H5N1 Molecular

Since March 2024, highly pathogenic avian influenza A(H5N1) viruses have caused outbreaks in dairy cattle and poultry in the United States, and they continue to spill over into humans. However, data on human immune response to those viruses is limited. We report neutralizing antibody responses in 2 …

Analysis of H5N1 2.3.4.4b sublineage origins and K193 and N193 prevalence in human isolates

During 2023-2024, highly pathogenic avian influenza A(H5N1) viruses from clade 2.3.2.1c caused human infections in Cambodia and from clade 2.3.4.4b caused human infections in the Americas. We assessed the susceptibility of those viruses to approved and investigational antiviral drugs. Except for 2 v …

The newly emerged avian influenza A H5N1 Clade 2.3.4.4b can infect dairy cows and shed live virus in their milk. Sporadic cattle-to-human infections have been reported, highlighting the urgent need to understand its pathogenesis in mammals. Using both non-lactating and lactating BALB/c mice, we exam …

Reports of human infections with influenza A(H5N1) clade 2.3.4.4b viruses associated with outbreaks in dairy cows in the United States underscore the need to assess the potential cross-protection conferred by existing influenza immunity. We serologically evaluated ferrets previously infected with an …

The global dissemination of H5 avian influenza viruses represents a significant threat to both human and animal health. In this study, we conducted a genome-wide siRNA library screening against the highly pathogenic H5N1 influenza virus, leading us to the identification of 457 cellular cofactors (44 …

Discover the initiatives addressing Bird flu in British Columbia as researchers tackle H5N1 subtype risks and human infections.

A recent study suggests that prior infections with seasonal H1N1 flu may strengthen immunity and reduce the severity of H5N1 bird flu.

Biosecurity and human risk mitigation strategies urgently needed for an evolving virus poised for severe, human-to-human outbreaks.

In recent months, Americans looking for eggs have faced empty shelves in their grocery stores. The escalating threat of avian flu has forced farmers to kill millions of chickens to prevent its spread.

Chief of Infectious Diseases, Dr. Elizabeth Asiago-Reddy gives an update on bird flu (avian influenza). Computational neuroscientist Christopher Gaiteri discusses what research into brain connectivity reveals about dementia and other disorders.

A recent preprint filled with fundamental scientific flaws is fueling anti-vaccine disinformation.

Since 2020, H5N1 highly pathogenic avian influenza (HPAI) viruses of clade 2.3.4.4b have been rapidly spreading in wild birds but have also caused a large number of mammalian infections and more than 70 known human cases. Importantly, this H5N1 clade has also crossed the species barrier into dairy c …

The evolution and adaptation of highly pathogenic avian influenza (HPAI) viruses pose ongoing challenges for animal and public health. We investigated the pathogenic characteristics of the newly emerged H5N1/2022 and H5N8/2022 of clade 2.3.4.4b compared to the previously circulating H5N1/2016 of cla …

The 2 patients exposed to poultry had severe infections, with H5N1 confirmed only from lower respiratory tract samples.

Pre-existing immunity against seasonal H1N1 flu might help explain why most reported human cases of H5N1 bird flu in the U.S. have not resulted in lethal outcomes.

Previous infections with seasonal H1N1 flu may boost immunity and reduce the severity of H5N1 bird flu, according to a study.

New research also found that molecules on the inside of highly pathogenic influenza A H5N1 virus could be promising targets for human vaccines.

H5N1, or bird flu, is startlingly good at adapting.

