Meta-Analysis of Seroprevalence and Prevalence of Influenza A Viruses (Subtypes H3N2, H3N8, and H1N1) in Dogs.

Influenza A is a zoonotic disease that affects dogs, pigs, horses, poultry, and birds. In this report, a meta-analysis according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) was conducted. Studies of influenza A viruses in dogs providing prevalence or seroprevalence in any location worldwide were included.

Lovastatin enhances humoral and cellular immune responses to H1N1 influenza vaccine.

The Swine Influenza Virus (SIV) is a major respiratory pathogen in swine, causing acute, febrile, and highly transmissible infections. This virus is widespread globally and poses significant risks to human health and social development. Traditional prevention strategies for SIV rely on the use of inactivated vaccines combined with Alum adjuvants.

Porcine Airway Organoid-Derived Well-Differentiated Epithelial Cultures as a Tool for the Characterization of Swine Influenza a Virus Strains.

Swine influenza A viruses (IAVsw) are important causes of disease in pigs but also constitute a public health risk. IAVsw strains show remarkable differences in pathogenicity. We aimed to generate airway organoids from the porcine lower respiratory tract and use these to establish well-differentiated airway epithelial cell (WD-AEC) cultures grown at an air-liquid interface (ALI) for in vitro screening of IAVsw strain virulence.

H1N1 swine influenza viruses upregulate NEU1 expression through histone H3 acetylation regulated by HDAC2.

Mammalian membrane sialic acid is the key receptor for influenza virus. Sialidases, the main type of enzyme that can hydrolyze membrane sialic acids in mammalian cells, have the potential to affect the invasion process of influenza viruses, including H1N1. For the first time, this study focused on the regulation mechanism of sialidase NEU1 expression, and revealed that swine-origin influenza (H1N1) virus infection can promote NEU1 expression through histone H3 acetylation, which is regulated by HDAC2 in host cells.

Reverse zoonotic transmission of human seasonal influenza to a pig herd in Sweden.

In January 2023, a Swedish piglet-producing farm with 2800 sows in production (SIP) was diagnosed with IAV (Influenza A virus) and the isolates were shown to cluster with the human seasonal influenza (2022/2023). In December 2022, employees with flu like symptoms tended to the pigs and a few weeks later, respiratory signs appeared in different age groups; sows in farrowing units were anorectic and pyrectic. Lung and nasal swabs were tested positive for IAV and other respiratory infectious agents.

Potent Anti-Influenza Synergistic Activity of Theobromine and Arainosine.

Influenza represents one of the biggest health threats facing humanity. Seasonal epidemics can transition to global pandemics, with cross-species infection presenting a continuous challenge. Although vaccines and several anti-viral options are available, constant genetic drifts and shifts vitiate any of the aforementioned prevention and treatment options.

A Single-Component Multilayered Self-Assembling Protein Nanoparticle Vaccine Based on Extracellular Domains of Matrix Protein 2 against Both Influenza A and B.

The development of an effective and broadly protective influenza vaccine against circulating and emerging strains remains elusive. In this study, we evaluated a potentially universal influenza vaccine based on single-component self-assembling protein nanoparticles (1c-SApNPs) presenting the conserved matrix protein 2 ectodomain (M2e) from influenza A and B viruses (IAV and IBV, respectively). We previously designed a tandem antigen comprising three IAV M2e domains of human, avian/swine, and human/swine origins (termed M2ex3).

Mechanistic Models of Influenza Transmission in Commercial Swine Populations: A Systematic Review.

Influenza in commercial swine populations leads to reduced gain in fattening pigs and reproductive issues in sows. This literature review aims to analyze the contributions of mathematical modeling in understanding influenza transmission and control among domestic swine. Twenty-two full-text research articles from seven databases were reviewed, categorized into swine-only ( = 13), swine-avian ( = 3), and swine-human models ( = 6).

Impact of the Swine flu pandemic on General Practitioner (GP) visits in Finland: sex and age differences.

Background: Swine flu might serve as a model for challenges that primary care faces during pandemics. This study examined changes in the numbers and diagnoses of general practitioner (GP) visits during and after the Swine flu pandemic in Vantaa, a Finnish city, and how GP activities recovered after the pandemic. Putative sex and age group differences were also evaluated.

A Self-Fulfilling Prophecy Pandemic: The 1977 "Russian Flu".

Surprisingly, the 1977 "Russian flu" H1N1 pandemic influenza virus was genetically indistinguishable from strains that had circulated decades earlier but had gone extinct in 1957. This essay puts forward the most plausible chronology to explain the reemergence of the 1977 H1N1 pandemic virus: (1) in January-February 1976, a self-limited small outbreak of a swine H1N1 influenza virus occurred among Army personnel at Fort Dix, New Jersey; (2) in March 1976, the US launched a nationwide H1N1 swine influenza vaccine program; (3) other countries then also launched their own H1N1 R&D efforts; (4) a new H1N1 outbreak, genetically unrelated to the Fort Dix swine virus but indistinguishable from previously extinct H1N1 viruses, was detected early in 1977 in China; (5) the leading Chinese influenza virologist later disclosed that the Chinese military had conducted large H1N1 vaccine R&D studies in 1976. It is likely that the resurrected H1N1 influenza viruses were laboratory-stored strains that were unfrozen and studied as part of the emergency response to a perceived epidemic threat, and that accidentally escaped.

