Structural #insights into #antibody responses against #influenza A virus in its natural reservoir

 

Abstract

While influenza A virus undergoes rapid antigenic drift in humans, at least some subtypes, such as H3, have relatively stable antigenicity in natural waterfowl reservoirs, despite the presence of immune pressure. However, the underlying mechanisms remain poorly understood. This study identified and characterized 187 antibodies to H3 hemagglutinin from experimentally infected mallard ducks, 18 of which were further analyzed by cryo-EM. Compared with human H3 antibodies, duck H3 antibodies exhibited higher glycan-binding propensity, more balanced immunodominance hierarchy, and targeted distinct epitopes. Other unique features of duck H3 antibodies included a convergent CDR H3-independent heavy chain-only binding mode and an N-glycosylated CDR H3 as decoy receptor. By annotating duck immunoglobulin germline genes, we also demonstrated the importance of gene conversion in duck H3 antibodies. Overall, our findings provide insights into how millennia of coevolution have shaped the interplay between influenza A virus antigenic drift and antibody responses in the natural reservoir.

Competing Interest Statement

N.C.W. consults for HeliXon. The authors declare no other competing interests.

Funder Information Declared

National Institutes of Health, https://ror.org/01cwqze88, R01 AI165692

Carl R. Woese Institute for Genomic Biology, Carl R. Woese Institute for Genomic Biology Postdoctoral Fellowship

Vallee Foundation, https://ror.org/05nmp3276, Vallee Scholars Program

Foundation for Partnership Initiatives in the Niger Delta, https://ror.org/041nz5a71, Searle Scholars Program

Howard Hughes Medical Institute, https://ror.org/006w34k90, Emerging Pathogens Initiative

Source: BioRxIV, https://www.biorxiv.org/

Link: https://www.biorxiv.org/content/10.64898/2026.03.11.711171v1

____

Interim Estimates of 2025–26 Seasonal #Influenza #Vaccine #Effectiveness — #USA, September 2025–February 2026 (CDC MMWR)

 

Abstract

In the United States, annual influenza vaccination has been recommended for all persons aged ≥6 months, including during the 2025–26 season. Interim influenza vaccine effectiveness (VE) estimates were calculated for patients with acute respiratory illness–associated outpatient visits and hospitalizations from three U.S. respiratory virus VE networks during the 2025–26 influenza season, using a test-negative case-control design. Among children and adolescents aged <18 years, VE was 38%–41% against influenza outpatient visits and 41% against influenza-associated hospitalization. Among adults aged ≥18 years, VE was 22%–34% against influenza outpatient visits and 30% against influenza-associated hospitalization. Among children and adolescents, VE against influenza A ranged from 37% (against outpatient visits) to 42% (against hospitalization) across settings; among adults, VE against influenza A ranged from 30% (against hospitalization) to 34% (against outpatient visits) across settings. Among children and adolescents, VE against influenza A(H3N2)–associated outpatient visits was 35% and against influenza A(H3N2)–associated hospitalization was 38%. VE against influenza B outpatient visits ranged from 45%–71% among children and adolescents and was 63% among adults. Other estimates of VE were not statistically significant or were not reportable. Although interim influenza VE is lower during the 2025–26 influenza season than it was during recent influenza seasons, these findings demonstrate that influenza vaccination still provides protection against influenza. CDC recommends influenza vaccination; U.S. influenza vaccines remain available for persons aged ≥6 months.

Source: 

Link: http://dx.doi.org/10.15585/mmwr.mm7509a2

____

Identification of a Key #Hemagglutinin #Mutation Mediating #Antibody Escape in #Influenza #H1N1pdm09 Viruses

 

Abstract

Background: 

The H1N1 influenza A virus evades host immunity through continuous antigenic drift, posing a significant challenge to broad-spectrum neutralizing antibody therapies. This study aims to systematically evaluate the neutralizing capacity of the broad-spectrum antibody C12H5 against H1N1 strains from different eras and identify key immune escape mutation sites. 

Methods: 

Three representative H1N1 virus strains from 2009, 2018, and 2023 were selected. An antigen–antibody binding prediction model based on the ESM-2 large language model was constructed by integrating 48,762 GISAID sequence data and deep mutation scanning data from the Bloom laboratory. Candidate escape sites were screened using SHAP (SHapley Additive exPlanations) value analysis. Mutant viruses were constructed via reverse genetics, and their neutralizing capacity and replication fitness were validated through hemagglutination inhibition assays, microneutralization assays, and viral growth kinetics analysis. 

