ETIDIOH - NEW

  Abstract Influenza remains a significant global public health concern. Live-attenuated influenza vaccines (LAIVs) are recognized as effective interventions for influenza prevention. Currently, two types of LAIVs are licensed for human use: one developed through cold-adapted viral gene mutation and the other through the deletion of the viral NS1 gene . However, the similarities and differences in these two LAIVs’ efficacy, safety, and immune responses have not been thoroughly studied. This study constructed a gene-deficient live-attenuated vaccine strain, CA4-dNS1, and a gene locus-mutated attenuated vaccine strain, CA4-cold , to compare their in vivo and in vitro replication capacity , broad-spectrum protective efficacy , safety, and immunogenicity . The results showed that both LAIVs provide comparable broad-spectrum protection against lethal H1N1 and H5N1 influenza challenges in mice and induce similar humoral and mucosal immune responses . Notably, the CA4-cold vaccine strain ...

{Excerpt} Country 2024 (cases - deaths) - 2025 (cases - deaths) - Total (cases - deaths) 1) Australia - 1 - 0 - 0 - 0 - 1 - 0   2) Azerbaijan - ... - ... - 0 - 0 - 8 - 5  3) Bangladesh - ... - ... -  3 - 0 - 11 - 1  4) Cambodia - 10 - 2 - 17 - 8 - 89 - 51  5) Canada - 1 - 0 - 0 - 0 - 2 - 1  6) Chile - ... - ... - 0 - 0 - 1 - 0  7) China - 1 - 0 - 1 - 0 - 57 - 32  8) Djibouti - ... - ... - 0 - 0 - 1 - 0  9) Ecuador - ... - ... - 0 - 0 - 1 - 0  10) Egypt - ... - ... - 0 - 0 - 359 - 120  11) India - ... - ... - 2 - 2 - 3 - 3  12) Indonesia - ... - ... - 0 - 0 - 200 - 168  13) Iraq - ... - ... - 0 - 0 - 3 - 2  14) Lao People's Democratic Republic - ... - ... - 0 - 0 - 3 - 2  15) Mexico - ... - ... - 1 - 1 - 1 - 1  16) Myanmar - ... - ... - 0 - 0 - 1 - 0  17) Nepal - ... - ... - 0 - 0 - 1 - 1  18) Nigeria - ... - ... - 0 - 0 - 1 - 1  19) Pakistan - ... - ... - 0 - 0 - 3 - 1  20) Spain - ... - ...

  Abstract Finland faced an outbreak of highly pathogenic clade 2.3.4.4b A(H5N1) avian influenza in 2023, which spread from wild birds to fur farms . Vaccinations of at-risk individuals began in June 2024 using the MF59-adjuvanted inactivated A(H5N8) vaccine (Seqirus; A/Astrakhan/3212/2020, clade 2.3.4.4b). Here, in an observational study , we assessed vaccine-induced immune responses in occupational at-risk individuals participating in the phase IV trial , including virus-specific antibody (n = 39 individuals) and T-cell (n = 18 individuals) responses. Vaccination elicited functional antibodies against the vaccine virus and two heterologous clade 2.3.4.4b strains associated with outbreaks on Finnish fur farms and dairy cattle in the United States . Among previously unvaccinated individuals, seroprotection rates against the vaccine virus were 83% (95% CI 70–97%) by microneutralization assay (titre ≥20) and 97% (90–100%) by haemagglutination inhibition assay (titre ≥40). In those pr...

  Abstract Increase in human H5N1 spillover infections resulting from dissemination of highly pathogenic avian influenza (HPAI) virus into bird and mammal populations raises concerns about HPAI gaining human transmissibility . 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 are poorly understood 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 H5 HPAI HA , their transmission-adapted HA , and a contemporary HA . We identify variation in receptor binding site flexibility and demonstrate that adaptive mutations result in suppression of fusion peptide dynam...

