ETIDIOH - NEW

Abstract Neuroinvasive arboviruses such as tick-borne encephalitis virus (TBEV), West Nile virus (WNV), Usutu virus (USUV), and Toscana virus (TOSV) have (re-)emerged with increasing incidence and geographic range . We analyzed the epidemiology of arboviral infections in Croatia during the 2024 transmission season. A total of 154 patients with neuroinvasive diseases (NID), 1596 horses , 69 dead birds , and 7726 mosquitoes were tested. Viral RNA was detected using RT-qPCR. IgM/IgG-specific antibodies were detected using commercial ELISA or IFA, with confirmation of cross-reactive samples by virus neutralization test. RT-qPCR-positive samples were Sanger sequenced. Arboviral etiology was confirmed in 33/21.42% of patients with NID. WNV was most frequently detected (17/11.03%), followed by TBEV (10/6.49%), USUV (5/3.24%), and TOSV (1/0.64%). WNV infections were reported in regions previously known as endemic, while in one continental county, WNV was recorded for the first time. USUV infec...

 A wild Peregrine falcon in Kagoshima Region. Source: WOAH,  https://wahis.woah.org/#/in-review/6545 ____

The samples collected in two (2) wild bird species : Red Shank (Tringa totanus) and Arctic Warbler (Phylloscopus borealis), that tested positive for Notifiable Avian Influenza Subtype H5N1 were part of the regular wildlife disease surveillance activity being conducted by the wetland park. In response, additional samples were collected from wild birds, and all tested negative for Avian Influenza. Comprehensive surveillance and sample collection efforts in the surrounding domestic poultry population also confirmed no presence of Avian Influenza. Source: WOAH,  https://wahis.woah.org/#/in-review/6523 ____

Abstract Background Avian influenza, a significant threat to public health , requires monitoring for the development of control strategies. This study aims to analyze the spatiotemporal distribution of avian influenza virus in the external environment of Xinjiang from 2021 to 2023, to enhance understanding of its transmission patterns and provide a scientific basis for public health response measures. Methods A total of 3913 avian-related environmental samples were collected from nine monitoring areas in Xinjiang . Sample types included poultry drinking water, meat cutting boards, cage surfaces, feces, and wastewater. Real-time RT-PCR was used to detect nucleic acid for H5, H7, and H9 subtypes. Data were statistically analyzed using Excel and SPSS, and spatial distribution was visualized through Kriging interpolation using ArcGIS. Results Among the collected samples, 810 tested positive , with an overall positivity rate of 20.70%. The H9 subtype was predominant , accounting for 85.43% ...

Abstract Avian influenza virus (AIV) is a significant global concern, causing widespread mortality in wild birds, domestic poultry and most recently wild and domestic mammals . This study presents a retrospective analysis of AIV detections in the Republic of Ireland . Data was sourced from official surveillance databases, peer-reviewed literature and grey literature sources. Spatio-temporal, host-specific and subtype patterns were assessed using descriptive statistics, chi-square tests, linear regression and kernel density estimations. A total of 2,888 confirmed AIV detections were recorded from 25 of Ireland's 26 counties . Wild birds accounted for 98.7% of detections, with domestic birds comprising 1.3% and two detections in foxes . H5N1 was the most prevalent subtype (96.7%) followed by H5N8 and H6N1 . Spatial clustering was observed in urban areas, particularly Dublin . The highest seasonal peak occurred during summer, contrasting with traditional winter-associated patterns. Se...

Abstract Avian influenza (AI) is a highly contagious viral disease affecting poultry and wild water birds , posing significant global challenges due to its high mortality rates and economic impacts. Highly pathogenic avian influenza (HPAI) outbreaks , particularly those caused by H5N1 and its variants , have surged since their first occurrence in 1959. The HPAI H5N1 clade 2.3.4.4b viruses have notably expanded its geographical reach, affecting numerous countries, diverse avian species, and now wild and domestic mammals . Using an ecological niche modelling approach, this study aims to elucidate the environmental factors associated with the increased HPAI H5 cases since 2020, investigate potential shifts in ecological niches , and predict new areas suitable for local viral circulation. Focusing on H5N1 and H5Nx strains, we have developed ecological niche models for HPAI case in both wild and domestic birds while considering two distinct periods: 2015-2020 and 2020-2022. Key environmenta...

