H5N1 Flu

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

News on avian flu has been moving fast, and cases are still on the rise.

Kano, 24 February, 2025- Following an alert of a highly pathogenic avian Influenza (H5N1) outbreak in poultry, commonly known as bird flu, in Kano state,  the World Health Organization ( WHO) has stepped up its support to the Government of Nigeria to prevent transmission of the virus to humans. While the virus spreads rapidly among birds, it also has the potential to infect mammals, including humans. It poses a significant threat to both animal and public health.

AAHA will be hosting an upcoming webinar and sharing bimonthly H5N1 updates. Check back next month to stay up to date!

Exposure of Alaska mammals to H5N1

In January 2025, the highly pathogenic avian influenza A(H5N1) virus clade 2.3.2.1a infection was detected in domestic cats and whole-genome sequencing of two cat H5N1 isolates was performed using the Oxford Nanopore MinION sequencing platform. Phylogenetic analysis revealed the circulation of triple reassortant viruses in cats. Although cat viruses lacked classic mammalian adaptation markers they carried mutations associated with enhanced polymerase activity in mammalian cells and increased affinity for α2-6 sialic acid receptor suggesting their potential role in facilitating infection in cats. The identification of reassortant HPAI H5N1 clade 2.3.2.1a viruses in domestic cats in India highlights the urgent need for enhanced surveillance in domestic poultry, wild birds, and mammals, including humans, to track genomic diversity and molecular evolution of circulating strains. ### Competing Interest Statement The authors have declared no competing interest.

Jonathan E. Pekar, Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, UK Thomas P. Peacock, The Pirbright Institute, Woking, UK, GU24 0NF; Department of Infectious Disease, Imperial College London, UK, W2 1PG Louise Moncla, University of Pennsylvania, PA 19104, USA Praneeth Gangavarapu, Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA Divya Venkatesh, Department of Biology, University of Oxford, Oxford OX1 3SY, UK Daniel H. Go...

H5N1 Response among Ferrets with H1N1 Immunity

Influenza A(H5N1) Clade 2.3.4.4b Virus

First it hit poultry farms, forcing farmers to cull millions of hens.  Egg prices jumped, and some grocery stores began to ration the number of cartons per customer. Next infections spread to dairy cows, stoking fears of a wider outbreak. Now, avian influenza has been detected in domesticated cats, and humans, with about seventy confirmed cases in in the U.S. Lena […]

Amid heightened fears of immigration raids, Alianza Agricola has spent months educating hundreds of their coworkers on how to prepare for an avian flu outbreak.

This report describes highly pathogenic avian influenza virus infection among two indoor cats living in homes of dairy workers.

During the systemwide UC Health Grand Rounds, learn how health professionals are navigating the current highly pathogenic avian influenza outbreak throughout...

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Airborne transmission via aerosols is a dominant route for the transmission of respiratory pathogens, including avian H5N1 influenza A virus and E. coli bacteria. Rapid and direct detection of respiratory pathogen aerosols has been a long-standing technical challenge. Herein, we develop a novel label-free capacitive biosensor using an interlocked Prussian blue (PB)/graphene oxide (GO) network on a screen-printed carbon electrode (SPCE) for direct detection of avian H5N1 and E. coli. A single-step electro-co-deposition process grows GO branches on the SPCE surface, while the PB nanocrystals simultaneously decorate around the GO branches, resulting in an ultrasensitive capacitive response at nanofarad levels. We tested the biosensor for H5N1 concentrations from 2.0 viral RNA copies/mL to 1.6 × 105 viral RNA copies/mL, with a limit of detection (LoD) of 56 viral RNA copies/mL. We tested it on E. coli for concentrations ranging from 2.0 bacterial cells/mL to 1.8 × 104 bacterial cells/mL, with a LoD of 5 bacterial cells/mL. The detection times for both pathogens were under 5 min. When integrated with a custom-built wet cyclone bioaerosol sampler, our biosensor could detect and quasi-quantitatively estimate H5N1 and E. coli concentrations in air with spatial resolutions of 93 viral RNA copies/m3 and 8 bacterial cells/m3, respectively. The quasi-quantification method, based on dilution and binary detection (positive/negative), achieved an overall accuracy of 90% for pathogen-laden aerosol samples. This biosensor is adaptable for multiplexed detection of other respiratory pathogens, making it a versatile tool for real-time airborne pathogen monitoring and risk assessment.

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.

A cat picked up by Clovis’ animal control officers has tested positive for H5N1, also known as avian influenza or bird flu. Shelter supervisor Larry Jacquez said the stray cat was located in the back yard of a Clovis home and picked up at the homeowner’s request on Feb. 9. The cat showed signs of rabies, which mirror the signs of bird flu, Jacq...

Nautilus looks at how commercial poultry creates perfect conditions

The U.S. Department of Agriculture has confirmed five more dairy herds in California have tested positive for bird flu. The USDA's Animal and Plant Health

LSU Vet Professor weighs in on potential poultry vaccine for bird flu

The Department of Disease Control, Ministry of Public Health of Thailand emphasized the danger level of avian influenza A (H5N1) and issued many warnings, including not drinking raw milk (unprocessed fresh milk).

A recent case of H5N1 in pigs and poultry on an Oregon farm has highlighted significant concerns about disease transmission and biosecurity on small lifestyle farms, while emphasizing the unique role pigs play in potential viral mutations.

Elsewhere in the Asia-Pacific region, poultry have tested positive for the virus in Australia, Nepal and Turkey.

Experts say current US outbreak is unlikely to end without intervention with further mutation of virus likely

Two house cats died after contracting bird flu in the homes of dairy workers, a troubling sign that the virus may be moving between species and becoming more widespread.

CDC researchers call for further investigation of the risk of fomite transmission of H5N1

“It’s just a matter of time,” said Regina Massaro, the founder of Spay Neuter Intervention Project NYC, to The Post.

Oregon health officials say they are continuing to alert pet owners of cats getting sick with bird flu.