Community-Level Differences in the Microbiome of Healthy Wild Mallards and Those Infected by Influenza A Viruses

ABSTRACT Seasonal influenza causes 3 to 5 million severe illnesses and 250,000 to 500,000 human deaths each year. While pandemic influenza viruses emerge only periodically, they can be devastating—for example, the 1918 H1N1 pandemic virus killed more than 20 million people. IAVs infect the respiratory tract and cause significant morbidity and mortality in humans. In contrast, IAVs infect the gastrointestinal tract of waterfowl, producing little pathology. Recent studies indicated that viruses can alter the microbiome at the respiratory and gastrointestinal mucosa, but there are no reports of how the microbiota of the natural host of influenza is affected by infection. Here we find that the mallard microbiome is altered during IAV infection. Our results suggest that detailed examination of humans and animals infected with IAVs may reveal individualized microbiome profiles that correspond to health and disease. Moreover, future studies should explore whether the altered microbiome facilitates maintenance and transmission of IAVs in waterfowl populations. Waterfowl, especially ducks and geese, are primary reservoirs for influenza A viruses (IAVs) that evolve and emerge as important pathogens in domestic animals and humans. In contrast to humans, where IAVs infect the respiratory tract and cause significant morbidity and mortality, IAVs infect the gastrointestinal tract of waterfowl and cause little or no pathology and are spread by fecal-oral transmission. For this reason, we examined whether IAV infection is associated with differences in the cloacal microbiome of mallards (Anas platyrhyncos), an important host of IAVs in North America and Eurasia. We characterized bacterial community composition by sequencing the V4 region of 16S rRNA genes. IAV-positive mallards had lower species diversity, richness, and evenness than IAV-negative mallards. Operational taxonomic unit (OTU) cooccurrence patterns were also distinct depending on infection status. Network analysis showed that IAV-positive mallards had fewer significant cooccurring OTUs and exhibited fewer coassociation patterns among those OTUs than IAV-negative mallards. These results suggest that healthy mallards have a more robust and complex cloacal microbiome. By combining analytical approaches, we identified 41 bacterial OTUs, primarily representatives of Streptococcus spp., Veillonella dispar, and Rothia mucilaginosa, contributing to the observed differences. This study found that IAV-infected wild mallards exhibited strong differences in microbiome composition relative to noninfected mallards and identified a concise set of putative biomarker OTUs. Using Random Forest, a supervised machine learning method, we verified that these 41 bacterial OTUs are highly predictive of infection status. IMPORTANCE Seasonal influenza causes 3 to 5 million severe illnesses and 250,000 to 500,000 human deaths each year. While pandemic influenza viruses emerge only periodically, they can be devastating—for example, the 1918 H1N1 pandemic virus killed more than 20 million people. IAVs infect the respiratory tract and cause significant morbidity and mortality in humans. In contrast, IAVs infect the gastrointestinal tract of waterfowl, producing little pathology. Recent studies indicated that viruses can alter the microbiome at the respiratory and gastrointestinal mucosa, but there are no reports of how the microbiota of the natural host of influenza is affected by infection. Here we find that the mallard microbiome is altered during IAV infection. Our results suggest that detailed examination of humans and animals infected with IAVs may reveal individualized microbiome profiles that correspond to health and disease. Moreover, future studies should explore whether the altered microbiome facilitates maintenance and transmission of IAVs in waterfowl populations.

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Kallikrein-Related Peptidase 5 Contributes to H3N2 Influenza Virus Infection in Human Lungs

Journal of Virology ◽

10.1128/jvi.00421-17 ◽

2017 ◽

Vol 91 (16) ◽

Cited By ~ 7

Author(s):

Mélia Magnen ◽

Fabien Gueugnon ◽

Antoine Guillon ◽

Thomas Baranek ◽

Virginie C. Thibault ◽

...

