Evaluating the Role of Canada Goose Populations in Transmission Dynamics During Peak HPAI Incidence in Iowa, February 2022–December 2023

Since its emergence in the United States in February 2022, Highly Pathogenic Avian Influenza (HPAI) H5N1 has caused significant losses for poultry operations, particularly in Iowa between February 2022 and December 2023. Branta canadensis (Canada goose), an abundant North American waterfowl species, is considered a potential reservoir host for H5N1. This study examined the relationship between Canada goose abundance and H5N1 occurrence in Iowa counties. Although counties with H5N1 cases comprised 13% of the state’s Canada goose population—and 32% of those counties had high goose abundance—an inverse relationship was observed. Bivariate analysis indicated that counties with high goose abundance were significantly less likely to report HPAI cases (χ2 = 4.29, p = 0.04). Notably, intermediate goose abundance was associated with a 79% lower likelihood of HPAI occurrence (RR = 0.21, 95% CI [0.05, 0.90], p = 0.04). These findings highlight the limitations posed by the lack of accessible, high-resolution poultry farm location data, which hinders a definitive understanding of Canada geese’s role in H5N1 transmission. To address this gap, stakeholders should consider adopting next-generation surveillance tools like the Biothreats Emergence Analysis and Communication Network (BEACON) AI platform, or AI-integrated chemical sensors that generate real-time, actionable data for biosecurity decision-making. Given the uncertainty surrounding Canada goose role transmission dynamics, the species remains a relevant One Health concern.