influenza virulence.
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26
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Svinti V, Cotton JA, McInerney JO. New approaches for unravelling reassortment pathways. BMC Evol Biol 2013; 13:1. [PMID: 23279962 PMCID: PMC3541980 DOI: 10.1186/1471-2148-13-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 11/21/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Every year the human population encounters epidemic outbreaks of influenza, and history reveals recurring pandemics that have had devastating consequences. The current work focuses on the development of a robust algorithm for detecting influenza strains that have a composite genomic architecture. These influenza subtypes can be generated through a reassortment process, whereby a virus can inherit gene segments from two different types of influenza particles during replication. Reassortant strains are often not immediately recognised by the adaptive immune system of the hosts and hence may be the source of pandemic outbreaks. Owing to their importance in public health and their infectious ability, it is essential to identify reassortant influenza strains in order to understand the evolution of this virus and describe reassortment pathways that may be biased towards particular viral segments. Phylogenetic methods have been used traditionally to identify reassortant viruses. In many studies up to now, the assumption has been that if two phylogenetic trees differ, it is because reassortment has caused them to be different. While phylogenetic incongruence may be caused by real differences in evolutionary history, it can also be the result of phylogenetic error. Therefore, we wish to develop a method for distinguishing between topological inconsistency that is due to confounding effects and topological inconsistency that is due to reassortment. RESULTS The current work describes the implementation of two approaches for robustly identifying reassortment events. The algorithms rest on the idea of significance of difference between phylogenetic trees or phylogenetic tree sets, and subtree pruning and regrafting operations, which mimic the effect of reassortment on tree topologies. The first method is based on a maximum likelihood (ML) framework (MLreassort) and the second implements a Bayesian approach (Breassort) for reassortment detection. We focus on reassortment events that are found by both methods. We test both methods on a simulated dataset and on a small collection of real viral data isolated in Hong Kong in 1999. CONCLUSIONS The nature of segmented viral genomes present many challenges with respect to disease. The algorithms developed here can effectively identify reassortment events in small viral datasets and can be applied not only to influenza but also to other segmented viruses. Owing to computational demands of comparing tree topologies, further development in this area is necessary to allow their application to larger datasets.
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Affiliation(s)
- Victoria Svinti
- Department of Biology, National University of Ireland at Maynooth, Maynooth, Co Kildare, Ireland
- Current address: Department of Microbiology & Immunology, Life Sciences Centre, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - James A Cotton
- Department of Biology, National University of Ireland at Maynooth, Maynooth, Co Kildare, Ireland
- Current address: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - James O McInerney
- Department of Biology, National University of Ireland at Maynooth, Maynooth, Co Kildare, Ireland
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Co-circulation of influenza A virus strains and emergence of pandemic via reassortment: the role of cross-immunity. Epidemics 2012; 5:20-33. [PMID: 23438428 DOI: 10.1016/j.epidem.2012.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 10/09/2012] [Accepted: 10/29/2012] [Indexed: 12/24/2022] Open
Abstract
Reassortment is an important evolutionary route for influenza A viruses to generate pandemic strains. The pre-requisite for reassortment to occur is co-infection of different influenza virus strains in the same host population. Empirical evidence suggests that co-circulation of influenza A virus strains is common and co-infection in patients has been reported. Whether a novel virus can successfully spread among a host population is determined by its life-history (infectivity and infectious period). It is also well known that different influenza A strains interfere through the immune response of human body cells. The reassortant virus strain generated from co-infections deviates dramatically in antigenic and genetic properties from its parental strains such that human populations have limited immunity against it. We consider a mathematical model which includes two strains of influenza virus within a standard SIR model and integrate life history and cross-immunity into the evolutionary dynamics of influenza virus. We assume that, following primary infection by one strain and recovery, individuals are susceptible to secondary infection by the other strain only but with reduced probability due to cross-immunity. Co-infection is included to examine how life-history and cross-immunity interplay to regulate the co-circulation and co-infection of different influenza A virus strains in human populations. Further, we introduce novel strains via reassortment and investigate how the opportunities of a reassortant strain developing into a pandemic are constrained by its life-history and the residual immunity within human populations. We find that though the probability of pandemic emergence via reassortment increases with transmissibility of reassortant strains and the rate of reassortment, the existence of cross-immunity acquired through previous infections or vaccination can greatly constrain pandemic emergence.
