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Volume 32, Number 10—October 2026

Perspective

Reassortment of Highly Pathogenic Avian Influenza as a Driver for Zoonotic Spillover, Asia

Alexander M.P. Byrne1, Lorcan Carnegie1, Nicola S. Lewis, Ian G. Barr, Erik A. Karlsson, and Michelle WilleComments to Author 
Author affiliation: Worldwide Influenza Centre, The Francis Crick Institute, London, UK (A.M.P. Byrne, N.S. Lewis); Food and Agriculture Organization of the United Nations, Rome, Italy (L. Carnegie); World Health Organization Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia (I.G. Barr, M. Wille); Institut Pasteur du Cambodge, Phnom Penh, Cambodia (E.A. Karlsson); Environment and Infectious Risks Unit, Laboratory for Urgent Response to Biological Threats, Institut Pasteur, Paris, France (E.A. Karlsson)

Main Article

Figure 1

Emergence and human case trends of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.2.1 viruses in study of reassortment of HPAI as a driver for zoonotic spillover, Asia. A, B) Case notification data of HPAI H5N1 in Cambodia (A) and India and Bangladesh (B), demonstrating the clear resurgence of zoonotic spillover occurring in 2023, driven by reassortant clade 2.3.2.1c/e and 2.3.2.1a viruses. C) Time-scaled phylogeny of the H5 hemagglutinin gene for clade 2.3.2.1 viruses, highlighting the divergence of clade 2.3.2.1a and clade 2.3.2.1c/e.

Figure 1. Emergence and human case trends of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.2.1 viruses in study of reassortment of HPAI as a driver for zoonotic spillover, Asia. A, B) Case notification data of HPAI H5N1 in Cambodia (A) and India and Bangladesh (B), demonstrating the clear resurgence of zoonotic spillover occurring in 2023, driven by reassortant clade 2.3.2.1c/e and 2.3.2.1a viruses. C) Time-scaled phylogeny of the H5 hemagglutinin gene for clade 2.3.2.1 viruses, highlighting the divergence of clade 2.3.2.1a and clade 2.3.2.1c/e.

Main Article

1These first authors contributed equally to this article.

Page created: August 13, 2026
Page updated: September 28, 2026
Page reviewed: September 28, 2026
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