Avian influenza in Ireland: a spatiotemporal, subtype and host-based analysis (1983-2024).

Avian influenza virus (AIV) is a significant global concern, causing widespread mortality in wild birds, domestic poultry and, more recently, wild and domestic mammals. This study presents a retrospective analysis of AIV detections in the Republic of Ireland. Data were sourced from official surveillance databases, peer-reviewed literature and grey literature sources. Spatio-temporal, host-specific and subtype patterns were assessed using descriptive statistics, chi-square tests, linear regression and kernel density estimations. A total of 2,888 confirmed AIV detections were recorded across 25 of Ireland's 26 counties. Wild birds accounted for 98.7% of detections, with domestic birds comprising 1.3%, and two detections in foxes. H5N1 highly pathogenic avian influenza (HPAI) was the most prevalent subtype (96.7%), followed by H5N8 HPAI and H6N1. Spatial clustering was observed in urban areas, particularly Dublin. The highest seasonal peak occurred during summer, contrasting with traditional winter-associated patterns. Several detections occurred in migratory species outside of typical residency periods, suggesting potential climate-related shifts in migration behaviour. This study represents the first review of AIV surveillance data in Ireland to date. The findings highlight evolving patterns in virus distribution, seasonality and host dynamics, with implications for national surveillance strategies. Continued cross-species monitoring and integration of ecological data are essential to inform effective management strategies.