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Xu J, Davis CT, Christman MC, Rivailler P, Zhong H, Donis RO, Lu G. Evolutionary history and phylodynamics of influenza A and B neuraminidase (NA) genes inferred from large-scale sequence analyses. PLoS One 2012; 7:e38665. [PMID: 22808012 PMCID: PMC3394769 DOI: 10.1371/journal.pone.0038665] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 05/10/2012] [Indexed: 12/22/2022] Open
Abstract
Background Influenza neuraminidase (NA) is an important surface glycoprotein and plays a vital role in viral replication and drug development. The NA is found in influenza A and B viruses, with nine subtypes classified in influenza A. The complete knowledge of influenza NA evolutionary history and phylodynamics, although critical for the prevention and control of influenza epidemics and pandemics, remains lacking. Methodology/Principal findings Evolutionary and phylogenetic analyses of influenza NA sequences using Maximum Likelihood and Bayesian MCMC methods demonstrated that the divergence of influenza viruses into types A and B occurred earlier than the divergence of influenza A NA subtypes. Twenty-three lineages were identified within influenza A, two lineages were classified within influenza B, and most lineages were specific to host, subtype or geographical location. Interestingly, evolutionary rates vary not only among lineages but also among branches within lineages. The estimated tMRCAs of influenza lineages suggest that the viruses of different lineages emerge several months or even years before their initial detection. The dN/dS ratios ranged from 0.062 to 0.313 for influenza A lineages, and 0.257 to 0.259 for influenza B lineages. Structural analyses revealed that all positively selected sites are at the surface of the NA protein, with a number of sites found to be important for host antibody and drug binding. Conclusions/Significance The divergence into influenza type A and B from a putative ancestral NA was followed by the divergence of type A into nine NA subtypes, of which 23 lineages subsequently diverged. This study provides a better understanding of influenza NA lineages and their evolutionary dynamics, which may facilitate early detection of newly emerging influenza viruses and thus improve influenza surveillance.
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Affiliation(s)
- Jianpeng Xu
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska, United States of America
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29
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Löndt BZ, Brookes SM, Nash BJ, Núñez A, Stagg DA, Brown IH. The infectivity of pandemic 2009 H1N1 and avian influenza viruses for pigs: an assessment by ex vivo respiratory tract organ culture. Influenza Other Respir Viruses 2012; 7:393-402. [PMID: 22716314 PMCID: PMC5779844 DOI: 10.1111/j.1750-2659.2012.00397.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Pigs are thought to act as intermediate hosts in the ecology of influenza viruses of both avian and human origin. The recent development of procedures for pig ex vivo respiratory organ explants has provided new tools for the assessment of influenza virus infection in pigs. OBJECTIVES To use pig ex vivo organ explants to assess the susceptibility of pigs to infection with contemporary viruses, for which there is evidence of human infection and that are thought to pose the greatest threat to pig and human populations. METHODS Pig tracheal, bronchi and lung ex vivo organ explants were infected with both highly pathogenic and low pathogenic avian influenza (AI) virus and the pandemic H1N1 [A(H1N1)pdm/09] virus. Successful infection of explants was detected using a positive-sense RNA real-time RT-PCR assay and anti-nucleoprotein immunohistochemistry. The distribution of cell-surface α2-3- and α2-6-linked sialic acid receptors, the avian- and mammalian influenza A virus-preferred host receptors, respectively, was also characterised for the ex vivo organ cultures and uninfected pig material following necropsy. RESULTS The α2-3 and α2-6 sialic acid receptor staining on tracheal, bronchi and lung organ explant sections showed similar distributions to those seen for pig tissue following necropsy. While the pig ex vivo organ cultures were susceptible to nearly all viruses tested, lower levels of virus were detected in trachea and bronchi after infection. CONCLUSION These results confirm that pigs are susceptible to contemporary viruses that may threaten both veterinary and human health and contribute to the ecology of influenza A viruses.
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Affiliation(s)
- Brandon Z Löndt
- Animal Health and Veterinary Laboratories Agency-Weybridge, Addlestone, Surrey, UK.
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30
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Digital genotyping of avian influenza viruses of H7 subtype detected in central Europe in 2007–2011. Virus Res 2012; 165:126-33. [DOI: 10.1016/j.virusres.2012.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 02/02/2012] [Accepted: 02/05/2012] [Indexed: 11/18/2022]
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Genetic structure of Pacific Flyway avian influenza viruses is shaped by geographic location, host species, and sampling period. Virus Genes 2012; 44:415-28. [PMID: 22222690 DOI: 10.1007/s11262-011-0706-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 12/20/2011] [Indexed: 10/14/2022]
Abstract
The eight gene segments of avian influenza virus (AIV) reassort frequently and rapidly to generate novel genotypes and subtypes that are transmissible to a broad range of hosts. There is evidence that AIV can have a restricted host range and can segregate in space and time. Host-virus relationships at the species, geographic, and spatial scales have not been fully defined for AIV populations of the Pacific Flyway, particularly among the diverse waterfowl that occupy the Flyway in Alaska and California. Using the sequence analysis program Bayesian Tip-association Significance testing (BaTS) created for analysis of phylogeny-trait associations, we determined whether the genetic structure of Pacific Flyway AIVs sampled between 2006 and 2008 was influenced by the host species, geographic location of virus collection, and time of sampling. In posterior sets of trees, genetically similar viruses clustered by host species for thick-billed murres and glaucous gulls (order Charadriiformes), and for northern shovelers, northern pintails, and mallards (order Anseriformes). AIVs from Alaska and California were strongly spatially structured, clustering separately by region across all segments. The timing of sampling influenced the genetic structure of California AIV gene segments, possibly reflecting waves of host species movement into wintering areas. The strength of phylogeny-trait association varied by virus segment and by trait of interest, which we hypothesize is related to the frequent genetic reassortment and interspecies transmission in waterfowl.
