Search Results (1,965)

Highly pathogenic avian influenza (HPAI) viruses have recently had a substantial impact on global poultry production and public health. In Egypt, clade 2.3.4.4b HPAI H5N1 viruses were first isolated from wild birds in 2021 and then became dominant in domestic poultry. In this study, we aimed to genetically characterize the H5N1 viruses isolated in Egypt during 2021–2023 and examine the pathogenicity and transmissibility of two H5N1 strains isolated from wild and domestic poultry in chickens. We collected 7588 specimens from live bird markets including poultry, wild birds, and environmental samples. Influenza A viruses were detected in 20.94% (484/2311) of tested samples, and 17 isolates were identified as H5N1 through complete genome sequencing. Phylogenetic analysis revealed that all H5N1 viruses were closely related to Eurasian viruses and classified into three distinct genetic groups, suggesting multiple introductions likely linked to migratory birds. Experimental infections of chickens with two H5N1 isolates, A/Pintail/Egypt/RA19853OP/2021 and A/duck/Egypt/BA20361C/2022, showed efficient replication, systemic infection, and transmission by direct contact. These findings underscore the need for continued surveillance of H5N1 at the poultry-wild bird interface to identify circulating strains, evaluate their biological characteristics, and assess their zoonotic potential. Full article

The antigenic relationship between Eurasian avian-like H1N1 swine influenza viruses (EA H1N1) and human pandemic 2009 H1N1 viruses (2009/H1N1) remains a critical question for influenza surveillance and vaccine efficacy. This study systematically investigated the antigenic differences between strains A/swine/Tianjin/312/2016 (TJ312, EA H1N1) and A/Guangdong-Maonan/SWL1536/2019 (GD1536, 2009/H1N1). Cross-hemagglutination inhibition (HI) assays revealed a significant antigenic disparity, with a 16-fold reduction in heterologous versus homologous HI titers. Comparative sequence analysis identified 22 amino acid differences across the five major antigenic sites (Sa, Sb, Ca1, Ca2, and Cb) of the HA1 subunit. Using reverse genetics, a panel of mutant viruses was generated. This study revealed that a single histidine (H)-to-asparagine (N) substitution at residue 128 (H3 numbering) in the Sa antigenic site acts as a primary determinant of antigenic variation, sufficient to cause a four-fold change in HI titers and a measurable drift in antigenic distance. Structural modeling via AlphaFold3 and PyMOL software suggests that the H128N mutation may alter the local conformation of the antigenic site. It is plausible that H at position 128 could exert electrostatic repulsion with adjacent amino acids, whereas N might facilitate hydrogen bond formation with neighboring residues. These interactions would potentially lead to structural changes in the antigenic site. Our findings confirm that residue 128 is a critical molecular marker for the antigenic differentiation of EA H1N1 and 2009/H1N1 viruses. The study underscores the necessity of monitoring specific HA mutations that could reduce cross-reactivity and provides valuable insights for refining vaccine strain selection and pandemic preparedness strategies. Full article

In this work, we synthesized a small library of tricyclic compounds to assess whether they might have both anticancer and antiviral activity against three viruses that have recently caused epidemics. Concerning their anti-tumour activity, derivative 1 was found to be the compound with the highest GI₅₀ values on some cancer cell line panels. Particularly, in melanoma cell lines, its GI₅₀ values ranged between 1.54 μM (MALME-3M) and 2.03 μM (M14). Several derivatives with considerable anti-tumour activity showed antiviral activity as well, against influenza A virus (e.g., derivative 19, selectivity index of 21.36 in MDCK cells) or against Zika virus (compound 13, selectivity index of 20.20 in Huh-7 cells). Moreover, compounds 13 and 12 showed anti-SARS-CoV-2 activity, with selectivity indices of 150.00 and 63.63, respectively. Compound 1, for its anticancer activity, and 13, for its anti-SARS-CoV-2 activity, together with the compounds active against Zika virus and influenza A virus, are promising candidates for further studies. Full article