Results: 

Machine learning scoring identified five potential escape sites, with K147 exhibiting the highest overall score (0.92). SHAP analysis revealed that the K147 site within the HA protein’s 130-loop region received the highest importance score (0.28), significantly surpassing other candidate sites. Experimental validation revealed that the K147N mutation reduced neutralizing potency against C12H5 by 8-fold (from 1:1024 to 1:128) and approximately 6-fold in microneutralization assays (from 8.3 log2 to 5.7 log2), while exhibiting a replication advantage in MDCK cells. Microneutralization assays further confirmed an approximately 6-fold reduction in neutralization sensitivity. Structural analysis indicated that K147 is located at the periphery of the HA receptor-binding domain, immediately adjacent to the receptor-binding site. 

Conclusions: 

K147N is identified as the critical mutation mediating C12H5 immune escape, and this mutation has emerged in 2023 circulating strains. This study provides important molecular targets and early warning mechanisms for broad-spectrum antibody optimization and influenza vaccine updates.

Source: 

Link: https://www.mdpi.com/1999-4915/18/3/349

____

Structures of #Marburgvirus #glycoprotein and its complex with NPC1 #receptor

 

Abstract

Marburgviruses (MBVs) cause severe haemorrhagic fever with higher fatality rates than Ebola virus (EBOV). Here we show that the MBV glycoprotein (GP) mediates viral entry more efficiently than EBOV GP. Using cryo-EM, we determined structures of MBV GP in three states: (1) unbound; (2) bound to its endosomal receptor NPC1; and (3) complexed with a neutralizing nanobody. The glycan cap shields the receptor-binding site from NPC1 but only partially from the nanobody, enabling limited immune evasion. After glycan cap cleavage, NPC1 binds to MBV GP in a distinct orientation compared with EBOV GP, providing an additional anchor and enhancing receptor affinity. NPC1 engagement also induces substantial conformational changes in MBV GP, probably facilitating membrane fusion. Furthermore, MBV GP is susceptible to the neutralizing nanobody, which mimics NPC1 at the receptor-binding site. Together, our findings reveal MBV GP as a highly efficient entry mediator and suggest structural mechanisms that may contribute to its enhanced entry efficiency.

Source: Nature, https://www.nature.com/

Link: https://www.nature.com/articles/s41586-026-10240-0

____

A #clinical #SARS-CoV-2 #Mpro #inhibitor blocks replication of multiple #enteroviruses and confers oral in vivo protection in animal models

 

Abstract

Enteroviruses, which belong to the family Picornaviridae, cause hand, foot, and mouth disease (HFMD), respiratory symptoms, and severe neurological complications in children. Since vaccines cannot provide cross-protection against different serotypes of enteroviruses, the development of broad-spectrum anti-enteroviral drugs is imperative. The viral 3C protease (3Cpro), which is essential for polyprotein processing represents a validated target for therapeutic intervention. Importantly, enterovirus 3Cpro shares conserved structural and catalytic features with coronavirus main protease (Mpro, also known as 3C-like protease, 3CLpro), providing a rationale for cross-target inhibitor repurposing. Through targeted screening of peptidomimetic protease inhibitors, a clinical-stage SARS-CoV-2 Mpro inhibitor was identified as a potent inhibitor of enterovirus A71 (EV71) 3Cpro. Bofutrelvir displayed nanomolar antiviral activity in multiple cell lines and demonstrated broad-spectrum efficacy against several enteroviruses including coxsackievirus B5, coxsackievirus A16 (CA16) and echovirus 11. In EV71 infected neonatal mice, intraperitoneal administration of bofutrelvir markedly reduced viral loads in brain, spinal cord, and muscle, alleviated clinical symptoms, and suppressed tissue inflammation. Oral administration of bofutrelvir also provided therapeutic benefits in neonatal mice models of both EV71 and CA16. Crystallographic analysis revealed that bofutrelvir binds in the conserved substrate-binding cleft of EV71 3Cpro, elucidating its molecular mechanism of inhibition. These findings identify bofutrelvir as a broad-spectrum peptidomimetic 3Cpro inhibitor with strong antiviral efficacy against enteroviruses and highlight its potential for repurposing as a promising antiviral candidate for the treatment of enteroviral infections.

