Showing posts with label abstract. Show all posts
Showing posts with label abstract. Show all posts

Tuesday, April 14, 2026

#Vaccine-Elicited #Antibody Responses to #Influenza #H3N2 Subclade K

 


{Summary}

Influenza A(H3N2) subclade K (J.2.4.1) is a genetic branch of H3N2 with 11 mutations in hemagglutinin compared with the A/H3N2/Croatia/10136RV/2023 (H3N2 CR/23) vaccine strain, of which 8 mutations are on the hemagglutinin head surface (...) (...). As of February 2026, influenza A viruses currently represent approximately 96.3% of circulating influenza strains in the US, with H3N2 accounting for 88.4% of influenza isolates and subclade K comprising 91.5% of H3N2 isolates. The rapid expansion of H3N2 subclade K represents a major public health concern. This study reports antibody responses to H3N2 subclade K and other influenza strains before and after influenza vaccination.

(...)

Source: 


Link: https://jamanetwork.com/journals/jama/article-abstract/2846268

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Monday, April 13, 2026

#Population #immunity to clade 2.3.4.4b #H5N1 is dominated by anti - #neuraminidase #antibodies

 


ABSTRACT

Clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses continue to expand geographically and across mammalian hosts, raising concern about pandemic potential. The degree and specificity of pre-existing immunity in humans are key determinants of this risk. We analyzed hemagglutinin (HA)- and neuraminidase (NA)-specific antibody responses in 300 sera collected from adults in New York City. While HA directed binding antibodies to clade 2.3.4.4b H5 were low and hemagglutination-inhibiting antibodies were absent, we detected widespread binding and functional NA antibodies against N1 neuraminidases from clade 2.3.4.4b H5N1 viruses. Neuraminidase inhibition (NI) titers were highest against North American D1.1 genotype N1 viruses and correlated strongly with neutralizing activity, whereas HA-binding antibodies did not. An additional N-linked glycosylation site, as found in the NA of a human D1.1 isolate from British Columbia, reduced susceptibility to NI antibodies. Antibodies titer to N5 from H5N5 were low to minimal. These findings indicate that population-level immunity to clade 2.3.4.4b H5 viruses is dominated by NA-directed antibodies, with important implications for pandemic risk assessment.


IMPORTANCE

Understanding how pre-existing human immunity shapes susceptibility to emerging influenza viruses is central to pandemic preparedness. Here, we determined that human sera contain widespread, functional antibodies targeting H5N1 neuraminidase, which correlate with virus neutralization, whereas HA-directed responses are limited. We further show that acquisition of an NA glycosylation site reduces antibody inhibition, highlighting a potential pathway for immune evasion. These results identify neuraminidase-specific immunity as a major immunological barrier to severe H5N1 disease in humans and emphasize the need to incorporate NA antigenicity into influenza surveillance, risk assessment, and next-generation vaccine design.

Source: 


Link: https://journals.asm.org/doi/10.1128/mbio.00445-26

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#Genomic similarity to quantitatively evaluate the #reassortment #potential of #H7N9 with other subtypes of avian #influenza viruses

 


Abstract

Introduction

The H7N9 influenza virus poses a significant public health threat due to its potential for reassortment and cross-species transmission. This study aims to systematically evaluate the genomic similarity between H7N9 and other influenza A subtypes to identify strains with high reassortment potential and characterize their spatiotemporal and host distribution patterns.

Methods

We analyzed nearly 4,000 H7N9 sequences from GISAID and NCBI, alongside representative sequences of other influenza A subtypes. Open reading frames were extracted, and a genomic similarity index was constructed using Euclidean distance, dot product, and cosine similarity measures, with weights optimized via principal component analysis. The index was applied to quantify inter-subtype similarity and predict reassortment-prone strains.

Results

High sequence similarity was observed between H7N9 and cognate subtypes (e.g., H7N3, H15N9), with H7N3 exhibiting the highest similarity index (1.00). Validation using known reassortant strains, such as A/Yixing/805/2022 (H3N2), confirmed that strains with high reassortment potential showed significantly elevated similarity scores across all gene segments (p< 0.001). High-similarity outliers analysis identified 581 spillover events, temporally concentrated during 2014–2017, and spatially clustered in regions like the United States, Europe, and Hong Kong. Host analysis highlighted birds—especially chickens, ducks, and turkeys—as key reservoirs for reassortment.

