#Bulgaria - High pathogenicity avian #influenza #H5 viruses (#poultry) (Inf. with) - Immediate notification

 

A poultry farm in Haskovo Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6861

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#Netherlands - High pathogenicity avian #influenza #H5 viruses (#poultry) (Inf. with) - Immediate notification

 

On 6 October 2025, an outbreak of H5 was confirmed on a breeding poultry farm in Gasselternijveenschemond, a 3 km protection zone and a 10 km surveillance zone have been established. In the 3 km zone there are 6 other poultry premises. The poultry farms in the 3 km zone have been screened (examined, sampled and tested) and results coming in next follow up report. The subtype HPAI H5 is confirmed by the national reference laboratory (NRL). All susceptible animals on the infected premise have been killed.

Source: WOAH, https://wahis.woah.org/#/in-review/6856

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#Denmark - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 

The Danish Veterinary and Food Administration has established a 3 km and 10 km zone around the poultry holding and is implementing the necessary measures in accordance with the European Union Animal Health Law.

On 6 October 2025 a clinical suspicion was reported to the Danish Veterinary and Food Administration. The affected poultry holding consists of 150000 laying hens. On 7 October 2025 highly pathogenic avian influenza sub. H5N1 was confirmed by the national reference laboratory. A 3 km protection zone and a 10 km surveillance zone has been established. The culling is planned to be initiated on 8 October 2025.

Source: WOAH, https://wahis.woah.org/#/in-review/6858

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Molecular divergence and #convergence of mammalian #antibody responses to the #influenza virus #hemagglutinin stem

 

Significance

Since pigs serve as intermediate hosts between humans and the natural reservoir of influenza viruses in wild birds, they play a key role in the emergence of influenza strains with pandemic potential, as demonstrated by the 2009 pandemic. Therefore, influenza pandemic preparedness will benefit from the development of vaccines that broadly protect pigs against diverse influenza A strains. However, progress is limited by our poor molecular understanding of porcine antibody responses to influenza virus. This study isolates and characterizes a panel of broadly neutralizing influenza antibodies from pigs. Our findings not only have significant implications for the development of broadly protective influenza vaccines for pigs, but also reveal the molecular differences in the antibody responses between pigs and humans.

Abstract

Antibody responses to the influenza virus hemagglutinin (HA) stem, a major target for broadly protective vaccine development, have been extensively characterized in humans. However, they remain largely elusive in other natural influenza hosts, including pigs, which are considered intermediate hosts for the emergence of pandemic strains. By leveraging single-cell variable, diversity, and joining (VDJ) sequencing, this study identified 25 porcine antibodies to the HA stem, including two cross-group bnAbs, 14-8 and 15-1, from vaccinated specific-pathogen-free pigs and unvaccinated domestic pigs. Cryogenic electron microscopy analysis showed that 14-8 targeted the well-characterized central stem epitope, whereas 15-1 bound to a linear epitope spanning the HA1/HA2 junction. Additionally, while some porcine and human bnAbs targeted the central stem epitope via convergent molecular signatures, our results revealed a pig-specific recurring binding motif. Overall, our findings provide important insights into the commonalities and uniqueness of antibody responses between different species, which have significant implications for vaccine development for nonhuman animals.

Source: Proceedings of the National Academy of Sciences of the United States of America, https://www.pnas.org/doi/abs/10.1073/pnas.2510927122?af=R

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Molecular basis of #SARS-CoV-2 proofreading enzyme–mediated #resistance to #remdesivir

 

Abstract

SARS-CoV-2’s remarkable resistance to nucleotide analog antivirals such as remdesivir, which thwarts RNA synthesis by inhibiting viral polymerase (RdRp), challenges available therapies. We reveal that remdesivir incorporation destabilizes RdRp–RNA complex while enhancing RNA binding to the proofreading exoribonuclease (ExoN), facilitating remdesivir excision. Conserved ExoN determinants for remdesivir recognition and excision underpin ExoN-mediated resistance across all coronaviruses. These findings inform the design of next-generation antivirals and combination therapies capable of overcoming ExoN-mediated resistance.

Source: Proceedings of the National Academy of Sciences of the United States of America, https://www.pnas.org/doi/full/10.1073/pnas.2519755122

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Association of 2024–2025 #Covid19 #Vaccine with Covid-19 #Outcomes in #US #Veterans

 

Abstract

Background

Amid the declining clinical severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and diminishing public uptake of annual coronavirus disease 2019 (Covid-19) vaccines, contemporary evidence on vaccine effectiveness against clinically relevant outcomes is needed.