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Hill NJ, Takekawa JY, Cardona CJ, Meixell BW, Ackerman JT, Runstadler JA, Boyce WM. Cross-seasonal patterns of avian influenza virus in breeding and wintering migratory birds: a flyway perspective. Vector Borne Zoonotic Dis 2011; 12:243-53. [PMID: 21995264 DOI: 10.1089/vbz.2010.0246] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The spread of avian influenza viruses (AIV) in nature is intrinsically linked with the movements of wild birds. Wild birds are the reservoirs for the virus and their migration may facilitate the circulation of AIV between breeding and wintering areas. This cycle of dispersal has become widely accepted; however, there are few AIV studies that present cross-seasonal information. A flyway perspective is critical for understanding how wild birds contribute to the persistence of AIV over large spatial and temporal scales, with implications for how to focus surveillance efforts and identify risks to public health. This study characterized spatio-temporal infection patterns in 10,389 waterfowl at two important locations within the Pacific Flyway--breeding sites in Interior Alaska and wintering sites in California's Central Valley during 2007-2009. Among the dabbling ducks sampled, the northern shoveler (Anas clypeata) had the highest prevalence of AIV at both breeding (32.2%) and wintering (5.2%) locations. This is in contrast to surveillance studies conducted in other flyways that have identified the mallard (Anas platyrhynchos) and northern pintail (Anas acuta) as hosts with the highest prevalence. A higher diversity of AIV subtypes was apparent at wintering (n=42) compared with breeding sites (n=17), with evidence of mixed infections at both locations. Our study suggests that wintering sites may act as an important mixing bowl for transmission among waterfowl in a flyway, creating opportunities for the reassortment of the virus. Our findings shed light on how the dynamics of AIV infection of wild bird populations can vary between the two ends of a migratory flyway.
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Affiliation(s)
- Nichola J Hill
- Western Ecological Research Center, San Francisco Bay Estuary Field Station, U.S. Geological Survey, Vallejo, California, USA
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Takekawa JY, Hill NJ, Schultz AK, Iverson SA, Cardona CJ, Boyce WM, Dudley JP. Rapid diagnosis of avian influenza virus in wild birds: use of a portable rRT-PCR and freeze-dried reagents in the field. J Vis Exp 2011:2829. [PMID: 21847073 PMCID: PMC3217620 DOI: 10.3791/2829] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Wild birds have been implicated in the spread of highly pathogenic avian influenza (HPAI) of the H5N1 subtype, prompting surveillance along migratory flyways. Sampling of wild birds for avian influenza virus (AIV) is often conducted in remote regions, but results are often delayed because of the need to transport samples to a laboratory equipped for molecular testing. Real-time reverse transcriptase polymerase chain reaction (rRT-PCR) is a molecular technique that offers one of the most accurate and sensitive methods for diagnosis of AIV. The previously strict lab protocols needed for rRT-PCR are now being adapted for the field. Development of freeze-dried (lyophilized) reagents that do not require cold chain, with sensitivity at the level of wet reagents has brought on-site remote testing to a practical goal. Here we present a method for the rapid diagnosis of AIV in wild birds using an rRT-PCR unit (Ruggedized Advanced Pathogen Identification Device or RAPID, Idaho Technologies, Salt Lake City, UT) that employs lyophilized reagents (Influenza A Target 1 Taqman; ASAY-ASY-0109, Idaho Technologies). The reagents contain all of the necessary components for testing at appropriate concentrations in a single tube: primers, probes, enzymes, buffers and internal positive controls, eliminating errors associated with improper storage or handling of wet reagents. The portable unit performs a screen for Influenza A by targeting the matrix gene and yields results in 2-3 hours. Genetic subtyping is also possible with H5 and H7 primer sets that target the hemagglutinin gene. The system is suitable for use on cloacal and oropharyngeal samples collected from wild birds, as demonstrated here on the migratory shorebird species, the western sandpiper (Calidrus mauri) captured in Northern California. Animal handling followed protocols approved by the Animal Care and Use Committee of the U.S. Geological Survey Western Ecological Research Center and permits of the U.S. Geological Survey Bird Banding Laboratory. The primary advantage of this technique is to expedite diagnosis of wild birds, increasing the chances of containing an outbreak in a remote location. On-site diagnosis would also prove useful for identifying and studying infected individuals in wild populations. The opportunity to collect information on host biology (immunological and physiological response to infection) and spatial ecology (migratory performance of infected birds) will provide insights into the extent to which wild birds can act as vectors for AIV over long distances.
