One Health: A Structured Review and Commentary on Trends and Challenges
The One Health (OH) concept has gained significant traction in recent years, emerging as a unifying approach to address complex health challenges at the intersection of human, animal, and environmental domains. By recognizing the intrinsic linkages and interdependencies between these realms, OH seeks to foster collaborative, multidisciplinary solutions that optimize the well-being of all living beings and their shared ecosystems.
Definitions and Principles
One Health is defined as “an integrated and unifying approach that sustainably balances and optimizes the health of people, animals and ecosystems.” This holistic perspective acknowledges that the health of humans, domestic and wild animals, plants, and the broader environment are inherently intertwined, with each domain influencing the others through direct and indirect pathways. The OH approach aims to address issues of global significance, such as emerging zoonotic diseases and antimicrobial resistance (AMR), which can have widespread ramifications across human, animal, and environmental spheres.
The roots of OH can be traced back to the concept of “One Medicine” proposed by veterinarian Calvin W. Schwabe in the 1960s, who argued against the compartmentalization of scientific research. The term “One Health” was later popularized in 2004 through the 12 Manhattan Principles, which urged governing and scientific bodies to adopt a more cross-disciplinary approach to resolving complex health challenges. Since then, OH has experienced a surge in popularity, with its adoption by prominent organizations like the World Health Organization, the Food and Agriculture Organization, and the World Organisation for Animal Health.
Interdisciplinary Collaboration
Central to the OH approach is the facilitation of collaboration across disciplines, organizational levels, and stakeholder groups. This integration of efforts from diverse fields, such as human and veterinary medicine, environmental sciences, and social sciences, is essential for tackling the multifaceted nature of global health issues.
The degree of integration can vary, with multidisciplinary, interdisciplinary, and transdisciplinary frameworks representing different levels of collaboration and knowledge synthesis. While these terms are often used interchangeably, they denote distinct collaboration models. Multidisciplinary approaches draw on multiple disciplines without necessarily integrating their methods and ideas, whereas interdisciplinary efforts require the harmonization of different fields in a coordinated manner. Transdisciplinary collaboration, on the other hand, transcends traditional boundaries, creating new ideas and methods that transcend individual disciplines.
Holistic Approach
The OH approach contrasts with more traditional, specialized methods in scientific research, embracing a holistic perspective that considers the interconnectedness of human, animal, and environmental health. This shift aligns with the growing trend of alternative frameworks, such as EcoHealth, Planetary Health, and conservation medicine, which share the core belief that different domains of health are inherently interdependent, necessitating a more systematic and integrative approach.
By adopting a holistic lens, OH aims to foster innovation, efficiency, and collaborative problem-solving. Through the merging of efforts across disciplines, OH can facilitate the amelioration of issues common to human, animal, and environmental health while mitigating detrimental effects on the economy and the environment.
Trends in One Health
The increasing popularity of the OH approach is reflected in the growing body of literature, which has seen a marked expansion since 2019. A review of the OH-related publications in PubMed and Web of Science databases revealed several key trends and themes:
Emerging Infectious Diseases
The predominant focus of the OH literature was on understanding pathogen transmission between species, particularly the surveillance of zoonotic agents and their transmission between humans and animals, often domestic species in close contact with humans. This emphasis aligns with the OH concept’s application as a public health approach, primarily towards the end of disease surveillance and control.
Antimicrobial Resistance
Another notable trend was the increasing interest in AMR, which coincided with the publication of the influential UK O’Neill report on the global social and economic impact of AMR. The literature highlighted the importance of adopting an OH lens to address the complex challenge of AMR, which requires interventions across human, animal, and environmental domains.
Environmental Sustainability
While the predominant focus of the OH literature was on human and veterinary health, a small but growing number of studies addressed the environmental aspects of OH, including the impact of climate change on health, the role of wildlife in disease dynamics, and the detection of environmental pollutants and toxins.
Challenges in One Health
Despite the growing popularity of the OH approach, its implementation and interpretation have faced several challenges, which can dilute its potential impact and integrative action.
Coordination and Integration
One of the key challenges is the variation in how OH is interpreted and applied across different studies and geographical regions. Some authors have characterized OH as a reactive, transdisciplinary approach, while others have described it as a concept focused on long-term, multidisciplinary goals. These contrasting perspectives can hinder the development of a cohesive, coordinated OH framework.
Knowledge Gaps
Another challenge is the uneven representation of disciplines within the OH literature, with a stronger emphasis on human and veterinary health compared to environmental sciences. This anthropocentric focus can lead to the underrepresentation and underfunding of non-human disciplines, potentially limiting the holistic nature of OH initiatives.