The Stockholm Paradigm, a multilevel framework for studying coevolutionary interactions, it is a promising method for obtaining a globally relevant understanding of the emergence of present and past host–parasite and insect–plant interactions. This research aimed to expand the application of the Paradigm to virus–host interactions, considering that viruses are being subjected to the same evolutionary forces as any other living organism. By applying different data science techniques, we described and discussed capacity and opportunity traits for Influenza A H1N1 strains, and how they might influence the pathogen’s host repertoire evolution, and thus ranked different strains according to their emergence risk in the human population. We hope to contribute to the application of different methods for understanding disease emergence, and consequently to the development of new public health strategies for preventing (re)emerging diseases. Full article

We investigated respiratory virus epidemiology in older adults across pre-pandemic (2007–2019), pandemic (2020–2022), and post-pandemic (2023–2024) periods, focusing on how public health interventions shaped surveillance, prevalence, and sex-specific trends. We conducted a retrospective cross-sectional study at a 1000-bed tertiary hospital in the Republic of Korea during 2007–2024, analyzing 4692 nasopharyngeal swab specimens collected from adults aged ≥ 65 years with suspected respiratory infections during 2007–2024. The specimens were tested for 15 respiratory viruses using multiplex real-time polymerase chain reaction. The outcomes included virus-specific detection rates and seasonal, sex-based and temporal trends before and after the COVID-19 pandemic. During the pre-pandemic period, older adults accounted for 13.2% of the tested individuals, which significantly increased to 52.0% in the later periods. Influenza A was the most frequently detected virus, followed by rhinovirus and human metapneumovirus. Influenza, RSV A/B, and coronaviruses 229E and OC43 showed peak positivity in winter, parainfluenza virus type 3 peaked in summer, and rhinovirus circulated year-round. Virus circulation was markedly suppressed during 2020–2022 and partially rebounded during 2023–2024. This study highlights the shift in diagnostic access and epidemiologic patterns of respiratory virus infections in older adults following the COVID-19 pandemic. Full article

This study evaluated the epidemiology and seasonal patterns of respiratory viruses in adults hospitalized with acute respiratory tract infections during two consecutive post-COVID-19 pandemic seasons. A retrospective study was conducted at the University Hospital “P. Giaccone”, Palermo, from September 2022 to September 2024. Multiplex molecular assays were used to detect the ten respiratory viruses most relevant from an epidemiological perspective in respiratory samples (n = 1110) of 1081 patients. A respiratory viral infection was identified in 29.6% of patients. The highest viral infection rate was observed in the 31–50 age group. Human rhinovirus/enterovirus (HRV/EV) was the most frequently detected (40%), followed by influenza A virus (IAV; 18.4%) and human coronaviruses (HuCoVs; 12.8%). Viral co-infections were identified in 10.9% of positive cases, with HRV/EV, adenovirus (ADV), and parainfluenza virus (PIV) being most frequently involved. Influenza and respiratory syncytial viruses (RSVs) showed a winter seasonality, while diverse circulation patterns were revealed for the other viruses. This study demonstrated a sustained circulation of respiratory viruses in adults hospitalized with severe respiratory symptoms, with HRV/EV accounting for most of them. Syndromic multiplex molecular testing, although limited to the detection of a small fraction of epidemiologically relevant known viruses, has proven to be a valuable tool, not only for diagnostic purposes but also for acquiring genotyping data and implementing epidemiological information from sentinel surveillance systems. Full article

The 14-3-3 protein family, which includes the isoforms η, γ, ε, θ, β, and ζ, is essential for controlling a number of pathways linked to DNA and RNA viruses, including HIV, influenza A virus (IAV), measles virus, HRSV, and double-stranded DNA viruses. TRIM32, an E3 ubiquitin ligase, has been reported to target IAV’s PB1 polymerase for species-specific degradation via ubiquitination. Notably, 14-3-3η binds to phosphorylated TRIM32, preventing its autoubiquitylation and forming soluble but inactive cytoplasmic aggregates that regulate TRIM32 levels. However, the functional link between 14-3-3η, TRIM32, and PB1 during viral infection remains unclear. In this study, we establish a mechanistic connection between 14-3-3η–TRIM32 and TRIM32–PB1 interactions in IAV (H1N1) infection. We demonstrate that 14-3-3η directly interacts with PB1, influencing viral replication. Using transient knockdown models, we show that 14-3-3η deficiency alters influenza virus-induced cytotoxicity, cell death, immune responses, and reactive oxygen species (ROS) production. Additionally, we observe a significant reduction in the soluble TRIM32 levels in 14-3-3η-deficient cells, which leads to increased PB1 accumulation and thus suggests a critical regulatory role for 14-3-3η in PB1 stability. Our findings reveal a novel function of 14-3-3η in influenza virus infection, demonstrating its role in PB1 regulation via TRIM32 and its impact on innate immune activation. This study highlights 14-3-3η as a possible target for antiviral treatments against influenza and offers fresh insights into the host–virus relationship. Full article

