Detection of Divergent Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus, São Paulo, Brazil, 2025
J. de Araújo
Luciano M. Thomazelli
Thomas P. Fabrizio
Gustavo O. Fenner
E. Dorlass
A. K. A. Eisen
V. Botosso
Marcello S. Nardi
Caroline C. Aires
Sergio M. N. Teixeira
R. M. de Azevedo
M. Frediani
T. Ometto
M. G. Barboza
E. E. de Souza
Carsten Wrenger
R. Webby
E. Durigon
Medicine
Abstract
In 2025, we detected highly pathogenic avian influenza H5N1 virus in dead waterfowl at Ibirapuera Park, São Paulo, Brazil. Genomic characterization indicated a reassortant virus that emerged from locally circulating low pathogenicity avian influenza viruses and highly pathogenic North American lineages. Our results highlight cross-species transmission risk and underscore the need for enhanced surveillance.