  {Summary} Time Period: November 23, 2025 - November 29, 2025 -- H5 Detection :  2 site(s) ( 0.6% ) -- No Detection :  352 site(s) ( 99.4% ) -- No samples in last week :  102 site(s) (...) Source:   Link:  https://www.cdc.gov/nwss/rv/wwd-h5.html ____

  A backyard, multi-species, farming operation was tested and confirmed positive for HPAI H5N1. Source:  Link:  https://wahis.woah.org/#/in-review/7072 ____

  Highlights •  Fermentation of raw milk for 7 h at 42 °C to pH 4.4 reduced AIV levelsAIV by ≤ 4.1 log10 EID50. •  Incubation of raw milk for 7 h at 42 °C to pH 6.6 reduced levels by ≤ 4.3 log10 EID50. •  PH, temperature and/or bacterial degradation appreciably reduced AIV levels in raw milk. Abstract In March 2024, highly pathogenic avian influenza (HPAIV) H5N1 was first detected in U.S. dairy cattle and has since spread to herds across at least 17 states. Infected cows typically present with mastitis, decreased milk production, and poor milk quality with high viral loads in milk . While commercial pasteurization of milk effectively inactivates avian influenza virus (AIV), growing consumer interest in raw milk and derived products raises public health concerns due to the risk of zoonotic transmission . Standard yogurt production includes an initial heating step at 82 °C for 30 min to denature milk proteins which also inactivates AIV . However, some home yogurt recip...

  Abstract The spillover of H5N1 clade 2.3.4.4b into dairy cattle has raised concerns over the safety of fluid milk . While no foodborne infection has been reported in humans, this strain has infected at least 70 people and milk from infected cows is known to be infectious by ingestion in multiple other species. Investigation into the public health threat of this outbreak is warranted. This farm-to-table quantitative microbial risk assessment (QMRA) uses stochastic models to assess the risk of human infection from consumption of raw and pasteurized fluid cow's milk from the United States supply chains. These models were parameterized with literature emerging from this outbreak, then employed to estimate the H5N1 infection risk and evaluate multiple potential interventions aimed at reducing this risk. The median (5th, 95th percentiles) probabilities of infection per 240-mL serving of pasteurized, farmstore-purchased raw, or retail-purchased raw milk were 7.66E-19 (2.39E-20, 4.02E-17...

  {Excerpt} To the Editor : In March 2024, public health agencies in the United States reported highly pathogenic avian influenza (HPAI) virus of subtype A( H5N1 ) in dairy cattle , with virus detected in milk samples from symptomatic animals. Viral genetic fragments were subsequently found in pasteurized retail dairy products , which aroused concern about potential exposure through the human food supply . Heat treatment has been shown to reduce or eliminate infectious virus from both milk from infected cows and milk spiked with HPAI A(H5N1) virus. However, whether HPAI A(H5N1) virus in spiked milk from healthy cows replicates the properties of virus in milk from infected cows is unclear. We directly compared the stability of HPAI A(H5N1) virus in infected cows’ milk with that in spiked milk at 4°C (refrigeration temperature) and after heat treatment at 63°C (low-temperature, longer-duration pasteurization) or 72°C (high-temperature, shorter-duration pasteurization). (...) (...) So...

{Excerpt} Several cats in Neuruppin have been infected with avian influenza , according to the Ostprignitz-Ruppin district administration . They have been taken into the care of the Office for Consumer Protection and Agriculture, the district announced. A cat infected with the H5N1 strain of the avian influenza virus was found dead in a wooded area near the town. Several media outlets have reported on this.  (...) Source:  Link:  https://www.tagesspiegel.de/berlin/vogelgrippe-in-brandenburg-katzen-mit-geflugelpest-infiziert--warnung-vom-kreis-15014940.html ____

  Fattening birds suddenly dead. No biosecurity measures or vaccination plan. San Marcos Region. Source:  Link:  https://wahis.woah.org/#/in-review/7064 ____

  Within the epidemiological surveillance carried out by the Colombian Agricultural Institute (ICA) aimed at the early detection of clinical signs consistent with avian influenza, an outbreak of Highly Pathogenic Avian Influenza (HPAI) was confirmed in the village of Las Mercedes , in the municipality of Guaranda , in the department of Sucre . The event concerns non-poultry in a backyard , where respiratory and neurological signs were observed. The National Veterinary System activated epidemiological tracing and follow-up 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. The affected population is composed of birds in a backyard not considered to be poultry which tested positive for Highly Pathogenic Avian Influe...

Farmed and  Backyard poultry in Uttarakhand State. Source:  Link:  https://wahis.woah.org/#/in-review/6804 ____

  Abstract Highly pathogenic avian influenza (HPAI) represents a threat to animal and human health, with the ongoing H5N1 outbreak within the H5 2.3.4.4b clade being one of the largest on record . However, it remains unclear what factors have contributed to its intercontinental spread . We use Bayesian additive regression trees , a machine learning method designed for probabilistic modelling of complex nonlinear phenomena , to construct species distribution models (SDMs) for HPAI clade 2.3.4.4b presence. We identify factors driving geospatial patterns of infection and project risk distributions across Europe . Our models are time-stratified to capture both seasonal changes in risk and shifts in epidemiology associated with the succession of H5N6/H5N8 by H5N1 within the clade . While previous studies aimed to model HPAI presence from physical geography, we explicitly consider wild bird ecology by including estimates of bird species richness, abundance of specific taxa, and “abundanc...