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Zhang J, Mamlouk AM, Martinetz T, Chang S, Wang J, Hilgenfeld R. PhyloMap: an algorithm for visualizing relationships of large sequence data sets and its application to the influenza A virus genome. BMC Bioinformatics 2011; 12:248. [PMID: 21689434 PMCID: PMC3142226 DOI: 10.1186/1471-2105-12-248] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 06/20/2011] [Indexed: 11/10/2022] Open
Abstract
Background Results of phylogenetic analysis are often visualized as phylogenetic trees. Such a tree can typically only include up to a few hundred sequences. When more than a few thousand sequences are to be included, analyzing the phylogenetic relationships among them becomes a challenging task. The recent frequent outbreaks of influenza A viruses have resulted in the rapid accumulation of corresponding genome sequences. Currently, there are more than 7500 influenza A virus genomes in the database. There are no efficient ways of representing this huge data set as a whole, thus preventing a further understanding of the diversity of the influenza A virus genome. Results Here we present a new algorithm, "PhyloMap", which combines ordination, vector quantization, and phylogenetic tree construction to give an elegant representation of a large sequence data set. The use of PhyloMap on influenza A virus genome sequences reveals the phylogenetic relationships of the internal genes that cannot be seen when only a subset of sequences are analyzed. Conclusions The application of PhyloMap to influenza A virus genome data shows that it is a robust algorithm for analyzing large sequence data sets. It utilizes the entire data set, minimizes bias, and provides intuitive visualization. PhyloMap is implemented in JAVA, and the source code is freely available at http://www.biochem.uni-luebeck.de/public/software/phylomap.html
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Affiliation(s)
- Jiajie Zhang
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Śmietanka K, Pikuła A, Minta Z, Meissner W. Evidence of persistence and multiple genetic modifications of H7N7 low-pathogenic avian influenza virus in wild mallards in Poland provided by phylogenetic studies. Avian Pathol 2011; 40:131-8. [DOI: 10.1080/03079457.2010.537304] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abdel-Moneim AS, Shehab GM, Abu-Elsaad AAS. Molecular evolution of the six internal genes of H5N1 equine influenza A virus. Arch Virol 2011; 156:1257-62. [PMID: 21431346 DOI: 10.1007/s00705-011-0966-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 02/28/2011] [Indexed: 11/24/2022]
Abstract
Phylogenetic and evolutionary patterns of the six internal genes of an equine H5N1 influenza A virus isolated in Egypt on 2009 were analyzed using direct sequencing. All of the internal genes of the equine H5N1 strain showed a genetic pattern potentially related to Eurasian lineages. Variable dendrogram topologies revealed an absence of reassortment in the equine strain while confirming its close relatedness to other Egyptian H5N1 strains from human and avian species. The equine strain is characterized by a variety of amino acid substitutions in six internal proteins compared to the available Egyptian H5N1 strains. Interestingly, the equine strain displayed amino acids in the PB2, PA, M2 and NS2 proteins that are unique among the available H5N1 sequences in the flu database, and their potential effect on virulence needs to be further investigated.
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Affiliation(s)
- Ahmed S Abdel-Moneim
- Virology Department, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, 62511, Egypt.
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Phylogenetic diversity and genotypical complexity of H9N2 influenza A viruses revealed by genomic sequence analysis. PLoS One 2011; 6:e17212. [PMID: 21386964 PMCID: PMC3046171 DOI: 10.1371/journal.pone.0017212] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 01/23/2011] [Indexed: 11/30/2022] Open
Abstract
H9N2 influenza A viruses have become established worldwide in terrestrial poultry and wild birds, and are occasionally transmitted to mammals including humans and pigs. To comprehensively elucidate the genetic and evolutionary characteristics of H9N2 influenza viruses, we performed a large-scale sequence analysis of 571 viral genomes from the NCBI Influenza Virus Resource Database, representing the spectrum of H9N2 influenza viruses isolated from 1966 to 2009. Our study provides a panoramic framework for better understanding the genesis and evolution of H9N2 influenza viruses, and for describing the history of H9N2 viruses circulating in diverse hosts. Panorama phylogenetic analysis of the eight viral gene segments revealed the complexity and diversity of H9N2 influenza viruses. The 571 H9N2 viral genomes were classified into 74 separate lineages, which had marked host and geographical differences in phylogeny. Panorama genotypical analysis also revealed that H9N2 viruses include at least 98 genotypes, which were further divided according to their HA lineages into seven series (A–G). Phylogenetic analysis of the internal genes showed that H9N2 viruses are closely related to H3, H4, H5, H7, H10, and H14 subtype influenza viruses. Our results indicate that H9N2 viruses have undergone extensive reassortments to generate multiple reassortants and genotypes, suggesting that the continued circulation of multiple genotypical H9N2 viruses throughout the world in diverse hosts has the potential to cause future influenza outbreaks in poultry and epidemics in humans. We propose a nomenclature system for identifying and unifying all lineages and genotypes of H9N2 influenza viruses in order to facilitate international communication on the evolution, ecology and epidemiology of H9N2 influenza viruses.
