One Health implementation: A systematic scoping review using the Quadripartite One Health Joint Plan of Action.

Background: One Health (OH) recognizes the interconnectedness of humans, animals, and their shared environment and mobilizes multiple sectors to achieve sustainable and optimal health outcomes. We synthesized current OH implementations at global, regional, national, and local community levels using the OH Joint Plan of Action (OH JPA) developed to enhance best practices in OH implementation. Methods: We applied the OH JPA Theory of Change, supported by three pathways mapped out across six action tracks to guide our review. Searches were conducted in PubMed, Embase and Scopus. Eligibility of studies was based on implementation of OH undertaken across two or more sectors within the human-animal-environment interface. Selection was guided by the PRISMA-ScR. Results: Of the 54 studies, 77 unique programs reported OH implementations, and of these, 42 (54.5 %) involved human and animal sectors only. No studies involved the environment sector and its impact on human-environment or animal-environment. The majority (90.9 %) of programs incorporated at least one aspect of policy, legislation, advocacy and financing (Pathway 1). Capacity development, community engagement, multisectoral coordination, collaboration or communication was identified in 96.1 % of programs (Pathway 2). Data, evidence and knowledge featured in 60 % of OH initiatives (Pathway 3). Conclusion: Pathway 2 was the most engaged pathway building the foundation for OH implementation and action. There is opportunity for further growth concerning community engagement, monitoring and evaluation strategies with enhanced future investment for implementation of community-centric and risk-based solutions. Furthermore, it is important to foster better understanding of environmental issues and to build capacity for the environment sector to be better represented in the implementation of OH.