influenza virus
Pathogenesis and ImmunityAn R195K Mutation in the PA-X Protein Increases the Virulence and Transmission of Influenza A Virus in Mammalian HostsFour influenza pandemics in humans (the Spanish flu of 1918 [H1N1], the Asian flu of 1957 [H2N2], the Hong Kong flu of 1968 [H3N2], and the swine origin flu of 2009 [H1N1]) are all proposed to have been caused by avian or swine influenza viruses that acquired virulence factors through adaptive mutation or reassortment with circulating human viruses. Currently, influenza viruses circulating in animals are repeatedly transmitted to humans...
Pathogenesis and ImmunityOutbreak Severity of Highly Pathogenic Avian Influenza A(H5N8) Viruses Is Inversely Correlated to Polymerase Complex Activity and Interferon InductionCompared to the 2014-15 outbreak, the 2016-17 outbreak of influenza A(H5N8) viruses in the Netherlands and Europe was more virulent; the number of dead or diseased wild birds found and the severity of pathological changes were higher during the 2016-17 outbreak. The polymerase complex plays an important role in influenza virus virulence, and the gene segments of influenza A(H5N8) viruses reassorted extensively between the outbreaks. In...
Cellular Response to InfectionSuppression of Cytotoxic T Cell Functions and Decreased Levels of Tissue-Resident Memory T Cells during H5N1 InfectionInfluenza viruses cause upper respiratory tract infections in humans. In healthy adults, seasonal influenza virus infections result in mild disease. Occasionally, influenza viruses endemic in domestic birds can cause severe and fatal disease even in healthy individuals. In avian influenza virus-infected patients, the host immune system is activated in an uncontrolled manner and is unable to control infection in a timely fashion. In this...
Pathogenesis and ImmunityA Single Amino Acid at Position 431 of the PB2 Protein Determines the Virulence of H1N1 Swine Influenza Viruses in MiceThe frequent reassortment among different influenza viruses in pigs adds complexity to the epidemiology of swine influenza. The diverse viral virulence phenotypes underline the need to investigate the possible genetic determinants for evaluating the pandemic potential to human public health. Here, we found that multiple genotypes of influenza viruses cocirculate in the swine population in Liaoning Province, China. Furthermore, we...
Vaccines and Antiviral Agents | SpotlightIdentification and Characterization of Novel Compounds with Broad-Spectrum Antiviral Activity against Influenza A and B VirusesInfluenza viruses are highly contagious pathogens and are a major threat to human health. Vaccination remains the most effective tool to protect humans against influenza infection. However, vaccination does not always guarantee complete protection against drifted or, more noticeably, shifted influenza viruses. Although U.S. Food and Drug Administration (FDA) drugs are approved for the treatment of influenza infections, influenza viruses...
Vaccines and Antiviral AgentsRepurposing Papaverine as an Antiviral Agent against Influenza Viruses and ParamyxovirusesInfluenza viruses are important human pathogens that are the causative agents of epidemics and pandemics. Despite the availability of an annual vaccine, a large number of cases occur every year globally. Here, we report that papaverine, a vasodilator, shows inhibitory action against various strains of influenza virus as well as the paramyxoviruses PIV5, HPIV3, and RSV. A significant effect of papaverine on the influenza virus morphology...
Genetic Diversity and Evolution | SpotlightInfluenza B Viruses Exhibit Lower Within-Host Diversity than Influenza A Viruses in Human HostsThe evolution of influenza virus is a significant public health problem and necessitates the annual evaluation of influenza vaccine formulation to keep pace with viral escape from herd immunity. Influenza B virus is a serious health concern for children, in particular, yet remains understudied compared to influenza A virus. Influenza B virus evolves more slowly than influenza A virus, but the factors underlying this are not completely...
GemBreaking the Convention: Sialoglycan Variants, Coreceptors, and Alternative Receptors for Influenza A Virus EntryThe influenza A virus (IAV) envelope protein hemagglutinin binds α2,6- or α2,3-linked sialic acid as a host cell receptor. Bat IAV subtypes H17N10 and H18N11 form an exception to this rule and do not bind sialic acid but enter cells via major histocompatibility complex (MHC) class II.
Vaccines and Antiviral AgentsBroadly Inhibiting Antineuraminidase Monoclonal Antibodies Induced by Trivalent Influenza Vaccine and H7N9 Infection in HumansAntibodies to the influenza virus NA can provide protection against influenza disease. Analysis of human antibodies to NA lags behind that of antibodies to HA. We show that human monoclonal antibodies against NA induced by vaccination and infection can be very broadly reactive, with the ability to inhibit a wide spectrum of N1 NAs on viruses isolated between 1918 and 2018. This suggests that antibodies to NA may be a useful therapy and...
