Emerging and Re-Emerging Viral Pathogens: Mechanisms of Spillover and Global Health Implications

This chapter examines the ecological, evolutionary, and immunological drivers underlying the emergence of novel viral pathogens at the human-animal interface, with a focus on high-consequence viruses including filoviruses, coronaviruses, arboviruses, and henipaviruses. It provides a comprehensive analysis of zoonotic spillover dynamics, host range determinants, and the molecular adaptations that facilitate sustained human-to-human transmission. The chapter further explores surveillance frameworks, early-warning systems, and global health governance structures that inform pandemic preparedness and response in an era of accelerating emergence events.