ETIDIOH - NEW

  Abstract Since early-2024 unprecedented outbreaks of highly pathogenic avian influenza H5N1 clade 2.3.4.4b have been ongoing in dairy cattle in the United States with significant consequences for the dairy industry and public health . Estimation of key epidemiological parameters is required to support outbreak response , including predicting the likely effectiveness of interventions and testing strategies . Here, we pool limited publicly available data from four studies of naturally and experimentally infected dairy cattle. We quantify Ct value trajectories of infected dairy cattle and the relationship between Ct value and the log-titer of infectious virus , a proxy for infectiousness . We estimate that following infection minimum Ct values are rapidly reached within 1–2 days with a population mean Ct value of 15.7 (12.9, 18.4). We identify a threshold Ct value of 21.8 (19.9, 24.6), with values of Ct value above this threshold representing little-to-no infectious viral load . Fin...

  Abstract Highly pathogenic avian influenza H5N1 viruses of clade 2.3.4.4b have caused widespread avian mortality and sporadic mammalian infections , raising concerns about their potential for efficient replication in the human population . Efficient replication in the human upper respiratory tract is considered a key barrier to transmission . Here, we demonstrate that an H5N1 virus isolated from bovine milk in Texas in 2024 (H5N1Tex/24) replicates as efficiently as the 2009 pandemic H1N1 virus (H1N1HH4/09) in well-differentiated human nasal epithelial cells . These cells express both avian- and human-type influenza receptors , indicating receptor adaptation is unnecessary for entry . H5N1Tex/24 replicates effectively at 33 degrees Celsius , reflecting nasal cavity temperature , whereas earlier avian H5N1 strains require 37 degrees Celsius, suggesting that H5N1Tex/24 has acquired another key adaptive feature to the human upper respiratory tract. H5N1Tex/24 remains sensitive to int...

  Abstract In 2024, an unprecedented outbreak of H5N1 high pathogenicity avian influenza was detected in dairy cattle in the USA resulting in spillbacks into poultry, wild birds and other mammals including humans . Here, we present molecular and virological evidence that the cattle B3.13 genotype H5N1 viruses rapidly accumulated adaptations in polymerase genes that enabled better replication in bovine cells and tissues , as well as cells of other mammals including humans . We find evidence of several mammalian adaptations in cattle including PB2 M631L , which is found in all cattle sequences, and PA K497R , which is found in the majority. Structurally, PB2 M631L maps to the polymerase-ANP32 interface , an essential host factor for viral genome replication. We show that this mutation adapts the polymerase to better interact with bovine ANP32 proteins , particularly ANP32A, and thereby enhances virus replication in bovine mammary systems and primary human airway cultures . We show th...

  {Excerpt} Time Period: January 04, 2026 - January 10, 2026 -- H5 Detection :  8 site(s) ( 1.5% ) -- No Detection :  541 site(s) ( 98.5% ) -- No samples in last week :  66 site(s) (...) Source:  Link:  https://www.cdc.gov/nwss/rv/wwd-h5.html ____

  Two mute swans in Kyiv City. Source:  Link:  https://wahis.woah.org/#/in-review/7201 ____

Two mute swan in Teleneşti Region. Source:  Link:  https://wahis.woah.org/#/in-review/7195 ____

  Abstract Seasonal and pandemic influenza viruses are continuous threats to human health, requiring rapid development of vaccines to multiple evolving viral strains. RNA vaccine technologies have the adaptability and manufacturability to facilitate pandemic preparedness but have limited flexibility in their route of administration , reducing the ability to establish local protective immune responses such as respiratory mucosal immunity . Here, we describe monovalent and bivalent replicon vaccines against A/Vietnam/1203/2004 H5N1 and A/Anhui/PA-1/2013 H7N9. These replicon vaccines express either H5 or H7 hemagglutinin and are formulated with a nanostructured lipid carrier (NLC) that permits both intramuscular (IM) and intranasal (IN) dosing. In mice , IM vaccination established systemic humoral and cellular responses but no detectable mucosal response , while IN administration induced robust systemic and mucosal immunity . The replicon-NLC vaccines protected against morbidity and m...

  Abstract The emergence and broad circulation of highly pathogenic avian influenza (HPAI) H5N1 virus in wild birds and its spillover into dairy cows with sustained transmission in this species pose a major risk to felines , which are highly susceptible and often succumb to the infection . Here, we developed a novel recombinant hemagglutinin H5-based vaccine and evaluated its safety, immunogenicity, and protective efficacy against HPAI H5N1 virus in domestic cats . Immunization of cats with H5-vaccine candidate elicited robust levels of neutralizing antibodies against H5N1 virus and protection against disease, mortality, and infection upon H5N1 virus challenge. The vaccine-elicited immunity significantly reduced virus shedding and viremia , limiting systemic spread and disease severity in immunized animals. Importantly, beyond protecting susceptible felids, vaccinating cats against the H5N1 virus could also reduce the risk of human exposure - underscoring the One Health impact of i...