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Nagarajan N, Kingsford C. GiRaF: robust, computational identification of influenza reassortments via graph mining. Nucleic Acids Res 2010; 39:e34. [PMID: 21177643 PMCID: PMC3064795 DOI: 10.1093/nar/gkq1232] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Reassortments in the influenza virus—a process where strains exchange genetic segments—have been implicated in two out of three pandemics of the 20th century as well as the 2009 H1N1 outbreak. While advances in sequencing have led to an explosion in the number of whole-genome sequences that are available, an understanding of the rate and distribution of reassortments and their role in viral evolution is still lacking. An important factor in this is the paucity of automated tools for confident identification of reassortments from sequence data due to the challenges of analyzing large, uncertain viral phylogenies. We describe here a novel computational method, called GiRaF (Graph-incompatibility-based Reassortment Finder), that robustly identifies reassortments in a fully automated fashion while accounting for uncertainties in the inferred phylogenies. The algorithms behind GiRaF search large collections of Markov chain Monte Carlo (MCMC)-sampled trees for groups of incompatible splits using a fast biclique enumeration algorithm coupled with several statistical tests to identify sets of taxa with differential phylogenetic placement. GiRaF correctly finds known reassortments in human, avian, and swine influenza populations, including the evolutionary events that led to the recent ‘swine flu’ outbreak. GiRaF also identifies several previously unreported reassortments via whole-genome studies to catalog events in H5N1 and swine influenza isolates.
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Affiliation(s)
- Niranjan Nagarajan
- Computational and Mathematical Biology, Genome Institute of Singapore, Singapore.
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39
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Nikolai Kaverin. Postreassortment amino acid substitutions in influenza A viruses. Future Microbiol 2010; 5:705-15. [DOI: 10.2217/fmb.10.43] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The genome of the influenza A virus consists of eight single-stranded negative sense RNA segments. Segmentation allows reassortment of genes between influenza A virus strains when two strains infect one host cell. Reassortment may lead to the emergence of pandemic influenza viruses. The process of reassortment is limited by the necessity of a functional balance among viral genes. The nature of the functional constraint on reassortment is currenty not well understood. An insight into the basis of functional matching of virus genes, its restrictions and its restoration after reassortment may be provided by the analysis of postreassortment mutations in model systems. This article summarizes the data on postreassortment amino acid changes in virus glycoproteins and polymerase proteins and their effect on the intergenic functional match.
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Neumann G, Green MA, Macken CA. Evolution of highly pathogenic avian H5N1 influenza viruses and the emergence of dominant variants. J Gen Virol 2010; 91:1984-1995. [PMID: 20392897 DOI: 10.1099/vir.0.020750-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Highly pathogenic avian H5N1 viruses have circulated in South-east Asia for more than a decade and have now spread to more than 60 countries. The evolution of these viruses is characterized by frequent reassortment of the so-called 'internal' genes, creating novel genotypes. Additionally, over time, the surface glycoprotein, haemagglutinin (HA), which is the primary target of the adaptive immune response, has evolved by point mutation into 20 genetically and potentially antigenically distinct clades. To investigate the evolution of avian H5N1 influenza viruses, we undertook a high-resolution analysis of the reassortment of internal genes and evolution of HA of 651 avian H5N1 viruses from 2000 to 2008. Our analysis suggested: (i) all current H5N1 genotypes were derived from a single, clearly defined sequence of initial reassortment events; (ii) reassortment of just three of the internal genes had the most importance in avian H5N1 virus evolution; (iii) HA and the constellation of internal genes may be jointly important in the emergence of dominant variants. Further, our analysis led to the identification of evolutionarily significant molecular changes in the internal genes that may be significant for the emergence of these dominant variants.
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Affiliation(s)
- Gabriele Neumann
- Influenza Research Institute, Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI 53717, USA
| | - Margaret A Green
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Catherine A Macken
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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Montalvo-Corral M, Hernández J. Genetic analysis of avian influenza virus from migratory waterfowl in Mexico. Arch Virol 2010; 155:97-101. [PMID: 20069401 DOI: 10.1007/s00705-009-0554-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Accepted: 10/22/2009] [Indexed: 10/20/2022]
Abstract
This study describes the genetic characterization of avian influenza virus from waterfowl in Mexico. Partial sequences of two H5, one H6, and one H9 hemmaglutinin (HA) genes were determined. The deduced amino acid sequences showed that they were low-pathogenic viruses (LPAI). Phylogenetic analysis of H5 and H6 HA indicates a North American lineage, closely related to contemporary Californian isolates, and H9 HA was closer to the Korean-like lineage. These results demonstrate the introduction of a diverse genetic pool of subtypes to Sonora estuaries through circulation of bird species carriers from the Pacific flyway.
