Avian influenza and One Health: bridging animal and human health through integrated surveillance and vaccination.

The ongoing threat of avian influenza over the past three decades represents a significant challenge for global health, livestock farming, and animal conservation. Notwithstanding the considerable strides made in research and the formulation of control strategies, the persistence of highly pathogenic strains gives rise to concerns pertaining to both animal and human health. This review examines the history and the role of the "One Health" concept in combating the disease, while first investigating the historical spread of avian influenza, its circulation in wild bird populations, the amplification and adaptation in domestic poultry, and its occasional spillover into humans, often facilitated by close contact in agricultural and live animal market settings. Historical patterns are key in understanding the dynamics of the virus and developing adequate countermeasures. Such surveillance methods and novel and rapid monitoring techniques now play a bigger role than ever. Meanwhile, improvements in genome sequencing have revolutionized our understanding of viral evolution allowing for more detailed monitoring of epidemics. Moreover, recent arguments in favor of vaccination of animals against avian influenza highlight its potential to reduce virus burden at source, reduce economic losses in agriculture, and reduce the risk of spillover to humans and other animal species, underlining its role in a comprehensive One Health approach. By integrating insights from recent technological and methodological innovations, this work advocates for a more coordinated, interdisciplinary approach to surveillance, monitoring, and vaccination. Addressing these gaps will be essential for improving outbreak preparedness and reducing the impact of this enduring threat.