  The Hague, December 2 (Xinhua)  Dutch Minister of Agriculture, Fisheries, Food Safety and Nature, Femke Wilsma, reported on December 1 that the country had confirmed its first death from the H5N1 highly pathogenic avian influenza virus . In a letter to the House of Representatives that day, Wilsma stated that the Institute of Biological Veterinary Medicine at Wageningen University had recently reported that a kitten at a goat farm tested positive for the highly pathogenic H5N1 avian influenza virus .  The kitten was found dead by its owner.  The remaining seven kittens from the same litter also died after being given to other new owners, suggesting that they may have also been infected with the avian influenza virus, but the specific route of infection is still uncertain. The letter stated that, according to the cat owner, the mother cat had brought back a dead wild bird , which was suspected to have carried the avian influenza virus, and the kittens were infected ...

{Al-Anbar Region} During routine inspections of poultry houses by veterinarians, several cases were detected by rapid tests. Samples were then sent to the central laboratory for confirmation of infection. All disease control protocols were implemented, including restricting movement, culling both healthy and infected poultry, and disinfecting the premises. A follow-up report will be submitted. Source:  Link:  https://wahis.woah.org/#/in-review/7067 ____

  {Summary} Time Period: November 16, 2025 - November 22, 2025 -- H5 Detection :  6 site(s) ( 1.4% ) -- No Detection :  410 site(s) ( 98.6% ) -- No samples in last week :  50 site(s) (...) Source:  Link:  https://www.cdc.gov/nwss/rv/wwd-h5.html ____

  Abstract The global spread of highly pathogenic avian influenza A(H5N1) viruses poses a serious pandemic threat . While sustained human-to-human transmission has not occurred, widespread circulation in birds , increased detection in mammals , and occasional human spillovers underscore the need for safe and effective vaccines . We evaluated an H5 mRNA vaccine candidate in ferrets using recent clade 2.3.4.4b A(H5N1) human isolates. Vaccination elicited strong neutralizing antibodies , conferred robust protection against lethal challenge , and significantly reduced viral titers . In a direct contact transmission model , mRNA vaccination decreased virus shedding in inoculated ferrets and reduced onward transmission ; it also protected vaccinated contact ferrets from infection following exposure to virus-shedding, unvaccinated ferrets. Additionally, sera from vaccinated animals cross-neutralized clade 2.3.2.1e human viruses to varying degrees, depending on the strain. These findings d...

  Abstract Highly pathogenic avian influenza (HPAI) H5 viruses have recently been documented in mammals including humans , posing a major threat to global public health . To prevent a potential H5 pandemic , it is critical to elucidate the antigenic evolutionary pattern and identify key drivers underlying its evolution . In this work, we construct a comprehensive antigenic map of H5 influenza viruses spanning their evolutionary history and classified three antigenic clusters with no cross-neutralization . The first corresponds to ancestral clades, the second to 2.3.4.4* clades being predominant since 2010, and the third to 2.3.4.4 h clade. Despite the gradually increasing genetic distances from ancestral to 2.3.4.4* to 2.3.4.4 h, their antigenic evolution does not follow the same progressive pattern: the antigenic distance between 2.3.4.4 h and ancestral is smaller than that between 2.3.4.4* and ancestral . This divergence is associated with two distinct mutation patterns at six ke...

  Abstract Laridae birds, such as gulls, are known reservoirs of H13 and H16 low pathogenic avian influenza subtypes . However, during the recent outbreaks linked to the reemergence of high pathogenicity avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b of the Goose/Guangdong lineage, European populations of those birds suffered significant losses. HPAI cases were registered not only along the coastlines but also inland areas , particularly in France and Central Europe . During a diagnostic investigation of a group of Laridae birds , part of a HPAIV outbreak registered in the South of France in 2023, larval stages of Ornithodoros maritimus , a nidicolous soft tick parasitizing seabirds, were recovered from a slender-billed gull (Chroicocephalus genei). Affected birds exhibited gross and histopathological lesions consistent with systemic HPAI infection . Immunohistochemistry revealed marked neurotropism , oculotropism and multicentric epitheliotropism . Viral isolation and sequencin...