Source: 

Link: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014051

____

Defining the transmissible dose 50% for two #pandemic #influenza viruses in #ferrets

 

ABSTRACT

Ferrets are widely used to model airborne transmission of influenza viruses in humans. Airborne transmission is evaluated by infecting donor ferrets with a high virus dose and monitoring transmission to contact animals sharing the same airspace. Humans can be infected with a broad range of influenza virus doses. Therefore, we evaluated the relationship between inoculation dose and transmission for two pandemic influenza viruses in ferrets. Donor ferrets were inoculated with 100 to 106 tissue culture infectious dose 50 (TCID50) of the 2009 pandemic H1N1 or 1968 pandemic H3N2 virus and were then paired with respiratory contacts. Using the proportion of donors that became infected across virus doses, we calculated the infectious dose 50 (ID50). Subsequently, by comparing the proportion of contacts that became infected, we calculated the transmissible dose 50% (TD50): the donor inoculation dose that resulted in transmission to 50% of contacts. For the 2009 pandemic H1N1 virus, the ID50 and TD50 were equivalent at <1 TCID50. However, for the 1968 pandemic H3N2 virus, the ID50 and TD50 were 100.5 and 104.08 TCID50 (95% CI: 102.34–105.82), respectively. The increased TD50 for the H3N2 virus was associated with significant reductions in peak viral titers and viral shedding in donors over decreasing virus inoculation doses. Collectively, these studies define a new measure of transmission that permits comparisons of transmissibility between viral strains and subtypes in ferrets. We show that the 1968 pandemic H3N2 virus has a higher TD50 and reduced transmissibility in ferrets relative to the 2009 pandemic H1N1 virus.

Source: 

Link: https://journals.asm.org/doi/full/10.1128/jvi.01635-25?af=R

____

{#Iran} #Conflict deepens #health #crisis across Middle East, #WHO says (March 11 '26)

 

More than ten days into the latest escalation of conflict in the Middle East, health systems across the Region are coming under strain as injuries and displacement rise, attacks on health care continue, and public health risks increase.

National health authorities in Iran report more than 1300 deaths and 9000 injuries, and in Lebanon report at least 570 deaths and more than 1400 injuries. In Israel, authorities report 15 deaths and 2142 injuries.

At the same time, the conflict is affecting the very services meant to save lives. 

In Iran, WHO has verified 18 attacks on health care since 28 February, resulting in 8 deaths among health workers. 

Over the same period in Lebanon, 25 attacks on health care have resulted in 16 deaths and 29 injuries. These attacks not only cost lives but deprive communities of care when they need it most. 

Health workers, patients and health facilities must always be protected under international humanitarian law.

Beyond the immediate impact, the conflict is creating wider public health risks. 

Current estimates indicate more than 100 000 people in Iran have relocated to other areas of the country due to insecurity, and up to 700 000 people have been internally displaced in Lebanon, with many in crowded collective shelters under deteriorating public health conditions, with limited access to safe water, sanitation and hygiene. These conditions increase the risk of respiratory infections, diarrhoeal diseases, and other communicable illnesses, especially for the most vulnerable populations, such as women and children.

Environmental hazards are also a raising concern. In Iran, petroleum fires and smoke from damaged infrastructure exposed nearby communities to toxic pollutants that potentially cause breathing problems, eye and skin irritation, and contaminated water and food sources.

Access to health services is becoming increasingly constrained across several countries. 

In Lebanon, 49 primary health-care centres and five hospitals have shut following evacuation orders issued by Israel’s military, reducing the availability of essential services as medical needs rise.

In the occupied Palestinian territory, increased movement restrictions and checkpoint closures are delaying ambulance and mobile clinics’ access across several governorates in the West Bank. 

In Gaza, medical evacuations remain suspended since 28 February, while hospitals continue to operate under strain amid ongoing shortages of medicines, medical supplies and fuel, which is being rationed to prioritize essential health services such as emergency and trauma care, maternal and neonatal services, and management of communicable diseases.

Temporary airspace restrictions have disrupted the movement of medical supplies from WHO’s global logistics hub in Dubai. 

More than 50 emergency supply requests, intended to benefit over 1.5 million people across 25 countries, are affected, resulting in significant backlogs. 

Current priority shipments include supplies planned for Al Arish, Egypt, to support the Gaza response, as well as Lebanon and Afghanistan. The first shipment, containing cholera response supplies for Mozambique, is expected to depart from the hub in the coming week.

The escalation comes at a time when humanitarian needs in the Eastern Mediterranean Region were already among the highest in the world. 

Across the Region, 115 million people require humanitarian assistance – almost half of all people in need globally – while humanitarian health emergency appeals remain 70% underfunded.

