ETIDIOH - NEW

Abstract Avian influenza A viruses (AIVs) pose a significant pandemic threat due to their cross-species transmission potential . However, AIV surveillance at the critical “ migratory birds–poultry-exposed population ” interface remains limited. Between 2021 and 2024, we implemented a prospective One Health surveillance program around Nansi Lake , monitoring AIVs in migratory birds, poultry, and environmental samples, as well as serological investigations against representative AIVs among migratory birds or poultry-exposed subjects. AIVs were detected in 2.1% (30/1417) of migratory bird samples and 10.2% (100/978) of poultry samples . Among these, we identified ten highly pathogenic avian influenza (HPAI) H5 subtype viruses, one HPAI H7N9 virus, and five low pathogenic avian influenza (LPAI) H9N2 viruses. Phylogenetic analysis revealed evidence of frequent genomic reassortment events involving H5 subtype viruses among migratory birds, poultry, and humans . Serological investigation also...

  {By gary noon - Flickr, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4077294 } __ {England, Devon} Premises with 5200 pheasants. Increased mortality, reduced water consumption and other clinical signs were reported. Samples were taken and were tested positive for HPAI H5N1. Source: WOAH,  https://wahis.woah.org/#/in-review/6716 ____

  Two Poultry Farms in the Odisha State. Source: WOAH,  https://wahis.woah.org/#/in-review/6694 ____

  On 30th July 2025 HPAI H5N1 was confirmed in a young chicken in a backyard flock in Co Donegal . The bird was submitted to the Regional Veterinary Laboratory and virological testing confirmed HPAI at the CVRL. Control measures were put in place following detection on 30th July 2025. The 7 remaining birds of the backyard flock were euthanised and have tested negative for AI PCR. Further results to follow. Update: report updated to reflect the control measures applied (stamping out applied) as per the above report. Source: WOAH,  https://wahis.woah.org/#/in-review/6691 ____

{Scotland, Aberdeenshire} Commercial layer flock with approx. 88,000 laying hens. Increased mortality and other clinical signs reported. Samples taken were found positive for HPAI H5N1. Source: WOAH,  https://wahis.woah.org/#/in-review/6695 ____

{England, Norfolk} Commercial indoor unit with 59562 turkeys. Increased mortality and other clinical signs were reported. Samples were taken and were tested positive for HPAI H5N1. Source: WOAH,  https://wahis.woah.org/#/in-review/6693 ____

Abstract In 2024, highly pathogenic avian influenza A H5N1 caused outbreaks in wild birds, poultry, cows, and other mammals in the United States with 61 human cases also reported by the CDC. Detection of influenza A H5 RNA in wastewater has been previously reported in sewersheds in Texas and North Carolina with nearby impacted dairy herds following the emergence of H5N1 in dairy cows. Here, we conduct retrospective testing of total influenza A and H5 hemagglutinin genes in wastewater as well as present and apply new assays for detection of H1 and H3 genes across a respiratory virus season in an urban California sewershed from September 2023 to May 2024. Total influenza A, H1, and H3 were regularly detected, while H5 was first detected in March . We developed a model that uses Monte Carlo simulations and previously published parameters to estimate the numbers of infected people, poultry, wild birds, or liters of H5-contaminated milk required to result in measured H5 concentrations in wa...

Abstract The highly pathogenic avian influenza (HPAI) subtype H5N1 is a severe viral disease which continues to pose a significant threat to public health and a rigorous understanding of its transmission dynamics across its major pathways is essential for developing effective control strategies . Phylogenetic analysis suggests that H5N1 spillover occurs primarily between wild and domestic birds . However, increasing contact between these species and humans increases the risk of zoonotic transmission . In this work, we develop a mathematical model to examine the transmission dynamics of H5N1 and evaluate the effectiveness of proposed control measures. The model employs a compartmental framework that includes human, domestic, and wild bird populations. We then use this model to estimate the basic reproduction number for each population group and perform a sensitivity analysis to assess the contribution of the parameters to the spread of the disease. Numerical simulations are also conduct...

