Introduction. One Health: over a decade of progress on the road to sustainability.

One Health has gained momentum in every region across the world over the past decade. The human, animal and environmental health sectors of countries worldwide have increasingly requested support for the implementation of a multisectoral, One Health approach to best address health threats at the human-animal-environment interface. Such threats include zoonotic diseases, emerging infectious diseases, antimicrobial resistance (AMR), food safety, wildlife diseases and other issues that affect health, such as poverty. A variety of successes covering One Health topics at the sub-national, national, regional and global levels ranging from AMR to zoonoses are highlighted in this issue of the World Organisation for Animal Health (OIE) Scientific and Technical Review. Authors contributing to this Review were asked to highlight One Health success stories and discuss remaining challenges that might help in achieving a better understanding of the most efficient way to implement a One Health approach. The series of articles in this issue is not meant to form an exhaustive reference of every known health issue that might benefit from a One Health approach, but rather is a collection of ideas for further reflection that contributes to a better understanding of how to successfully advance the approach. This publication also highlights the challenges remaining in One Health, and its numerous authors share success stories and point out gaps so as to help others to implement One Health effectively. At the same time, these authors advocate the value of using a One Health approach to improve the health of humans and animals living in a shared environment. Readers will notice that a number of key themes are raised time and again, most notably, the value of taking a One Health approach to coordination, collaboration and communication, and the steps required to make One Health sustainable. These steps include formalising multisectoral, One Health coordination mechanisms and using One Health tools developed by national and global partners to support the approach and its implementation. The One Health approach brings together all relevant sectors and disciplines across the human-animal-environment interface in a collaboration that is more effective, efficient and sustainable than might be achieved without the shared goal of improving health for all, both humans and animals.