Backyard poultry systems (BPS) are the most widespread form of animal production worldwide, contributing to household economies and improving food availability. However, limited biosecurity measures and close human–animal interactions raise concerns regarding zoonotic disease transmission. In recent years, consumer-driven motivations have given rise to non-traditional BPS with differential attributes (BPS-DA), yet there is limited knowledge about their food production practices. This study aimed to characterize and compare practices across 25 BPS and 25 BPS-DA in the Metropolitan Region using surveys, interviews, and direct observations of egg collections and poultry slaughters. Eggs were the main animal product in both systems, with women primarily responsible for care. Poultry slaughter was reported exclusively in BPS (60%), generally performed under inadequate hygienic conditions and without veterinary oversight. These practices, (poultry slaughter, food production and handling), may considerably increase the risk of human exposure to zoonotic pathogens, such as avian influenza viruses. In contrast, BPS-DA prioritized birds as companion animals (60%), free-range rearing (68%), and hobby-based production (80%). While both systems showed limited biosecurity, significant differences were found in the use of dedicated footwear (p = 0.01; V = 0.35), egg collection sites (p = 0.04; V = 0.29), and refrigeration (p = 0.004; V = 0.41). Veterinary access was limited in both (32% in BPS; 44% in BPS-DA). These findings highlight critical gaps in health management and underscore the need for context-specific educational and regulatory strategies for safer backyard poultry production. Full article

The emergence of H5N1 highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4b in dairy cattle across multiple U.S. states in early 2024 marks a major shift in the virus’s host range and epidemiological profile. Traditionally limited to bird species, the ongoing detection of H5N1 in cattle, a mammalian host not previously considered vulnerable, raises urgent animal and human health concerns about zoonoses and mammalian adaptation. We assessed the feasibility of using commercially available pasteurized milk as a sentinel matrix for the molecular detection and genetic characterization of H5N1 HPAIV. Our aim was to determine whether retail milk could serve as a practical tool for virological monitoring and to evaluate the use of full-length genome segment amplification for extracting genomic sequence information from this highly processed matrix. Our results link HPAIV sequences in store-bought milk to the cattle outbreak and highlight both the potential and the limitations of retail milk as a surveillance window. Together, these findings provide evidence that influenza A virus RNA can be repeatedly detected in retail milk in patterns linked to specific supply chains, with genomic data confirming close relationships with the viruses circulating in cattle. Full article

Wastewater-based epidemiology is a robust, scalable, cost-effective, and high-performing tool to monitor and predict SARS-CoV-2 trends. We aimed to investigate whether this approach could be applied to influenza A/B viruses and respiratory syncytial virus (RSV) in Marseille, southern France. Wastewater concentrations of SARS-CoV-2, influenza A/B viruses, and RSV in Marseille were monitored by qPCR between January 2021 and October 2024. These concentrations were compared with the diagnosis numbers for the three viruses collected at public hospitals in Marseille, using cross-correlation analyses. The Granger causality test was used to determine whether wastewater concentrations can predict the number of clinical cases. SARS-CoV-2 and influenza virus concentrations in wastewater preceded the rise in the incidence of patient diagnoses by a lag of five days and nine/ten days, respectively. In contrast, for RSV, the rise in incidence of clinical cases preceded that of wastewater concentrations. We conclude that wastewater-based epidemiology is a powerful tool to monitor the level of circulation of these viruses independently of tests carried out on people. It enables earlier alerts than monitoring patients for SARS-CoV-2 and influenza symptoms. However, for RSV, it does not provide an early warning, and clinical data-based surveillance appears to be more suitable. Full article

