ETIDIOH - NEW

Abstract Highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b was first detected in birds in the United States in 2021 and an ongoing outbreak in dairy cattle began in early 2024. At least 70 U.S. cases have been identified in humans with exposure to infected cattle, poultry, and wild birds. No human-to-human transmission has been documented . However, as part of diagnostic preparedness, we evaluated the ability of currently available influenza tests to detect 2024 U.S. H5N1 strains. Contrived nasal swab samples were prepared using live or inactivated 2024 H5N1 and used to test twelve rapid antigen tests (lateral flow assays, or LFA), including 10 commercially-available influenza A LFAs and two H5-specific LFAs. Five point-of-care (POC) molecular assays were also tested. An inclusivity testing protocol was used, wherein a predetermined dilution series is used to evaluate each assay, enabling head-to-head comparison of assay performance. All lateral flow assays and POC molecu...

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 exposed persons is low to moderate depending on the risk mitigation 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 of the risk of zoonotic transmission (for example, ani...

  Situation at a glance On 2 April 2025, the International Health Regulations (IHR) National Focal Point (NFP) for Mexico notified the World Health Organization (WHO) of the country’s first laboratory-confirmed human infection with an avian influenza A(H5N1) virus in the state of Durango .  In response, local and national health authorities have implemented a range of measures to monitor, prevent, and control the situation.  There have been reports of A(H5N1) outbreaks in birds in Durango , although the exact source of infection in this case remains under investigation .  To date, no further cases of human infection with influenza A(H5N1) linked to this case have been identified.  In accordance with the IHR (2005), any human infection caused by a new influenza A virus subtype is considered a potentially significant public health event and is subject to mandatory notification to WHO.  Based on the information currently available on this and previous cases, W...

Abstract   Background :  The current avian influenza A(H5N1) epizootic poses a significant threat to public health , with sporadic infections in humans raising concerns about potential adaptation for efficient human transmission . Laboratory studies have provided evidence that the polymerase basic protein 2 (PB2) E627K mutation facilitates more efficient replication in mammals and humans. This mutation has been detected in Canadian poultry, wild birds and mammals .  Objective :  Our objective was to summarize the current state of evidence on the impact of the avian influenza PB2 E627K mutation on human adaptation, transmission, epidemiology and clinical outcomes in natural human infections.  Methods :  We employed a search strategy across MEDLINE, Embase, Scopus, Global Health and CAB Abstracts for articles published from each database’s inception until mid-May 2023.  Results :  We identified nine eligible articles for review that addressed human ...

Abstract Prion transmission into rodents is essential for understanding prion strains. However, it is often limited by a “ species barrier ” that makes transmission challenging and complicates the study of animal and human prion diseases. Here, we report that North American deer mice (Peromyscus maniculatus) are susceptible to infection with both human sporadic Creutzfeldt–Jakob disease (sCJD) and chronic wasting disease (CWD). Experimental transmission of both sCJD and CWD in deer mice resulted in 100% attack rates , albeit with differing incubation times, with CWD-inoculated mice taking nearly three times longer than sCJD-inoculated mice to succumb. We observed distinct patterns of spongiform vacuolation and prion-protein deposition in the brain , as well as distinct protein-glycosylation profiles and seeding kinetics in RT-QuIC for each strain. Adaptation on the second passage led to reduced incubation periods and marked strain-specific pathology, as seen predominantly in the cortex...

Abstract Circulating bat coronaviruses present a significant pandemic threat, yet our  understanding of  their genetic diversity and evolutionary dynamics remains limited.  Over 3 years, we sampled  1,462 bats in Cambodia’s Steung Treng province,  identifying extensive and diverse  coronaviruses co-circulation. Using  metatranscriptomic and amplicon sequencing, we  generated 33 complete  sarbecovirus genomes, revealing novel lineages that cluster into four  distinct  groups, each associated with different Rhinolophus bat species. Our analysis  highlights rapid migration and recombination of sarbecovirus lineages over  short distances  and timescales. Of note, the receptor-binding domains of two novel  viral groups exhibit high  similarity to SARS-CoV-2, and pseudovirus assays  confirmed the ability of this spike protein  to mediate entry into cells expressing  human ACE2, suggesting a potentia...

{Excerpt} Highly pathogenic H5N1 avian influenza (HPAI) viruses started circulating in lactating dairy cattle in the USA at the end of 2023 (ref. 1) and these viruses are now rapidly spreading between cows2. Eisfeld et al.3 found that a clade 2.3.4.4b H5N1 virus from this cattle outbreak can bind to α2,6-linked sialyl-glycopolymers on microtitre plates . Here we show that the haemagglutinin from a clade 2.3.4.4b H5N1 virus binds poorly to glycans that terminate with α2-6 sialic acids. This is an important finding, as α2,6 sialic acid is abundant in the upper respiratory tract of humans , and acquisition of α2,6 sialic acid receptor specificity is believed to be required for efficient transmission of influenza virus in humans and is considered a risk factor for the emergence of a new pandemic virus4. (...) Source: Nature,  https://www.nature.com/articles/s41586-025-08821-6 ____

Abstract In 2023, an outbreak of highly pathogenic avian influenza occurred among critically endangered California condors (Gymnogyps californianus), and >21 died. We evaluated safety, immunogenicity, vaccination strategies, and correlates of antibody response of an influenza vaccine for poultry in black vultures (Coragyps atratus) and then California condors. We noted differences in antibody titers between vaccinated and unvaccinated birds (vultures p<0.004; condors p­<0.02) but no adverse effects of vaccination. All vaccinated vultures and 80% of vaccinated condors showed maximum measured antibody response within the published range associated with survival of vaccinated and virally challenged chickens. We noted weak evidence of higher antibody responses for birds given two 0.5-mL vaccines versus those given one 1-mL vaccine but no correlation between antibody titers and sex for either species or between antibody titers and bone lead concentrations in vultures. Our results p...

Significance We explored how H5Nx influenza viruses , which can infect many different birds and mammals, could adapt to infect humans by altering the hemagglutinin (HA). HA must change to bind human-type receptors for transmission between people. We compared two strains from viruses isolated in 2016 and found that one ( 2.3.4.4e ) can switch to human receptor binding with a single mutation , while another ( 2.3.4.4b ) might require more complex changes to bind simple human-type receptors. These findings highlight the potential for specific strains to evolve and become a pandemic threat, underscoring the importance of monitoring mutations that could lead to human-type receptor adaptation. Abstract H5Nx viruses continue to wreak havoc in avian and mammalian species worldwide . The virus distinguishes itself by the ability to replicate to high titers and transmit efficiently in a wide variety of hosts in diverse climatic environments. Fortunately, transmission to and between humans is sca...