Keyword(s):

Influenza Virus ◽

Respiratory Tract ◽

Serine Proteases ◽

Lower Respiratory Tract ◽

Influenza A ◽

Seasonal Influenza ◽

Influenza Viruses ◽

H3n2 Virus ◽

Influenza A Viruses

ABSTRACT Hemagglutinin (HA) of influenza virus must be activated by proteolysis before the virus can become infectious. Previous studies indicated that HA cleavage is driven by membrane-bound or extracellular serine proteases in the respiratory tract. However, there is still uncertainty as to which proteases are critical for activating HAs of seasonal influenza A viruses (IAVs) in humans. This study focuses on human KLK1 and KLK5, 2 of the 15 serine proteases known as the kallikrein-related peptidases (KLKs). We find that their mRNA expression in primary human bronchial cells is stimulated by IAV infection. Both enzymes cleaved recombinant HA from several strains of the H1 and/or H3 virus subtype in vitro, but only KLK5 promoted the infectivity of A/Puerto Rico/8/34 (H1N1) and A/Scotland/20/74 (H3N2) virions in MDCK cells. We assessed the ability of treated viruses to initiate influenza in mice. The nasal instillation of only the KLK5-treated virus resulted in weight loss and lethal outcomes. The secretion of this protease in the human lower respiratory tract is enhanced during influenza. Moreover, we show that pretreatment of airway secretions with a KLK5-selective inhibitor significantly reduced the activation of influenza A/Scotland/20/74 virions, providing further evidence of its importance. Differently, increased KLK1 secretion appeared to be associated with the recruitment of inflammatory cells in human airways regardless of the origin of inflammation. Thus, our findings point to the involvement of KLK5 in the proteolytic activation and spread of seasonal influenza viruses in humans. IMPORTANCE Influenza A viruses (IAVs) cause acute infection of the respiratory tract that affects millions of people during seasonal outbreaks every year. Cleavage of the hemagglutinin precursor by host proteases is a critical step in the life cycle of these viruses. Consequently, host proteases that activate HA can be considered promising targets for the development of new antivirals. However, the specific proteases that activate seasonal influenza viruses, especially H3N2 viruses, in the human respiratory tract have remain undefined despite many years of work. Here we demonstrate that the secreted, extracellular protease KLK5 (kallikrein-related peptidase 5) is efficient in promoting the infectivity of H3N2 IAV in vitro and in vivo. Furthermore, we found that its secretion was selectively enhanced in the human lower respiratory tract during a seasonal outbreak dominated by an H3N2 virus. Collectively, our data support the clinical relevance of this protease in human influenza pathogenesis.

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Broadly Reactive H2 Hemagglutinin Vaccines Elicit Cross-Reactive Antibodies in Ferrets Pre-Immune to Seasonal Influenza A Viruses

10.1101/2021.02.17.431747 ◽

2021 ◽

Author(s):

Z. Beau Reneer ◽

Amanda S. Skarlupka ◽

Parker J. Jamieson ◽

Ted M. Ross

Keyword(s):

