At the Frontline of Global Health Security: Rethinking Zoonotic and Vector-Borne Diseases at the Climate–Biodiversity–Health Nexus

Abstract

Climate change, biodiversity loss, land-use transformation, urbanization, and human mobility are reshaping the global epidemiology of infectious diseases. These interacting forces alter the abundance, distribution, and behaviour of vectors and animal reservoirs, modify pathogen development and transmission, and increase opportunities for spillover into human populations. As a result, climate- and ecology-sensitive infectious diseases are emerging in new locations, extending their transmission seasons, and affecting populations and health systems that may have limited prior experience or preparedness. The resulting risks are neither uniform nor linear. Temperature, rainfall, humidity, ecosystem disruption, socioeconomic conditions, and population movement act together to create context-specific patterns of disease emergence and spread. In some settings, warming may increase transmission suitability, while in others it may shift risk geographically or favour different pathogens and vectors. These dynamics underscore the limitations of isolated, pathogen-specific approaches to preparedness. Effective prevention and control therefore require an integrated One Health framework that connects human, animal, and environmental health systems. Climate-informed surveillance, ecological and vector monitoring, interoperable laboratory networks, early-warning systems, clinical readiness, and coordinated multisectoral response should be embedded within routine public health infrastructure. Cross-border data sharing, standardized case definitions, and targeted capacity building are also essential, particularly in regions where changing transmission risks intersect with limited surveillance and response capacity. Moving from reactive outbreak control to anticipatory health security will enable earlier detection, more timely prevention, and more resilient responses to emerging and re-emerging infectious disease threats. This transformation can also support equitable allocation of preparedness resources according to evolving local vulnerabilities.