Without protection for health care, sustained humanitarian access and stronger financial and operational support for the humanitarian health response, the strain on vulnerable populations and already fragile health systems will continue to grow.

WHO calls on all parties to protect civilians and health care, ensure unimpeded and sustained humanitarian access, and pursue de-escalation of the conflict so communities can begin to recover and move towards peace.

Source: 

Link: https://www.who.int/news/item/11-03-2026-conflict-deepens-health-crisis-across-middle-east--who-says

____

Post-discharge #sequelae of #Lassa fever #survivors in #Nigeria: an analysis of the LASCOPE prospective cohort

 

Summary

Background

Lassa fever is one of the most important viral haemorrhagic fevers, yet post-discharge sequelae remain inadequately characterised. Previous studies have been limited by small sample sizes and unsystematic assessments. We aimed to describe post-discharge sequelae in Lassa fever survivors and explore the effect of disease severity on sequelae patterns.

Methods

LASCOPE was a prospective study of patients with PCR-confirmed Lassa fever hospitalised at Federal Medical Centre Owo, Owo, Nigeria, between April 23, 2018, and Feb 17, 2023. All patients who provided informed consent were included, with no age restriction. Severe disease was defined as the presence of at least one of the following during the acute phase: National Early Warning Score version 2 score of 7 or higher, Kidney Disease Improving Global Outcomes stage 2 or higher, or Lassa virus PCR Ct value of less than 25. At hospital discharge, follow-up of survivors was planned for day 60 after admission, or before that, based on medical need. A systematic symptom assessment was done at each visit. The main outcome was clinical remission, defined as complete absence of symptoms. Other outcomes were post-discharge death, symptom incidence, and prevalence of symptoms over time. Subgroup analyses were performed by age group (children aged <18 years or adults aged ≥18 years) and disease severity (severe or not severe).

Findings

Of 882 survivors (median age 32 years [IQR 22–46], 459 [52%] female and 423 [48%] male), post-discharge data were available for 807 (91%), with a total of 2603 person-months of follow-up. For three of 807 survivors with post-discharge information, only the vital status was collected. 736 (91%) of 807 reached clinical remission, with a median time to clinical remission of 19 days (95% CI 16–23) post discharge. The most frequently reported symptoms were asthenia (158 [20%] of 804), headache (148 [18%]), and post-exertional malaise (123 [15%]). Hearing symptoms were reported by only 17 (2%) of 804 survivors, which was substantially lower than previous studies. Disease severity did not affect time to remission. Six (1%) survivors died after hospital discharge.

Interpretation

Patient-reported symptoms suggest good recovery with few hearing or neurosensory disorders in most survivors of Lassa fever. Future research would benefit from extended follow-up periods and standardised diagnostic assessments, including objective audiometry, to further characterise the full spectrum of post-Lassa fever complications.

Funding

Institut National de la Santé et de la Recherche Médicale, University of Oxford, EU, UK Department for International Development, Wellcome Trust, French Ministry of Foreign Affairs, Agence Nationale de Recherches sur le SIDA et les Hépatites Virales, and French National Research Institute for Sustainable Development.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(26)00057-5/abstract?rss=yes

____

A newly emergent N1 #neuraminidase associated with clade 2.3.4.4b highly pathogenic avian #influenza #H5 viruses in North #America

 

Abstract

We investigated the evolutionary history of the newly emergent neuraminidase (am4N1) associated with the D1.1 and D1.2 genotypes of highly pathogenic avian influenza A(H5N1) viruses in North America. Phylogenetic inference places am4N1 in a sister clade to Eurasian avian, swine, and human A(H1N1)pdm09 viruses and distinct from 1918, pre-2009 human seasonal, and classical swine A(H1N1) lineages. Am4N1 descends from diverse avian N1 genes endemic to the Americas. Phylodynamic analysis indicates a monophyletic am4N1 lineage with numerous introductions of viruses carrying the am4N1 gene likely originating from western Canada into the United States during emergence of the D1.1 and D1.2 genotypes. The lineage has diversified and accumulated deletions in the stalk domain. Despite amino acid divergence, structural modeling shows conserved neuraminidase architecture in the globular head. Given its distinct ancestry and amino acid sequence, further studies are needed to assess cross-reactivity of antibodies from prior human A(H1N1)pdm09 infections.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study did not receive any external funding.

Source: 

Link: https://www.medrxiv.org/content/10.64898/2026.03.09.26347929v1

____

#Chile - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

{Valparaíso} The birds shared a pond with wild birds. All birds were culled and buried on the property under strict biosecurity protocols. Cleaning and disinfection measures are being carried out.