Abstract In 2023, highly pathogenic avian influenza (HPAI) heavily affected gulls in Europe. In July, a mass mortality event was reported in the Black-legged Kittiwake (Rissa tridactyla) breeding colony at Ekkerøy in Northern Norway . The cause was confirmed to be infection with the HPAI H5N1 clade 2.3.4.4b virus , genotype EA-2022- BB. We describe the outbreak in Kittiwakes, including pathological and virological investigations , and discuss the management and zoonotic potential . With more than 15,000 dead birds reported , we estimate that the outbreak caused a reduction in the Kittiwake population at Ekkerøy of at least 50%. Diseased birds exhibited neurological signs . Necropsy of ten birds revealed a peracute fatal systemic disease , with severe lesions in the brain and pancreas co-localizing with the presence of viral RNA and antigen. Vascular expression of α2,3-linked sialic acids and viral RNA/antigen may reflect hematogenous virus spread . Further studies should investigate th...

ABSTRACT Long-distance migratory ducks play a critical role in the maintenance and dissemination of A(H5N1) viruses . Comparative pathogenicity studies were conducted on blue-winged teal (BWTE; Anas discors) using three distinct genotypes of A(H5N1) clade 2.3.4.4b viruses (A1, B1.3, and B4.1) isolated from wild ducks in Canada . Twenty-four hours post-intranasal infection of BWTE, contact turkeys and chickens were introduced into each of the groups to evaluate viral transmission. The levels of viral shedding in BWTE increased from 3 to 7 days post-infection (dpi) and continued at lower levels until 14 dpi. The A1 genotype virus (MALL/NS/22) was found to be the least pathogenic to BWTE compared to the reassortant genotypes, B4.1 (RBME/BC/22) and B1.3 (BWTE/MB/22). The B1.3 genotype was the most virulent to BWTE and caused 66.7% mortality compared to 12.5% mortality caused by the B4.1 genotype. The extent of transmission from infected BWTE to contact turkeys and chickens showed variation...

Abstract We characterized highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b genotype D1.1 in wild birds and a human in British Columbia, Canada, during 2024. D1.1, the predominant genotype circulating in fall 2024, is a reassortment between Eurasian A3 lineage viruses , introduced to North America in 2022, and North American lineage viruses. Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/6/24-1862_article ____

Abstract H5Nx clade 2.3.4.4b high-pathogenicity avian influenza viruses (HPAIVs) have decimated wild bird and poultry populations globally since the autumn of 2020. In the United Kingdom (UK) and in continental Europe , the H5N8 subtype predominated during the first epizootic wave of 2020/21 , with few detections of H5N1. However, during the second (2021/22) and third (2022/23) epizootic waves, H5N1 was the dominant subtype. The rapid shift in dominance from H5N8 to H5N1 was likely driven by a combination of virological, immunological, and/or host-related factors. In this study, we compared viral fitness and immunological responses in ducks , a key reservoir species, using dominant genotypes of H5N1 (genotype AB) and H5N8 (genotype A) from the second wave. While viral shedding dynamics were similar for both viruses, H5N8 was more pathogenic . Antigenic analysis of post-infection duck sera revealed that the haemagglutinin (HA) protein was antigenically similar across clade 2.3.4.4b H5 H...

Abstract Highly pathogenic avian influenza (HPAI) A/H5N1 viruses threaten animal and human health worldwide . The first documented cases in the Middle East were reported in 2005 ; however, despite extensive phylogenetic studies , there is limited information on the transmission dynamics of the virus within this region. We analyzed HA and NA gene sequences from various hosts to address this gap and to understand the virus’s spread and evolution in the Middle East. We hypothesized that H5N1 transmission exhibits host-specific or geographically influenced clade structures in this region . This study traced transmission pathways of HPAI A/H5N1 through a phylogenetic and amino acid sequence analysis of HA and NA gene segments from isolates across different hosts in Middle Eastern countries, using the MUSCLE algorithm for alignments and MEGA11 software for phylogenetic analysis. Sequences were selected from NCBI’s virus database based on geographic and host diversity, including those from bi...

