scholarly journals Identification, Genetic Analysis, and Pathogenicity of Classical Swine H1N1 and Human-Swine Reassortant H1N1 Influenza Viruses from Pigs in China

Viruses ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 55 ◽  
Author(s):  
Yafen Song ◽  
Yong Zhang ◽  
Bing Zhang ◽  
Ling Chen ◽  
Min Zhang ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Swine Industry ◽  
Ha Gene ◽  
Lethal Infection ◽  
Duration Of Infection ◽  
Imminent Threat

Swine influenza virus causes a substantial disease burden to swine populations worldwide and poses an imminent threat to the swine industry and humans. Given its importance, we characterized two swine influenza viruses isolated from Shandong, China. The homology and phylogenetic analyses showed that all eight gene segments of A/swine/Shandong/AV1522/2011(H1N1) were closely related to A/Maryland/12/1991(H1N1) circulating in North America. The HA, NA, M, and NS genes of the isolate were also confirmed to have a high homology to A/swine/Hubei/02/2008(H1N1) which appeared in China in 2008, and the virus was clustered into the classical swine lineage. The gene segments of A/swine/Shandong/AV1523/2011(H1N1) were highly homologous to the early human H1N1 and H2N2 influenza viruses, except for the HA gene, and the virus was a reassortant H1N1 virus containing genes from the classical swine (HA) and human (NA, PB2, PB1, PA, NP, M, and NS) lineages. Both the viruses could cause lethal infection and replicate efficiently in the lungs, brains, spleens, and kidneys of mice. Histopathological examinations showed that AV1522 and AV1523 viruses caused a spectrum of marked pneumonia and meningoencephalitis according to the duration of infection, demonstrating a progression of respiratory disease and neurological disease over the course of infection that ultimately resulted in lethality for the infected mice. The changes in the pathogenicity of swine influenza viruses to mammals, accompanied with the continuous reassortment and evolution of the viruses, highlights the importance of ongoing epidemiological investigation.

scholarly journals Cocirculation of Swine H1N1 Influenza A Virus Lineages in Germany

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 762 ◽  
Author(s):  
Roland Zell ◽  
Marco Groth ◽  
Andi Krumbholz ◽  
Jeannette Lange ◽  
Anja Philipps ◽  
...  
Keyword(s):  
Influenza A ◽  
Antigenic Variation ◽  
Phylogenetic Analyses ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Antigenic Drift ◽  
Influenza Surveillance ◽  
Northwest Germany

The genome analysis of 328 H1N1 swine influenza virus isolates collected in a 13-year long-term swine influenza surveillance in Germany is reported. Viral genomes were sequenced with the Illumina next-generation sequencing technique and conventional Sanger methods. Phylogenetic analyses were conducted with Bayesian tree inference. The results indicate continued prevalence of Eurasian avian swine H1N1 but also emergence of a novel H1N1 reassortant, named Schneiderkrug/2013-like swine H1N1, with human-like hemagglutinin and avian-like neuraminidase and internal genes. Additionally, the evolution of an antigenic drift variant of A (H1N1) pdm09 was observed, named Wachtum/2014-like swine H1N1. Both variants were first isolated in northwest Germany, spread to neighboring German states and reached greater proportions of the H1N1 isolates of 2014 and 2015. The upsurge of Wachtum/2014-like swine H1N1 is of interest as this is the first documented persistent swine-to-swine spread of A (H1N1) pdm09 in Germany associated with antigenic variation. Present enzootic swine influenza viruses in Germany now include two or more co-circulating, antigenically variant viruses of each of the subtypes, H1N1 and H1N2.

scholarly journals Isolation and Genetic Characterization of New Reassortant H3N1 Swine Influenza Virus from Pigs in the Midwestern United States

2006 ◽  
Vol 80 (10) ◽  
pp. 5092-5096 ◽  
Author(s):  
Wenjun Ma ◽  
Marie Gramer ◽  
Kurt Rossow ◽  
Kyoung-Jin Yoon
Keyword(s):  
United States ◽  
Influenza Virus ◽  
Genetic Characterization ◽  
Phylogenetic Analyses ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Virus Origin ◽  
Reassortant Viruses