Discussion

The genomic similarity index effectively identifies influenza A subtypes with high reassortment potential, supported by retrospective validation and spatiotemporal congruence with documented outbreaks. The concentration of high-similarity strains in specific hosts and regions underscores the role of ecological factors in viral evolution. These findings provide a predictive framework for monitoring emergent reassortants and inform targeted surveillance strategies.

Source: 


Link: https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2026.1777911/full

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ONWARD: a #OneHealth, pan - #European multidisciplinary #network advancing #surveillance, #research, clinical management and control of zoonotic #hepeviruses

 


Highlight

• HEV remains the leading cause of acute viral hepatitis in Europe

• Surveillance and diagnostics for HEV are heterogeneous across EU/EEA

• Zoonotic HEV circulates widely in pigs, wildlife and food chains

• Rat HEV expands the zoonotic spectrum and clinical burden in Europe

• ONWARD integrates One Health surveillance, research and capacity building


Abstract

Zoonotic hepeviruses, particularly hepatitis E virus (HEV, species Paslahepevirus balayani) represent a major yet underestimated public health challenge in Europe. Despite being the leading cause of acute viral hepatitis, surveillance, diagnostic practices and prevention strategies remain heterogeneous across EU/EEA countries, limiting comparability and hindering accurate burden estimates. Underdiagnosis is further compounded by extrahepatic manifestations and the growing impact of chronic HEV infection in immunocompromised patients. At the human–animal–environment interface, zoonotic HEV circulates widely in domestic pigs, wildlife and food products, while coordinated surveillance and control measures remain inconsistently implemented. The recent recognition of ratHEV (species Rocahepevirus ratti) as a cause of acute and chronic hepatitis in Europe further expands the spectrum of zoonotic hepevirus infections and underscores the need for integrated One Health approaches. To address these challenges, the One Health Zoonotic Hepevirus Network (ONWARD; COST Action CA24140) was launched in 2025 as a pan-European, multidisciplinary collaboration uniting experts across human, veterinary, food safety and environmental health sectors. ONWARD aims to harmonise diagnostic tools, strengthen clinical research, integrate multisectoral surveillance, promote capacity building and support evidence-based policy development. By fostering coordination with European stakeholders ONWARD provides a structured framework to strengthen preparedness, surveillance and response to zoonotic hepevirus threats across Europe.

Source: 


Link: https://www.sciencedirect.com/science/article/pii/S1386653226000338?dgcid=rss_sd_all

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Saturday, April 11, 2026

Historical #Pandemic and Contemporary #Influenza A Viruses Reveal #PB2 M631L as a Convergent #Adaptation to #Human ANP32

 


Abstract

Understanding the genetic changes that allow avian influenza A viruses (IAVs) to switch their natural hosts and establish productive infection in humans is important for pandemic risk assessment. Adaptations in the IAV polymerase are required to overcome species-specific restrictions imposed by host ANP32 proteins. Notably, avian virus polymerase is generally only poorly supported by human ANP32 proteins due to species-specific differences. Consequently, efficient polymerase adaptation to the binding interface of human ANP32 requires distinct amino acid changes, such as PB2 E627K. A separate adaptation, PB2 M631L, has recently been reported in mammalian-adapted IAV; however, its functional role across divergent viral lineages and its relationship to host ANP32-dependent adaptation remain incompletely defined. Here, we examine PB2 M631L in the polymerases of a 1918 pandemic strain, a recombinant contemporary H1N1pdm09, and a recent clade 2.3.4.4b H5N1 virus. Using polymerase activity and protein-interaction assays, we show that PB2 M631L enhances polymerase activity and ANP32 binding in human—but not avian—contexts, and that this effect is conserved across multiple viral backgrounds. In H1N1pdm09, PB2 M631L also increased virus replication in mammalian cells. These findings indicate that PB2 M631L contributes to enhanced polymerase compatibility with human ANP32 proteins and are consistent with a role in adaptation across multiple influenza virus lineages. Our results highlight how analysis of historical pandemic strains can inform risk assessment for future emerging viruses.

