Written By Elizabeth Díaz-General and Sara Savić
Health is often thought of in terms of human health and our well-being, but from a systemic perspective, the health of humans, animals, plants, and ecosystems is deeply interconnected and mutually dependent. This idea is adopted within the "One Health" approach. But what is One Health and why should we care about it?
The History of One Health
According to the most recent definition of One Health, developed by the One Health High-Level Expert Panel, 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, taking action on climate change, and contributing to sustainable development.
The concept of One Health dates back to early zoonotic disease discoveries. German pathologist Dr Rudolf Virchow coined the term "zoonosis" to indicate an infectious disease passed between humans and animals. The modern age of One Health approach began in the early 2000s. In 2004, the Wildlife Conservation Society organized a symposium where diseases among humans, domestic animals, and wildlife were discussed. At the symposium, 12 priorities were set to manage health threats to human and animal health, known as the "Manhattan Principles”, proposing an international, interdisciplinary approach to prevent diseases, which represent the basis of the One Health, One World concept. After the Avian influenza outbreaks, the American Veterinary Medical Association established a One Health Initiative Task Force in 2006, and the American Medical Association endorsed One Health collaboration in 2007.
In 2010, the World Organisation for Animal Health (WOAH), the Food and Agriculture Organization of the United Nations (FAO), and the World Health Organization (WHO) published the Tripartite Concept Note to promote global cooperation in managing emerging diseases. In 2011, the first International One Health Congress was held in Melbourne, Australia, where a range of disciplines came together to discuss the benefits of working together to promote a One Health approach to human, animal and environmental health, but also economics, social behavior, and food security and safety. In 2017, a Berlin Declaration was provided by the G20 Health Ministers, addressing antimicrobial resistance, health systems strengthening and global health crisis management.
Finally, in 2021, the One Health High-Level Expert Panel was established to advise FAO, the United Nations Environment Programme (UNEP), WHO and WOAH, in their collaboration on One Health. But what does One Health mean in everyday life?
How does biodiversity affect health and vice versa?
First of all, biodiversity influences the health of humans, animals, plants, and entire ecosystems in multiple ways. Nature provides direct physical and mental health benefits—being in green spaces, forests, or near bodies of water has been shown to reduce stress, improve mood, and support overall well-being. People often experience a spiritual or emotional connection with nature and non-human animals, which can enhance social cohesion and cultural identity while also stimulating cognitive processes.
In addition, biodiversity provides essential services that support health in various ways:
- Food Security: A diverse range of plant and animal species ensures access to nutritious food, preventing malnutrition and diet-related diseases.
- Medicinal Resources: Many medicines originate from natural sources, including antibiotics from fungi and cancer treatments derived from plants and marine organisms.
- Clean Air and Water: Forests, wetlands, and other ecosystems act as natural filters, purifying air and water and reducing the risk of respiratory and waterborne diseases.
- Climate Regulation: Biodiverse ecosystems like rainforests and coral reefs help mitigate climate change by absorbing carbon dioxide, regulating temperatures, and reducing the frequency of extreme weather events.
- Disease Regulation: Healthy ecosystems regulate disease by maintaining balanced predator-prey relationships and limiting the spread of vectors such as mosquitoes and ticks. It also regulated the spreading of the pathogens within the known species. Once a species is extinct, the pathogens search to jump to another species.
Biodiversity also benefits non-human animals by providing habitats, maintaining stable food chains, and reducing competition for limited resources. Protecting biodiversity is not only crucial for environmental sustainability but also for ensuring a healthier future for all living beings.
On the other hand, negative interactions with nature—such as human-wildlife contact or the spread of zoonotic diseases—are often driven by ecosystem disruptions. Many infectious diseases, including COVID-19, Ebola, and Lyme disease, originate in wildlife and are exacerbated by deforestation, habitat destruction, intensive agriculture and dietary choices. When ecosystems are disturbed, the natural barriers that regulate pathogens break down, increasing the risk of disease transmission between animals and humans.
It must be noted that humans play a significant role in shaping biodiversity and, consequently, health outcomes. Sustainable land management, ecosystem restoration, and conservation efforts contribute positively by maintaining healthy environments that support both human and non-human health. Conversely, unsustainable activities such as deforestation, pollution, overuse of natural resources, and improper disposal of pharmaceuticals negatively impact biodiversity and can lead to cascading health consequences.
The healthcare sector also has an environmental footprint. The production and disposal of medical waste, excessive use of antibiotics leading to antimicrobial resistance, and carbon emissions from healthcare facilities all have indirect but significant effects on ecosystems and biodiversity.
Health in the BIONEXT project
The One Health approach acts as a bridge in the BIONEXT project. In addition to biodiversity, it has a central connection to other nexus elements: food, water, energy, transport and climate. One Health also provides a space for considering the non-human world in discussions, rather than focusing solely on human health.
BIONEXT has among its stable group of stakeholders four One Health experts who have participated in two stakeholder workshops aimed at co-creating visions and pathways for positive futures for people and nature. These experts have been recognised for bringing a unique lens to the discussions.
In addition, the nexus approach of BIONEXT is captured by the Nexus Modelling Framework. As part of an initiative of the BIONEXT Reflexivity Task Force, thanks to the funding and hosting of the University of Thessaly, a group of 10 One Health experts and BIONEXT modellers met in September 2024 to discuss how to improve the modelling of Health in the Nexus Modelling Framework.
The workshop ended with new insights and potential model-specific future collaboration. In addition, the meeting had experts from different backgrounds, both for One Health and for modelling, which reflected the complexity of both disciplinary sectors. Therefore, the workshop helped broaden the understanding of the One Health approach, modelling approaches and their potential interlinkages and limitations. More details on the developments of this work will be shared in the future.