ABSTRACT Since the introduction of H3N2 swine influenza viruses (SIVs) into U.S. swine in 1998, H1N2 and H1N1 reassortant viruses have emerged from reassortment between classical H1N1 and H3N2 viruses. In 2004, a new reassortant H3N1 virus (A/Swine/Minnesota/00395/2004) was identified from coughing pigs. Phylogenetic analyses revealed a hemagglutinin segment similar to those of contemporary cluster III H3N2 SIVs and a neuraminidase sequence of contemporary H1N1 origin. The internal genes were of swine, human, and avian influenza virus origin, similar to those of contemporary U.S. cluster III H3N2 SIVs. The recovery of H3N1 is further evidence of reassortment among SIVs and justifies continuous surveillance.

scholarly journals Identification and Characterization of Swine Influenza Virus H1N1 Variants Generated in Vaccinated and Nonvaccinated, Challenged Pigs

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2087
Author(s):  
Álvaro López-Valiñas ◽  
Marta Sisteré-Oró ◽  
Sergi López-Serrano ◽  
Laura Baioni ◽  
Ayub Darji ◽  
...  
Keyword(s):  
Influenza A ◽  
Influenza Pandemic ◽  
Viral Evolution ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Viral Fitness ◽  
Ns1 Protein ◽  
Trivalent Vaccine

Influenza viruses represent a continuous threat to both animal and human health. The 2009 H1N1 A influenza pandemic highlighted the importance of a swine host in the adaptation of influenza viruses to humans. Nowadays, one of the most extended strategies used to control swine influenza viruses (SIVs) is the trivalent vaccine application, whose formulation contains the most frequently circulating SIV subtypes H1N1, H1N2, and H3N2. These vaccines do not provide full protection against the virus, allowing its replication, evolution, and adaptation. To better understand the main mechanisms that shape viral evolution, here, the SIV intra-host diversity was analyzed in samples collected from both vaccinated and nonvaccinated animals challenged with the H1N1 influenza A virus. Twenty-eight whole SIV genomes were obtained by next-generation sequencing, and differences in nucleotide variants between groups were established. Substitutions were allocated along all influenza genetic segments, while the most relevant nonsynonymous substitutions were allocated in the NS1 protein on samples collected from vaccinated animals, suggesting that SIV is continuously evolving despite vaccine application. Moreover, new viral variants were found in both vaccinated and nonvaccinated pigs, showing relevant substitutions in the HA, NA, and NP proteins, which may increase viral fitness under field conditions.

scholarly journals Origin of the European avian-like swine influenza viruses

2014 ◽  
Vol 95 (11) ◽  
pp. 2372-2376 ◽  
Author(s):  
Andi Krumbholz ◽  
Jeannette Lange ◽  
Andreas Sauerbrei ◽  
Marco Groth ◽  
Matthias Platzer ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Phylogenetic Trees ◽  
Sequence Data ◽  
Swine Influenza ◽  
H1n1 Influenza ◽  
Molecular Data ◽  
Influenza Viruses ◽  
Time Resolved ◽  
Genotype Constellation ◽  
Tree Inference

The avian-like swine influenza viruses emerged in 1979 in Belgium and Germany. Thereafter, they spread through many European swine-producing countries, replaced the circulating classical swine H1N1 influenza viruses, and became endemic. Serological and subsequent molecular data indicated an avian source, but details remained obscure due to a lack of relevant avian influenza virus sequence data. Here, the origin of the European avian-like swine influenza viruses was analysed using a collection of 16 European swine H1N1 influenza viruses sampled in 1979–1981 in Germany, the Netherlands, Belgium, Italy and France, as well as several contemporaneous avian influenza viruses of various serotypes. The phylogenetic trees suggested a triple reassortant with a unique genotype constellation. Time-resolved maximum clade credibility trees indicated times to the most recent common ancestors of 34–46 years (before 2008) depending on the RNA segment and the method of tree inference.