Source: 


Link: https://www.mdpi.com/2076-2607/14/4/859

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#Coronavirus Disease Research #References (by AMEDEO, April 11 '26)

 


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    J Infect

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    J Virol

  11. JEFFERSON V, Endlich-Frazier A, Letko M
    Exploring coronavirus cell entry with functional viromics.
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  12. CHEN N, Kleine-Weber H, Alkharsah K, Winkler M, et al
    Q1020R in the spike proteins of MERS-CoV from Arabian camels confers resistance against soluble human DPP4.
    J Virol. 2026 Apr 6:e0028226. doi: 10.1128/jvi.00282.
    PubMed         Abstract available


    Life Sci

  13. CHEN W, Ji MC, Jung E, Shin JS, et al
    Broad-spectrum coronavirus inhibition by RSV fusion inhibitors targeting six-helix bundle formation.
    Life Sci. 2026 Mar 31:124357. doi: 10.1016/j.lfs.2026.124357.
    PubMed         Abstract available


    Science

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    Diagnostics investments and disease burden.
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    We survived COVID-19-Are we ready for Nipah?
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    PubMed        

#Influenza and Other Respiratory Viruses Research #References (by AMEDEO, April 11 '26)

 


    Biochemistry

  1. VOGET R, Gutschow M
    Early Kinetic Characterization of SARS-CoV-2 Main Protease Inhibitors: A Review and Guidance for Biochemical Assessments.
    Biochemistry. 2026;65:860-881.
    PubMed         Abstract available


    Epidemiol Infect

  2. MILLER AC, Boonstra DE, Cavanaugh JE, Boikos C, et al
    Disease burden associated with influenza activity at the population level.
    Epidemiol Infect. 2026 Apr 6:1-28. doi: 10.1017/S0950268826101320.
    PubMed        

  3. ABUNIJELA S, Greiner T, Haas W, Kerber R, et al
    Frequency, dynamics, and duration of faecal shedding in SARS-CoV-2-infected individuals, a scoping review.
    Epidemiol Infect. 2026;154:e44.
    PubMed         Abstract available


    J Exp Med

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    Nasal CD4+ tissue-resident memory T cells provide cross-protective immunity to influenza.
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    J Infect Dis

  5. ULANOWICZ CJ, Alarcon PC, Damen MSMA, Wayland JL, et al
    Distinct inflammatory programming of thoracic cavity white adipose immune cells regulates influenza pathogenesis.
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    N Engl J Med

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    Pediatrics

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    Pediatric Vaccine Effectiveness Against Influenza Hospitalization And Outpatient Visits: 2021-2024.
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    PLoS One

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    Leadership matters: ward manager vaccination status influences nursing staff influenza vaccine uptake.
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Predicting the #antigenic #evolution of seasonal #influenza viruses using phylogenetic #convergence

 


Abstract

The antigenic evolution of human seasonal influenza viruses is primarily driven by single amino acid substitutions immediately adjacent to the receptor binding site in the hemagglutinin (HA) protein. The ability to predict these substitutions would allow vaccine strains to be selected with an understanding of likely future antigenic variation. Here, we estimate the effect of HA substitutions on viral fitness using measurements of convergent evolution in a large phylogeny. We show that the substitutions which have historically caused major antigenic changes in H3N2 influenza viruses were nearly always one of few substitutions near the HA receptor binding site estimated to be under positive selection in sequences collected before the antigenic transition, based on convergent acquisition of the substitution in multiple independent lineages. Furthermore, this signal predates the establishment of the major clade containing the antigenic substitution by more than one year, so is highly informative for prospective prediction.


Competing Interest Statement

The authors have declared no competing interest.


Funder Information Declared

National Institute of Allergy and Infectious Diseases, https://ror.org/043z4tv69, 75N93021C00014

National Institutes of Health, https://ror.org/01cwqze88, R01AI165818

Medical Research Council, https://ror.org/03x94j517, MR/Y004337/1

Source: 


Link: https://www.biorxiv.org/content/10.64898/2026.04.10.717627v1

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Friday, April 10, 2026

Respirable #Aerosol #Production and Reduction of Avian #Influenza #Transmission #Risk during #Chicken Processing, #Bangladesh

 


Abstract

In Bangladesh, influenza A(H5N1) viruses are endemic in poultry. Processing infected chickens can aerosolize viruses, increasing the risk for human infections. We evaluated particulate matter (PM2.5) mass concentration during slaughtering and defeathering methods used in live bird markets in Bangladesh to identify solutions to reduce aerosol exposure. We slaughtered 675 chickens using cones and barrels with 3 lid types and defeathered 45 chickens using a defeathering machine with 5 lid types. We interviewed 3 slaughterers to understand method preference. For slaughtering, barrels with a solid or star-cut lid reduced PM2.5 mass concentrations by 65%–73% compared with uncovered barrels. For defeathering, machines fully covered by a solid lid or lid with a hole and pivot door reduced PM2.5 mass concentrations by 50% compared with machines with no lid. Slaughterers preferred barrels covered with solid lids and defeathering machines covered with solid or hinged lids. Those methods might reduce aerosol exposure during poultry processing.

