Potential role of viral surface glycoproteins in the replication of H3N2 triple reassortant influenza A viruses in swine and turkeys

As compared to other Anseriformes, data related to influenza A virus (IAV) detection and isolation, and IAV antibody detection in whistling ducks (Dendrocygna spp. and Thalassornis leuconotus; subfamily Dendrocygninae) are limited. To better evaluate the potential role of whistling ducks in the epidemiology of IAV, we (1) conducted surveillance for IAV from black-bellied whistling ducks (BBWD, Dendrocygnaautumnalis) sampled in coastal Louisiana, USA, during February 2018 and 2019, and (2) reviewed the published literature and Influenza Resource Database (IRD) that reported results of IAV surveillance of whistling ducks. In the prospective study, from 166 BBWD sampled, one H10N7 IAV was isolated (0.6% prevalence), and overall blocking enzyme-linked immunosorbent assay (bELISA) antibody seroprevalence was 10%. The literature review included publications and data in the IRD from 1984 to 2020 that reported results from nearly 5000 collected samples. For any given collection, the IAV isolation rate never exceeded 5.5%, and seroprevalence estimates ranged from 0 to 42%. Results from our prospective study in Louisiana are consistent with this historic literature; however, although all data consistently demonstrated a low prevalence of infection, the potential role of this species in the epidemiology of IAV should not be totally discounted. In sum, whistling ducks can be infected with IAV, they represent important species on many areas where waterfowl winter, and their distribution across the globe appears to be changing.

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Serological Screening of Influenza A Virus Antibodies in Cats and Dogs Indicates Frequent Infection with Different Subtypes

Journal of Clinical Microbiology ◽

10.1128/jcm.01689-20 ◽

2020 ◽

Vol 58 (11) ◽

Author(s):

Shan Zhao ◽

Nancy Schuurman ◽

Malte Tieke ◽

Berit Quist ◽

Steven Zwinkels ◽

...

Keyword(s):

Influenza A ◽

Close Contact ◽

Animal Health ◽

Companion Animals ◽

Added Value ◽

Influenza A Viruses ◽

Serum Samples ◽

Serological Screening ◽

H1n1 Outbreak

ABSTRACT Influenza A viruses (IAVs) infect humans and a variety of other animal species. Infections with some subtypes of IAV were also reported in domestic cats and dogs. In addition to animal health implications, close contact between companion animals and humans also poses a potential risk of zoonotic IAV infections. In this study, serum samples from different cat and dog cohorts were analyzed for IAV antibodies against seven IAV subtypes, using three distinctive IAV-specific assays differing in IAV subtype-specific discriminatory power and sensitivity. Enzyme-linked immunosorbent assays against the complete hemagglutinin (HA) ectodomain or the HA1 domain were used, as well as a novel nanoparticle-based, virus-free hemagglutination inhibition assay. Using these three assays, we found cat and dog sera from different cohorts to be positive for antibodies against one or more IAV subtypes and/or strains. Cat and dog serum samples collected after the 2009 pandemic H1N1 outbreak exhibit much higher seropositivity against H1 compared to samples from before 2009. Cat sera, furthermore, displayed higher reactivity for avian IAVs than dog sera. Our findings show the added value of using complementary serological assays, which are based on reactivity with different numbers of HA epitopes, to study IAV antibody responses and for improved serosurveillance of IAV infections. We conclude that infection of cats and dogs with both human and avian IAVs of different subtypes is prevalent. These observations highlight the role of cats and dogs in IAV ecology and indicate the potential of these companion animals to give rise to novel (reassorted) viruses with increased zoonotic potential.

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Genetic Adaptation of Influenza A Viruses in Domestic Animals and Their Potential Role in Interspecies Transmission: A Literature Review

EcoHealth ◽

10.1007/s10393-014-1004-1 ◽

2015 ◽

Vol 13 (1) ◽

pp. 171-198 ◽

Cited By ~ 15

Author(s):

Olga Munoz ◽

◽

Marco De Nardi ◽

Karen van der Meulen ◽

Kristien van Reeth ◽

...

Keyword(s):

Literature Review ◽

Influenza A ◽

Potential Role ◽

Domestic Animals ◽

Interspecies Transmission ◽

Genetic Adaptation ◽

Influenza A Viruses

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Erratum to: Genetic Adaptation of Influenza A Viruses in Domestic Animals and Their Potential Role in Interspecies Transmission: A Literature Review

EcoHealth ◽

10.1007/s10393-015-1031-6 ◽

2015 ◽

Vol 13 (1) ◽

pp. 199-199 ◽

Cited By ~ 1

Author(s):

Olga Munoz ◽

◽

Marco De Nardi ◽

Karen van der Meulen ◽

Kristien van Reeth ◽

...