Methods

We conducted an observational study that used the electronic health records of the Department of Veterans Affairs to evaluate the effectiveness of the 2024–2025 Covid-19 vaccine among veterans who received the Covid-19 and influenza vaccines on the same day (164,132 participants) and in an active-comparator group of veterans who received the influenza vaccine only (131,839 participants), between September 3 and December 31, 2024. Participants were followed for 180 days or until the occurrence of an outcome, whichever came first. We used inverse-probability–weighted models to estimate vaccine effectiveness (calculated as 1 minus the risk ratio) against Covid-19–associated emergency department visits, hospitalizations, and deaths at 6 months.

Results

At 6 months of follow-up, the estimated vaccine effectiveness was 29.3% (95% confidence interval [CI], 19.1 to 39.2) against Covid-19–associated emergency department visits (risk difference per 10,000 persons, 18.3; 95% CI, 10.8 to 27.6), 39.2% (95% CI, 21.6 to 54.5) against Covid-19–associated hospitalizations (risk difference per 10,000 persons, 7.5; 95% CI, 3.4 to 13.0), and 64.0% (95% CI, 23.0 to 85.8) against Covid-19–associated deaths (risk difference per 10,000 persons, 2.2; 95% CI, 0.5 to 6.9). Vaccine effectiveness against a composite of these outcomes was 28.3% (95% CI, 18.2 to 38.2), with a risk difference per 10,000 persons of 18.2 (95% CI, 10.7 to 27.5). The Covid-19 vaccine was associated with decreased risks of these outcomes across prespecified subgroups defined according to age (<65 years, 65 to 75 years, and >75 years), the presence or absence of major coexisting conditions, and immunocompetence status.

Conclusions

In this national cohort of U.S. veterans, the receipt of the 2024–2025 Covid-19 vaccine was associated with decreased risks of severe clinical outcomes. (Funded by the Department of Veterans Affairs.)

Source: The New England Journal of Medicine, https://www.nejm.org/doi/full/10.1056/NEJMoa2510226?query=TOC

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

 

{By Charles J. Sharp - Own work, from Sharp Photography, sharpphotography.co.uk, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116380120}

Nineteen captive Painted Storks in the National Zoological Park, Delhi.

Source: WOAH, https://wahis.woah.org/#/in-review/6803

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Comparative #risk #assessment of highly pathogenic avian #influenza #H5 viruses spread in French #broiler and layer sectors

 

Abstract

Since 2015, French poultry production is threatened almost every year by a reintroduction of highly pathogenic avian influenza H5 viruses. The duck sector was the most concerned by this crisis but other sectors such as broiler, layer and turkey were also affected by outbreaks. The objective of this work was to assess the risk of highly pathogenic avian influenza H5 virus transmission from one farm to another within the French broiler and layer production network. This study used the WOAH risk assessment framework. After drawing up a scenario tree of virus transmission from one farm to another, data were collected through a literature review or through experts elicitation. Three questionnaires were developed according to the experts field of expertise: avian influenza, broiler and layer sectors. The experts estimates were combined using a beta distribution weighted by their confidence level. A Monte Carlo iteration process was used to combine the different probabilities of the scenario tree and to assess the transmission risk. In the broiler sector, the highest transmission probabilities were observed if the exposed farm was an indoor broiler farm and the source a broiler farm (indoor or free-range). The high transmission probability between broiler farms integrated within the same association suggests that integration is an important risk factor. Person movement, transport of feed and manure management were the pathways with the highest transmission probabilities between two integrated indoor broiler farms with good biosecurity levels. In the layer sector, the highest transmission probabilities were observed if the source farm was a free-range farm and the exposed farm a production farm (indoor or free-range). The pathways with the highest transmission probabilities were egg transport and person movement. The sensitivity analysis showed that the exposed farm's biosecurity had a significant impact on the transmission probability. Our results provide an insight on the role of each type of farms in the virus spread within the French broiler and layer production sectors and will be useful for the implementation of control measures such as movement restriction or vaccination.

Competing Interest Statement

The authors have declared no competing interest.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2024.09.11.612235v5

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Maternal #Influenza A Virus #Infection Induces Antiviral and Immune Dysregulation in the #Placenta and #Fetus Without Vertical Transmission

 

Abstract

Influenza A virus (IAV) infection during pregnancy is associated with stillbirth and preterm birth, possibly by disrupting placental and fetal immunity. To investigate this, pregnant pigtail macaques were inoculated with IAV [A/California/07/2009 (H1N1)] and examined at necropsy 5 days post-infection (N=11) versus uninfected controls (N=16). Stillbirth occurred in 18% of infected pregnancies but not in controls. While vertical transmission was not observed, low levels of viral RNA were detected in two placentas. Maternal IAV infection was associated with increased placental IL-1β and IFN-β levels and an upregulated type I interferon and integrated stress transcriptional response. Fetuses exposed to IAV had greater frequencies of innate immune cells in lymph nodes and CD4+ T cells in lungs. These results suggest that placental and fetal immune environments undergo immune activation independent of the severity of maternal lung infection. Influenza vaccination during pregnancy may protect against potentially harmful effects on fetal development.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

