ETIDIOH - NEW

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 We conducted a multicenter, observational, 12-month follow-up study to identify the extended health burden of severe COVID-19 pneumonia by characterizing long-term sequelae of acute infection in participants previously enrolled in clinical trials for severe COVID-19 pneumonia requiring hospitalization. Overall, 134 (77.5%) of 173 participants completed the study. At 12 months, 51 (29.5%) participants reported cough , 60 (34.7%) reported dyspnea , 56 (32.4%) had residual lung texture abnormalities on high-resolution computed tomography scans, 26 (15.0%) had impaired forced vital capacity , 52 (30.1%) had cognitive impairment , and 77 (44.5%) reported fatigue . Disease severity during acute infection and age were associated with persistent lung abnormalities ; history of hypertension was associated with higher prevalence of fatigue and more frequent dyspnea and cough; and age and obesity were associated with long-term cognitive impairment . Our findings underscore the long-term ...

Abstract The interspecies transmission of avian influenza viruses remains a significant public health concern. H6 viruses have gained attention following the first human infection by a chicken-origin H6N1 virus (A/Taiwan/02/2013, Hu/13), highlighting their zoonotic potential . To understand the evolutionary trajectory and mammalian adaptation of this Taiwan lineage , we compared two avian isolates (A/Chicken/Taiwan/CF19/2009, Ck/09; A/Chicken/Taiwan/2267/2012, Ck/12) and Hu/13 in vitro and in vivo. Hu/13 exhibited enhanced replication in MDCK cells , producing larger plaques and higher viral titers than Ck/09 and Ck/12. In BALB/c mice , Hu/13 demonstrated the highest pathogenicity and mortality , followed by Ck/12, while Ck/09 induced minimal morbidity. Hu/13 and Ck/12 replicated efficiently in respiratory tissues , eliciting robust cytokine responses and severe pulmonary lesions . In ferrets , Hu/13 showed relatively efficient transmission , infecting all direct physical-contact and t...

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 As an avian influenza virus (AIV) panzootic is underway , the threat of a human pandemic is emerging . Infections among mammalian species in frequent contact with humans should be closely monitored. One mammalian family , the Felidae , is of particular concern. Domestic cats are susceptible to AIV infection and provide a potential pathway for zoonotic spillover to humans. Here, we provide a systematic review of the scientific literature to describe the epidemiology and global distribution of AIV infections in felines reported from 2004 to 2024. We identified 607 AIV infections in felines , including 302 associated deaths , comprising 18 countries and 12 felid species . We observed a drastic flux in the number of AIV infections among domestic cats in 2023 and 2024, commensurate with the emergence of H5N1 clade 2.3.4.4b. We estimate that this phenomenon is underreported in the scientific literature and argue that increased surveillance among domestic cats is urgently needed. Sou...

ABSTRACT Recent documented infection with an endemic coronavirus (eCoV) is associated with less severe coronavirus disease 2019 (COVID-19), yet the immune mechanism behind this protection has not been fully explored. We measured both antibody and T-cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in SARS-CoV-2- naïve individuals , classified into two groups: those with or without presumed recent eCoV infections . There was no difference in neutralizing antibodies and T-cell responses against SARS-CoV-2 antigens between the two groups. SARS-CoV-2-naïve individuals with recent presumed eCoV infection, however, had higher and significantly correlated levels of Fc receptor (FcR)-binding antibodies against eCoV spikes (S) and SARS-CoV-2 S2. Recent eCoV infection boosts cross-reactive antibodies that can mediate Fc effector functions, and this may play a role in the observed heterotypic immune protection against severe COVID-19. IMPORTANCE With the recent e...

Agreement’s adoption follows three years of intensive negotiation launched due to gaps and inequities identified in national and global COVID-19 response. Agreement boosts global collaboration to ensure stronger , more equitable response to future pandemics. Next steps include negotiations on Pathogen Access and Benefits Sharing system. Member States of the World Health Organization (WHO) today formally adopted by consensus the world's first Pandemic Agreement. The landmark decision by the 78th World Health Assembly culminates more than three years of intensive negotiations launched by governments in response to the devastating impacts of the COVID-19 pandemic, and driven by the goal of making the world safer from – and more equitable in response to – future pandemics. “The world is safer today thanks to the leadership , collaboration and commitment of our Member States to adopt the historic WHO Pandemic Agreement,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General.  “The Ag...

{Summary} Situation at a glance On 9 May 2025, the International Health Regulations (IHR) National Focal Point (NFP) for Papua New Guinea (PNG) notified WHO of the detection of circulating vaccine-derived poliovirus type 2 (cVDPV2) from stool specimens of two healthy children from Morobe province, Papua New Guinea (PNG).  The detection of wild poliovirus (WPV) or vaccine-derived poliovirus (VDPV), including from samples taken from healthy children, is considered a serious public health event .  Given the country's suboptimal routine immunization coverage , especially at the subnational level, the risk of potential spread locally is considered high .  WHO advises all countries —especially those with frequent travel and connections to polio-affected areas—should strengthen acute flaccid paralysis (AFP) and environmental surveillance while maintaining high level of immunization coverage to quickly detect and respond to virus importation and prevent further spread by closing ...

Abstract Fever during influenza A virus (IAV) infection is triggered by the innate immune response . Various factors contribute to this response, including IAV mini viral RNAs (mvRNA), which trigger RIG-I signaling when their replication and transcription are dysregulated by template loops (t-loop). It is presently not well understood whether the fever response to IAV infection impacts subsequent viral replication and innate immune activation . Here we show that IAV infection at temperatures that simulate fever leads to increased mvRNA synthesis and antiviral signaling . Mathematical modeling and experimental analyses reveal that differential IAV nucleoprotein and RNA polymerase production underlies the increased mvRNA level. Moreover, at the higher infection temperature mvRNAs with dysregulating t-loops contribute most to the innate immune activation. We propose that fever during IAV infection can establish a positive feedback loop in which elevated aberrant RNA synthesis and innate i...