Risk assessment of the transmission of HPAI-H5 in wild birds in the United States based on spatio-temporal distribution and climate change

Wild birds play a significant role in the cross-species transmission of avian influenza. This study evaluates the transmission patterns of HPAI-H5 in wild birds from multiple aspects. Transmission capabilities of different orders were estimated through generational transmission and exponential growth models. The STL decomposition was used to analyze the seasonality and trend of its transmission. Spatial analysis revealed the spatiotemporal distribution characteristics of avian influenza in wild birds. Combined with meteorological data, machine learning models were used to analyze the impact of meteorological factors on wild bird infections. From 2022 to 2025, a total of 12,808 H5-infected wild bird samples were collected. The basic reproduction number (R ₀ ) revealed the strongest transmission capacity in Strigiformes (R ₀  = 3.164 (95% CI: 2.711–3.726)) and the weakest in Anseriformes (R ₀  = 0.992 (95% CI: 0.990–0.994)). The number of infections in autumn and winter was twice that in spring and five times that in summer. Spatial analysis showed significant spatial autocorrelation during migratory bird seasons, with coastal areas, Central and Pacific migratory bird route areas being the main hotspots. Since 2022, the number of H5 infections in wild birds in the United States has gradually declined, but seasonality persists. H5 infections in wild birds are closely tied to migratory bird movements, with migration routes and coastal areas being key areas for prevention and control. While the transmission capacity of H5 among migratory birds is relatively weak, it is stronger in Strigiformes. Meteorological factor analysis indicated non-linear relationships in avian influenza infection. Surveillance of avian influenza in wild birds should be strengthened, and contact between wild birds and other animals should be reduced to prevent its transmission among animals.