Influenza Virus ◽

Immune Responses ◽

Recombinant Proteins ◽

Human Population ◽

Influenza A ◽

Seasonal Influenza ◽

Influenza Viruses ◽

Morbidity And Mortality ◽

Influenza A Viruses ◽

Global Pandemic

AbstractInfluenza vaccines have traditionally been tested in naïve mice and ferrets. However, humans are first exposed to influenza viruses within the first few years of their lives. Therefore, there is a pressing need to test influenza virus vaccines in animal models that have been previously exposed to influenza viruses before being vaccinated. In this manuscript, previously described H2 computationally optimized broadly reactive antigen (COBRA) HA vaccines (Z1, Z5) were tested in influenza virus ‘pre-immune’ ferret models. Ferrets were infected with historical, seasonal influenza viruses to establish pre-immunity. These pre-immune ferrets were then vaccinated with either COBRA H2 HA recombinant proteins or WT H2 HA recombinant proteins in a prime-boost regimen. A set of naïve pre-immune or non pre-immune ferrets were also vaccinated to control of the effects of the multiple different pre-immunities. All of the ferrets were then challenged with a swine H2N3 influenza virus. Ferrets with pre-existing immune responses influenced recombinant H2 HA elicited antibodies following vaccination as measured by HAI and classical neutralization assays. Having both H3N2 and H1N1 immunological memory regardless of the order of exposure significantly decreased viral nasal wash titers and completely protected all ferrets from both morbidity and mortality, including the mock vaccinated ferrets in the group. While the vast majority of the pre-immune ferrets were protected from both morbidity and mortality across all of the different pre-immunities, the Z1 COBRA HA vaccinated ferrets had significantly higher antibody titers and recognized the highest number H2 influenza viruses in a classical neutralization assay compared to the other H2 HA vaccines.ImportanceH1N1 and H3N2 influenza viruses have co-circulated in the human population since 1977. Nearly every human alive today has antibodies and memory B and T cells against these two subtypes of influenza viruses. H2N2 influenza viruses caused the 1957 global pandemic and people born after 1968 have never been exposed to H2 influenza viruses. It is quite likely that a future H2 influenza virus could transmit within the human population and start a new global pandemic, since the majority of people alive today are immunologically naïve to viruses of this subtype. Therefore, an effective vaccine for H2 influenza viruses should be tested in an animal model with previous exposure to influenza viruses that have circulated in humans. Ferrets were infected with historical influenza A viruses to more accurately mimic the immune responses in people who have pre-existing immune responses to seasonal influenza viruses. In this study, pre-immune ferrets were vaccinated with WT and COBRA H2 recombinant HA proteins in order to examine the effects of pre-existing immunity to seasonal human influenza viruses have on the elicitation of broadly cross-reactive antibodies from heterologous vaccination.

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Broadly Reactive H2 Hemagglutinin Vaccines Elicit Cross-Reactive Antibodies in Ferrets Preimmune to Seasonal Influenza A Viruses

mSphere ◽

10.1128/msphere.00052-21 ◽

2021 ◽

Vol 6 (2) ◽

Author(s):

Z. Beau Reneer ◽

Amanda L. Skarlupka ◽

Parker J. Jamieson ◽

Ted M. Ross

Keyword(s):

Influenza Virus ◽

Immune Responses ◽

Recombinant Proteins ◽

Human Population ◽

Influenza A ◽

Seasonal Influenza ◽

Influenza Viruses ◽

Wild Type ◽

Influenza A Viruses ◽

Global Pandemic

ABSTRACT Influenza vaccines have traditionally been tested in naive mice and ferrets. However, humans are first exposed to influenza viruses within the first few years of their lives. Therefore, there is a pressing need to test influenza virus vaccines in animal models that have been previously exposed to influenza viruses before being vaccinated. In this study, previously described H2 computationally optimized broadly reactive antigen (COBRA) hemagglutinin (HA) vaccines (Z1 and Z5) were tested in influenza virus “preimmune” ferret models. Ferrets were infected with historical, seasonal influenza viruses to establish preimmunity. These preimmune ferrets were then vaccinated with either COBRA H2 HA recombinant proteins or wild-type H2 HA recombinant proteins in a prime-boost regimen. A set of naive preimmune or nonpreimmune ferrets were also vaccinated to control for the effects of the multiple different preimmunities. All of the ferrets were then challenged with a swine H2N3 influenza virus. Ferrets with preexisting immune responses influenced recombinant H2 HA-elicited antibodies following vaccination, as measured by hemagglutination inhibition (HAI) and classical neutralization assays. Having both H3N2 and H1N1 immunological memory regardless of the order of exposure significantly decreased viral nasal wash titers and completely protected all ferrets from both morbidity and mortality, including the mock-vaccinated ferrets in the group. While the vast majority of the preimmune ferrets were protected from both morbidity and mortality across all of the different preimmunities, the Z1 COBRA HA-vaccinated ferrets had significantly higher antibody titers and recognized the highest number of H2 influenza viruses in a classical neutralization assay compared to the other H2 HA vaccines. IMPORTANCE H1N1 and H3N2 influenza viruses have cocirculated in the human population since 1977. Nearly every human alive today has antibodies and memory B and T cells against these two subtypes of influenza viruses. H2N2 influenza viruses caused the 1957 global pandemic and people born after 1968 have never been exposed to H2 influenza viruses. It is quite likely that a future H2 influenza virus could transmit within the human population and start a new global pandemic, since the majority of people alive today are immunologically naive to viruses of this subtype. Therefore, an effective vaccine for H2 influenza viruses should be tested in an animal model with previous exposure to influenza viruses that have circulated in humans. Ferrets were infected with historical influenza A viruses to more accurately mimic the immune responses in people who have preexisting immune responses to seasonal influenza viruses. In this study, preimmune ferrets were vaccinated with wild-type (WT) and COBRA H2 recombinant HA proteins in order to examine the effects that preexisting immunity to seasonal human influenza viruses have on the elicitation of broadly cross-reactive antibodies from heterologous vaccination.