Source: 


Link: https://wwwnc.cdc.gov/eid/article/32/4/25-1878_article

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#Investigation and #impact of mammalian #adaptation markers on #H5N8 high pathogenicity avian #influenza #polymerase activity

 


Abstract

Highly pathogenic H5Nx viruses of clade 2.3.4.4b have spread worldwide, causing major economic losses and increased human exposure. Since 2020, multiple mammalian infections have been reported, raising concerns about further adaptation to mammalian hosts. We analyzed influenza A virus sequences from the Influenza Virus Database at the National Center for Biotechnology Information to identify new mammalian adaptation markers in the polymerase complex and nucleoprotein, using recursive partitioning. These markers were grouped into “proteotypes” to assess their co-occurrence and association with host origin. This analysis revealed distinct groups of proteotypes linked to mammalian adaptation, including those seen in historical and pandemic human strains. Identified mutations were introduced alone or in combination into a 2.3.4.4b H5N8 virus to evaluate their impact on polymerase activity in mammalian cells using a minigenome assay. PB1 V336I and PB2 K702R increased polymerase activity in human cells, particularly with PB2 E627K, supporting enhanced surveillance of 2.3.4.4b H5Nx viruses. These findings highlight mutation combinations relevant for enhanced surveillance of 2.3.4.4b H5Nx viruses.

Source: 


Link: https://www.nature.com/articles/s44298-026-00188-3

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Easily Scalable, Rapidly Deployable Mechanical Ventilator for Pandemic Health Crises in Resource-Limited Areas

 


Abstract

Background

The COVID-19 pandemic exposed critical shortages of mechanical ventilators, particularly in low-resource settings. Disruptions in global supply chains and dependence on specialized components highlighted the need for scalable, locally manufacturing alternatives for emergency respiratory support. 

Aim

To describe and evaluate a simplified, supply-chain-independent mechanical ventilator assembled from widely available automotive and simple hardware components, and intended as a last-resort solution

Methods

The ventilator is based on a reciprocating air pump driven by an automotive windshield wiper motor coupled to parallel shaft bellows and readily assembled passive membrane valves, only requiring materials available from standard hardware retailers, minimal tools, and basic manual skills. Ventilator performance was assessed through bench testing using a patient model simulating severe lung disease in an adult (R=20 cmH2O*s/L, C=15 mL/cmH2O) and pediatric (R=50 cmH2O*s/L, C=10 mL/cmH2O) patients. Realistic proof of concept was performed in four mechanically ventilated 50-kg pigs

Results

The device delivered tidal volumes up to 600 mL and respiratory rates up to 45 breaths/min with PEEP up to 10 cmH₂O, covering pediatric and adult ventilation ranges. In vivo testing showed that the ventilator maintained arterial blood gases within the targeted range. Technical details for ventilator construction are provided in an open-source video tutorial. 

Discussion

This low-cost ventilator demonstrated adequate performance under demanding conditions. Although not a substitute for commercial intensive care ventilators, its simplicity, autonomy, and independence from fragile supply chains provide a potentially life-saving option in resource-constrained emergency scenarios.


Competing Interest Statement

The authors have declared no competing interest.


Funding Statement

This work was partially supported by Sociedad Espanola de Neumologia y Cirugia Toracica (SEPAR) (grant 1381-2022). SEPAR had no involvement other than providing funding for the independently submitted research project.