Keyword(s):

Literature Review ◽

Influenza A ◽

Potential Role ◽

Domestic Animals ◽

Interspecies Transmission ◽

Genetic Adaptation ◽

Influenza A Viruses

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Wild Birds in Live Birds Markets: Potential Reservoirs of Enzootic Avian Influenza Viruses and Antimicrobial Resistant Enterobacteriaceae in Northern Egypt

Pathogens ◽

10.3390/pathogens9030196 ◽

2020 ◽

Vol 9 (3) ◽

pp. 196 ◽

Cited By ~ 2

Author(s):

Nehal M. Nabil ◽

Ahmed M. Erfan ◽

Maram M. Tawakol ◽

Naglaa M. Haggag ◽

Mahmoud M. Naguib ◽

...

Keyword(s):

Influenza A ◽

Migratory Birds ◽

Wild Birds ◽

Influenza Viruses ◽

Northern Coast ◽

Influenza A Viruses ◽

E Coli ◽

Ha Gene ◽

Live Bird

Wild migratory birds are often implicated in the introduction, maintenance, and global dissemination of different pathogens, such as influenza A viruses (IAV) and antimicrobial-resistant (AMR) bacteria. Trapping of migratory birds during their resting periods at the northern coast of Egypt is a common and ancient practice performed mainly for selling in live bird markets (LBM). In the present study, samples were collected from 148 wild birds, representing 14 species, which were being offered for sale in LBM. All birds were tested for the presence of AIV and enterobacteriaceae. Ten samples collected from Northern Shoveler birds (Spatula clypeata) were positive for IAV and PCR sub-typing and pan HA/NA sequencing assays detected H5N8, H9N2, and H6N2 viruses in four, four, and one birds, respectively. Sequencing of the full haemagglutinin (HA) gene revealed a high similarity with currently circulating IAV in Egypt. From all the birds, E. coli was recovered from 37.2% and Salmonella from 20.2%, with 66–96% and 23–43% isolates being resistant to at least one of seven selected critically important antimicrobials (CIA), respectively. The presence of enzootic IAV and the wide prevalence of AMR enterobacteriaceae in wild birds highlight the potential role of LBM in the spread of different pathogens from and to wild birds. Continued surveillance of both AIV and antimicrobial-resistant enterobacteriaceae in wild birds’ habitats is urgently needed.

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The Surface-Exposed PA51-72-Loop of the Influenza A Virus Polymerase Is Required for Viral Genome Replication

Journal of Virology ◽

10.1128/jvi.00687-18 ◽

2018 ◽

Vol 92 (16) ◽

Cited By ~ 2

Author(s):

Benjamin E. Nilsson-Payant ◽

Jane Sharps ◽

Narin Hengrung ◽

Ervin Fodor

Keyword(s):

Influenza A Virus ◽

Viral Genome ◽

Influenza A ◽

Replication Initiation ◽

Genome Replication ◽

Influenza A Viruses ◽

Viral Polymerase ◽

Virus Rna ◽

Endonuclease Domain

ABSTRACTThe heterotrimeric influenza A virus RNA-dependent RNA polymerase complex, composed of PB1, PB2, and PA subunits, is responsible for transcribing and replicating the viral RNA genome. The N-terminal endonuclease domain of the PA subunit performs endonucleolytic cleavage of capped host RNAs to generate capped RNA primers for viral transcription. A surface-exposed flexible loop (PA51-72-loop) in the PA endonuclease domain has been shown to be dispensable for endonuclease activity. Interestingly, the PA51-72-loop was found to form different intramolecular interactions depending on the conformational arrangement of the polymerase. In this study, we show that a PA subunit lacking the PA51-72-loop assembles into a heterotrimeric polymerase with PB1 and PB2. We demonstrate that in a cellular context, the PA51-72-loop is required for RNA replication but not transcription by the viral polymerase. In agreement, recombinant viral polymerase lacking the PA51-72-loop is able to carry out cap-dependent transcription but is inhibited inde novoreplication initiationin vitro. Furthermore, viral RNA (vRNA) synthesis is also restricted during ApG-primed extension, indicating that the PA51-72-loop is required not only for replication initiation but also for elongation on a cRNA template. We propose that the PA51-72-loop plays a role in the stabilization of the replicase conformation of the polymerase. Together, these results further our understanding of influenza virus RNA genome replication in general and highlight a role of the PA endonuclease domain in polymerase function in particular.IMPORTANCEInfluenza A viruses are a major global health threat, not only causing significant morbidity and mortality every year but also having the potential to cause severe pandemic outbreaks like the 1918 influenza pandemic. The viral polymerase is a protein complex which is responsible for transcription and replication of the viral genome and therefore is an attractive target for antiviral drug development. For that purpose it is important to understand the mechanisms of how the virus replicates its genome and how the viral polymerase works on a molecular level. In this report, we characterize the role of the flexible surface-exposed PA51-72-loop in polymerase function and offer new insights into the replication mechanism of influenza A viruses.