  A layer poultry farm (located near small rivers, ponds, and migratory birds) began showing clinical signs of an outbreak of highly pathogenic avian influenza in its hens. These signs included pale combs and wattles, followed by increased mortality. The farm owner contacted the veterinary clinic in Taji, near Baghdad. A team of veterinarians was formed, samples were taken, and sent to the central laboratory for PCR testing. Control measures were initiated, including a ban on the movement of poultry. The entire flock will be culled in accordance with the procedures stipulated in Animal Health Law No. 32 of 2013, which mandates the culling of poultry infected with highly pathogenic avian influenza. Source:  Link:  https://wahis.woah.org/#/in-review/7181 ____

  A breeding goose holding in Nógrád Region. Source:  Link:  https://wahis.woah.org/#/in-review/7185 ____

  {Excerpt} Time Period: December 28, 2025 - January 03, 2026 -- H5 Detection :  3 site(s) ( 0.7% ) -- No Detection :  428 site(s) ( 99.3% ) -- No samples in last week :  111 site(s) (...) Source:  Link:  https://www.cdc.gov/nwss/rv/wwd-h5.html ____

  {A barnacle goose} By Andreas Trepte - Own work, CC BY-SA 2.5,  https://commons.wikimedia.org/w/index.php?curid=32487518 ___ 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 or birds kept in a single household, and therefore do not fall within the WOAH definition of poultry. {Sjöbo Region} A barnacle goose was killed. It was sent to the Swedish Veterinary Agency for laboratory analysis as part of the national surveillance program for avian influenza. Source:  Link:  https://wahis.woah.org/#/in-review/7180 ____

  ABSTRACT Current U.S. surveillance for highly pathogenic avian influenza A(H5N1) in humans prioritizes individuals with known animal exposures , potentially missing community-acquired infections . To address this gap, we implemented universal H5 subtyping of all influenza A-positive respiratory samples collected within our hospital system , regardless of patient exposure history. Between August 2024 and April 2025, we subtyped 4,488 influenza A-positive samples and identified two cases positive for H5 RNA in Alameda County, California, USA . The first case was a 14-month-old girl with mild respiratory symptoms and no H5N1 exposure risks ; sequencing of the sample revealed an H5 gene closely related to clade 2.3.4.4b, genotype B3.13 viruses circulating in U.S. dairies . The second case was a 79-year-old male, also with no known exposures , whose sample reproducibly tested positive with a high cycle threshold value but could not be confirmed by public health laboratories. Both pati...

  Poultry farms in Podlaskie Region. Source:  Link:  https://wahis.woah.org/#/in-review/7177 ____

  Abstract Highly pathogenic H5N1 avian influenza viruses of clade 2.3.4.4b cause sporadic human infections and currently raise concerns about a new influenza pandemic . Heterogeneities in disease severity have been observed in the past and are reported among infected farm workers in the United States . These may be attributed to differences in pre-existing H5N1 cross-reactive antibodies . In this study, we characterize H5N1 cross-reactive antibody landscapes in the current population (#NCT05794412 and #NCT01022905) and assess the effect of AS03-adjuvanted pandemic H1N1 and non-adjuvanted seasonal influenza vaccination on H5N1 cross-neutralizing and IgG antibody titers targeting a range of influenza virus-derived antigens. We detect H5N1 cross-neutralizing antibodies using a vesicular stomatitis virus-based pseudovirus system that correlate well with antibodies inhibiting the spread of authentic H5N1 viruses, anti-group 1 hemagglutinin stalk and anti-trimeric hemagglutinin antibodi...

  Abstract Ongoing transmission of influenza A virus (H5N1) in U.S. dairy cattle threatens both animal and human health , underscoring the need to understand the durability of host immunity against reinfection with evolving genotypes . We challenged naive and convalescent cows , infected one year prior with H5N1 genotype B3.13, with either homologous B3.13 or heterologous D1.1 genotype virus . Homologous rechallenge resulted in complete clinical protection with no infectious viral shedding . Conversely, heterologous rechallenge led to transient clinical disease and limited infectious viral shedding . Convalescent cows experienced significantly milder disease than naive cows, which developed severe illness with high viral shedding and required early euthanasia , regardless of the strain. These findings indicate that naturally acquired immunity offers strong protection against severe illness but may allow silent transmission of divergent strains . Therefore, natural herd immunity alo...

  {Scotland} A small commercial poultry premise. Samples taken were positive for HPAI H5N1. Birds presented clinical signs prior to testing. Source:  Link:  https://wahis.woah.org/#/in-review/7173 ____

  A fattening turkey holding in Csongrád-Csanád Region. Source:  Link:  https://wahis.woah.org/#/in-review/7172 ____

  ABSTRACT Avian influenza virus cross-species infection in humans poses a major threat to global public health . Species-specific differences between avian ANP32A and mammalian ANP32 proteins create a natural barrier against viral cross-species infection by directly impairing the functional interaction between the avian-origin viral RNA polymerase and mammalian ANP32 proteins , thereby restricting viral genome replication . The key to overcoming this barrier lies in the adaptation of viral RNA polymerase to host ANP32 family proteins . This mini-review summarizes the mechanisms and variations in influenza virus adaptation to ANP32 proteins across different species. Influenza viruses adapt to species-specific ANP32 proteins through various mutations and display distinct preferences for specific ANP32 family members within the same host. Additionally, alternative splicing variants of ANP32A within a single species further modulate viral RNA polymerase adaptability. Despite this dive...

  Reproductive ducks. 41 months old. Drop in lay and reduction of water consumption. Gastrointestinal symptoms. HaZafon Region. Source:  Link:  https://wahis.woah.org/#/in-review/7168 ____