Source: 


Link: https://www.medrxiv.org/content/10.64898/2026.04.08.26350386v1

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Thursday, April 9, 2026

#Species - and #variant - specific #ACE2 compatibility shapes #SARS-CoV-2 #spillover potential in North American #cervids

 


Abstract

Free-ranging white-tailed deer (WTD) are established SARS-CoV-2 reservoirs, but the susceptibility of other cervid species remains unclear. Here we integrate receptor analysis, structural modeling, and field surveillance to assess SARS-CoV-2 susceptibility across North American cervids. We identify species- and variant-specific differences in ACE2–spike compatibility. Elk ACE2 exhibits weak binding to the ancestral strain (Wuhan-Hu-1) and Delta spike receptor-binding domains (RBDs), likely due to a unique K31N substitution. In contrast, it shows stronger binding to Alpha, Beta, Gamma, and Omicron RBDs containing N501Y. Biophysical assays, gel filtration chromatography, and cryo-EM confirm stable complex formation between elk ACE2 and Alpha RBD, but not RBD from the ancestral strain. Despite weak binding, elk ACE2 supports viral entry and replication in vitro. However, surveillance revealed limited evidence of infection in the United States, contrasting with widespread WTD transmissions. These findings demonstrate that ACE2 compatibility alone is insufficient to predict reservoir potential and provide a framework for assessing species susceptibility to emerging coronaviruses.

Source: 


Link: https://www.nature.com/articles/s41467-026-71623-5

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#Preclinical evaluation of an #mRNA #vaccine developed from the first #human isolate of #bovine #H5N1

 


Highlights

• SM102 and DB-Y ionizable lipids deliver H5 mRNA vaccine with high efficiency and safety

• Vaccine-induced antibody and T cell response protect mice from H5N1 challenge

• Pre-existing H1 immunity does not diminish H5-specific immunogenicity

• Vaccine fully protects chicken against clade 2.3.4.4b/h H5 virus challenge


Summary

Given the global threat posed by H5N1 clade 2.3.4.4b avian influenza, rapid development of effective vaccines is imperative. We design an mRNA vaccine encoding hemagglutinin (HA) from A/Texas/37/2024, the first bovine-to-human strain. In murine models, both wild-type and cleavage-site-modified HA vaccines elicit robust and durable humoral immunity, along with a balanced Th1/Th2 response, conferring complete protection against lethal homologous viral challenge. The vaccine, along with the World Health Organization (WHO)-recommended candidate (A/Astrakhan/3212/2020), elicits cross-clade binding antibody responses and demonstrates improvement against specific clades at a 1 μg dose. Pre-existing H1 immunity does not diminish H5-specific immunogenicity. In avian species, the vaccine also provides full protection against lethal clades (2.3.4.4b and 2.3.4.4h). Formulated with another ionizable lipid, the vaccine elicits responses comparable to benchmark lipid nanoparticles (LNPs) and shows a favorable safety profile in rats. This work establishes a rapidly adaptable mRNA-LNP vaccine prototype for pandemic preparedness against evolving avian influenza threats.

Source: 


Link: https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(26)00119-9?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2666379126001199%3Fshowall%3Dtrue

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#Birth #imprinting effects on the #antibody responses of #H7N9 patients from 2013-2018 in #China

 


Abstract

Background

There is an urgent need to understand the immune correlates of protection against avian influenza viruses (AIV), where pre-existing immunity may be limited.

Methods

Here, we characterized the antibody response in 12 severely ill A(H7N9) patients and examined its association with early-life imprinting and clinical outcome.

Results

We find that A(H7N9) patients imprinted with A(H2N2) during early life show minimal H7-IgM and a rapid IgG response across diverse hemagglutinin subtypes. They also have more high avidity H7-antibodies compared to older or younger patients. Early antibody titers against seasonal H1, H3, and conserved stalk domains trend negatively with clinical severity in A(H7N9) infection, while an inverse pattern is observed following severe A(H1N1) infection, potentially suggesting a different mechanism of immune regulation between seasonal and avian influenza virus infections.

Conclusions

These data provide direct serological evidence that birth imprinting profoundly shapes the humoral immune landscape during zoonotic influenza infection and may influence subsequent disease outcome.

Source: 


Link: https://www.nature.com/articles/s43856-026-01554-1

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Genetic characterization of a novel triple - #reassortant #influenza #H1N2 virus from #pigs, #China, 2021

 


