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Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.

Volume 31, Number 12—December 2025

Dispatch

Novel Highly Pathogenic Avian Influenza A(H5N1) Virus, Argentina, 2025

Ralph E.T. Vanstreels, Martha I. Nelson, María C. Artuso, Vanina D. Marchione, Luana E. Piccini, Estefania Benedetti, Alvin Crespo-Bellido, Agostina Pierdomenico, Thorsten Wolff, Marcela M. Uhart, and Agustina RimondiComments to Author 
Author affiliation: University of California Davis School of Veterinary Medicine, Davis, California, USA (R.E.T. Vanstreels, M.M. Uhart); National Institutes of Health, Bethesda, Maryland, USA (M.I. Nelson, A. Crespo-Bellido); Servicio Nacional de Sanidad y Calidad Agroalimentaria, Martínez, Buenos Aires, Argentina (M.C. Artuso, V.D. Marchione, L.E. Piccini); Instituto Nacional de Enfermedades Infecciosas Dr. Carlos G. Malbrán, Buenos Aires, Argentina (E. Benedetti); Servicio Nacional de Sanidad y Calidad Agroalimentaria, Buenos Aires, Argentina (A. Pierdomenico); Robert Koch-Institut, Berlin, Germany (T. Wolff, A. Rimondi)

Main Article

Table

Amino acid differences in hemagglutinin and neuraminidase of novel triple reassortant influenza A(H5N1) virus from Argentina, 2025, compared with previously reported South American highly pathogenic avian influenza A(H5N1) viruses

Protein (subunit) Position* Amino acid in previous viruses Mutated amino acid in reassortant virus Protein domain
Hemagglutinin (HA1) 64 E D Vestigial esterase domain
172 L Y Receptor-binding domain
181 S P Receptor-binding domain
208 T K Receptor-binding domain
235
 P
 S
 Receptor-binding domain
Hemagglutinin (HA2) 493 E K Helical globule
510 V I Transmembrane domain
532
 M
 I
 Cytoplasmic tail
Neuraminidase 35 S V Stalk domain
49 C R Stalk domain
68 N Y Head domain
454 G S Stalk domain

*HA positions refer to H5 numbering.

Main Article

Page created: November 17, 2025
Page updated: December 12, 2025
Page reviewed: December 12, 2025
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