By gary noon - Flickr, CC BY-SA 2.0,  https://commons.wikimedia.org/w/index.php?curid=4077294 {England, Somerset} A game rearing site with approx. 2.500 9-week-old pheasants. Increased mortality and other clinical signs were reported. Samples were taken and were tested positive for HPAI H5N1. Source: WOAH,  https://wahis.woah.org/#/in-review/6679 ____

This case indicates the recurrence of the high pathogenicity avian influenza (HPAI) H5N1 subtype (clade 2.3.4.4b) on a poultry farm in Taiwan . The owner of the poultry farm reported the situation to the local veterinary authority in Yunlin County , and samples were collected on July 10. These samples were sent to the National Reference Laboratory for diagnosis on July 11. Clinical signs included increased mortality rates, reduced appetite , and decreased egg production . On July 13, the outbreak was confirmed as HPAI. Subsequently, 2,616 geese were culled, and comprehensive cleaning and disinfection were conducted on July 21. Farms within a 3-kilometer radius of this location will undergo heightened surveillance and visits for the next 28 days. Source: WOAH,  https://wahis.woah.org/#/in-review/6670 ____

  Key points   -- At the present time , based on available information, FAO-WHO-WOAH assess the global public health risk of influenza A(H5) viruses to be low , while the risk of infection for occupationally or frequently exposed (e.g., with backyard poultry) persons is low to moderate depending on the risk mitigation and hygiene measures in place and the local avian influenza epidemiological situation.  -- Transmission between animals continues to occur and, to date, a growing yet still limited number of human infections are being reported. Although additional human infections associated with exposure to infected animals or contaminated environments are expected to occur, the overall public health impact of such infections at a global level , at the present time, is considered minor . The assessment could change if and when additional epidemiological or virological information becomes available.  -- This risk assessment from FAO, WHO and WOAH updates the assessment ...

  Backyard poultry operation in Chobe Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6676 ____

Abstract Previous research efforts on highly pathogenic H5N1 avian influenza (HPAI) suggest that different avian species exhibit a varied severity of clinical signs after infection. Waterfowl, such as ducks or geese , can be asymptomatic and act as silent carriers of H5N1, making detection harder and increasing the risk of further transmission, potentially leading to significant economic losses. For backyard hobby farmers , passive reporting is a common HPAI detection strategy. We aim to quantify the effectiveness of this strategy by simulating the spread of H5N1 in a mixed-species, small-population backyard flock. Quantities such as detection time and undetected burden of infection in various scenarios are compared. Our results indicate that the presence of ducks can lead to a higher risk of an outbreak and a higher burden of infection . If most ducks within a flock are resistant to H5N1, detection can be significantly delayed. We find that within-flock infection dynamics can heavily ...

  A poultry farm in Extremadura Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6639 ____

The Official Veterinary Services received a notification concerning bird mortality and signs consistent with high pathogenicity avian influenza (HPAI) in a backyard in the Buenos Aires province . On the same day, the suspicion was addressed and samples were taken for analysis. The samples were analysed by the Official Laboratory and came back positive for HPAI H5 clade 2.3.4.4. The affected premises are adjacent to bodies of water, so contact with wild birds is presumed On 14/07/2025 , the Official Veterinary Services received a notification concerning bird mortality and signs consistent with high pathogenicity avian influenza (HPAI) in a backyard in the town of Lezama, in the Buenos Aires province . On the same day, the suspicion was addressed and samples were taken for analysis. On 15/07/2025 the samples were analysed by the Official Laboratory and came back positive for HPAI H5 clade 2.3.4.4. The species involved are chickens, peacocks, pheasants and guinea fowl . The affected premi...

