The influenza A viral heterotrimeric polymerase complex (PA, PB1, PB2) is known to be involved in many aspects of viral replication and to interact with host factors, thereby having a role in host specificity. The polymerase protein sequences from the 1918 human influenza virus differ from avian consensus sequences at only a small number of amino acids, consistent with the hypothesis that they were derived from an avian source shortly before the pandemic. However, when compared to avian sequences, the nucleotide sequences of the 1918 polymerase genes have more synonymous differences than expected, suggesting evolutionary distance from known avian strains. Here we present sequence and phylogenetic analyses of the complete genome of the 1918 influenza virus, and propose that the 1918 virus was not a reassortant virus (like those of the 1957 and 1968 pandemics), but more likely an entirely avian-like virus that adapted to humans. These data support prior phylogenetic studies suggesting that the 1918 virus was derived from an avian source. A total of ten amino acid changes in the polymerase proteins consistently differentiate the 1918 and subsequent human influenza virus sequences from avian virus sequences. Notably, a number of the same changes have been found in recently circulating, highly pathogenic H5N1 viruses that have caused illness and death in humans and are feared to be the precursors of a new influenza pandemic. The sequence changes identified here may be important in the adaptation of influenza viruses to humans.
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http://dx.doi.org/10.1038/nature04230 | DOI Listing |
PLoS One
January 2025
Special Infectious Agents Unit-BSL3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
The ongoing increase in the prevalence and mutation rate of the influenza virus remains a critical global health issue. A promising strategy for antiviral drug development involves targeting the RNA-dependent RNA polymerase, specifically the PB2-cap binding domain of Influenza A H5N1. This study employs an in-silico approach to inhibit this domain, crucial for viral replication, using potential inhibitors derived from marine bacterial compounds.
View Article and Find Full Text PDFExpert Rev Vaccines
January 2025
Hospital Universitario La Paz-IdiPAZ, Madrid, Spain.
Introduction: Vaccines to prevent important infections involving, e.g. influenza viruses, severe acute respiratory syndrome-causing coronaviruses (e.
View Article and Find Full Text PDFOpen Respir Med J
December 2024
Pulmonology Department, Prime Medical Hospital, Dubai, United Arab Emirates.
Traditional testing methods in the Middle East Region, including the United Arab Emirates (UAE), particularly the testing of Respiratory Syncytial Virus (RSV), influenza, group A streptococcus (GAS), and COVID-19 have the potential to be upgraded to new and advanced diagnostics methods that improve lead time to diagnosis, consumption of healthcare resources and patient experience. In addition, based on the research, it was reported that there is an underreporting of respiratory cases, overuse of antibiotics, and prolonged hospitalizations which is posing pressure on UAE healthcare stakeholders. A literature review was done exploring UAE's current diagnostic practices, recommended guidelines, diagnostic gaps, and challenges in RSV, GAS, Influenza, and COVID-19.
View Article and Find Full Text PDFMicrobiome
January 2025
Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
Background: Numerous studies have confirmed a close relationship between the pathogenicity of influenza and respiratory microbiota, but the mechanistic basis for this is poorly defined. Also, the majority of these studies have been conducted on murine models, and it remains unclear how far these findings can be extrapolated from murine models to other animals. Considering that influenza A virus is increasingly recognized as an important canine respiratory pathogen, this study investigated the cross-talk between nasal and lung tissues mediated by microbes and its association with influenza susceptibility in a beagle dog model.
View Article and Find Full Text PDFClin Microbiol Infect
January 2025
National Center for Respiratory Medicine; State Key Laboratory of Respiratory Health and Multimorbidity; New Cornerstone Science Laboratory; National Clinical Research Center for Respiratory Diseases; Department of Respiratory Medicine, Capital Medical University, Institute of Respiratory Medicine of Capital Medical University; Chinese Academy of Medical Sciences; Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China. Electronic address:
Objectives: To evaluate the therapeutic effect of suraxavir marboxil (GP681, abbreviated as suraxavir) in adults with uncomplicated influenza.
Methods: We conducted a multi-center randomized, double-blind, placebo-controlled phase 2 trial in 18 Chinese centers. Participants had to be aged 18-65 years with positive influenza test, presenting with at least one influenza systemic and respiratory symptoms in at least moderate severity within 48 hours of onset.
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