Abstract Thousands of outbreaks of the highly pathogenic avian influenza A(H5N1) virus in birds and an increasing number of mammal infections are registered annually. In 2023, multiple avian influenza outbreaks were registered among wild birds, poultry and seals in Russia . The genetic characterization of seventy-seven avian viruses and three viruses from seals showed that they belonged to the 2.3.4.4b clade and represented four distinct reassortant genotypes . The majority of viruses represented genotype BB , which was widespread in Europe in 2023. Viruses from seals and four viruses from birds , isolated from outbreaks in the Far East region , belonged to the G1 (A3) genotype and had the amino acid substitution N319K in the NP protein , previously associated with an increased virulence for mammals . In addition, one virus of the G10 genotype and two viruses, representing a previously undescribed genotype (designated as Ru-23-G4) were identified. The viruses analyzed showed normal inh...

Abstract In February 2024, H5N1 highly pathogenic avian influenza viruses (HPAIVs) of clade 2.3.4.4b were first reported in dairy cows in the USA. Subsequent multiple outbreaks on dairy farms and sporadic human infections have raised substantial public health concerns . In the same year, four H5N1 HPAIVs of clade 2.3.4.4b were isolated from ducks and geese in live poultry markets (LPMs) spanning seven provinces in China . Evolutionary analysis demonstrated that these viruses had undergone two genetic reassortments with H5 influenza viruses from wild birds in different countries. Except for 565/H5N1, the other three viruses exhibited over 99% genetic homology with avian-origin H5N1 HPAIVs from South Korea and Japan . Notably, 571/H5N1 demonstrated high replication efficiency in bovine-derived cells , particularly in bovine mammary epithelial (MAC-T) cells, and caused 16.7% (1/6) mortality in mice at a dose of 10⁵ EID₅₀/50 μL, indicating its zoonotic potential . Given the potential cross...

ABSTRACT Since 2020, the clade 2.3.4.4b highly pathogenic avian influenza (HPAI) H5N1 viruses have caused unprecedented outbreaks in wild birds and domestic poultry globally , resulting in significant ecological damage and economic losses due to the disease and enforced stamp-out control. In addition to the avian hosts, the H5N1 viruses have expanded their host range to infect many mammalian species , potentially increasing the zoonotic risk . Here, we review the current knowns and unknowns of clade 2.3.4.4b HPAI H5N1 viruses, and we highlight common challenges in prevention. By integrating our knowledge of viral evolution and ecology, we aim to identify discrepancies and knowledge gaps for a more comprehensive understanding of the virus. Ultimately, this review will serve as a theoretical foundation for researchers involved in related avian influenza virus studies, aiding in improved control and prevention of H5N1 viruses. Source: Journal of Virology,  https://journals.asm.org/doi...

{Source: Wikipedia,  https://commons.wikimedia.org/wiki/File:White_tailed_eagle_raftsund_square_crop.jpg  - Under CC: Christoph Müller (http://www.christophmueller.org), CC BY 4.0 , via Wikimedia Commons} A White tailed eagle was found dead . It was sent to the Swedish Veterinary Agency (formerly National Veterinary Institute) for laboratory analysis as part of the national surveillance program for avian influenza. Source: WOAH,  https://wahis.woah.org/#/in-review/6466?reportId=174166&fromPage=event-dashboard-url ____

Abstract Low pathogenic H9N2 avian influenza viruses have become widespread in wild birds and poultry worldwide, raising concerns about their potential to spark pandemics or their role in enhancing the virulence and infectivity of H5Nx viruses through genetic reassortment . Therefore, influenza monitoring studies, including those of H9N2 viruses, are crucial for understanding, evaluating, and mitigating the risks associated with avian infections, and have broader implications for global public health. Although H9N2 viruses are not considered enzootic in Kazakhstan , they have been repeatedly detected in wild waterfowls and domestic poultry . In this study, all eight gene segments of influenza A/H9N2 viruses isolated in various regions of Kazakhstan between 2014 and 2020 were sequenced and analyzed. Molecular characterization revealed the presence of genetic markers associated with mammalian infectivity and disease potential . Furthermore, their predicted receptor binding site sequences...