ABSTRACT In recent years, high pathogenicity avian influenza viruses (HPAIVs) have spread among wild, captive, and domestic birds, as well as mammals . Beyond the resulting economic and ecological losses , spillover into mammals has raised concerns about a potential pandemic . Viral tropism refers to the spectrum of host species, organs, and cells susceptible and permissive to viral infection . It is a potent driver of infection dynamics and shedding patterns, which presents important variations both between and within hosts: in poultry, HPAIV leads to systemic endothelial infection in domestic chickens , whereas neurological and selective epithelial infections are observed in domestic ducks . In mammals , infection can result in respiratory and neurological disease , but the recent outbreaks in domestic dairy cows highlighted a unique and remarkable adaptation to the mammary gland prone to viral shedding in milk. The present review explores viral tropism of HPAIV across recent spillov...

Abstract The current study aimed to investigate the genetic characterization and evolution of low pathogenic avian influenza virus H9N2 in Egypt . Ten H9N2 viruses were recently isolated from samples collected between 2019 and 2023. Phylogenetic analysis of the haemagglutinin (HA) gene segment of the H9N2 isolates showed a relatedness with G1 H9 4.2 lineage and clustered within genotype III of the Egyptian strains identified earlier in 2018. The majority of H9N2 strains had seven and eight glycosylation sites in HA and neuraminidase (NA) respectively . All strains carried H191 and L234 residues in their hemagglutinin which are markers facilitating avian-to-human cross species barrier transmission . No stalk deletions were detected in NA gene. In addition, genetic analysis of the NA and M encoding proteins revealed the absence of substitutions associated with resistance to oseltamivir and amantadine . The NA showed S372A and R403W substitutions which were previously detected in H3N2 and...

Abstract The November 2021 introduction of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b into North America triggered a devastating outbreak , affecting more than 180 million domestic birds and spreading to more than 80 wildlife species across Canada and the US . From this outbreak, we have sequenced 2955 complete A( H5N1 ) viral genomes from samples collected in Canada and, in conjunction with previously published data, performed multifaceted phylodynamic analyses. These analyses reveal extensive diversification of A(H5N1) viruses via reassortment with low-pathogenic avian influenza viruses. We find evidence of repeated ancestral strain replacement by direct descendants, indicative of compounding viral fitness increases . Spatiotemporal modeling identified critical geographic areas facilitating transcontinental spread and demonstrated genotype-specific host dynamics, offering essential data for ongoing control and prevention strategies. Source: Science Advances,  https:...

Summary The recent emergence of highly pathogenic H5N1 avian influenza virus infections in dairy cows and humans in the U.S. has raised alarms regarding the potential for a pandemic . Over 995 dairy cow herds and at least 70 humans have been affected, including cases of severe disease and the first reported H5N1-related death in the U.S . Sporadic human infections with no known contact with infected animals highlight the possibility of viral adaptation for efficient human-to-human transmission. Concurrently, the virus continues to circulate in wild birds, backyard flocks, and hunted migratory species , further amplifying the risk to humans and domestic animals. This article provides an overview of the current outbreak status , emphasizes the importance of robust surveillance systems to detect emerging strains with pandemic potential, and highlights risks to the U.S. dairy and poultry industries. Recommendations for risk mitigation include enhanced biosecurity measures, improved surveil...

Abstract As of 20 May, the US Department of Agriculture (USDA) has confirmed highly pathogenic avian influenza (HPAI) in more than 173.1 million birds since the outbreak began in January 2022. The secretary of the US Department of Health and Human Services, Robert Kennedy Jr., has suggested allowing the unmitigated spread of HPAI in turkeys and chickens to identify surviving birds—a sentiment supported by Brooke Rollins, secretary of the USDA , which, along with state-level departments of agriculture, has jurisdiction over animal disease outbreaks (1). This approach would be dangerous and unethical . Allowing a highly lethal, rapidly evolving, and contagious virus to run a natural course of infection in poultry would lead to unnecessary suffering of poultry and put other susceptible animals on and near affected farms at risk . It would prolong exposure for farmworkers , which could increase viral adaptation and transmission risks for poultry, other peridomestic animals, and humans. Sou...