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Pathogenesis and Transmission of Genetically Diverse Swine-Origin H3N2 Variant Influenza A Viruses from Multiple Lineages Isolated in the United States, 2011–2016

Journal of Virology ◽

10.1128/jvi.00665-18 ◽

2018 ◽

Vol 92 (16) ◽

Cited By ~ 7

Author(s):

Xiangjie Sun ◽

Joanna A. Pulit-Penaloza ◽

Jessica A. Belser ◽

Claudia Pappas ◽

Melissa B. Pearce ◽

...

Keyword(s):

United States ◽

Respiratory Tract ◽

Influenza A ◽

Seasonal Influenza ◽

The United States ◽

Influenza Viruses ◽

Upper Respiratory Tract ◽

Pandemic Preparedness

ABSTRACTWhile several swine-origin influenza A H3N2 variant (H3N2v) viruses isolated from humans prior to 2011 have been previously characterized for their virulence and transmissibility in ferrets, the recent genetic and antigenic divergence of H3N2v viruses warrants an updated assessment of their pandemic potential. Here, four contemporary H3N2v viruses isolated during 2011 to 2016 were evaluated for their replicative ability in bothin vitroandin vivoin mammalian models as well as their transmissibility among ferrets. We found that all four H3N2v viruses possessed similar or enhanced replication capacities in a human bronchial epithelium cell line (Calu-3) compared to a human seasonal influenza virus, suggestive of strong fitness in human respiratory tract cells. The majority of H3N2v viruses examined in our study were mildly virulent in mice and capable of replicating in mouse lungs with different degrees of efficiency. In ferrets, all four H3N2v viruses caused moderate morbidity and exhibited comparable titers in the upper respiratory tract, but only 2 of the 4 viruses replicated in the lower respiratory tract in this model. Furthermore, despite efficient transmission among cohoused ferrets, recently isolated H3N2v viruses displayed considerable variance in their ability to transmit by respiratory droplets. The lack of a full understanding of the molecular correlates of virulence and transmission underscores the need for close genotypic and phenotypic monitoring of H3N2v viruses and the importance of continued surveillance to improve pandemic preparedness.IMPORTANCESwine-origin influenza viruses of the H3N2 subtype, with the hemagglutinin (HA) and neuraminidase (NA) derived from historic human seasonal influenza viruses, continue to cross species barriers and cause human infections, posing an indelible threat to public health. To help us better understand the potential risk associated with swine-origin H3N2v viruses that emerged in the United States during the 2011-2016 influenza seasons, we use bothin vitroandin vivomodels to characterize the abilities of these viruses to replicate, cause disease, and transmit in mammalian hosts. The efficient respiratory droplet transmission exhibited by some of the H3N2v viruses in the ferret model combined with the existing evidence of low immunity against such viruses in young children and older adults highlight their pandemic potential. Extensive surveillance and risk assessment of H3N2v viruses should continue to be an essential component of our pandemic preparedness strategy.

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Efficient Inhibition of Avian and Seasonal Influenza A Viruses by a Virus-Specific Dicer-Substrate Small Interfering RNA Swarm in Human Monocyte-Derived Macrophages and Dendritic Cells

Journal of Virology ◽

10.1128/jvi.01916-18 ◽

2018 ◽

Vol 93 (4) ◽

Cited By ~ 2

Author(s):

Miao Jiang ◽

Pamela Österlund ◽

Veera Westenius ◽

Deyin Guo ◽

Minna M. Poranen ◽

...

