Scaling up the integration of the environment and wildlife sectors for enhanced One Health outcomes in Southeast Asia.

Emerging infectious diseases (EIDs) are increasing in frequency due to anthropogenic pressures such as habitat loss, land-use change, biodiversity decline, and climate change. Southeast Asia, with its high biodiversity, large livestock population, increasing human population, rapid development, and expanding agriculture, is one of the global hotspots for EIDs and as such offers a strategic opportunity for the region to place itself as a leader in pandemic prevention. The One Health approach, which emphasizes the interconnectedness of human, animal, and environmental health, presents a vital framework for addressing these risks. However, despite growing international commitment through the One Health Joint Plan of Action and the ASEAN Leaders' Declaration on One Health Initiative, environmental and wildlife sectors remain underrepresented in policy influence, governance, and resource allocation. This paper presents a roadmap for mainstreaming and integrating wildlife and environment sectors into One Health in Southeast Asia, shifting from reactive outbreak response to proactive prevention by addressing upstream drivers of disease emergence. Field based, or bottom-up approaches include community-based interventions, land use planning, integrated surveillance, and sustainable food production while top-down measures focus on policy harmonization, capacity enhancement, regulatory reform, cross-sectoral governance, workforce development, and data sharing. An additional core principle is that existing mandates and priorities of each sector be fully integrated into national One Health strategies, action plans, and policies, ensuring inclusive and effective governance. We advocate for upstream preventative actions, where threats to ecosystems and health are mitigated at source, to the greatest extent possible, rather than waiting for crises to unfold. Finally, this paper calls for aligning One Health with the Multilateral Environmental Agreements to ensure coherent policy action. By institutionalizing environmental considerations into One Health systems, countries can move beyond project-based efforts toward sustainable, multisectoral governance. Southeast Asia is well positioned to lead this transformation and can serve as a global model of how integrated, preventive, and environmentally conscious One Health approaches can reduce pandemic risk and promote planetary health.