One Health Newsletter

One Health Newsletter: Volume 14 Issue 1

One Health formally defined: mainstreaming the approach to respond to future global health threats


Cheyenne Brunkow, Sierrah Haas, Ryan Walker

In December 2021, the Joint Tripartite and United Nations Environment Programme (UNEP) adopted the operational definition of One Health from the One Health High-Level Expert Panel (OHLEP), signifying an important milestone for mainstreaming the One Health approach to prepare and respond to future global health threats. The new operational definition declares: "One Health is an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals, and ecosystems. It recognizes that the health of humans, domestic and wild animals, plants, and the wider environment (including ecosystems) are closely linked and interdependent. 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, acting on climate change, and contributing to sustainable development."1

The comprehensive One Health definition is a result of many years of dedicated work by the organizations represented in the Joint Tripartite and United Nations. Representing international organizations include the Food and Agricultural Organization of the United Nations (FAO), the World Organisation for Animal Health (OIE), the World Health Organization (WHO), and UNEP. This article briefly describes their missions and history to frame their roles in defining One Health.

Food and Agriculture Organization of the United Nations (Rome, Italy)

Since its founding in 1945, FAO has served as a source of information to modernize and improve agriculture, forestry, and fishery practices with the goal to end hunger and poverty through food security.2 It partners with civil society organizations and private sectors as a knowledge network, shares policy expertise, provides a physical meeting place for nations, and helps generate knowledge in the field. Headquarters and field offices are neutral spaces for policymakers to negotiate agreements and policies important for developing agricultural policy, planning, legislation, and strategies to develop rural areas and alleviate hunger.3 They manage monies provided by countries, banks, and others to achieve their designated health goals and work with humanitarian agencies engaged in relief work.3

World Organisation for Animal Health (Paris, France)

In 1924, the Office International des Epizooties (OIE) was created, and in 2003 it was renamed the World Organisation for Animal Health and kept the OIE acronym.4 Its mission is to improve animal health globally by processing and analyzing veterinary scientific information, controlling zoonoses internationally, publishing health standards for the trade of animals and animal products, and improving the legal framework of National Veterinary Services. The organization reports on zoonoses in new geographic regions, and develops global initiatives to mitigate the spread of zoonotic diseases. They were also involved in the development of the World Trade Organization's Agreement on the Application of Sanitary and Phytosanitary Measures (SPS) agreement as a tool for nations to base their sanitary guidelines for health standards. The OIE champions the One Health concept while providing expertise in the animal-human-ecosystems relationship.4

World Health Organization (Geneva, Switzerland)

Efforts of the WHO has been aiming to ensure a healthy life for all since 1948. The original focus was on women's and children's health, nutrition, sanitation, and fighting malaria and tuberculosis. Now, the WHO is responsible for coordinating international health efforts through partnerships with other health initiatives, research, and monitoring health trends.5 The WHO defines health as "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity".5 With this definition in mind, the WHO directs efforts to expand universal health coverage, global emergency response, and using science-based policies and programs to achieve healthier lives at all ages.

United Nations Environment Programme (Nairobi, Kenya)

The UNEP has been an authoritative advocate for the global environment since its founding in 1972.6 It promotes the sustainable development of the environment by working with countries to achieve low-emission pathways and investing in clean technologies. The three focus areas are climate, nature, and chemical and pollution action. With programs in adaptation, forestry, and energy efficiency, UNEP aims to reduce emissions, protect biodiversity, alleviate poverty, and strengthen resilience to climate change. It works with private and public financial communities for investments in climate-resilient developments, climate finance readiness, capacity-building, policy, and research analysis.6

Brief History of One Health

One Health as a general concept has been recorded in various forms starting as early as the 1800s. The establishment of the US Centers for Disease Control and Prevention's (CDC) Veterinary Public Health Division in the mid-1940s introduced the strong correlation between human, animal, and environmental health.7 Presently, the term One Health is used to demonstrate and monitor the interconnectedness of humans, animals, and the environment.

Foundation of One Health
Figure 1. The Foundation of One Health. (Source: Centers for Disease Control and Prevention, 2018;

The optimal health of humans, animals, ecosystems, and shared habitats is promoted through continuous One Health research. One Health issues that continue to be closely monitored by several organizations sharing an interest in public health include emerging zoonotic diseases, food safety and security, and antimicrobial resistance.7 With ever-changing populations, increased human-animal and human-environmental interaction, frequent global travel, and changing climates, it has become more important to recognize and define One Health accurately. A clear and collaborative One Health definition, like that created by the OHLEP, strengthens, and increases awareness of the importance of the One Health approach and enables consistent implementation of policy and practice aimed at improving health outcomes.1

Figure 2. Joint Tripartite and UNEP One Health Approach. (Source: World Health Organization, 2021;


  1. World Health Organization. Tripartite and UNEP support OHHLEP's definition of "One Health”. Joint Tripartite (FAO, OIE, WHO) UNEP Statement. 2021. Accessed December 29, 2021.

  2. Food and Agriculture Organization of the United Nations. Food and Agriculture Organization of the United Nations. 2021. Accessed December 30, 2021.

  3. Food and Agriculture Organization of the United Nations (FAO). 2021. Accessed December 30, 2021.

  4. World Organisation for Animal Health. What we offer. 2021. Accessed December 30, 2021.

  5. World Health Organization. About WHO. 2021. Accessed December 30, 2021.

  6. United Nations Environment Programme. Climate Action. Accessed December 30, 2021.

  7. US Centers for Disease Control and Prevention. Timeline: people and events in One Health. One Health. 2016. Accessed December 24, 2021.

  8. US Centers for Disease Control and Prevention. One Health basics. One Health. 2018. Accessed December 24, 2021.


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One Health Newsletter

The One Health Newsletter is a collaborative effort by a diverse group of scientists and health professionals committed to promoting One Health. This newsletter was created to lend support to the One Health Initiative and is dedicated to enhancing the integration of animal, human, and environmental health for the benefit of all by demonstrating One Health in practice.

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