ETIDIOH - NEW

  Abstract In 2024, a human infection with clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) virus was identified in the United States in an individual with no known exposure . Genetic analysis revealed two hemagglutinin (HA) substitutions, P136S and A156T, which may alter viral antigenicity . Virus isolation was unsuccessful, preventing timely serologic analysis. To overcome this limitation, we generated recombinant viruses by reverse genetics and characterized the effects of the substitutions on antigenicity, receptor binding , and replicative fitness. The A156T substitution introduced a potential N-linked glycosylation site , resulting in altered antigenicity and reduced replication in primary human nasal epithelial cells and ferrets . Importantly, the A(H5N1) candidate vaccine virus (CVV) IDCDC-RG80A, which possesses HA-T156, remained antigenically effective against viruses with and without these substitutions. These findings highlight the importance of sequencing, rever...

  Abstract In North-East Germany's offshore islands and mainland coast, wild ruminants, boar, and carnivores were tested for H5-HPAI antibodies . Wild ruminants were seronegative ; 3.5% of boar and 12.5-21.9% of carnivores were seropositive , evidencing frequent spillover . Because such events may accelerate mammalian - and ultimately human - adaptation , sustained One-Health monitoring is essential. Competing Interest Statement The authors have declared no competing interest. Funder Information Declared European Union, 101084171 "KAPPA-FLU" Helmholtz Institute for One Health, WiMoPOH Source: BioRxIV,  https://www.biorxiv.org/content/10.1101/2025.09.30.678011v1 ____