Swine influenza vaccines: current status and future perspectives

2010 ◽  
Vol 11 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Wenjun Ma ◽  
Jürgen A. Richt
Keyword(s):  
Influenza A ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Current Status ◽  
Economic Losses ◽  
Influenza A Viruses ◽  
Swine Industry ◽  
Effective Strategies ◽  
Swine Disease ◽  
And Control

AbstractSwine influenza is an important contagious disease in pigs caused by influenza A viruses. Although only three subtypes of influenza A viruses, H1N1, H1N2 and H3N2, predominantly infect pigs worldwide, it is still a big challenge for vaccine manufacturers to produce efficacious vaccines for the prevention and control of swine influenza. Swine influenza viruses not only cause significant economic losses for the swine industry, but are also important zoonotic pathogens. Vaccination is still one of the most important and effective strategies to prevent and control influenza for both the animal and human population. In this review, we will discuss the current status of swine influenza worldwide as well as current and future options to control this economically important swine disease.

scholarly journals Bat influenza vectored NS1-truncated live vaccine protects pigs against heterologous virus challenge

2020 ◽  
Author(s):  
Jinhwa Lee ◽  
Yonghai Li ◽  
Yuhao Li ◽  
A. Giselle Cino-Ozuna ◽  
Michael Duff ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Live Vaccine ◽  
H3n2 Virus ◽  
Swine Industry ◽  
Vaccine Candidates ◽  
Virus Challenge ◽  
Significant Difference

AbstractSwine influenza is an important disease for the swine industry. Currently used whole inactivated virus (WIV) vaccines can induce vaccine-associated enhanced respiratory disease (VAERD) in pigs when the vaccine strains mismatch with the infected viruses. Live attenuated influenza virus vaccine (LAIV) is effective to protect pigs against homologous and heterologous swine influenza virus infections without inducing VAERD, but has safety concerns due to potential reassortment with circulating viruses. Herein, we used a chimeric bat influenza Bat09:mH3mN2 virus, which contains both surface HA and NA gene open reading frames of the A/swine/Texas/4199-2/1998 (H3N2) and six internal genes from the novel bat H17N10 virus, to develop modified live-attenuated viruses (MLVs) as vaccine candidates which cannot reassort with canonical influenza A viruses by co-infection. Two attenuated MLV vaccine candidates including the virus that expresses a truncated NS1 (Bat09:mH3mN2-NS1-128, MLV1) or expresses both a truncated NS1 and the swine IL-18 (Bat09:mH3mN2-NS1-128-IL-18, MLV2) were generated and evaluated in pigs against a heterologous H3N2 virus using the WIV vaccineb as a control. Compared to the WIV vaccine, both MLV vaccines were able to reduce lesions and virus replication in lungs and limit nasal virus shedding without VAERD, also induced significantly higher levels of mucosal IgA response in lungs and significantly increased numbers of antigen-specific IFN-γ secreting cells against the challenge virus. However, no significant difference was observed in efficacy between the MLV1 and MLV2. These results indicate that bat influenza vectored MLV vaccines can be used as a safe live vaccine to prevent swine influenza.

scholarly journals Swine-Origin H1 Influenza Viruses Isolated from Humans Exhibit Sustained Infectivity in an Aerosol State

2019 ◽  
Vol 85 (10) ◽  
Author(s):  
Joanna A. Pulit-Penaloza ◽  
Jessica A. Belser ◽  
Terrence M. Tumpey ◽  
Taronna R. Maines
Keyword(s):  
Influenza Virus ◽  
Swine Influenza Virus ◽  
Virus Transmission ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Aerosol State ◽  
The Stability ◽  
Higher Doses ◽  
Enhanced Stability