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Affiliation(s)
- Maricela Montalvo-Corral
- Laboratorio de Inmunología, Centro de Investigación en Alimentación y Desarrollo, A.C. Carretera a Victoria Km 0.6. AP. 1735, CP 83000 Hermosillo, Sonora, Mexico
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Briand FX, Le Gall-Recule G, Guillou-Cloarec C, Ogor K, Jestin V. Phylogeny and genotyping of recent avian low-pathogenic H5 subtype influenza viruses from French ducks. J Gen Virol 2009; 91:960-70. [DOI: 10.1099/vir.0.016733-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Chen JM, Sun YX, Chen JW, Liu S, Yu JM, Shen CJ, Sun XD, Peng D. Panorama phylogenetic diversity and distribution of type A influenza viruses based on their six internal gene sequences. Virol J 2009; 6:137. [PMID: 19737421 PMCID: PMC2746212 DOI: 10.1186/1743-422x-6-137] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 09/08/2009] [Indexed: 12/31/2022] Open
Abstract
Background Type A influenza viruses are important pathogens of humans, birds, pigs, horses and some marine mammals. The viruses have evolved into multiple complicated subtypes, lineages and sublineages. Recently, the phylogenetic diversity of type A influenza viruses from a whole view has been described based on the viral external HA and NA gene sequences, but remains unclear in terms of their six internal genes (PB2, PB1, PA, NP, MP and NS). Methods In this report, 2798 representative sequences of the six viral internal genes were selected from GenBank using the web servers in NCBI Influenza Virus Resource. Then, the phylogenetic relationships among the representative sequences were calculated using the software tools MEGA 4.1 and RAxML 7.0.4. Lineages and sublineages were classified mainly according to topology of the phylogenetic trees and distribution of the viruses in hosts, regions and time. Results The panorama phylogenetic trees of the six internal genes of type A influenza viruses were constructed. Lineages and sublineages within the type based on the six internal genes were classified and designated by a tentative universal numerical nomenclature system. The diversity of influenza viruses circulating in different regions, periods, and hosts based on the panorama trees was analyzed. Conclusion This study presents the first whole views to the phylogenetic diversity and distribution of type A influenza viruses based on their six internal genes. It also proposes a tentative universal nomenclature system for the viral lineages and sublineages. These can be a candidate framework to generalize the history and explore the future of the viruses, and will facilitate future scientific communications on the phylogenetic diversity and evolution of the viruses. In addition, it provides a novel phylogenetic view (i.e. the whole view) to recognize the viruses including the origin of the pandemic A(H1N1) influenza viruses.
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Affiliation(s)
- Ji-Ming Chen
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, PR China.
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Iqbal M, Yaqub T, Reddy K, McCauley JW. Novel genotypes of H9N2 influenza A viruses isolated from poultry in Pakistan containing NS genes similar to highly pathogenic H7N3 and H5N1 viruses. PLoS One 2009; 4:e5788. [PMID: 19517011 PMCID: PMC2690689 DOI: 10.1371/journal.pone.0005788] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 04/28/2009] [Indexed: 12/27/2022] Open
Abstract
The impact of avian influenza caused by H9N2 viruses in Pakistan is now significantly more severe than in previous years. Since all gene segments contribute towards the virulence of avian influenza virus, it was imperative to investigate the molecular features and genetic relationships of H9N2 viruses prevalent in this region. Analysis of the gene sequences of all eight RNA segments from 12 viruses isolated between 2005 and 2008 was undertaken. The hemagglutinin (HA) sequences of all isolates were closely related to H9N2 viruses isolated from Iran between 2004 and 2007 and contained leucine instead of glutamine at position 226 in the receptor binding pocket, a recognised marker for the recognition of sialic acids linked α2–6 to galactose. The neuraminidase (NA) of two isolates contained a unique five residue deletion in the stalk (from residues 80 to 84), a possible indication of greater adaptation of these viruses to the chicken host. The HA, NA, nucleoprotein (NP), and matrix (M) genes showed close identity with H9N2 viruses isolated during 1999 in Pakistan and clustered in the A/Quail/Hong Kong/G1/97 virus lineage. In contrast, the polymerase genes clustered with H9N2 viruses from India, Iran and Dubai. The NS gene segment showed greater genetic diversity and shared a high level of similarity with NS genes from either H5 or H7 subtypes rather than with established H9N2 Eurasian lineages. These results indicate that during recent years the H9N2 viruses have undergone extensive genetic reassortment which has led to the generation of H9N2 viruses of novel genotypes in the Indian sub-continent. The novel genotypes of H9N2 viruses may play a role in the increased problems observed by H9N2 to poultry and reinforce the continued need to monitor H9N2 infections for their zoonotic potential.
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Affiliation(s)
- Munir Iqbal
- Division of Microbiology, Institute for Animal Health, Compton Laboratory, Compton, Newbury, Berkshire, UK.
