ETIDIOH - NEW

  Abstract Highly pathogenic avian influenza H5N1 rarely infects mammals. In 2024-2025, however, genotypes B3.13 and D1.1 caused two independent spillovers into U.S. dairy cattle . By analysing 26,930 complete H5N1 genomes from global surveillance , we identified 73 major viral groups , most of which show continent-specific distribution in Europe, Asia, Africa , and North America . North American viruses exhibit higher genetic diversity in specific viral segments , including variants potentially associated with mammalian adaptation . Both dairy-cattle-associated B3.13 and D1.1 genotypes originate from the same geographic macro-area , suggesting a possible regional hotspot where avian-mammalian interfaces may facilitate viral adaptation. Our findings place the U.S. outbreaks in a global framework and indicate that North American H5N1 may be predisposed to cross-species transmission. Competing Interest Statement The authors have declared no competing interest. Funder Information Decl...

  Abstract Efficient replication of influenza A viruses (IAVs) requires balanced activities of hemagglutinin (HA), neuraminidase (NA), and the RNA polymerase complex, whose functions are strongly influenced by PB2 mutations . We previously revealed three distinct evolutionary pathways for PB2 mutations, with two pathways leading to the emergence of viral strains responsible for human seasonal infections and the 2009 pandemic , and a third pathway giving rise to H5Nx highly pathogenic avian influenza viruses (HPAIVs) defined by a triad of mutations (I147T, K339T, and A588T) that occasionally spill over to humans . Here, we investigated the zoonotic risk posed by this triad and elucidated its evolutionary relationship with HA, NA, and vaccination . Recombinant PR8 and clade 2.3.2.1c H5N1 viruses carrying the triad replicated efficiently in embryonated chicken eggs and had moderate replication efficiency in mammalian cells ; moreover, mice infected with these viral strains exhibited m...

  A Common Teal in Jeollanam-do Region. Source:  Link:  https://wahis.woah.org/#/in-review/7034 ____

  {England, Kent} Laying flock with around 31K birds. Samples taken were positive for HPAI H5N1. Birds presented clinical signs prior to testing. {England, Suffolk} Backyard flock. Samples taken were positive for HPAI H5N1. Birds presented clinical signs of AI prior to testing. Source:  Link:  https://wahis.woah.org/#/in-review/7081 ____

  Summary Background Chikungunya outbreaks have recurred in Brazil since 2014 . Building on earlier 28-day post-vaccination data , we now report 12-month safety and immunogenicity results of the VLA1553 vaccine in Brazilian adolescents. Methods In this double-blind, randomised, placebo-controlled, phase 3 trial , generally healthy adolescents aged 12–17 years were recruited at ten sites across Brazil. Individuals were excluded for immune-mediated or chronic arthritis or arthralgia, who are are immunologically compromised, or any recent live vaccines. Random allocation via simple block randomisation in a 2:1 ratio was stratified by baseline IgG and IgM serostatus by ELISA to receive a single intramuscular dose of VLA1553 or placebo . Assessed in the per-protocol population 28 days after vaccination, the primary endpoint was the proportion of baseline seronegative participants with chikungunya virus neutralising antibody levels assessed by a serum dilution achieving a 50% plaque redu...

  Abstract The unprecedented 2.3.4.4b. A(H5N1) outbreak in dairy cattle, poultry, and spillover to humans in the United States (US) poses a major public health threat. Population immunity is a critical component of influenza pandemic risk assessment . We assessed the pre-existing cross-reactive immunity to 2.3.4.4b A(H5N1) viruses and analyzed 1794 sera from 723 people (0.5–88 yrs) in multiple US geographic regions during 2021–2024. Pre-existing neutralizing and hemagglutinin (HA)-head- binding antibodies to A(H5N1) were low , but there were substantial cross-reactive binding antibodies to N1 neuraminidase (NA) of 2.3.4.4b A(H5N1). Antibodies to group 1 HA stalk were also prevalent and increased with age . A(H1N1)pdm09 infection and influenza vaccination did not induce neutralizing antibodies to A(H5N1) viruses but induced significant rise of functional NA inhibition (NAI) antibodies to N1 of 2.3.4.4b A(H5N1), and group 1 HA stalk antibodies . Moreover, pre-pandemic stockpiled 2.3....

  Abstract Adding to the global burden of high pathogenicity avian influenza (HPAI) H5N1, an unprecedented five HPAI H7 outbreaks occurred globally in 2024 . Of these, three occurred in southeast Australia , with the independent emergence of HPAI H7N9, H7N8, and H7N3 , resulting in the destruction of 2 million poultry . Historical data demonstrates that H7 outbreaks in Australia do not occur randomly , rather, there is a strong association between the timing of the previous H7 outbreaks and rainfall patterns in southeastern Australia. We aimed to address a hypothesis wherein prior to H7 outbreaks in poultry, there was a detectable change in H7 prevalence and/or virus diversity in wild bird populations . We addressed this using virological and serological surveillance data generated from multiple programs. Despite the collection of thousands of samples, there was only weak evidence to support our hypothesis, which provides strong incentive to evaluate current surveillance approaches...