National Institutes of Health, https://ror.org/01cwqze88, AI164588, AI176777, AI007509

Foundation for the National Institutes of Health, https://ror.org/00k86s890, OD010425, TR002318, GM007266, OD011123

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.10.06.675688v1

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#Iran - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 

A backyard village poultry in Ardebil Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6849

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#Poland - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 

{By JJ Harrison - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=5014480}

A slaugthter geese farm in Wielkopolskie Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6852

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

 

{By Aviceda - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4017548}

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In accordance with the WOAH Terrestrial Animal Health Code, Article 10.4.1, point 4, this outbreak does not change the disease-free status of Sweden as these are wild birds, and therefore do not fall within the WOAH definition of poultry.

A Mediterranean Gull was found dead. It was sent to the Swedish Veterinary Agency for laboratory analysis as part of the national surveillance program for avian influenza.

Source: WOAH, https://wahis.woah.org/#/in-review/6853

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Host Switching #Mutations in #H5N1 #Influenza Hemagglutinin Suppress Site-specific Activation Dynamics

 

Abstract

Increase in the occurrence of human H5N1 spillover infections resulting from dissemination of highly pathogenic avian influenza (HPAI) virus into bird and mammal populations raises concerns about HPAI adapting to become human transmissible. Studies identified hemagglutinin (HA) acid stability and receptor preference as essential traits that shape host tropism. Mutations that increase HA stability and affinity for α-2,6-linked sialic acids have been shown to confer airborne transmissibility in a ferret model, however mechanisms of activation of H5 subtype HA have not been probed and the effect of adaptive mutations on HA function has been largely inferred from static structures. Here, we use hydrogen/deuterium-exchange mass spectrometry to dissect activation dynamics for two ancestral HPAI H5 HA, their matched HA with adaptive mutations, and a contemporary H5 HA. By measuring dynamics, we identify variation in active site flexibility among the HA and demonstrate that adaptive mutations result in suppression of fusion peptide dynamics and stabilization of a key subunit interface involved in activation. The contemporary H5 isolated from a recent human spillover case exhibits a relatively protected fusion peptide and moderately depressed pH of activation compared to the HAs examined in this study. Our studies of activation dynamics in the H5 HAs in conjunction with prior analysis of H1 and H3 HA reveal subtype-specific patterns that correlate with adaptive mutation sites and indicate underlying physical constraints on influenza HA adaptation.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

NIH Common Fund, https://ror.org/001d55x84, R01AI165808, T32-GM007750

Hope Barnes Fellowship

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.10.06.680362v1

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Re-emergence of #chikungunya virus in #China by 2025: What we know and what to do?

 

Abstract

In July 2025, China witnessed its most significant chikungunya virus (CHIKV) outbreak since 2010. As of August 1, with over 6,000 cases reported in Foshan city, Guangdong Province. Although the clinical manifestations have been relatively mild, the rapid transmission within communities warrants our attention. In this context, we emphasize our current knowledge and the necessary actions to take. Specifically, we identify critical gaps in CHIKV control efforts and assess the effectiveness of current measures. These include vector management strategies, viral genomic surveillance, the deployment of newly approved vaccines, and the development of antiviral agents. Overall, to effectively control the epidemic of CHIKV, we require a comprehensive and multifaceted strategy for its prevention and management.

Source: PLoS Pathogens, https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013556

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#Germany - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 

A poultry farm in Thüringen Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6844

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

 

According to article 10.4.1.4 of the Terrestrial Animal Health Code, Member Countries should not impose bans on the trade in poultry commodities in response to notification on the presence of any influenza A virus in birds other than poultry.

A wild black-headed gull in Vordingborg. 

Source: WOAH, https://wahis.woah.org/#/in-review/6846

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Protective efficacy of the UniFluVec #influenza #vaccine vector against the highly pathogenic influenza A/Indonesia/5/2005 #H5N1 strain in #ferrets

 

Highlights

• UniFluVec, an H1N1pdm vaccine candidate, includes NS1 and NEP modifications to boost attenuation and immunity.

• UniFluVec protects ferrets from H5N1, enhancing clearance, limiting lung damage, and ensuring 100 % survival after one dose.

• Replication-deficient UniFluVec shows cross-protection, supporting its potential as a pre-pandemic intranasal vaccine.

Abstract

Background

The emergence of new influenza strains with unpredictable antigenic properties poses a significant vaccination challenge. The increasing incidence of human H5 infections underscores the urgent need for effective pre-pandemic vaccines.

