tetano
Editor, Senior Moderator
Emerg Infect Dis
. 2026 Sep 16;32(10).
doi: 10.3201/eid3210.260067. Online ahead of print.
Alexander M P Byrne, Lorcan Carnegie, Nicola S Lewis, Ian G Barr, Erik A Karlsson, Michelle Wille
Highly pathogenic avian influenza H5Nx viruses remain a major zoonotic threat, yet global attention has focused largely on clade 2.3.4.4b, potentially overlooking major changes within long-endemic H5N1 lineages in Asia. Recent reports from South and Southeast Asia describe the emergence of reassortant clade 2.3.2.1 viruses alongside renewed human infections after apparent prolonged epidemiologic stability. Collectively, those events suggest a regional pattern rather than isolated anomalies. In this article, we argue that reassortment, rather than point mutation alone, might be an underrecognized driver of zoonotic risk in endemic H5N1 lineages and is reshaping those lineages. We examine why such events might be underrecognized in settings with entrenched poultry influenza, identify limitations of current surveillance systems, and call for integrated, real-time approaches linking genomic detection with phenotypic assessment across animal and human health sectors to enable timely risk assessment and coordinated public health action.
Keywords: Asia; H5N1; One Health; avian influenza; clade 2.3.2.1; influenza; reassortment; respiratory infections zoonoses; spillover; viruses.
. 2026 Sep 16;32(10).
doi: 10.3201/eid3210.260067. Online ahead of print.
Reassortment of Highly Pathogenic Avian Influenza as a Driver for Zoonotic Spillover, Asia
Alexander M P Byrne, Lorcan Carnegie, Nicola S Lewis, Ian G Barr, Erik A Karlsson, Michelle Wille
- PMID: 42749686
- DOI: 10.3201/eid3210.260067
Abstract
Highly pathogenic avian influenza H5Nx viruses remain a major zoonotic threat, yet global attention has focused largely on clade 2.3.4.4b, potentially overlooking major changes within long-endemic H5N1 lineages in Asia. Recent reports from South and Southeast Asia describe the emergence of reassortant clade 2.3.2.1 viruses alongside renewed human infections after apparent prolonged epidemiologic stability. Collectively, those events suggest a regional pattern rather than isolated anomalies. In this article, we argue that reassortment, rather than point mutation alone, might be an underrecognized driver of zoonotic risk in endemic H5N1 lineages and is reshaping those lineages. We examine why such events might be underrecognized in settings with entrenched poultry influenza, identify limitations of current surveillance systems, and call for integrated, real-time approaches linking genomic detection with phenotypic assessment across animal and human health sectors to enable timely risk assessment and coordinated public health action.
Keywords: Asia; H5N1; One Health; avian influenza; clade 2.3.2.1; influenza; reassortment; respiratory infections zoonoses; spillover; viruses.