Source: 

Link: https://wahis.woah.org/#/in-review/7357

____

Deep #earthquake off the #coast of #Campania, ML 5.9, March 10, 2026 (INGV, edited)

 

{Excerpts}

On March 10, 2026, at 12:03 AM Italian time, a magnitude 5.9 earthquake occurred off the coast of Campania. 

The seismic event occurred at an  extremely deep depth , approximately  414 km , well below the common seismogenic depths of Italian earthquakes, which predominantly occur in the upper crust.

This deep event, quite rare for this geographical area, can be traced back to a geological process typical of the southern Tyrrhenian Sea  due to the presence in the Earth's mantle of a " slab " of oceanic lithosphere that has been sinking for several million years beneath the Tyrrhenian Sea.

This phenomenon is accompanied by  frequent seismicity along the Calabrian and Sicilian coasts – less frequent off the Campanian coast – , with earthquakes that in the last 40 years have reached  magnitude ML 5.8 on 28 October 2016 ,  at a depth  of  481 km ,  and magnitude Mw 5.8 on 29 October 2006,  at a depth  of  221 km . 

Another earthquake with a magnitude greater than 5 occurred on 3 November 2010, ML 5.4, at a depth of 506 km, and a significant deep earthquake of magnitude ML 4.2  occurred on the night between  26 and 27 October 2023 off the Sorrento Peninsula (province of Naples).

The strongest known deep earthquake in the area occurred on December 27, 1978, with a magnitude of 5.9 , at a  depth of 392 km off the coast of Gaeta (LT). 

In addition to this event, a 1951 study describes a very strong deep earthquake in the Tyrrhenian Sea in 1938 with an estimated magnitude between 6.8 and 7.1 ! One of the strongest earthquakes in our historical catalog.

Fortunately, in these cases, the great depth causes a strong attenuation of the seismic waves and therefore a lesser impact on the territory.

The earthquake was felt throughout Italy. In fact, the preliminary map of macroseismic tremors, continuously updated (1:23 a.m. Italian time), obtained from approximately 130 questionnaires sent to the website " Did you feel the earthquake? " shows tremors up to  grade III-IV MCS .

This work is licensed under a  Creative Commons Attribution-NoDerivatives 4.0 International License.

Source: 

Link: https://ingvterremoti.com/2026/03/10/terremoto-profondo-al-largo-delle-coste-campane-ml-5-9-10-marzo-2026/

____

Novel #Reassortant #H5N2 Highly Pathogenic Avian #Influenza Viruses from Backyard #Poultry in #Mexico

 

Abstract

Highly pathogenic influenza A viruses of the H5 subtype continue to diversify worldwide through mutation and genetic reassortment, generating novel variants with unpredictable consequences under the One Health approach. Between 2024 and 2025, five outbreaks of avian influenza A viruses were detected in backyard poultry across Michoacán, Estado de México, and Ciudad de México. We conducted molecular and genetic characterization of five highly pathogenic H5N2 viruses isolated from these events. All cases tested positive for influenza A virus and the H5 hemagglutinin, exhibiting high pathogenicity with intravenous pathogenicity index values ranging from 2.88 to 3.0. Whole-genome sequencing revealed novel reassortants containing hemagglutinin from Eurasian H5N1 clade 2.3.4.4b and neuraminidase from the endemic Mexican H5N2 lineage. The viral genome of the isolate from Michoacán contained six segments derived from Eurasian H5N1 viruses introduced into North America in 2021–2022, while nucleoprotein and neuraminidase originated from Mexican H5N2 viruses. In contrast, viruses from Estado de México and Ciudad de México contained five H5N1-derived segments and incorporated polymerase basic protein 1, nucleoprotein, and neuraminidase from low-pathogenic H5N2 viruses circulating in 2024. Phylogenetic analyses confirmed the emergence of a distinct H5N2 Mexican sublineage, providing evidence of active viral reassortment and local evolutionary processes in Mexico.

Source: 

Link: https://www.mdpi.com/1999-4915/18/3/337

____

Immunogenicity and #safety of MVA-BN #vaccine administered 5 years after a two-dose primary series in #DRC: a prospective cohort study

 

Summary

Background

The expanding mpox outbreak in Africa and travel-associated cases in other continents have increased efforts to vaccinate populations at high risk. This study aimed to assess serological immune responses 5 years after individuals received a primary vaccination (two-dose series) with the smallpox and mpox vaccine modified vaccinia Ankara-Bavarian Nordic (MVA-BN), as well as to evaluate the safety and immunogenicity of a third dose (booster). To date, there are no data for immunological memory or third-dose-induced immunity for MVA-BN at these long-term timescales.