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Pearce JM, Ramey AM, Flint PL, Koehler AV, Fleskes JP, Franson JC, Hall JS, Derksen DV, Ip HS. Avian influenza at both ends of a migratory flyway: characterizing viral genomic diversity to optimize surveillance plans for North America. Evol Appl 2009; 2:457-68. [PMID: 25567891 PMCID: PMC3352445 DOI: 10.1111/j.1752-4571.2009.00071.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 03/20/2009] [Indexed: 11/26/2022] Open
Abstract
Although continental populations of avian influenza viruses are genetically distinct, transcontinental reassortment in low pathogenic avian influenza (LPAI) viruses has been detected in migratory birds. Thus, genomic analyses of LPAI viruses could serve as an approach to prioritize species and regions targeted by North American surveillance activities for foreign origin highly pathogenic avian influenza (HPAI). To assess the applicability of this approach, we conducted a phylogenetic and population genetic analysis of 68 viral genomes isolated from the northern pintail (Anas acuta) at opposite ends of the Pacific migratory flyway in North America. We found limited evidence for Asian LPAI lineages on wintering areas used by northern pintails in California in contrast to a higher frequency on breeding locales of Alaska. Our results indicate that the number of Asian LPAI lineages observed in Alaskan northern pintails, and the nucleotide composition of LPAI lineages, is not maintained through fall migration. Accordingly, our data indicate that surveillance of Pacific Flyway northern pintails to detect foreign avian influenza viruses would be most effective in Alaska. North American surveillance plans could be optimized through an analysis of LPAI genomics from species that demonstrate evolutionary linkages with European or Asian lineages and in regions that have overlapping migratory flyways with areas of HPAI outbreaks.
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Affiliation(s)
- John M Pearce
- Alaska Science Center, U.S. Geological Survey Anchorage, AK, USA
| | - Andrew M Ramey
- Alaska Science Center, U.S. Geological Survey Anchorage, AK, USA
| | - Paul L Flint
- Alaska Science Center, U.S. Geological Survey Anchorage, AK, USA
| | - Anson V Koehler
- Alaska Science Center, U.S. Geological Survey Anchorage, AK, USA
| | - Joseph P Fleskes
- Western Ecological Research Center, U.S. Geological Survey Dixon, CA, USA
| | | | - Jeffrey S Hall
- National Wildlife Health Center, U.S. Geological Survey Madison, WI, USA
| | - Dirk V Derksen
- Alaska Science Center, U.S. Geological Survey Anchorage, AK, USA
| | - Hon S Ip
- National Wildlife Health Center, U.S. Geological Survey Madison, WI, USA
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Liu S, Ji K, Chen J, Tai D, Jiang W, Hou G, Chen J, Li J, Huang B. Panorama phylogenetic diversity and distribution of Type A influenza virus. PLoS One 2009; 4:e5022. [PMID: 19325912 PMCID: PMC2658884 DOI: 10.1371/journal.pone.0005022] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 02/18/2009] [Indexed: 01/08/2023] Open
Abstract
Background Type A influenza virus is one of important pathogens of various animals, including humans, pigs, horses, marine mammals and birds. Currently, the viral type has been classified into 16 hemagglutinin and 9 neuraminidase subtypes, but the phylogenetic diversity and distribution within the viral type largely remain unclear from the whole view. Methodology/Principal Findings The panorama phylogenetic trees of influenza A viruses were calculated with representative sequences selected from approximately 23000 candidates available in GenBank using web servers in NCBI and the software MEGA 4.0. Lineages and sublineages were classified according to genetic distances, topology of the phylogenetic trees and distributions of the viruses in hosts, regions and time. Conclusions/Significance Here, two panorama phylogenetic trees of type A influenza virus covering all the 16 hemagglutinin subtypes and 9 neuraminidase subtypes, respectively, were generated. The trees provided us whole views and some novel information to recognize influenza A viruses including that some subtypes of avian influenza viruses are more complicated than Eurasian and North American lineages as we thought in the past. They also provide us a framework to generalize the history and explore the future of the viral circulation and evolution in different kinds of hosts. In addition, a simple and comprehensive nomenclature system for the dozens of lineages and sublineages identified within the viral type was proposed, which if universally accepted, will facilitate communications on the viral evolution, ecology and epidemiology.
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Affiliation(s)
- Shuo Liu
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
| | - Kang Ji
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
- College of Veterinary Sciences, University of Northeastern China, Harbin, China
| | - Jiming Chen
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
- * E-mail:
| | - Di Tai
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
- College of Veterinary Sciences, University of Northeastern China, Harbin, China
| | - Wenming Jiang
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
| | - Guangyu Hou
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
| | - Jie Chen
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
| | - Jinping Li
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
| | - Baoxu Huang
- The Laboratory of Animal Epidemiological Surveillance, China Animal Health & Epidemiology Center, Qingdao, China
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Naffakh N, Tomoiu A, Rameix-Welti MA, van der Werf S. Host restriction of avian influenza viruses at the level of the ribonucleoproteins. Annu Rev Microbiol 2008; 62:403-24. [PMID: 18785841 DOI: 10.1146/annurev.micro.62.081307.162746] [Citation(s) in RCA: 169] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although transmission of avian influenza viruses to mammals, particularly humans, has been repeatedly documented, adaptation and sustained transmission in the new host is a rare event that in the case of humans may result in pandemics. Host restriction involves multiple genetic determinants. Among the known determinants of host range, key determinants have been identified on the genes coding for the nucleoprotein and polymerase proteins that, together with the viral RNA segments, form the ribonucleoproteins (RNPs). The RNP genes form host-specific lineages and harbor host-associated genetic signatures. The functional significance of these determinants has been studied by reassortment and reverse genetics experiments, underlining the influence of the global genetic context. In some instances the molecular mechanisms have been approached, pointing to the importance of the polymerase activity and interaction with cellular host factors. Better knowledge of determinants of host restriction will allow monitoring of the pandemic potential of avian influenza viruses.