Abstract

Swine influenza virus (SIV) is a highly contagious respiratory pathogen in pigs, with bidirectional transmission posing a potential threat to human health. In this study, nasal swab samples were collected from pigs in Shandong Province, China, and yielded an H1N2 SIV strain, designated A/swine/Shandong/QD726/2021 (H1N2). Whole-genome sequencing was performed for Sw/SD/QD726/2021, and phylogenetic analysis was conducted together with 156 Chinese H1N2 reference sequences obtained from the Global Initiative on Sharing All Influenza Data (GISAID) database and the National Center for Biotechnology Information (NCBI) Influenza Virus Resource database. The results indicated that Sw/QD726/2021 represents a novel reassortant genotype (G21), with the HA gene derived from Eurasian avian-like H1N1 (EA H1N1), the NA and NS genes from triple-reassortant H1N2 (TR H1N2), and the remaining internal genes (PB2, PB1, PA, NP, M) from the 2009 pandemic H1N1 (pdm/09 H1N1). Key amino acid analysis revealed N31 in M2, responsible for adamantane resistance, and S42 in NS1, which influences viral virulence in mouse models. BALB/c mouse experiments demonstrated efficient viral replication in the lungs and nasal turbinates, accompanied by moderate body weight loss and lung lesions, indicating only moderate pathogenicity. These findings underscore the ongoing evolution of H1N2 SIV in pigs and emphasize the importance of enhanced surveillance and preventive strategies to mitigate public health risks.

Source: 


Link: https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1779293/full

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Wednesday, April 8, 2026

#Genetic and #biological characterization of a #duck-origin clade 2.3.4.4b #H5N6 avian #influenza virus reveals partial #mammalian #adaptation

 


Highlights

• Duck-origin H5N6 virus A/Duck/Jiangsu/628/2022 shares high homology with the human strain A/Yangzhou/125/2022.

• The 628 strain shows mammalian adaptation markers: HA mutations enhance human receptors affinity and NA mutations reduce sensitivity to neuraminidase inhibitors.

• Limited airborne transmission but detectable droplet-mediated spread suggests increased mammalian transmission risk.


Abstract

Clade 2.3.4.4b H5Nx highly pathogenic avian influenza viruses (HPAIVs) have caused extensive outbreaks in poultry worldwide. H5 HPAIVs have caused sporadic but severe human infections in China, representing a persistent zoonotic threat. Here, we identified a duck-origin H5N6 HPAIV (A/Duck/Jiangsu/628/2022) through routine surveillance and assessed its biological characteristics and mammalian pathogenesis. Phylogenetic analysis revealed > 98% nucleotide identity between strain 628 and the concurrent human H5N6 strain A/Yangzhou/125/2022. Molecular characterization identified multiple mammalian adaptation markers: hemagglutinin substitutions (S137A, T160A, T192I) associated with enhanced human receptor binding; neuraminidase mutations (I117T, D198N) linked to reduced neuraminidase inhibitor susceptibility; and polymerase complex changes (PB1-D622G, PA-K142Q) conferring increased mammalian cell replication. In vitro studies demonstrated that 628 virus replicated more efficiently in mammalian than in avian cells and exhibited dual receptor-binding specificity. Mouse pathogenicity assays revealed moderate virulence with progressive lung pathology. Critically, transmission experiments confirmed both direct contact and airborne transmission capabilities of 628 in guinea pigs. These findings demonstrate that circulating H5N6 viruses have acquired partial mammalian adaptation while retaining avian fitness, significantly elevating pandemic potential. Enhanced surveillance of wild bird populations, poultry farms, and live poultry markets is urgently needed to develop effective prevention and control strategies.

Source: 


Link: https://www.sciencedirect.com/science/article/abs/pii/S037811352600146X?via%3Dihub

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Using an evolutionary epidemiological #model of #pandemics to estimate the #infection #fatality ratio for #humans infected with avian #influenza viruses

 


Abstract

The risk of highly pathogenic avian influenza virus infection to humans is challenging to estimate as many human avian influenza virus (AIV) infections are undetected because infections may be asymptomatic, symptomatic but not tested, and difficult to identify through contact tracing, as human-to-human transmission is rare. We derive equations that consider the evolutionary mechanisms that give rise to pandemics and are parameterized to be consistent with records of past pandemics. We estimate that thousands of human AIV infections occur worldwide in an average year and estimate the infection fatality ratio as 32 deaths per 10,000 infections (95% confidence interval: [9.6, 75]). This estimate is comparable to SARS-CoV-2 during the recent pandemic and higher than seasonal human influenza. We estimate that preventing animal-to-human influenza spillovers would delay pandemic emergence by several years. Preventing human infections with AIV is necessary given the high risk of severe outcomes to individuals and to reduce the risk of pandemics occurring in the future.


Competing Interest Statement

The authors have declared no competing interest.


