Bridging Continents and Pathogens: The Role of Migratory Birds in Antimicrobial Resistance Dissemination in Tropical Ecosystems

Antimicrobial resistance [AMR] is a silent yet intensifying global threat, with particularly severe consequences in tropical and subtropical ecosystems, where high ecological connectivity, widespread antimicrobial use, and inadequate sanitation create ideal conditions for the persistence and spread of antimicrobial resistance genes [ARGs]. Within the One Health framework, migratory birds warrant special attention because they traverse tropical AMR hotspots, linking contaminated aquatic, agricultural, and peri-urban environments along established flyways. Evidence from tropical regions demonstrates that migratory birds frequently carry clinically meaningful ARGs, including extended-spectrum β-lactamases [ESBLs], carbapenemases, and colistin resistance [mcr] genes, highlighting their role as biological connectors that redistribute resistant bacteria between human-dominated and natural ecosystems and contribute to the expansion of the global resistome. Addressing the complex interface among AMR, migratory birds, and ARGs requires integrative surveillance strategies that explicitly incorporate wildlife into existing health systems. Genomic and metagenomic monitoring of migratory bird populations, combined with cross-sectoral data sharing, can provide early warning signals of emerging resistance patterns and inform evidence-based interventions. Understanding the ecological role of migratory birds in tropical ecosystems is therefore essential for designing effective One Health strategies to curb transboundary AMR dissemination and preserve the long-term efficacy of antimicrobial therapies.