Abstract
Highly pathogenic avian influenza (HPAI) is a growing risk for both wild birds and the poultry industry. The 2022–2023 HPAI H5N1 outbreak in the United States is the largest and most costly animal health event in U.S. history. Based on the results of full genome sequencing, wild bird introductions have been the primary mechanism of introduction of virus into poultry operations. As prevalence increases in North America, better tools are needed to assess changing risks associated with HPAI spillover from wild animal populations into poultry operations. Through an interagency partnership, we have created a series of spatially explicit models for the United States to assess the prevalence of avian influenza in various waterfowl host species and the relative risk of spillover events at poultry operations across different times of year. These models account for not only the number of waterfowl in an area, but also species-specific prevalence rates to determine the effective waterfowl population or presented disease risk. When paired with information on the distribution of poultry farms, we can identify an area’s risk of spillover. Preliminary models have been validated using genetically identified wild bird introduction events from the current outbreak and have performed well at predicting spillover events during the 2022 HPAI outbreak. Over 90 percent of wild bird introductions occurred in areas with predicted moderately high and high spillover risks. Next steps will include incorporating climate, landcover, and anthropogenic inputs and using phylogenetic analyses of the current H5N1 outbreak.
Preliminary results are publicly available in an interactive model data visualization tool and allow for investigation across spatial scales at specific locations, for more informed decisions regarding overall risk, monitoring, and prevention.