Multi-omics analysis reveals the impact of influenza a virus host adaptation on immune signatures in pig tracheal tissue.

Introduction: Influenza A virus (IAV) infection is a global respiratory disease, which annually leads to 3-5 million cases of severe illness, resulting in 290,000-650,000 deaths. Additionally, during the past century, four global IAV pandemics have claimed millions of human lives. The epithelial lining of the trachea plays a vital role during IAV infection, both as point of viral entry and replication as well as in the antiviral immune response.

The C-terminal amino acid motifs of NS1 protein affect the replication and virulence of naturally NS-truncated H1N1 canine influenza virus.

The vast majority of data obtained from sequence analysis of influenza A viruses (IAVs) have revealed that nonstructural 1 (NS1) proteins from H1N1 swine, H3N8 equine, H3N2 avian and the correspondent subtypes from dogs have a conserved four C-terminal amino acid motif when independent cross-species transmission occurs between these species. To test the influence of the C-terminal amino acid motifs of NS1 protein on the replication and virulence of IAVs, we systematically generated 7 recombinants, which carried naturally truncated NS1 proteins, and their last four C-terminal residues were replaced with PEQK and SEQK (for H1N1), EPEV and KPEI (for H3N8) and ESEV and ESEI (for H3N2) IAVs. Another recombinant was generated by removing the C-terminal residues by reverse genetics.

Two amino acid residues in the N-terminal region of the polymerase acidic protein determine the virulence of Eurasian avian-like H1N1 swine influenza viruses in mice.

Reassortant Eurasian avian-like H1N1 (rEA H1N1) viruses carrying the internal genes of H1N1/2009 virus have been circulating in pigs for more than 10 years and have caused sporadic human infections. The enhanced virulence phenotype of the rEA H1N1 viruses highlights potential risks to public health. However, the molecular mechanism underlying the viral pathogenicity of the currently circulating rEA H1N1 viruses remains unclear.

Evaluation of a novel intramuscular prime/intranasal boost vaccination strategy against influenza in the pig model.

Live-attenuated influenza vaccines (LAIV) offer advantages over the commonly used inactivated split influenza vaccines. However, finding the optimal balance between sufficient attenuation and immunogenicity has remained a challenge. We recently developed an alternative LAIV based on the 2009 pandemic H1N1 virus with a truncated NS1 protein and lacking PA-X protein expression (NS1(1-126)-ΔPAX).

Lipid nanoparticle-encapsulated DNA vaccine confers protection against swine and human-origin H1N1 influenza viruses.

Unlabelled: In 2009, a novel swine-origin H1N1 virus emerged, causing a pandemic. The virus, known as H1N1pdm09, quickly displaced the circulating H1 lineage and became the dominant seasonal influenza A virus subtype infecting humans. Human-to-swine spillovers of the H1N1pdm09 have occurred frequently, and each occurrence has led to sustained transmission of the human-origin H1N1pdm09 within swine populations.

Design, infectability, and transcriptomic analysis of transregionally differentiated and scalable lung organoids derived from adult bronchial cells.

The lung is a primary target for many lethal respiratory viruses, leading to significant global mortality. Current organoid models fail to completely mimic the cellular diversity and intricate tubular and branching structures of the human lung. Lung organoids derived from adult primary cells have so far only included cells from the input cell region, proximal or distal.

Single-cell analysis reveals lasting immunological consequences of influenza infection and respiratory immunization in the pig lung.

The pig is a natural host for influenza viruses and integrally involved in virus evolution through interspecies transmissions between humans and swine. Swine have many physiological, anatomical, and immunological similarities to humans, and are an excellent model for human influenza. Here, we employed single cell RNA-sequencing (scRNA-seq) and flow cytometry to characterize the major leukocyte subsets in bronchoalveolar lavage (BAL), twenty-one days after H1N1pdm09 infection or respiratory immunization with an adenoviral vector vaccine expressing hemagglutinin and nucleoprotein with or without IL-1β.

The evolution, complexity, and diversity of swine influenza viruses in China: A hidden public health threat.

Swine influenza viruses (SIVs), including H1N1, H1N2, and H3N2, have spread throughout the global pig population. Potential pandemics are a concern with the recent sporadic cross-species transmission of SIVs to humans. We collected 1421 samples from Guangdong, Fujian, Henan, Yunnan and Jiangxi provinces during 2017-2018 and isolated 29 viruses.