Keyword(s):

Dendritic Cells ◽

Influenza Virus ◽

Small Interfering Rna ◽

Influenza A ◽

Seasonal Influenza ◽

Influenza Viruses ◽

Influenza A Viruses ◽

Primary Monocyte ◽

Prevention And Treatment ◽

Interfering Rna

ABSTRACTInfluenza A viruses (IAVs) are viral pathogens that cause epidemics and occasional pandemics of significant mortality. The generation of efficacious vaccines and antiviral drugs remains a challenge due to the rapid appearance of new influenza virus types and antigenic variants. Consequently, novel strategies for the prevention and treatment of IAV infections are needed, given the limitations of the presently available antivirals. Here, we used enzymatically produced IAV-specific double-stranded RNA (dsRNA) molecules andGiardia intestinalisDicer for the generation of a swarm of small interfering RNA (siRNA) molecules. The siRNAs target multiple conserved genomic regions of the IAVs. In mammalian cells, the produced 25- to 27-nucleotide-long siRNA molecules are processed by endogenous Dicer into 21-nucleotide siRNAs and are thus designated Dicer-substrate siRNAs (DsiRNAs). We evaluated the efficacy of the above DsiRNA swarm at preventing IAV infections in human primary monocyte-derived macrophages and dendritic cells. The replication of different IAV strains, including avian influenza H5N1 and H7N9 viruses, was significantly inhibited by pretransfection of the cells with the IAV-specific DsiRNA swarm. Up to 7 orders of magnitude inhibition of viral RNA expression was observed, which led to a dramatic inhibition of IAV protein synthesis and virus production. The IAV-specific DsiRNA swarm inhibited virus replication directly through the RNA interference pathway although a weak induction of innate interferon responses was detected. Our results provide direct evidence for the feasibility of the siRNA strategy and the potency of DsiRNA swarms in the prevention and treatment of influenza, including the highly pathogenic avian influenza viruses.IMPORTANCEIn spite of the enormous amount of research, influenza virus is still one of the major challenges for medical virology due to its capacity to generate new variants, which potentially lead to severe epidemics and pandemics. We demonstrated here that a swarm of small interfering RNA (siRNA) molecules, including more than 100 different antiviral RNA molecules targeting the most conserved regions of the influenza A virus genome, could efficiently inhibit the replication of all tested avian and seasonal influenza A variants in human primary monocyte-derived macrophages and dendritic cells. The wide antiviral spectrum makes the virus-specific siRNA swarm a potentially efficient treatment modality against both avian and seasonal influenza viruses.

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Development of an interactive online tool for genome sequence-based influenza vaccine strain selection

10.32469/10355/85856 ◽

2021 ◽

Author(s):

◽

Sweta Pragyan Praharaj

Keyword(s):

Influenza Vaccine ◽

Phylogenetic Tree ◽

Influenza Vaccination ◽

Vaccine Strain ◽

Influenza A ◽

Seasonal Influenza ◽

Influenza Viruses ◽

Influenza A Viruses ◽

Seasonal Influenza Vaccine ◽

Antigenic Cartography

Seasonal influenza viruses in humans infect approximately 5 [percent] to 15 [percent] of the population and cause an estimated half-million deaths worldwide per year. Among the four co-circulating seasonal influenza viruses, subtype H3N2 and H1N1 influenza A viruses have rapid mutations and frequent antigenic drift events, leading to frequent updates of vaccine strains in the seasonal influenza vaccine. Seasonal influenza vaccination is the primary option to prevent and control influenza epidemics, and the selection of an antigenic matched vaccine strain is one of the keys to the success of seasonal influenza vaccination. Thus, it is critical to have robust and rapid antigenic analyses of epidemic strains and estimates of their genetic and antigenic relationship with the vaccine strain in use. In this study, we present vaccineEvol, an interactive and user-friendly web visualization tool that allows researchers to comprehend large sequence datasets into antigenic and genetic analyses. With the integration of the genomic sequences from the public database, the tool enables the users to track and analyze both genetic and antigenic evolutionary dynamics of seasonal influenza viruses. Primarily, our application can quantify both genetic and antigenic distances among seasonal H3N2 influenza A viruses and display genetic and antigenic variants using phylogenetic tree and antigenic cartography, respectively. The users can also interactively analyze genetic and antigenic variants between the phylogenetic tree and antigenic cartography. The application performs machine learning based computations in the backend, which was previously developed in our lab, and efficient construction of trees and maps in the frontend. In summary, in this study, an interactive web server was developed for rapid antigenic and genetic analyses of seasonal influenza viruses and thus facilitate seasonal influenza vaccine strain selection.

