Highlights • Global mobility, climate pressures, and ecological change drive emerging infections. • Highly pathogenic influenza strains, including H5N1, pose ongoing spillover risks and pandemic potential. • SARS, MERS, and COVID-19 illustrate the pandemic potential of novel coronaviruses. • Nipah, Ebola, Pteropine orthoreovirus and Zika remain high-impact threats for global health security. • Mass gatherings can amplify transmission risks of emerging high-consequence viruses. • Strengthened surveillance, diagnostics, and One Health strategies are essential for pandemic preparedness. Abstract Emerging infectious diseases have risen significantly in the twenty-first century as ecological disruption, climate change, expanding human–animal interfaces , and global mobility intensify opportunities for pathogen transmission . This review synthesizes historical and contemporary evidence across viral, bacterial, fungal, and parasitic threats to charact...