Funding Statement

AH was supported by a Natural Sciences and Engineering Research Council of Canada Discovery Grant (RGPIN 023-05905) and a Catalyst Grant: Avian Influenza OneHealth Research, Enhanced tracking of the circulation of and risk from highly pathogenic avian influenza viruses at the human-wildlife interface from the Canadian Institutes of Health Research. JM, ML, and AH were support by an Atlantic Canada Research in the Mathematical Sciences Collaborative Research Group award.

Source: 


Link: https://www.medrxiv.org/content/10.64898/2026.01.21.26344526v2

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Tuesday, April 7, 2026

#Genomic characterisation of Crimean-Congo haemorrhagic fever virus (#CCHFV) in #Tajikistan identifies a novel reassortant virus

 


Abstract

Crimean-Congo haemorrhagic fever virus (CCHFV) is an important human tick-borne pathogen, able to cause severe haemorrhagic fever. CCHFV is endemic in Tajikistan, which records between 5–38 cases of CCHF a year from southern regions. Molecular surveillance of CCHFV is crucial to implement effective prevention and control strategies, understand viral evolution, study transmission dynamics, and develop effective diagnostics, therapeutics, and vaccines. While the presence of Asia-1 and Asia-2 genotypes has been previously reported, only two historical samples from Tajikistan have been fully sequenced. In this study we developed and applied a genotype IV-specific tiling PCR enrichment approach recovering 52 CCHFV genome segment sequences from clinical and Hyalomma tick samples collected between 2017–2023. Most sequences belonged to the Asia-2 genotype, but one virus exhibited an Asia-1 S segment combined with Asia-2 M and L segments, representing the first evidence of such viral reassortment event in Tajikistan.

Source: 


Link: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014204

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Deep #disadvantage in #mortality on the frontlines of the #COVID19 #pandemic

 


Abstract

This study presents new evidence on the temporal and spatial impact of the COVID-19 pandemic on mortality among especially vulnerable New Yorkers. Using burial records from Hart Island—the City’s potter’s field—we study the distribution of unclaimed deaths over time and across boroughs in 2020 compared to pre-pandemic levels. We show that the Hart Island deaths began deviating from their historical pattern in early March 2020 and peaked five weeks later at 22 deaths for every death in the same week in 2019 (20:1 adjusted). COVID-19 excess death rates were more than twice as high in the Bronx compared to other boroughs. Citywide, we estimate that 10% of all COVID-related excess deaths during the initial outbreak (March–August 2020) were unclaimed. These findings suggest the pandemic greatly magnified existing inequalities in the City and, more broadly, illustrate the especially devastating impact of COVID-19 on economically and socially vulnerable populations.

Source: 


Link: https://www.nature.com/articles/s41598-026-41219-6

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MF59-adjuvanted A/Astrakhan #influenza #vaccine induces cross-neutralizing #H5N1 #antibodies in #ferrets against circulating clade 2.3.4.4b viruses

 


Abstract

The continued global spread of highly pathogenic avian influenza A(H5N1) viruses, particularly clade 2.3.4.4b, has increased zoonotic spillover risk and underscored the urgency of pandemic preparedness. Human vaccination is a key strategy for mitigating severe disease and limiting transmission, especially in a setting where avian influenza viruses pose a zoonotic threat. We evaluated the immunogenicity of the MF59-adjuvanted, egg-derived A/Astrakhan/3212/2020 (H5N8) influenza vaccine (CBER-RG8A) in ferrets. To assess cross-reactivity, we generated pseudoviruses bearing HA and NA from circulating A(H5N1) 2.3.4.4b viruses, including North American (B1.13 and D1.1) and Eurasian (DI.2) genotypes. Immunogenicity was assessed using hemagglutination inhibition and microneutralization assays. A single dose elicited robust neutralizing titers (GMT ≥ 160), while a second dose increased titers by ≥3.3-fold. Cross-reactivity was maintained across most strains; however, responses were reduced up to 8-fold against strains harboring the A156T HA mutation, which may introduce a glycosylation site at antigenic site B. Limited responses were detected against divergent clades, with modest titers against clade 2.3.2.1a. These findings suggest broad protection induced by the CSL Seqirus pandemic vaccine against contemporary clade 2.3.4.4b A(H5N1) viruses and underscore the value of ferret immunogenicity data in informing strain selection and regulatory preparedness when human clinical data are unavailable.

Source: 


Link: https://www.nature.com/articles/s41541-026-01438-4

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