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Infection of Mouse Macrophages by Seasonal Influenza Viruses Can Be Restricted at the Level of Virus Entry and at a Late Stage in the Virus Life Cycle

Journal of Virology ◽

10.1128/jvi.01455-15 ◽

2015 ◽

Vol 89 (24) ◽

pp. 12319-12329 ◽

Cited By ~ 17

Author(s):

Sarah L. Londrigan ◽

Kirsty R. Short ◽

Joel Ma ◽

Leah Gillespie ◽

Steven P. Rockman ◽

...

Keyword(s):

Life Cycle ◽

Cell Surface ◽

Influenza A ◽

Seasonal Influenza ◽

Virus Assembly ◽

Virus Entry ◽

Influenza Viruses ◽

Productive Infection ◽

Influenza A Viruses ◽

Virus Life Cycle

ABSTRACTAirway epithelial cells are susceptible to infection with seasonal influenza A viruses (IAV), resulting in productive virus replication and release. Macrophages (MΦ) are also permissive to IAV infection; however, virus replication is abortive. Currently, it is unclear how productive infection of MΦ is impaired or the extent to which seasonal IAV replicate in MΦ. Herein, we compared mouse MΦ and epithelial cells for their ability to support genomic replication and transcription, synthesis of viral proteins, assembly of virions, and release of infectious progeny following exposure to genetically defined IAV. We confirm that seasonal IAV differ in their ability to utilize cell surface receptors for infectious entry and that this represents one level of virus restriction. Following virus entry, we demonstrate synthesis of all eight segments of genomic viral RNA (vRNA) and mRNA, as well as seven distinct IAV proteins, in IAV-infected mouse MΦ. Although newly synthesized hemagglutinin (HA) and neuraminidase (NA) glycoproteins are incorporated into the plasma membrane and expressed at the cell surface, electron microscopy confirmed that virus assembly was defective in IAV-infected MΦ, defining a second level of restriction late in the virus life cycle.IMPORTANCESeasonal influenza A viruses (IAV) and highly pathogenic avian influenza viruses (HPAI) infect macrophages, but only HPAI replicate productively in these cells. Herein, we demonstrate that impaired virus uptake into macrophages represents one level of restriction limiting infection by seasonal IAV. Following uptake, seasonal IAV do not complete productive replication in macrophages, representing a second level of restriction. Using murine macrophages, we demonstrate that productive infection is blocked late in the virus life cycle, such that virus assembly is defective and newly synthesized virions are not released. These studies represent an important step toward identifying host-encoded factors that block replication of seasonal IAV, but not HPAI, in macrophages.

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Three Types of Broadly Reacting Antibodies against Influenza B Viruses Induced by Vaccination with Seasonal Influenza Viruses

Journal of Immunology Research ◽

10.1155/2018/7251793 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 6

Author(s):

Daisuke Hirano ◽

Nobuko Ohshima ◽

Ritsuko Kubota-Koketsu ◽

Ayami Yamasaki ◽

Gene Kurosawa ◽

...