Abstract Background .  Influenza A virus (IAV) is a major cause of morbidity and mortality globally , causing seasonal influenza in humans and infecting birds and some mammals. In 2024, IAV H5N1 highly pathogenic avian influenza (HPAI) in the United States moved into cattle. While the outbreak is currently of low risk to the general public, there is an urgent need to monitor the disease and prevent spread.  Methods .  We conducted a nationwide study evaluating the relationship between H5 hemagglutinin gene RNA concentrations in wastewater and reported outbreaks of IAV H5N1 in animals and humans . We utilized an H5-specific droplet digital RT-PCR test to quantify H5 RNA in wastewater in 40 states across the United States, and 1) examined the temporal association between outbreaks and wastewater detections and 2) utilized linear mixed models (LMM) to determine the relationship between measurements in wastewater and outbreak-related factors in the local area.  Results ....

Abstract Recently, Clade 2.3.4.4b H5N1 virus has been widely prevalent globally. Although no outbreaks of Avian Influenza have occurred in poultry in China recently, Clade 2.3.4.4b H5 virus can still be isolated from wild birds , live poultry markets and environment , indicating the ongoing co-circulation of H5N1 and H5N6 viruses. In this study, phylogenetic analysis of global Clade 2.3.4.4b viruses and 20 laboratory-isolated H5 strains revealed that Chinese H5N1 and H5N6 viruses since 2021 cluster into two distinct groups , G-I and G-II. Bayesian phylodynamic analysis reveals that G-I H5N6 virus has become an endemic virus in China . In contrast, G-II H5N1 virus, with South China as its main epicentre, has been disseminated in China and its surrounding countries, with its transmission more reliant on the connections of wild birds and waterfowl . Reassortment analysis indicates that since 2023, Clade 2.3.4.4b H5 viruses isolated in China have formed seven genotypes . The genome of H5 v...

Abstract In Europe, highly pathogenic avian influenza (HPAI) virus circulates in avian wildlife, undergoing frequent reassortment , sporadic introductions in domestic birds , and spillover to mammals . An H5N1 clade 2.3.4.4b reassortant, EA-2023-DG, affecting wild and domestic birds was detected in western Europe in November 2023. Six of its RNA segments came from the EA-2021-AB genotype, but the polymerase basic 2 and polymerase acidic segments originated from low pathogenicity avian influenza viruses . Discrete phylogeographic analyses of concatenated genomes and single polymerase basic 2 and polymerase acidic segments suggested reassortment in summer 2023 near the southwestern Baltic Sea . Subsequent continuous phylogeographic analysis of all concatenated EA-2023-DG genomes highlighted circulation in northwestern Europe until June 2024 and long-distance dispersal toward France, Norway, England, Slovakia, Switzerland, and Austria . Those results illustrate the value of phylodynamic a...

Abstract The ongoing panzootic of H5N1 high pathogenicity avian influenza virus (HPAIV) has caused the deaths of over half a billion wild birds and poultry , and has led to spillover events in both wild and domestic mammals , alongside sporadic human infections . A key driver of this panzootic is the apparent high viral fitness across diverse avian species, which facilitates an increased interface between wild and domestic species. Columbiformes (pigeons and doves) are commonly found on poultry premises and are highly connected to humans in urban settlements, yet relatively little is known about their potential role in contemporary HPAIV disease ecology. Here we investigated the epidemiological role of pigeons (Columba livia) by determining their susceptibility using decreasing doses of clade 2.3.4.4b H5N1 HPAIV (genotype AB). We investigated infection outcomes and transmission potential between pigeons and to chickens for each dose. Following direct inoculation, pigeons did not develo...