Clade 2.3. 4.4 H5Nx influenza viruses have further diversified into several subclades. Sub-
clade 2.3. 4.4 b H5N1 viruses have been widely circulating in wild birds and detected in
Europe, Africa, Asia, and North America since October 2020. In this study, we report the first
detection of highly pathogenic avian influenza H5N1 clade 2.3. 4.4 b viruses in wild birds
and domestic ducks from live bird markets in Egypt. Phylogenetic analysis revealed that the
Egyptian H5N1 virus retained the genomic composition of Eurasian strains. Mutations in the …

Highly pathogenic avian influenza A (H5N1) virus clade 2.3. 4.4 b was detected in four wild
birds of two species, Fregata magnificens and Sula nebouxii, on the Ecuadorian Coast. This
report highlights the importance of intersectoral collaboration and timely genotyping for
monitoring this zoonotic pathogen, especially in regions with a rich biodiversity.