H4N6 avian influenza virus in Iran: first isolation and molecular insights.

The rapid evolutionary dynamics of avian influenza viruses (AIVs) enable frequent genetic drift and reassortment, posing ongoing challenges to both poultry and public health. In this study, we report the isolation of an H4N6 virus strain (Duck/Qom/02-663/2024) from a commercial duck farm in Iran. BLAST analysis indicated that, while the surface glycoproteins and nucleoprotein closely matched those of other H4N6 viruses, the remaining gene segments were more closely related to other subtypes, suggesting a potentially reassortant virus. Phylogenetic analysis classified the isolate within the Eurasian lineage. These findings underscore the importance of continuous surveillance of AIVs in both wild and domestic bird populations.