Keyword(s):

Influenza A ◽

Seasonal Influenza ◽

Mononuclear Cells ◽

Cross Reactivity ◽

Influenza Viruses ◽

Influenza B ◽

Influenza A Viruses ◽

Phage Display Technology ◽

Display Technology ◽

2009 H1n1

We analyzed the antibody (Ab) repertoire against influenza B viruses induced by vaccination with seasonal influenza viruses in one individual who had never been vaccinated until 2009. The vaccine used in this study comprised B/Massachusetts/2/2012 (Yamagata lineage), A/Texas/50/2012 (H3N2), and A/California/7/2009 (H1N1). One month after the subject received two vaccinations, blood (200 ml) was obtained and peripheral mononuclear cells were prepared, and a large Ab library was constructed using phage display technology. The library was screened with HA-enriched fraction of B/Massachusetts/2/2012 and B/Brisbane/60/2008 (Victoria lineage) virus, and a total of 26 Abs that potentially bound to hemagglutinin (HA) molecules were isolated. Their binding activities to six influenza B viruses, three of Yamagata lineage and three of Victoria lineage, and two influenza A viruses, H1N1 and H3N2, were examined. The Abs showed cross-reactivity at three different levels. The first type bound to all Yamagata lineage viruses. The second type bound to both Yamagata and Victoria lineage viruses. The third type bound to both influenza A and B viruses. These results indicate that common epitopes exist on HA molecules of influenza virus at various levels, and humans have capability to produce Abs that bind to such common epitopes.

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Circulation patterns of human seasonal Influenza A viruses in Chile before H1N1pdm09 pandemic

Scientific Reports ◽

10.1038/s41598-021-00795-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Juan Mena ◽

Rodrigo Tapia ◽

Claudio Verdugo ◽

Luis Avendaño ◽

Paulina Parra-Castro ◽

...

Keyword(s):

Genetic Diversity ◽

Influenza A ◽

Seasonal Influenza ◽

Phylogenetic Analyses ◽

Influenza Viruses ◽

Surveillance Systems ◽

Influenza A Viruses ◽

Evolutionary Patterns ◽

Public Health Decision ◽

Health Decision

AbstractUnderstanding the diversity and circulation dynamics of seasonal influenza viruses is key to public health decision-making. The limited genetic information of pre-pandemic seasonal IAVs in Chile has made it difficult to accurately reconstruct the phylogenetic relationships of these viruses within the country. The objective of this study was to determine the genetic diversity of pre-pandemic human seasonal IAVs in Chile. We sequenced the complete genome of 42 historic IAV obtained between 1996 and 2007. The phylogeny was determined using HA sequences and complemented using other segments. Time-scale phylogenetic analyses revealed that the diversity of pre-pandemic human seasonal IAVs in Chile was influenced by continuous introductions of new A/H1N1 and A/H3N2 lineages and constant viral exchange between Chile and other countries every year. These results provide important knowledge about genetic diversity and evolutionary patterns of pre-pandemic human seasonal IAVs in Chile, which can help design optimal surveillance systems and prevention strategies. However, future studies with current sequences should be conducted.

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Oseltamivir susceptibility in south-western France during the 2007-8 and 2008-9 influenza epidemics and the ongoing influenza pandemic 2009

Eurosurveillance ◽

10.2807/ese.14.38.19334-en ◽

2009 ◽

Vol 14 (38) ◽

Cited By ~ 4

Author(s):

S Burrel ◽

L Roncin ◽

M E Lafon ◽

H Fleury

Keyword(s):

Influenza A ◽

Seasonal Influenza ◽

Influenza Pandemic ◽

Influenza Viruses ◽

Neuraminidase Inhibitors ◽

Influenza A Viruses ◽

Oseltamivir Resistance ◽

The Past ◽

Influenza A H1n1 ◽

Recent Emergence

The recent emergence of seasonal influenza A(H1N1) strains resistant to oseltamivir makes it necessary to monitoring carefully the susceptibility of human influenza viruses to neuraminidase inhibitors. We report the prevalence of the oseltamivir resistance among influenza A viruses circulating in south-western France over the past three years: seasonal influenza A(H1N1), seasonal influenza A(H3N2), and the influenza A(H1N1)v viruses associated with the ongoing 2009 pandemic. The main result of the study is the absence of oseltamivir resistance in the pandemic H1N1 strains studied so far (n=129).

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