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What Is One Health?

The One Health approach, which is used as a framework by government officials to influence public health policy, recognizes the interconnectedness of the health of humans, animals, and ecosystems.

The US Centers for Disease Control and Prevention (CDC) defines One Health as “an approach that recognizes that the health of people is closely connected to the health of animals and our shared environment.”[1]

One Health is an important step toward a more holistic and realistic view of global health, and it can be used to encourage policies that prevent rather than simply manage health crises.

In practice, the One Health approach has primarily resulted in specific attention to infectious diseases that can be transmitted across species (i.e., zoonoses). This approach often fails to address the central connections between the rights, health, and wellbeing of people, animals, and the planet.

One Health efforts commonly focus on monitoring and mitigating diseases, rather than on more holistic forms of primary prevention, such as improving the social, environmental, and political factors that influence health.


What Is the Origin of One Health?

The modern iteration of the One Health approach, as referred to by the World Health Organization (WHO), is a concept that grew in the early 2000s from efforts to push for the protection of great apes in their native habitats.[2]

Most species of great apes are endangered. Since chimpanzees and gorillas are close evolutionary relatives to humans, it is not surprising that each species is vulnerable to infection from more than 140 of the same diseases.[3]

The spread of pathogens from humans to great apes is a growing threat to apes worldwide, as human activities encroach upon nonhuman ape communities or exploit them directly. A 2018 study found dozens of cases of disease transmission from humans to chimpanzees and gorillas, including tuberculosis, measles, and giardia.[4]

Zoonotic disease transmission to nonhuman apes occurs directly from humans, or it can result from human activities such as animal exploitation in agriculture.

Experts in human, animal, and ecosystem health correctly realized the usefulness of a broader One Health approach. One Health is intended to be a systems view of health so that new health problems are not created by well-intended solutions.


Who Uses the One Health Approach Now?

Reference to the One Health approach has become commonplace among veterinarians working within industries engaged in animal exploitation for food and fiber.

The main international organizations that refer to One Health are the World Organization for Animal Health (formerly the Office International des Epizooties, or OIE) and the Food and Agriculture Organization (FAO), which are institutions that oversee the sustained exploitation of animals.[5]

More recently, the World Health Organization (WHO) has referenced the One Health approach as a response to potential pandemics from novel zoonoses, such as COVID-19.

However, WHO involvement in the so-called tripartite (FAO-OIE-WHO), which was established in 2010, has largely focused on animal exploitation in the name of food safety.[6] Only in November 2020 was the United Nations Environment Program (UNEP) invited to join FAO, OIE, and WHO in a One Health collaboration, specifically in response to the COVID-19 pandemic.[7]


How Does an Incomplete Approach to One Health Fail?

The COVID-19 pandemic illustrates how One Health approaches have failed by focusing on harm reduction instead of on more universal forms of primary prevention that address the roots of illness and disease.

Well before COVID-19 became a global public health crisis, the WHO, FAO, OIE, and CDC referred to One Health in policy discussions about preventing the spread of novel zoonoses.

These intergovernmental and governmental institutions focus mainly on specific health outcomes in humans and on the prevention of infectious disease transmission in captive animals.

The rights, health, and wellbeing of animals and the health of ecosystems are largely ignored by these institutions, unless the animals living in those ecosystems are considered potential vectors for human disease.[8] Institutions focused on the health and wellbeing of non-captive animals and ecosystems have also been largely left out of One Health policy discussions.

Human rights, including the right to health and to a healthy living environment, are also generally omitted from the current One Health approach. Although social, environmental, and political factors that affect health are now widely recognized throughout the fields of medicine and public health, One Health fails to sufficiently consider these factors.

The One Health approach also largely fails to consider the relationship between the treatment of animals in society and individual and public human health impacts, including

  • the risk for noncommunicable human diseases such as heart disease and certain forms of cancer, which have been linked to animal product consumption;
  • the risk for interpersonal and mass violence, trauma, and human mental disorders that are linked to animal abuse; and
  • the public health effects of the climate crisis; of air, water, and soil pollution; and of the global ecosystem collapse, which have all all been linked to meat and dairy consumption, as detailed in FAO’s 2006 Livestock’s Long Shadow report[9] and in a number of other intergovernmental and independent reports.


What is Just One Health?

Just One Health recognizes that the health of humans, animals, and our ecosystems is interconnected, and that sincere pursuits to achieve optimal health and wellbeing for all require inclusive, evidence-based approaches that advance rights and justice for humans and animals.

Just One Health aims to incorporate an emphasis on rights-based primary prevention into programs, policies, legislation, research, and institutions through a respectful, collaborative, multisectoral, and interdisciplinary approach—working at local, regional, national, and international levels.

Just One Health strives to create a foundation on which public policies, institutions, and practices can become socially, environmentally, and economically equitable, and which will uplift the most vulnerable. The Just One Health approach recognizes that humans and animals have a right to be free

  • from abuse and exploitation;
  • to meet their self-determined physiological, physical, and mental needs; and
  • to thrive as individuals, families, communities, or any self-selected group in natural, safe, and healthy environments.

Just One Health aims to prevent and respond to physical and mental trauma to individuals, communities, and populations, and to prevent, mitigate, and reverse global existential threats, including the climate crisis, pandemics, and ecosystem destruction.

The Just One Health approach asserts that these challenges can be adequately identified and solved only through policies and actions that validate, defend, and strengthen the inextricable links between the wellbeing of humans, animals, and our life-sustaining planet.



[1]One Health Basics,” Centers for Disease Control and Prevention, accessed January 29, 2021.

[2] Dr. William Karesh, interview by Serene Fang, Frontline World, PBS, accessed January 29, 2021.

[3]Great Apes,” World Conservation Society One World-One Health, accessed January 29, 2021. Also, see Christian A. Devaux et al., “Infectious Disease Risk Across the Growing Human-Non Human Primate Interface: A Review of the Evidence,” Frontiers in Public Health 7 (November 2019): 305.

[4] Emily Dunay et al., “Pathogen Transmission from Humans to Great Apes Is a Growing Threat to Primate Conservation,” EcoHealth 15, no. 1 (January 2018): 148-162.

[5] For example, one of the objectives of OIE is “food safety and animal welfare…[t]o provide a better guarantee of food of animal origin…”. One example of an FAO project promoting sustained or growth in animal exploitation includes Africa Sustainable Livestock 2050. FAO’s Animal Production and Health program includes an aim “to assist the member countries in exploiting the opportunities for livestock development and poverty alleviation through the promotion of safe, efficient and sustainable production, processing and market of meat and meat products.” All sites accessed January 29, 2021.

[6] See World Health Organization, “FAO/OIE/WHO Collaboration (Tripartite),” accessed January 29, 2021; also see, “The FAO-OIE-WHO Collaboration: A Tripartite Concept Note,” April 2010.

[7]UNEP Joins Three International Organizations in Expert Panel to Improve One Health,” United Nations Environment Program, November 12, 2020.

[8] Sarah Harrison et al., “EcoHealth and One Health: A Theory-Focused Review in Response to Calls for Convergence,” Environment International 132 (November 2019): 105058.

[9] Henning Steinfeld et al., Livestock’s Long Shadow: Environmental Issues and Options, Food and Agriculture Organization of the United Nations, 2006.



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