Urban environmental drivers of eukaryotic microbiota and parasite prevalence in domestic pigeon faeces: a metabarcoding-based public health risk assessment in Seoul, South Korea.

Feral pigeons in Seoul, South Korea, pose a significant public health risk due to their potential to spread zoonotic pathogens. However, the diversity of their eukaryotic microbiota, particularly parasitic organisms, remains underexplored with urban environmental factors. We aimed to characterize the eukaryotic microbiota in pigeon faeces and assess how urban factors such as housing density, proximity to water sources and parks and the presence of homeless individuals influence parasite diversity. Faecal samples were collected from pigeons in various regions of Seoul and adjacent cities. Metabarcoding identified Eimeria (86.58%), Isospora (40.94%) and Tetrameres (20.81%) as the most prevalent pathogens. Regions with homeless populations exhibited significantly lower eukaryotic diversity (p < 0.001), while areas with higher housing density and parks showed increased Eimeria prevalence (odds ratio (OR) = 1.0005, p = 0.0251 and OR = 5.3015, p = 0.0251, respectively). Water sources were positively associated with Isospora prevalence (OR = 2.5340, p = 0.0268). This study represents the first empirical investigation into the influence of urban environments on parasite diversity in feral pigeons in one of the world's most densely populated cities. The findings underscore the need for targeted public health interventions and urban planning strategies to mitigate zoonotic disease transmission from urban wildlife.