Methods

In this open-label, prospective cohort extension, we re-enrolled health-care workers from a 2017 vaccination study in Bokungu Health Zone, DR Congo, to receive a third dose of MVA-BN. All previous participants were offered the opportunity to re-enrol. Participants were grouped according to whether they had received a childhood smallpox vaccination with a replication-competent vaccine strain (historically vaccinated group) or had no history of smallpox vaccination (historically naive group). Participants were excluded from serological analyses if they had any history of mpox or mpox-like lesion-presenting illness, if their previous vaccination status during initial enrolment for the primary series was unknown, or if they had discordant vaccination information. The coprimary outcomes were sustained humoral immunity following primary vaccination with MVA-BN (5 years previously) and the immunogenicity and safety of the booster vaccination. Safety was analysed in patients with a completed immediate adverse event form or adverse event diary. Adverse events were assessed on days 0 (within 30 min of the booster), 7, and 14. Antibody responses were measured by ELISA, plaque reduction neutralisation tests, and endpoint titre at re-enrolment (day 0, before administration of the booster dose) and on days 7, 14, and 545 after the booster dose.

Findings

Between Sept 7 and 15, 2022, 170 (66·1%) of 257 Bokungu health-care personnel vaccinated in 2017 were re-enrolled to receive a third (booster) dose of MVA-BN. At re-enrolment, low levels of circulating antibody were observed, but 30 (61%) of 49 historically naive participants and 95 (96%) of 99 historically vaccinated participants with childhood smallpox vaccination remained seropositive 5 years after the primary MVA-BN two-dose series. After the third dose, there was a rapid and massive increase in anti-orthopoxvirus IgG but not IgM, and a 93-fold rise in orthopoxvirus neutralising antibody titres was observed by day 14 in historically naive participants, irrespective of participants' seropositivity at the time of booster vaccination. The third dose resulted in enhanced durability of circulating antibody concentrations, with endpoint titres on day 545 remaining more than six-fold higher than day 0 values. There was a greater risk of local reactogenicity after the booster dose than after the primary vaccination (relative risk 4·2, 95% CI 2·81–6·46), but there was no difference in the risk of systemic adverse events up to day 7 after vaccination. No grade 3 serious adverse events were recorded after booster dose administration.

Interpretation

These data show that primary MVA-BN vaccination induces sustained immunological memory up to 5 years after vaccination and that a booster dose strongly enhances circulating antibody levels and durability. Future studies should clarify the role of circulating antibody concentrations as a correlate of protection from monkeypox virus infection.

Funding

US Centers for Disease Control and Prevention and US Biomedical Advanced Research and Development Authority.

Translation

For the French translation of the abstract see Supplementary Materials section.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(26)00001-0/fulltext?rss=yes

____

Case presentation of #patients hospitalised with #mpox (subclade Ib/2023sh) including #children, #adolescents, and #adults in South Kivu, #DRC: an observational cohort study

 

Summary

Background

Mpox is a public health concern in eastern DR Congo. It continues to cause substantial numbers of hospital admissions, with changing demographics including children and adolescents, requiring comprehensive clinical and epidemiological investigation. In this study, we aim to describe the clinical characteristics of hospitalised participants infected with monkeypox virus (MPXV) subclade Ib/2023sh in the Kabare Territory in South Kivu, DR Congo.

Methods

This observational cohort study included patients admitted with suspected mpox to the reference centre of mpox treatment at Lwiro Hospital, South Kivu, DR Congo. Eligible participants must have had, at the time of inclusion, skin lesions compatible with the infection. Individuals who did not present lesions compatible with MPXV infection were also eligible if they had at least one of the following symptoms: fever, cervical lymphadenopathy, or pharyngitis, provided they had been in contact with someone with suspected mpox within the last 21 days. Data from hospital records and standardised clinical forms captured demographics, presenting symptoms and signs, outcomes, and general clinical characteristics. Descriptive analyses and statistics summarised the clinical and epidemiological profiles of participants with molecular confirmation of MPXV subclade Ib/2023sh.