Socioeconomic Factors
Socioeconomic and cultural factors can also pose significant challenges to the implementation of OH. Successful OH interventions require the incorporation of local and global perspectives, as well as an understanding of community-specific beliefs and practices. Failure to address these contextual factors can undermine the effectiveness and sustainability of OH initiatives.
Applications of One Health
The OH approach has been applied to a wide range of health challenges, showcasing its versatility and potential for impact.
Zoonotic Disease Surveillance
One of the primary applications of OH has been in the surveillance and control of zoonotic diseases, such as emerging viral outbreaks (e.g., SARS-CoV-2, Ebola) and the transmission of antimicrobial-resistant pathogens between humans, animals, and the environment.
Food Safety and Security
OH principles have also been applied to tackle issues related to food safety and security, addressing the interconnections between agricultural practices, animal health, and human nutrition. This includes monitoring the prevalence of foodborne pathogens, as well as the spread of toxins and contaminants through the food chain.
Wildlife Conservation
The OH approach has been leveraged to support wildlife conservation efforts, recognizing the important role of ecosystem health in maintaining the well-being of both animal and human populations. Studies have highlighted the impact of diseases, such as fungal infections in amphibians, on the decline of global biodiversity.
Multisectoral Engagement
Successful implementation of the OH approach requires the engagement and collaboration of multiple sectors, including public health, veterinary medicine, environmental sciences, and social sciences.
Public Health Sector
The public health sector has been a key driver of OH initiatives, with a focus on disease surveillance, control, and prevention. However, there is a need to further integrate environmental and social considerations into public health frameworks.
Veterinary Sector
The veterinary field has been at the forefront of OH education and implementation, with a strong emphasis on the interconnections between animal, human, and environmental health. Veterinary professionals have played a crucial role in bridging the gap between human and animal health domains.
Environmental Sector
The environmental sector’s participation in OH initiatives has been relatively limited, despite the growing recognition of the importance of ecosystem health. Strengthening the integration of environmental sciences and disciplines, such as ecology and conservation biology, is essential for a more comprehensive OH approach.
Education and Training
Effective implementation of the OH approach requires dedicated efforts in education and training, fostering interdisciplinary collaboration and transdisciplinary research.
Interdisciplinary Curricula
Several studies have highlighted the importance of integrating OH principles into the curricula of medical and veterinary schools, ensuring that future health professionals are equipped with the knowledge and skills to work across disciplines.
Continuing Professional Development
In addition to formal education, the OH approach has also been disseminated through continuing professional development opportunities, such as Massive Open Online Courses (MOOCs) and interdisciplinary workshops, which bring together experts from diverse backgrounds.
Transdisciplinary Research
The OH approach has also influenced the way research is conducted, promoting transdisciplinary collaborations that transcend traditional academic boundaries. This integration of knowledge and methods from various fields can lead to innovative solutions and a deeper understanding of complex health challenges.
Policy and Governance
Effective implementation of the OH approach requires robust policy frameworks and collaborative governance structures at both the national and international levels.
National Action Plans
Many countries have developed national action plans that incorporate OH principles, addressing issues such as zoonotic disease control, AMR mitigation, and environmental protection.
International Cooperation
At the global level, international organizations and initiatives, such as the One Health High-Level Expert Panel (OHHLEP), have been established to provide evidence-based advice, support cooperative activities, and facilitate the identification and surveillance of potential pandemic threats.
Funding and Resources
Securing adequate funding and resources is crucial for the successful implementation of OH initiatives. Collaborative efforts across sectors and disciplines can help leverage existing resources and ensure the sustainability of OH programs.
One Health in Practice
The application of the OH approach has yielded promising results in various case studies and best practices around the world.
Case Studies
Successful OH initiatives have addressed a range of health challenges, from the surveillance and control of zoonotic diseases to the mitigation of environmental pollution and the promotion of sustainable agriculture.
Best Practices
Key elements of successful OH implementation include the engagement of diverse stakeholders, the integration of local and global perspectives, the utilization of interdisciplinary teams, and the establishment of robust monitoring and evaluation frameworks.
Monitoring and Evaluation
Continuous monitoring and evaluation of OH initiatives are essential to assess their impact, identify areas for improvement, and ensure the long-term sustainability of these holistic approaches to health and well-being.
As the global population continues to expand and become more industrialized, the need for integrated, multidisciplinary solutions to complex health challenges has never been more pressing. The One Health approach, with its recognition of the inherent interconnectedness between human, animal, and environmental health, offers a promising framework for addressing these pressing issues and fostering a more sustainable and equitable future for all.