ABSTRACT The relative importance of influenza virus transmission via aerosols is not fully understood, but experimental data suggest that aerosol transmission may represent a critical mode of influenza virus spread among humans. Decades ago, prototypical laboratory strains of influenza were shown to persist in aerosols; however, there is a paucity of data available covering currently circulating influenza viruses, which differ significantly from their predecessors. In this study, we evaluated the longevity of influenza viruses in aerosols generated in the laboratory. We selected a panel of H1 viruses that exhibit diverse transmission profiles in the ferret model, including four human isolates of swine origin (referred to as variant) and a seasonal strain. By measuring the ratio of viral RNA to infectious virus maintained in aerosols over time, we show that influenza viruses known to transmit efficiently through the air display enhanced stability in an aerosol state for prolonged periods compared to those viruses that do not transmit as efficiently. We then assessed whether H1 influenza virus was still capable of infecting and causing disease in ferrets after being aged in suspended aerosols. Ferrets exposed to very low levels of influenza virus (≤17 PFU) in aerosols aged for 15 or 30 min became infected, with five of six ferrets shedding virus in nasal washes at titers on par with ferrets who inhaled higher doses of unaged influenza virus. We describe here an underreported characteristic of influenza viruses, stability in aerosols, and make a direct connection to the role this characteristic plays in influenza transmission. IMPORTANCE Each time a swine influenza virus transmits to a human, it provides an opportunity for the virus to acquire adaptations needed for sustained human-to-human transmission. Here, we use aerobiology techniques to test the stability of swine-origin H1 subtype viruses in aerosols and evaluate their infectivity in ferrets. Our results show that highly transmissible influenza viruses display enhanced stability in an aerosol state compared to viruses that do not transmit as efficiently. Similar to human-adapted strains, swine-origin influenza viruses are infectious in ferrets at low doses even after prolonged suspension in the air. These data underscore the risk of airborne swine-origin influenza viruses and support the need for continued surveillance and refinement of innovative laboratory methods to investigate mammalian exposure to inhaled pathogens. Determination of the molecular markers that affect the longevity of airborne influenza viruses will improve our ability to quickly identify emerging strains that present the greatest threat to public health.

scholarly journals Spatiotemporal Distribution and Evolution of the A/H1N1 2009 Pandemic Influenza Virus in Pigs in France from 2009 to 2017: Identification of a Potential Swine-Specific Lineage

2018 ◽  
Vol 92 (24) ◽  
Author(s):  
Amélie Chastagner ◽  
Séverine Hervé ◽  
Emilie Bonin ◽  
Stéphane Quéguiner ◽  
Edouard Hirchaud ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Phylogenetic Analyses ◽  
Swine Influenza ◽  
H1n1 Influenza ◽  
Antigenic Drift ◽  
Influenza A Viruses ◽  
Evolutionary Patterns ◽  
Increased Risk ◽  
Na Sequences

ABSTRACT The H1N1 influenza virus responsible for the most recent pandemic in 2009 (H1N1pdm) has spread to swine populations worldwide while it replaced the previous seasonal H1N1 virus in humans. In France, surveillance of swine influenza A viruses in pig herds with respiratory outbreaks led to the detection of 44 H1N1pdm strains between 2009 and 2017, regardless of the season, and findings were not correlated with pig density. From these isolates, 17 whole-genome sequences were obtained, as were 6 additional hemagglutinin (HA)/neuraminidase (NA) sequences, in order to perform spatial and temporal analyses of genetic diversity and to compare evolutionary patterns of H1N1pdm in pigs to patterns for human strains. Following mutation accumulation and fixation over time, phylogenetic analyses revealed for the first time the divergence of a swine-specific genogroup within the H1N1pdm lineage. The divergence is thought to have occurred around 2011, although this was demonstrated only through strains isolated in 2015 to 2016 in the southern half of France. To date, these H1N1pdm swine strains have not been related to any increased virulence in swine herds and have not exhibited any antigenic drift compared to seasonal human strains. However, further monitoring is encouraged, as diverging evolutionary patterns in these two species, i.e., swine and humans, may lead to the emergence of viruses with a potentially higher risk to both animal and human health.IMPORTANCE Pigs are a “mixing vessel” for influenza A viruses (IAVs) because of their ability to be infected by avian and human IAVs and their propensity to facilitate viral genomic reassortment events. Also, as IAVs may evolve differently in swine and humans, pigs can become a reservoir for old human strains against which the human population has become immunologically naive. Thus, viruses from the novel swine-specific H1N1pdm genogroup may continue to diverge from seasonal H1N1pdm strains and/or from other H1N1pdm viruses infecting pigs and lead to the emergence of viruses that would not be covered by human vaccines and/or swine vaccines based on antigens closely related to the original H1N1pdm virus. This discovery confirms the importance of encouraging swine IAV monitoring because H1N1pdm swine viruses could carry an increased risk to both human and swine health in the future as a whole H1N1pdm virus or gene provider in subsequent reassortant viruses.