Findings

Between Aug 3, 2024, and Feb 8, 2025, MPXV subclade Ib/2023sh was detected in 494 (77%) of 643 participants with a median age of 9 years (IQR 2–24). Participants who were positive for MPXV subclade Ib/2023sh infection were more often female (290 [59%]) and were generally older (median 16 years [4–25]) than male participants (204 [41%]; median age 4 years [1–14]). 300 (61%) of 494 participants were aged 15 years or younger. Fever (444 [90%]), skin lesions or rash (391 [79%]), and dysphagia (279 [56%]) were the most prevalent symptoms. Children aged 0–5 years had a higher frequency of lesions on the head (84 [41%] of 203), face (67 [33%]), neck (23 [11%]), back (27 [13%]), arm (35 [17%]), palm of hand (35 [17%]), chest (46 [23%]), posterior aspect of thighs (40 [20%]), legs (25 [12%]), dorsal foot (45 [22%]), and oral cavity (37 [18%]). 117 (24%) participants had lesions in the oral cavity. Oral cavity and oropharynx swabs were able to detect MPXV subclade Ib/2023sh in the absence of assayable skin lesions.

Interpretation

The high proportion of children and adolescents (aged ≤15 years) differentiates our cohort from other clinical descriptions of the novel MPXV subclade Ib/2023sh. Given that, we hypothesise a demographic shift in the target population that contributes to the community spread of mpox in the South Kivu region of DR Congo. Targeted public health measures should consider ways to reduce transmission among children and adolescents.

Funding

Canadian Institutes of Health Research (CIHR), Canadian Foundation for Innovation, Research Nova Scotia, Dalhousie Medical Foundation, Moderna, Li-Ka Shing Foundation, European & Developing Countries Clinical Trials Partnership (EDCTP).

Translations

For the French, Swahili and Mashi translations of the abstract see Supplementary Materials section.

Source: 

Link: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(26)00051-4/fulltext?rss=yes

____

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

 

{Excerpt}

(...)

Results

NAb geometric mean titers against H1N1 WI/22, H3N2 BA/22, H3N2 CR/23, H3N2-K BA/25, and H3N2-K NY/25 were 200, 231, 119, 50, and 60 at baseline and increased to 582, 661, 356, 85, and 119 at peak immunogenicity, respectively (...), reflecting a significant 2.86- to 2.99-fold increase in NAb titers against the prior H1N1 and H3N2 strains but a lower 1.70- to 1.98-fold increase in NAb titers against the H3N2-K strains. Baseline antibody titers to the H3N2-K strains were 2.0- to 4.6-fold lower than to the prior H1N1 and H3N2 strains (P < .001), and peak antibody titers to the H3N2-K strains following vaccination were 3.0- to 7.8-fold lower than to the prior H1N1 and H3N2 strains (P < .001).

(...)

Source: 

Link: https://jamanetwork.com/journals/jama/fullarticle/2846268?guestAccessKey=10f1c0a1-4189-438d-9f71-a588fdd0db53&utm_medium=email&utm_source=postup_jn&utm_campaign=article_alert-jama&utm_content=olf-tfl_&utm_term=030926#250858592

____

#Colombia - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 

Within the epidemiological surveillance carried out by the Colombian Agricultural Institute aimed at the early detection of clinical signs consistent with avian influenza, an outbreak of high pathogenicity avian influenza (HPAI) was confirmed in the village of Porvenir, in the municipality of Puerto Concordia in the department of Meta. The event concerns non-poultry in a backyard, for which respiratory and neurological signs were observed. The National Veterinary Authority activated epidemiological tracing and epidemiological monitoring actions in the area of origin of the affected birds. As a control measure, the stamping out of the birds in the epidemiological unit was carried out, and, as a complementary measure, epidemiological surveillance was strengthened in the surrounding area to identify other possible cases and prevent the spread of the disease.

Source: 

Link: https://wahis.woah.org/#/in-review/7345

____

Spatiotemporal #clustering of highly pathogenic avian #influenza (HPAI) #H5N1 at the wild #waterfowl - #poultry interface: Vector-specific #spillover risks in the #US, 2022–2025

 

Abstract

Background: 

The emergence of the highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b in North America, beginning in February 2022, has highlighted the dynamic, unpredictable, and regionally variable risk of infections. Studies are needed to assess the spatiotemporal clustering of HPAI H5 at the interface between wild waterfowl and commercial poultry to understand and mitigate this risk. 

Methods: 

Publicly available data on HPAI H5 detections in wild birds and commercial poultry from January 2022 to January 2026 were analyzed at the county level. Retrospective space-time permutation models were used to identify and scan for clusters with higher than expected detection rates. 

