The definition of One Health as described by the World Organization for Animal Health (OIE):
One Health is an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems. It recognizes the health of humans, domestic and wild animals, plants, and the wider environment (including ecosystems) are closely linked and inter-dependent.The approach mobilizes multiple sectors, disciplines and communities at varying levels of society to work together to foster well-being and tackle threats to health and ecosystems, while addressing the collective need for clean water, energy and air, safe and nutritious food, taking action on climate change, and contributing to sustainable development.
A classic and simple example of the One Health approach involves diseases that are shared between animals and people, also called zoonotic diseases. Consider the cases of Nipah virus in Bangladesh, which is responsible for hundreds of deaths each year. In order to innovate ideas to prevent this disease, a One Health approach is useful to highlight the areas of interface that lead to an increase in transmission: