Migratory birds as global pathogen vectors: Ecological roles, transmission pathways, and emerging zoonotic risks

Migratory birds have emerged as primary vectors of infectious agents, including viruses, bacteria, vector-borne pathogens, and fungal pathogens, posing a considerable and geographically unrestricted risk to global health security. As climate change alters bird populations and migration routes, new pathways for disease transmission are likely to emerge. Habitat overlap with densely populated urban areas may amplify the risk of zoonotic disease transmission. The current review examines the ecological and public health risks associated with migratory birds, emphasizing their role in cross-regional pathogen transmission, the underlying mechanisms of dissemination, and the environmental drivers that influence transmission dynamics. It highlights critical knowledge gaps in pathogen diversity that limit existing surveillance mechanisms, leading to inadequate genomic monitoring of pathogen evolution and poor integration of avian ecology into veterinary and human health frameworks. These limitations hinder initial detection of novel pathogens and undermine global preparedness for outbreak management. Therefore, this review provides a holistic assessment of these challenges by consolidating existing knowledge on pathogens transmitted by migratory birds while emphasizing the need for integrated monitoring strategies, biosecurity measures, and habitat conservation efforts to mitigate these risks. It further offers a comprehensive framework for addressing the identified challenges in the context of global health security and biodiversity conservation.