#Landscape changes elevate the #risk of avian #influenza virus diversification and emergence in the East Asian–Australasian #Flyway

 

Significance

Highly pathogenic avian influenza virus (HPAIV) threatens wildlife, agriculture, and humans. Along the East Asian–Australasian Flyway, a major waterfowl migration corridor and HPAIV hot spot, landscape changes are altering migratory bird distributions and increasing opportunities for wild–poultry interactions. By integrating empirical data into an individual-based model, we show that landscape change between 2000 and 2015 reshaped waterfowl migration, substantially increased wild-poultry spillover, and avian influenza virus (AIV) reassortment in poultry, our proxy for potential AIV diversification and emergence of novel subtypes. Risk regions expanded across southeastern China, the Yellow River basin, and northeastern China. These findings highlight the importance of landscape changes in potentially elevating AIV diversification and emergence, and the landscape dynamics should be integrated into future studies.

Abstract

Highly pathogenic avian influenza viruses (HPAIV) persistently threaten wild waterfowl, domestic poultry, and public health. The East Asian–Australasian Flyway plays a crucial role in HPAIV dynamics due to its large populations of migratory waterfowl and poultry. Over recent decades, this flyway has undergone substantial landscape changes, including both losses and gains of waterfowl habitats. These changes can affect waterfowl distributions, increase contact with poultry, and consequently alter ecological conditions that favor avian influenza virus (AIV) evolution. However, limited research has assessed these likely impacts. Here, we integrated empirical data and an individual-based model to simulate AIV transmission in migratory waterfowl and domestic poultry, including wild-to-poultry spillover and reassortment dynamics in poultry, across landscapes representing the years 2000 and 2015. We used the reassortment incidence as a proxy for ecological and transmission conditions that support viral diversification and the emergence of novel subtypes. Our simulations show that landscape change reshaped the waterfowl distribution, facilitated bird aggregation at improved habitats, increased coinfection, and raised reassortment rate by 1,593%, indicating a substantially higher potential for viral diversification and emergence. Model-generated risk maps show expanded and increased reassortment risk in southeastern China, the Yellow River Basin, and northeastern China. These findings suggest the importance of landscape change as a driver of potential AIV diversification and subtype emergence. This underscores the need for interdisciplinary approaches that integrate landscape dynamics, host movement, and viral evolution to better assess and mitigate future risk.

Source: Proceedings of the National Academy of Sciences of the United States of America, https://www.pnas.org/doi/abs/10.1073/pnas.2503427122?af=R

____