scholarly journals Mutations in the NS1 Protein of Swine Influenza Virus Impair Anti-Interferon Activity and Confer Attenuation in Pigs

2005 ◽  
Vol 79 (12) ◽  
pp. 7535-7543 ◽  
Author(s):  
Alicia Solórzano ◽  
Richard J. Webby ◽  
Kelly M. Lager ◽  
Bruce H. Janke ◽  
Adolfo García-Sastre ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Nonstructural Protein ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Model Systems ◽  
Ns1 Protein ◽  
Wild Type ◽  
Virulence Attenuation

ABSTRACT It has been shown previously that the nonstructural protein NS1 of influenza virus is an alpha/beta interferon (IFN-α/β) antagonist, both in vitro and in experimental animal model systems. However, evidence of this function in a natural host has not yet been obtained. Here we investigated the role of the NS1 protein in the virulence of a swine influenza virus (SIV) isolate in pigs by using reverse genetics. The virulent wild-type A/Swine/Texas/4199-2/98 (TX/98) virus and various mutants encoding carboxy-truncated NS1 proteins were rescued. Growth properties of TX/98 viruses with mutated NS1, induction of IFN in tissue culture, and virulence-attenuation in pigs were analyzed and compared to those of the recombinant wild-type TX/98 virus. Our results indicate that deletions in the NS1 protein decrease the ability of the TX/98 virus to prevent IFN-α/β synthesis in pig cells. Moreover, all NS1 mutant viruses were attenuated in pigs, and this correlated with the amount of IFN-α/β induced in vitro. These data suggest that the NS1 protein of SIV is a virulence factor. Due to their attenuation, NS1-mutated swine influenza viruses might have a great potential as live attenuated vaccine candidates against SIV infections of pigs.

Identification of a Small Benzamide Inhibitor of Influenza Virus Using a Cell-Based Screening

Chemotherapy ◽  
2016 ◽  
Vol 61 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Woo-Jin Shin ◽  
Ky-Youb Nam ◽  
Nam-Doo Kim ◽  
Sei-Hwan Kim ◽  
Kyoung-Tai No ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Global Pandemic ◽  
Lethal Infection ◽  
Avian Influenza A Virus ◽  
A Cell ◽  
Antiviral Activities

Background: The zoonotic transmission of highly pathogenic avian influenza viruses and the global pandemic of H1N1 influenza in 2009 signified the need for a wider coverage of therapeutic options for the control of influenza. Methods: An in-house compound library was screened using a cytopathic effect inhibition assay. Selected hits were then tested in vivo and used as a core skeleton for derivative synthesis. Results: The hit compound (BMD-2601505) was effective [50% effective concentration (EC50) of 60-70 μM] in reducing the death rate of cells infected with human influenza A and B viruses as well as avian influenza A virus. Furthermore, BMD-2601505 reduced the weight loss and increased the survival after lethal infection. The compound was further modified to enhance its antiviral potency. Results show that one derivative with bromobenzene moiety was most effective (EC50 of 22-37 μM) against the influenza viruses tested. Conclusion: We identified a small benzamide compound exhibiting antiviral activity against influenza viruses. The results warrant further evaluation of antiviral activities against drug-resistant influenza isolates.

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