H5N1 Response among Ferrets with H1N1 Immunity

Influenza A(H5N1) Clade 2.3.4.4b Virus

The highly pathogenic avian influenza H5N1 virus clade 2.3.4.4b has been spreading globally since 2022, causing mortality and morbidity in domestic and wild birds and mammals, including infection in humans, raising concerns about its pandemic potential. We aimed to generate a panel of anti-hemagglutinin (HA) human monoclonal antibodies (mAbs) against the H5 protein of clade 2.3.4.4b. H2L2 Harbour Mice, which express human immunoglobulin germline genes, were immunized with H5 and N1 recombinant proteins from A/mallard/New York/22-008760-007-original/2022 H5N1 virus, enabling the generation of human chimeric antibodies. Through hybridoma technology, sixteen full human mAbs were generated, most of which showed cross-reactivity against H5 proteins from different virus variants. The functionality of the sixteen mAbs was assessed in vitro using hemagglutination inhibition and microneutralization assays with viruses containing a clade 2.3.4.4b HA. Fourteen out of the sixteen mAbs neutralized the virus in vitro. The mAbs with the strongest hemagglutination inhibition activity also demonstrated greater neutralizing capacity and showed increased protective effects in vivo when administered prophylactically or therapeutically in a murine H5N1 challenge model. Using cryo-electron microscopy, we identified a cross-clonotype conserved motif that bound a hydrophobic groove on the head domain of H5 HA. Akin to mAbs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the coronavirus 2019 (COVID-19) pandemic, these mAbs could serve as important treatments in case of a widespread H5N1 epidemic or pandemic. ### Competing Interest Statement The Icahn School of Medicine at Mount Sinai has filed patent applications regarding the described H5 mAbs which list GPA, JAD and FK as inventors. The Icahn School of Medicine at Mount Sinai has filed patent applications relating to SARS-CoV-2 serological assays, NDV-based SARS-CoV-2 vaccines influenza virus vaccines and influenza virus therapeutics which list FK as co-inventor and FK has received royalty payments from some of these patents. Mount Sinai has spun out a company, Kantaro, to market serological tests for SARS-CoV-2 and another company, Castlevax, to develop SARS-CoV-2 vaccines. FK is co-founder and scientific advisory board member of Castlevax. FK has consulted for Merck, GSK, Sanofi, Curevac, Seqirus and Pfizer and is currently consulting for 3rd Rock Ventures, Gritstone and Avimex. The Krammer laboratory is also collaborating with Dynavax on influenza vaccine development and with VIR on influenza virus therapeutics. ABW has received royalty payments for the licensure of a prefusion coronavirus spike stabilization technology for which he is a co-inventor. ABW is currently consulting for Third Rock Ventures and Merida Biosciences. Julianna Han and Andrew Ward are consultants for Third Rock Ventures.

U.S. authorities also identified the more common H5N1 strain on the same farm in Merced County, California.

The mutation doesn't appear to reduce viral fitness, as evidenced by its rapid spread, the authors say.

(1) Background: The emergence of H5N1 Influenza A viruses clade 2.3.3.4b since 2020, have caused the mortality of thousands of birds/mammals worldwide, through evolu-tionary changes have been associated with acquired mutations and posttranslational modifications. (2) Methods: This study aimed to compare the mutational profile of H5N1 avian Influenza virus isolated from a Peruvian natural reserve, with recent data from other related international studies made in human and different species of domestic and wild birds and mammals. Briefly, the near complete protein sequences of Influenza virus coming from a Calidris alba were analyzed in a multisegmented level, altogether with 55 samples collected between 2022-2024 in different countries. Moreover, the glycosylation patterns were also predicted in silico. (3) Results: A total of 603 amino acid changes were found among H5N1 viruses analyzed, underscoring the detection of critical mutations HA:143T, HA:156A, HA:208K, NA: 71S, NP:52H, PA:336M, PA:36T, PA:85A/N, PB1-F2:66S, PB2:199S, PB2:292V, PB2:559T, as well as PA:86I, PA:432I, PA:558L, HA:492D, NA:70D, NS1-83P, PB1:515A, PA-X:57Q, PB1-F2:22E, NS1-21Q, NEP:67G, among others, considered of importance under One Health perspective. Similarly, changes in the N-linked glycosylation sites (NLGs) predicted in both HA and NA proteins were found, highlighting the loss/acquisition or changes in some NLGs sites such as 209NNTN, 100 NPTT, 302NSSM (HA) and 70NNTN, 68NISS, 50NGSV (NA). (4) Conclu-sions: This study provides our understanding about the evolution of current Influenza A viruses H5N1 HPAIV circulating globally. These findings outline the importance of sur-veillance updating mutational profiles and glycosylation patterns of these highly evolved virus.

Cross-reactive αβ T cell receptors (TCRs) recognizing multiple peptide variants can provide effective control of rapidly evolving viruses yet remain understudied. By screening 12 naturally occurring influenza-derived HLA-B*35:01-restricted nucleoprotein (NP)sub418-426/sub epitopes (B*35:01-NP …

We report the detection of a clade 2.3.4.4b A(H5N1) reassortant virus with a neuraminidase surface protein derived from a North American lineage low-pathogenic avian influenza virus. This virus caused a widespread and ongoing outbreak across 45 poultry farms in British Columbia, Canada. Isolates fro …

The women, ages 72 and 56, were both from Guangdong province in southern China.