Background/Objectives: Influenza A viruses—including highly pathogenic H5N1—remain a global threat due to rapid evolution, zoonoses, and pandemic potential. Strain-specific vaccines targeting variable antigens often yield limited, short-lived immunity. The HA receptor-binding domain (RBD), a functionally constrained and immunologically relevant region, is a promising target for broad and subtype-focused vaccines. We aimed to design multiepitope constructs targeting conserved HA-RBD and adjacent domains to elicit robust, durable, cross-protective responses. Methods: Extensive sequence analyses (>20,000 H5N1 and >190,000 influenza A sequences) were used to derive consensus sequences. Three HA-based candidates were developed: (i) EpitoCore-HA-VX, a multi-epitope construct containing CTL, HTL, and B-cell epitopes from the H5N1 HA-RBD; (ii) StructiRBD-HA-VX, incorporating a conformationally preserved RBD segment; and (iii) FusiCon-HA-VX, targeting the conserved HA fusion peptide shared across subtypes. Two external HA comparators—a 400-aa HA fragment and the literature-reported HA-13–263-Fd-His—were analyzed under the same pipeline. The workflow predicted epitopes; evaluated antigenicity, allergenicity, toxicity, conservation, and HLA coverage; generated AlphaFold models; performed TLR2/TLR4 docking with pyDockWEB; and carried out interface analysis with PDBsum; and C-ImmSim simulations. Results: Models suggested stable, energetically favorable TLR2/TLR4 interfaces supported by substantial binding surfaces and complementary electrostatic/desolvation profiles. Distinct docking patterns indicated receptor-binding flexibility. Immune simulations predicted strong humoral responses with modeled memory formation and, for the H5N1-focused designs, cytotoxic T-cell activity. All candidates and comparators were predicted to be antigenic, non-allergenic, and non-toxic, with combined HLA coverage approaching global breadth. Conclusions: This study compares three design strategies within a harmonized framework—epitope collation, structure-preserved RBD, and fusion-peptide targeting—while benchmarking against two HA comparators. EpitoCore-HA-VX and StructiRBD-HA-VX showed promise against diverse H5N1 isolates, whereas FusiCon-HA-VX supported cross-subtype coverage. As these findings are model-based, they should be interpreted qualitatively; nonetheless, the integrated, structure-guided approach provides an adaptable path for advancing targeted H5N1 and broader influenza A vaccine concepts. Full article

Infections, particularly those affecting the respiratory system, are a major cause of hospitalization among children. During the COVID-19 pandemic, the landscape of childhood infections underwent a significant transformation. To understand these changes, this study analyzes the epidemiological and clinical characteristics of infections in children hospitalized during the first quarters of years 2021–2024. The number of hospitalizations was four times greater in 2024 compared to 2021. The average patient age decreased from 4.6 years in 2021 to 2.3 years in 2024 due to the increase in proportion of infants. The most prevalent symptom changed from fever in 2021 to cough in subsequent years. Bacterial pathogens were dominant in 2021, and viral pathogens were more common in the other three years. SARS-CoV-2 and rotavirus were the most common viruses in 2021 and 2022 but were overtaken by influenza and respiratory syncytial virus in 2023 and 2024. The findings of the study highlight changes in patient characteristics caused by the easing of restrictions and subsequent resurgence of viral infections. Continued surveillance of infection trends is crucial for adapting clinical practices to the evolving challenges posed by infectious diseases in the post-pandemic world. Full article

Genetic and antigenic analyses were performed on highly pathogenic avian influenza viruses (HPAIVs) isolated in Hokkaido, northern Japan, during the winter of 2024–2025. Ninety-eight HPAIVs were isolated from feces of waterfowl, tracheal swabs from dead wild birds, or lung homogenates from dead chickens. Phylogenetic analysis of the hemagglutinin (HA) gene from 47 representative isolates revealed that all sequences belonged to the G2d subgroup of clade 2.3.4.4b H5HA, which has been the dominant lineage in Hokkaido since the winter of 2021–2022. These isolates were further divided into three major groups within the subgroup. The HPAIVs isolated in the Republic of Korea, China, and North America were genetically closely related to the Hokkaido isolates, whereas no HPAIVs genetically related to European strains or those detected in North American cattle were identified. Furthermore, HPAIVs isolated from seabirds were genetically closely related to those found in dead marine mammals along the eastern coast of Hokkaido in the spring of 2025. No apparent antigenic differences were observed between the HPAIVs isolated in this study and those from previous seasons. These findings highlight the wide distribution of HPAIVs in Hokkaido, particularly from Asian and North American lineages, and underscore the importance of continuous surveillance. Full article

