Long-Term Wetland Habitat Loss and H5N1 Outbreaks in Domestic Poultry in the United States, 2020 - 2026

Abstract

The emergence of the H5N1 2.3.4.4b clade virus in October 2020 has driven the world into a devastating H5N1 panzootic that has led to the deaths of millions of birds across the world1. In December 2021, this panzootic strain was detected in the United States, since which it has affected over 58 million birds1. In this study, we sought to characterize how wetland loss over time affected the odds of H5N1 outbreak occurrence. Using spatiotemporal modeling, we found that annual wetland loss over time within 10 km of a given location is associated with increased risk of H5N1 outbreak occurrence. Our results indicate that annual losses in wetland habitat increase the risk of H5N1 outbreaks in the surrounding regions. This study provides potential evidence that wetland loss reduces the productivity of wetland habitats that migratory birds rely on for resources, pushing them to travel outside traditional wetland breeding and wintering sites to meet their nutritional needs and spreading H5N1 to domestic poultry through direct and indirect means.