The health of humans, animals, and the planet are inextricably linked in a delicate dance of survival.
Imagine a world where a disease in a remote animal population can be detected early enough to prevent a global human pandemic. This is not science fiction—it's the goal of the "One Health" approach. This integrated concept, which gained significant momentum following the COVID-19 pandemic, recognizes that the health of people is closely connected to the health of animals and our shared environment. As the World Organisation for Animal Health (WOAH) states, "Because we share One World, we all share One Health" 3 .
This article explores the revolutionary One Health framework from a veterinary perspective, detailing how this collaborative approach is our strongest shield against modern global health threats.
The idea that human and animal health are intertwined is not new. For centuries, scientists have observed similarities in disease processes across species 7 . However, for a long time, human and veterinary medicine largely operated in separate silos.
The formal beginnings of One Health as a unified movement are often traced to 2004, when the Wildlife Conservation Society hosted a symposium at Rockefeller University. This meeting resulted in the "Manhattan Principles," which set 12 priorities for combating health threats at the interfaces between humans, domestic animals, and wildlife 7 .
The approach gained substantial political traction in the following years. In 2010, key international organizations—including the Food and Agriculture Organization of the United Nations (FAO), the World Organisation for Animal Health (WOAH), and the World Health Organization (WHO)—joined to publish the Tripartite Concept Note, a strategic document for coordinating global activities against health risks at the human-animal-ecosystem interface 7 .
Today, One Health is defined by the One Health High-Level Expert Panel as "an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems" 3 . It recognizes that the health of humans, domestic and wild animals, plants, and the wider environment are closely linked and interdependent 3 .
The push for a One Health approach is driven by stark realities. Consider these compelling facts 3 :
of human pathogens originate from animals
of global animal production is lost to disease
forest cover loss increases disease transmission risk
of the world's poorest depend on livestock for survival
Factors such as climate change, deforestation, unsustainable agricultural practices, and the globalized trade of animals and animal products have created a perfect storm, providing pathogens with unprecedented opportunities to evolve and spread 3 5 . The COVID-19 pandemic, caused by a virus of potential animal origin, is a powerful testament to the interconnectedness of global health 3 .
While the One Health framework is broad, its power lies in its practical application. Let's explore a hypothetical but representative example of how a One Health-oriented veterinary team might investigate a disease outbreak. This scenario is inspired by real-world methodologies and demonstrates the integrated approach called for in reviews like that of Dhama et al. (2013).
A rural community reports several cases of a febrile illness in people, coinciding with a mysterious decline in the local wildlife population. A multi-disciplinary One Health task force—comprising veterinarians, epidemiologists, environmental scientists, and public health officials—is assembled to investigate.
The team works to identify the pathogen. Veterinarians and ecologists collect samples from domestic animals and local wildlife. Environmental scientists gather water and soil samples from shared habitats.
All samples are analyzed in laboratories using compatible diagnostic methods to allow for direct comparison. Techniques like PCR and bacterial culture are used to identify the causative pathogen.
The results from human clinics, veterinary clinics, and environmental surveys are integrated into a Geographical Information System (GIS). This allows the team to map the outbreak's spread and identify hotspots 1 .
Based on the identified source and transmission route, the task force implements targeted control measures. The role of the veterinarian here is crucial in communicating risks and managing the animal side of the outbreak .
After a thorough investigation, the team's integrated data might reveal a clear transmission cycle:
| Section | Key Finding | Role in the Transmission Cycle |
|---|---|---|
| Human Health | 32 confirmed cases of leptospirosis; patients reported contact with contaminated water. | Affected Population: The endpoint of the spillover event, suffering from the disease. |
| Animal Health | 70% of tested rodents carried Leptospira bacteria; several farm animals showed mild symptoms. | Reservoir & Amplifiers: Wild rodents are the primary reservoir; livestock can amplify the pathogen in the environment. |
| Environmental Health | Significant rodent infestation near water sources; heavy rainfall led to flooding that spread contamination. | Transmission Bridge: Environmental conditions facilitated the pathogen's spread from animals to humans. |
This integrated analysis shows that addressing the human cases alone would be a temporary fix. A sustainable solution requires veterinary efforts to control the rodent population and manage livestock health, combined with environmental measures to improve sanitation and water management—a true One Health solution.
Rodents carrying bacteria
Contaminated water sources
Exposure and infection
To execute such intricate investigations, One Health researchers rely on a diverse toolkit. This includes everything from laboratory reagents to digital technology, all crucial for understanding and mitigating health threats.
To detect and identify pathogen DNA/RNA in samples from humans, animals, and the environment.
To map and visualize disease outbreaks in relation to environmental and animal data, identifying transmission hotspots 1 .
To detect antibodies or antigens, indicating exposure to a pathogen in a host population (human or animal).
To analyze complex, multi-sectoral data, identify correlations, and measure the impact of interventions.
The success of the One Health approach depends not just on collaboration, but on the rigor of the scientific research that informs it. This is especially critical in animal experimental research, which often provides the foundational knowledge for understanding diseases that affect both animals and humans.
This reporting gap is a moral issue as well as a scientific one. If animal experiments are not appropriately designed, conducted, and analyzed, the results are unlikely to be reliable, and the animals have effectively been wasted 6 .
These comprehensive literature reviews help optimize future experiments by summarizing all existing evidence, improving methodological quality, and making the translation from animals to humans more evidence-based 6 .
These are a set of recommendations to improve the reporting of animal research, ensuring that all critical design elements are transparently documented 2 .
The "One World, One Health" concept, as highlighted in the veterinary review by Dhama et al., is more than just an academic theory—it is a necessary and tangible framework for a safer, healthier world. It moves us from reacting to pandemics to preventing them by tackling health threats at their source in animals and the environment.
"Future pandemics can be prevented only with an integrated One Health approach."
The approach champions a future where doctors, veterinarians, farmers, ecologists, and policymakers break down disciplinary barriers. By recognizing that the health of animals is our health—is everyone's health—we can build a more resilient planet for all its inhabitants 3 .