Methods

The UniFluVec and UniFluVec-wtNS1 viruses were designed as H1N1pdm vaccine candidates. Both viruses contained a heterologous A/Singapore/1/57-like (H2N2) NEP gene, which served as an attenuation factor. UniFluVec additionally carried a truncated to 124 amino acids NS1 gene, and an insertion of conserved influenza sequences. UniFluVec-wtNS1 retained the wild-type NS1 gene. The impact of NS1 and NEP modifications on attenuation and phenotypic markers was assessed in cells and mice. Safety and prophylactic efficacy were assessed in ferrets following a single intranasal immunisation with the maximum feasible dose (8.7 log10 EID50), followed by challenge with the highly pathogenic avian influenza virus (HPAIV) A/Indonesia/5/2005 (H5N1).

Results

Modifications in NS1 and NEP independently and synergistically induced a temperature-sensitive phenotype and enhanced type I/II interferon response, resulting in a highly attenuated vaccine profile. UniFluVec, incorporating both modifications within the NS genomic segment, demonstrated superior viral clearance, reducing lung damage, and ensuring 100 % survival in infected animals.

Conclusion

The replication-deficient UniFluVec vector demonstrates safety, immunogenicity, and protective efficacy against the heterologous HPAIV strain in ferrets following a single intranasal administration.

Source: Vaccine, https://www.sciencedirect.com/science/article/pii/S0264410X25010928?via%3Dihub

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Highly pathogenic avian #influenza in South #America, 2022-25: temporality, affected #species, and southwards #expansion to #Antarctic region.

 

Abstract

The H5N1 highly pathogenic avian influenza (HPAI) virus has caused severe global losses, reaching South America in 2022 and Antarctica in 2024. Here we synthesize outbreak reports submitted to the World Organization for Animal Health (WOAH) by South American countries and document the virus's unprecedented expansion into Antarctica, affecting wild birds, wild mammals, and domestic poultry. More than 6 million domestic birds died or were culled, mostly from commercial operations. Of the 11 South American countries that reported H5N1 to WOAH, 10 reported infections in wild birds, spanning 104 species, 59.62% of which are migratory and predominantly non-trans-equatorial. Marine mammal cases occurred after wild bird detections, with the South American sea lion (Otaria flavescens) most affected, and several Antarctic bird species with migratory behavior were also reported in South America. To complement outbreak data, we examined available genomic sequences through phylogenetic and time-calibrated Bayesian analyses, which revealed multiple introduction events, viral diversity across regions, and evidence of interspecies transmission dynamics. These findings highlight the extensive ecological reach of H5N1 in the Southern Hemisphere and underscore the urgent need for a One Health approach that strengthens wildlife and backyard-poultry surveillance while fostering coordinated regional action to control and prevent further spread of HPAI.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.10.03.680239v1

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Paradise, Tintoretto (c. 1592)

 

Public Domain.

Source: WikiArt, https://www.wikiart.org/en/tintoretto/paradise

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First serological #evidence of equine #coronavirus and #SARS-CoV-2 in #horses in North #Africa

 

Abstract

Viral diseases cause significant economic losses within the equine population. Horses are susceptible to equine coronavirus (ECoV) and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), although only ECoV has been associated to clinical disease. The aim of this study was to investigate, for the first time in Algeria, the seroprevalence of ECoV and SARS-CoV-2 antibodies and the prevalence of ECoV infection in horses. In 2022, a total of 299 serum samples was collected from horses aged 1 to 27 years. Serological analysis for the presence of ECoV and SARS-CoV-2 was performed using a validated in-house and a commercially available ELISA, respectively. In addition, fecal samples of these animals were tested for the presence of ECoV RNA by RT-qPCR. SARS-CoV-2-ELISA positive sera with high S/P ratios and negative samples close to the doubtful threshold were retested using a virus neutralization test (VNT). The seroprevalence of ECoV and SARS-CoV-2 in the tested horses was 63.5% (190/299) and 4.3% (13/299), respectively. Among CoVs-seropositive horses, six were seropositive for both ECoV and SARS-CoV-2, thus 6/10 sera were VNT positive, including two ELISA-negative samples for SARS-CoV-2. ECoV seroprevalence varied according to age, breed and sex. None of the fecal samples tested positive for ECoV. Antibodies against SARS-CoV-2 were confirmed by VNT in six samples (2%). One SARS-CoV-2-positive serum tested by ELISA and confirmed through VNT was cytotoxic for VERO cells. This study is the first to report the circulation of ECoV and SARS-CoV-2 in the Algerian horse population. Further studies are necessary to isolate and obtain molecular characterisation of ECoV and SARS-CoV-2 from horses in Algeria.

Source: Veterinary Research Communications, https://link.springer.com/article/10.1007/s11259-025-10928-0

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