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Affiliation(s)
- Nadia Naffakh
- Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 3015, Institut Pasteur, Paris, 75015 France
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Owoade AA, Gerloff NA, Ducatez MF, Taiwo JO, Kremer JR, Muller CP. Replacement of sublineages of avian influenza (H5N1) by reassortments, sub-Saharan Africa. Emerg Infect Dis 2008; 14:1731-5. [PMID: 18976556 PMCID: PMC2630748 DOI: 10.3201/eid1411.080555] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Eight new full-length sequences from highly pathogenic avian influenza viruses (H5N1) from 4 states in southwest Nigeria were analyzed. All gene sequences were more closely related to the first strains found in Nigeria in 2006 than to any strain found outside the country. Six viruses had evolved by at least 3 reassortment events (AC HA/NS, AC NS) from previously identified sublineages A (EMA 2) and C (EMA 1). Our results suggest that highly pathogenic avian influenza viruses (H5N1) initially imported into Nigeria in 2006 have been gradually replaced by various reassortments. In all reassortants, nonstructural genes were derived from sublineage C with 2 characteristic amino acids (compared with sublineage A). If the high prevalence of reassortants was typical for West Africa in 2007, the absence of such reassortants anywhere else suggests that reintroductions of influenza A (H5N1) from Africa into Eurasia must be rare.
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49
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Codoñer FM, Elena SF. The promiscuous evolutionary history of the family Bromoviridae. J Gen Virol 2008; 89:1739-1747. [DOI: 10.1099/vir.0.2008/000166-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recombination and segment reassortment are important contributors to the standing genetic variation of RNA viruses and are often involved in the genesis of new, emerging viruses. This study explored the role played by these two processes in the evolutionary radiation of the plant virus family Bromoviridae. The evolutionary history of this family has been explored previously using standard molecular phylogenetic methods, but incongruences have been found among the trees inferred from different gene sequences. This would not be surprising if RNA exchange was a common event, as it is well known that recombination and reassortment of genomes are poorly described by standard phylogenetic methods. In an attempt to reconcile these discrepancies, this study first explored the extent of segment reassortment and found that it was common at the origin of the bromoviruses and cucumoviruses and at least at the origin of alfalfa mosaic virus, American plum line pattern virus and citrus leaf rugose virus. Secondly, recombination analyses were performed on each of the three genomic RNAs and it was found that recombination was very common in members of the genera Bromovirus, Cucumovirus and Ilarvirus. Several cases of recombination involving species from different genera were also identified. Finally, a phylogenetic network was constructed reflecting these genetic exchanges. The network confirmed the taxonomic status of the different genera within the family, despite the phylogenetic noise introduced by genetic exchange.
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Affiliation(s)
| | - Santiago F. Elena
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Valencia, Spain
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Wellehan JFX, Childress AL, Marschang RE, Johnson AJ, Lamirande EW, Roberts JF, Vickers ML, Gaskin JM, Jacobson ER. Consensus nested PCR amplification and sequencing of diverse reptilian, avian, and mammalian orthoreoviruses. Vet Microbiol 2008; 133:34-42. [PMID: 18656318 DOI: 10.1016/j.vetmic.2008.06.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 06/09/2008] [Accepted: 06/12/2008] [Indexed: 11/16/2022]
Abstract
The orthoreoviruses are segmented RNA viruses that infect diverse vertebrate host species. While the most common human orthoreovirus, Mammalian Reovirus, is not typically associated with significant disease, the majority of Orthoreovirus species have been shown to cause significant and often fatal disease in reptiles, birds, and primates. There is significant potential for jumping species. A consensus nested-PCR method was designed for investigation of the RNA-dependent RNA polymerase gene of Orthoreovirus and Aquareovirus. This protocol was used to obtain sequencing template from reoviruses of three different vertebrate classes. Bayesian and maximum likelihood phylogenetic analysis found that all viruses analyzed clustered in the genus Orthoreovirus, that reptile reoviruses formed three distinct clusters, and that an African grey parrot reovirus clustered with Nelson Bay virus from bats. This PCR method may be useful for obtaining templates for initial sequencing of novel orthoreoviruses from diverse vertebrate hosts.
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Affiliation(s)
- James F X Wellehan
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
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