Background/Objectives: This study identifies novel dihydroorotate dehydrogenase (DHODH) inhibitors exhibiting potent broad-spectrum antiviral agents, particularly against influenza A virus (A/PR/8/34(H1N1)) and SARS-CoV-2. Methods: Structure-based virtual screening of 1.6 million compounds (ChemDiv and TargetMol databases) yielded 10 candidates, with compounds 6, 9, and 10 demonstrating significant anti-influenza activity (IC₅₀ = 4.85 ± 0.58, 7.35 ± 1.65, and 1.75 ± 0.28 μM, respectively). Building on these, molecular hybridization principles and scaffold hopping principles were applied to design and synthesize six novel compounds (11–16) through cyclization, coupling, and carboxylate deprotection. Prior to subsequent biological assays, the molecular structures of each compound were elucidated by NMR spectroscopy and MS. Their antiviral activities were subsequently assessed against both influenza virus and SARS-CoV-2. The compound 11, demonstrating the most potent antiviral activity, was further subjected to surface plasmon resonance (SPR) analysis to assess its binding affinity for human DHODH. Results: Compound 11 emerged as the most potent DHODH inhibitor (K_D = 6.06 μM), exhibiting superior broad-spectrum antiviral activities (IC₅₀ = 0.85 ± 0.05 μM, A/PR/8/34(H1N1); IC₅₀ = 3.60 ± 0.67 μM, SARS-CoV-2) to the reported DHODH inhibitor (Teriflunomide, IC₅₀ = 35.02 ± 3.33 μM, A/PR/8/34(H1N1); IC₅₀ = 26.06 ± 4.32 μM, SARS-CoV-2). Mechanistic evaluations via 100 ns MD simulations and QM/MM calculations revealed stable binding interactions, particularly hydrogen bonds with GLN47 and ARG136, while alanine scanning mutagenesis confirmed these residues’ critical roles in binding stability. Conclusions: This work identifies compound 11 as a potent broad-spectrum antiviral compound, offering a promising strategy for broad-spectrum antiviral therapy against RNA viruses by depleting pyrimidine pools essential for viral replication. Full article

Background: Various studies have shown that viral pneumonia pathogens display distinct inflammatory profiles, and hematological indices, such as the Neutrophil/Lymphocyte Ratio (NLR), Lymphocyte/Monocyte Ratio (LMR), and Platelet/Lymphocyte Ratio (PLR), can serve as accessible markers of disease severity. Moreover, the seasonal distribution of respiratory viruses appears to have shifted during the COVID-19 pandemic. Methods: This retrospective case–control study was conducted on patients diagnosed with PCR-confirmed viral pneumonia in the emergency department of a tertiary care center between 1 January and 31 December 2024. The control group comprised age- and sex-matched individuals without viral pneumonia. Subjects with comorbidities or ongoing treatments potentially affecting hematological indices were excluded. Seasonal distribution of viral pathogens was recorded. Hematological and inflammatory parameters at admission—including neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR)—were evaluated. The associations between these biomarkers, Pneumonia Severity Index (PSI) scores, and hospitalization status were statistically analyzed. Results: In this study, it was determined that Influenza A/B was more common in winter (67.3%) and SARS-CoV-2 in summer (70.7%). The relationship between the Pneumonia Severity Index and hemogram parameters was examined in determining the severity of pneumonia. In SARS-CoV-2, leukocyte and neutrophil counts were positively correlated (R: 0.392, p: 0.003; R: 0.466, p: <0.001), while in Influenza A/B, lymphocyte, platelet, and monocyte counts showed a negative correlation (R: −0.402, p: 0.005; R: −0.331, p: 0.021; R: −0.327, p: 0.023). Correlations were found between inflammation parameters and the Pneumonia Severity Index, except for the Lymphocyte/Monocyte Ratio, between SARS-CoV-2 and Influenza A/B (p < 0.05). Conclusions: The seasonal distribution of viral pneumonia pathogens has been revealed following the COVID-19 pandemic. Due to differences in inflammation patterns in viral infections, different leukocyte subgroups have been suggested as biomarkers. Full article