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The role of fusion activity of influenza A viruses in their biological properties

Acta Virologica ◽

10.4149/av_2016_02_121 ◽

2016 ◽

Vol 60 (02) ◽

pp. 121-135 ◽

Cited By ~ 5

Author(s):

L. JAKUBCOVÁ ◽

J. HOLLÝ ◽

E. VAREČKOVÁ

Keyword(s):

Influenza A ◽

Biological Properties ◽

Fusion Activity ◽

Influenza A Viruses

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Correction: Potential Role of Invariant NKT Cells in the Control of Pulmonary Inflammation and CD8+ T Cell Response during Acute Influenza A Virus H3N2 Pneumonia

The Journal of Immunology ◽

10.4049/jimmunol.1190034 ◽

2011 ◽

Vol 187 (3) ◽

pp. 1515-1515 ◽

Cited By ~ 1

Author(s):

Christophe Paget ◽

Stoyan Ivanov ◽

Josette Fontaine ◽

Fany Blanc ◽

Muriel Pichavant ◽

...

Keyword(s):

Influenza A Virus ◽

Cell Response ◽

Influenza A ◽

Potential Role ◽

Pulmonary Inflammation ◽

Cd8 T Cell ◽

T Cell Response ◽

Invariant Nkt Cells ◽

Correction Potential

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Role of the PB2 627 Domain in Influenza A Virus Polymerase Function

Journal of Virology ◽

10.1128/jvi.02467-16 ◽

2017 ◽

Vol 91 (7) ◽

Cited By ~ 13

Author(s):

Benjamin E. Nilsson ◽

Aartjan J. W. te Velthuis ◽

Ervin Fodor

Keyword(s):

Influenza Virus ◽

Rna Polymerase ◽

Influenza A Virus ◽

Influenza A ◽

Influenza A Viruses ◽

Viral Polymerase ◽

Virus Rna ◽

Rna Genome ◽

Transcription And Replication

ABSTRACT The RNA genome of influenza A viruses is transcribed and replicated by the viral RNA-dependent RNA polymerase, composed of the subunits PA, PB1, and PB2. High-resolution structural data revealed that the polymerase assembles into a central polymerase core and several auxiliary highly flexible, protruding domains. The auxiliary PB2 cap-binding and the PA endonuclease domains are both involved in cap snatching, but the role of the auxiliary PB2 627 domain, implicated in host range restriction of influenza A viruses, is still poorly understood. In this study, we used structure-guided truncations of the PB2 subunit to show that a PB2 subunit lacking the 627 domain accumulates in the cell nucleus and assembles into a heterotrimeric polymerase with PB1 and PA. Furthermore, we showed that a recombinant viral polymerase lacking the PB2 627 domain is able to carry out cap snatching, cap-dependent transcription initiation, and cap-independent ApG dinucleotide extension in vitro, indicating that the PB2 627 domain of the influenza virus RNA polymerase is not involved in core catalytic functions of the polymerase. However, in a cellular context, the 627 domain is essential for both transcription and replication. In particular, we showed that the PB2 627 domain is essential for the accumulation of the cRNA replicative intermediate in infected cells. Together, these results further our understanding of the role of the PB2 627 domain in transcription and replication of the influenza virus RNA genome. IMPORTANCE Influenza A viruses are a major global health threat, not only causing disease in both humans and birds but also placing significant strains on economies worldwide. Avian influenza A virus polymerases typically do not function efficiently in mammalian hosts and require adaptive mutations to restore polymerase activity. These adaptations include mutations in the 627 domain of the PB2 subunit of the viral polymerase, but it still remains to be established how these mutations enable host adaptation on a molecular level. In this report, we characterize the role of the 627 domain in polymerase function and offer insights into the replication mechanism of influenza A viruses.

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