Results: 

A total of 17,091 HPAI H5 detections were reported in wild birds across 1,467 county-level locations. Four species, Mallard (Anas platyrhynchos) (2,848 detections, 16.66%), Canada goose (Branta canadensis) (1,496, 8.75%), Green-winged teal (Anas carolinensis) (1,364, 7.98%), and Snow goose (Anser caerulescens) (1,084, 6.34%), accounted for 39.73% of detections. In commercial poultry, 532 outbreaks in turkey operations, 148 outbreaks in table-egg layer operations, 99 outbreaks in broiler chicken operations, and 89 outbreaks in commercial duck operations were reported, respectively. Several spillover events followed an east-to-west expansion. In early 2022, mallard detections preceded outbreaks in Northeast egg-layer and duck farms, while snow goose detections in the Upper Midwest coincided with turkey farm outbreaks. In the Pacific and Mountain West during summer 2022, detections in Canada geese overlapped with turkey farm outbreaks. A resurgence occurred in the Midwest (2025), with snow and Canada goose detections overlapping severe outbreaks in turkey and layer flocks. Additionally, in the Upper Midwest, Canada goose and mallard detections overlapped with outbreaks in commercial duck farms during fall-winter 2025. 

Conclusions: 

The study findings demonstrate distinct vector-based transmission dynamics of HPAI H5 at the wild waterfowl-poultry interface. Farm biosecurity strategies must adapt to these recurrent, vector-specific risks.

Competing Interest Statement

The authors have declared no competing interest.

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.03.06.710020v1

____

#H5N1 2.3.4.4b HA E190D and Q226H #mutations, picked up as minority #variants in a #patient, result in an inability to bind #sialic acid.

 

Abstract

A human infection with clade 2.3.4.4b H5N1 influenza A virus in Canada revealed minority variants E190D and Q226H in the hemagglutinin (HA) receptor-binding site (RBS). Because mutations at positions 190 and 226 have been associated with altered receptor specificity in other influenza subtypes, we investigated their impact on receptor binding in H5 HA. Using a recombinant protein approach and an ELISA-based glycan-binding assay, we assessed binding to representative avian- and human-type sialylated glycans. Both single mutations and their combination resulted in a complete loss of detectable binding to the tested glycans. To evaluate whether this phenotype was background-dependent, Q226H was additionally introduced into two other H5 HA proteins, each representing a distinct clade. In both cases, the mutation similarly abolished receptor binding. These findings independently validate recent glycan microarray observations and demonstrate that the patient-derived E190D and Q226H substitutions severely impair receptor-binding capacity across multiple H5 backgrounds. Single mutations at key RBS residues in H5 often disrupt receptor binding rather than confer human-type receptor specificity, confirming complex mutational pathways required for adaptation to human-type receptors.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

ICRAD, n°862605 (Flu-Switch)

NWO, OCENW.M20.106

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.03.06.710037v1

____

The Grenouillère, Claude Monet (1869)

 

Public Domain.

Source: 

Link: https://www.wikiart.org/en/claude-monet/the-grenouill%C3%A8re

____

#Community-Based #Surveillance for Highly Pathogenic Avian #Influenza Viruses among Deceased #Birds

 

Abstract

Highly pathogenic avian influenza (HPAI) viruses of H5N1 clade 2.3.4.4b, are spreading worldwide, posing a threat to wildlife, domestic animals, and humans. In 2025, a multidisciplinary collaboration for HPAI H5N1 surveillance among birds within Galveston County, Texas, was initiated. Between November and December 2025, oropharyngeal and cloacal swabs were collected from wild and domestic birds reported as dead or dying by Galveston County residents. Specimens were studied with molecular assays, Sanger sequencing, virus isolation, and next-generation sequencing. Molecular evidence of HPAI H5N1 was detected in 7 of 10 (70%) birds, and the virus was successfully cultured in MDCK cells. Next-generation sequencing analysis of eight influenza A genome segments demonstrated a 4:4 gene segment reassortant constellation within clade 2.3.4.4b, consistent with genotype D1.1. Community members exposed to HPAI were offered antiviral prophylaxis. No human infections were identified. This surveillance demonstrates that community involvement combined with cross-sectoral collaboration can ensure rapid detection and characterization of circulating avian influenza viruses. Sustained local surveillance is essential for early warning, risk assessment, and prevention of virus spread to poultry, mammals, and humans.

Competing Interest Statement

The authors have declared no competing interest.

Source: 

Link: https://www.biorxiv.org/content/10.64898/2026.03.06.710164v1

____