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

Abstract

Antimicrobial resistance [AMR] is a silent yet intensifying global threat, with particularly severe consequences in tropical and subtropical ecosystems, where high ecological connectivity, extensive 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 and subtropical regions indicates that migratory birds frequently carry clinically relevant AMR-associated pathogens, including extended-spectrum β-lactamase-producing Escherichia coli, multidrug-resistant Salmonella enterica, and fluoroquinolone- and macrolide-resistant Campylobacter spp. These findings suggest that migratory birds primarily function as ecological sentinels and geographic redistributors of antimicrobial resistance, reflecting environmental contamination and ecological connectivity between human-dominated and natural ecosystems, while evidence for long-term reservoir status remains context-dependent. 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 mitigate transboundary AMR risks and preserve the long-term efficacy of antimicrobial therapies.