Planetary environmental health is tightly intertwined with human and animal health. In the past 30 years, nearly 75% of human infectious diseases and pathogens have originated from animals. Globally, despite the tremendous progress against infectious diseases, it’s estimated that 2.4 billion cases and 2.2 million deaths per year are attributable to zoonotic diseases and additional burden from vector-borne infections. Covid 19, of course, is one of those cases.
These infections are extremely costly. For example, the SARS epidemic in 2003, spread to 29 countries and cost between US$30–50 billion. Richard Kozul-Wright, Director of the Division on Globalization and Development Strategies at UNCTAD recently said about Covid 19: “We envisage a slowdown in the global economy to under 2% for this year, and that will probably cost in the order of $1 trillion”. The total cost in monetary -and emotional, social, political, environmental and collective- terms remains to be seen.
The concept of One Health
In light of the critical links between human, animal and environmental health, in the past decade, international agencies have expressed support for the “One Health” approach. Related examples are Ecohealth, Planetary Health, Ecological Public Health and Global Health. One Health emphasises the links, interdependencies and commonalities of human, animal, plant and ecosystem health.
One Health issues touch on zoonotic diseases, antimicrobial resistance, food safety and security, vector-borne diseases, environmental contamination, and other health threats shared by people, animals, and the environment. It is a collaborative and interdisciplinary approach to prevent, prepare, detect and respond to the issues that threaten human, animal, and environmental health.
No one person, organization, or sector can address these issues alone. Professionals and related institutes in human health (doctors, epidemiologists, nurses, public health experts), environmental health (ecologists, wildlife experts) and animal health (veterinarians, agricultural workers) have come together to collaborate and coordinate their activities. Law enforcement, policymakers, farmers, communities and pet owners are also part of the stakeholder landscape.
There are a few global programs tackling the challenges at the animal-human-environment interface:
- The Emerging Pandemic Threats-2 program by USAID, together with FAO, is conducting novel pathogen surveillance in “hotspot” countries where infectious diseases are most likely to emerge.
- ‘Our Planet, Our Health’, an initiative by the Wellcome Trust, provides strategic funding for transdisciplinary research that connects environment and health.
- Bill and Melinda Gates Foundation has funded One Health projects under the initiative ‘The One Health Concept: Bringing Together Human and Animal Health for New Solutions’.
- The Network for Evaluation of One Health (NEOH) (http://neoh.onehealthglobal.net) is an initiative by the European Cooperation in Science and Technology that brings together over 250 scientists and One Health practitioners from more than 30 countries globally.
- The WHO OneHealth Costing Tool (http://www.who.int/choice/onehealthtool/en/) is designed to inform national health planning in low- and middle-income countries and seeks to align disease control objectives and targets with needed investments.
These projects are in contrast to the lack of governmental funding and delivery of One Health initiatives and mechanisms. A recent publication by the World Bank and Ecohealth Alliance indicates that policy is slowly moving from funding research towards introducing multispecies and trans-sectoral healthcare services in practice.
Why is it challenging?
There are several reasons why it’s hard to adopt such a framework.
- We don’t have harmonised definitions of health across disciplines and sectors. This creates challenges with assessing outcomes, demarcating their geographical scope (national, regional) and choosing appropriate time scales of assessment. Quality-adjusted life years (QALY) or disability-adjusted life years (DALY) are commonly used to assess disease burden for humans. Animal health issues are usually reduced to monetary terms and interventions are modelled with a cost-benefit analysis. Some contest that not all aspects of livestock and domesticated animals can be monetised, yet economics used methods to place prices on outputs that have no markets. Plant and aquatic animal health is also reduced to monetary terms and it is rarely included in health assessments.
- We lack some fundamental cross-disciplinary knowledge. For example, assessing the risk of the emergence of zoonoses in human populations requires a more comprehensive understanding of the interaction networks between infectious agents, their hosts, and the environment in which they evolve and how these are affected by human activities, climate change and other factors.
- Most efforts to prevent future disease are limited, given the challenges in addressing their root causes. The drivers of zoonotic disease transmission are land use and habitat change, biodiversity loss, deforestation, extractive industries, agricultural practice changes, wildlife trade and hunting, climate change, international trade and travel among others. These drivers are typically outside of the control of the health sector and require multi-sectoral stakeholder engagement to facilitate comprehensive assessments and strategies.
- It’s difficult to coordinate between sectors and agencies. Health authorities have different priorities, data and information systems and resources and their risk management role may vary greatly by disease.
Why adopt a One Health Approach
An integrative, multispecies approach to healthcare may bring tremendous benefits in our understanding of the concept of health and into taking steps to address it holistically.
- One Health may result in more information sharing between those working in disease detection, diagnosis, education and research.
- It may lead to highly interdisciplinary programs in education, research, and policy which in turn may create new comparative knowledge spaces (see the concept of zoobiquity).
- One Health can create more intervention levers. Let’s take for example the case of Lassa fever prevention. A successful prevention strategy may target environmental factors such as improving household sanitation, animal factors such as removing rodents and human-related factors such as educating the healthcare personnel about safely disposing of contaminated materials. The ultimate goal of One Health is to identify opportunities for health improvement and risk mitigation across all three domains.
- We may develop new eco-inspired therapies and approaches to treatments. Nature can provide innovative solutions that use the properties of natural ecosystems and services. For example, phages are natural predators of bacteria, controlling bacterial behaviour and can inspire the development of new anti-infectious strategies. New methods of fighting vector-borne transmission can also be based on microbial symbiosis. For example, it has been found that symbiotic interactions between Wolbachia and insect species can be harnessed to control mosquito-borne pathogens, by manipulating insect reproduction and interfering with human pathogens.
Towards implementing One Health
The current pandemic is revealing a lot about our political leaders, our societal priorities, our healthcare systems, our supply chains, and our response mechanisms (or lack thereof). There are many learnings and insights we can take forward. With this post, I want us to reflect on the concept of One Health and decide how to best take it forward with us, as we plan for the next pandemic.
One Health requires a lot of mechanisms to be in place. These include:
It is essential to map and understand the connections, information flows and responsibilities of the relevant stakeholders who need to collaborate. These range from governmental ministries, nongovernmental organizations, private and business sectors, individuals and communities. These may typically include the Ministry of Health, the Ministry of Agriculture, and Ministry of Environment/Forestry and/or Wildlife and also other private or public organisations such as the Ministry of Tourism, pharmaceutical companies, etc.
The operationalisation of One Health requires multi-disciplinary collaboration to inform decision making. Perhaps it also requires extra coordinating bodies that act as translators and brokers between agencies, as illustrated by the diagram below (produced by the World Bank and Ecohealth Alliance).
Focus on joint prevention
As we improve our understanding of the drivers and mechanisms of pathogen spillover, more can be done to jointly mitigate risk and work toward prevention. This can be achieved, for example, via integrated risk assessments. Furthermore, understanding that the breadth of economic costs related to environmental impacts often affects human and animal health and other sectors (e.g., contamination of water can lead to public health problems, the spread of livestock disease, and requires clean-up or alternative planning interventions by government and other sectors using irrigation such as tourism) warrants greater efforts toward costing environmental impacts.
Researchers, practitioners and policymakers must work together to implement shared training programs, tools, and protocols. Collaborative cross-species disease monitoring is required. This means having shared databases and coordinated field surveillance activities. These may be disease-specific or broader e.g. a database for reporting unusual morbidity in humans, domestic animals, and wildlife. It can be an alert system that prompts investigation of an animal mortality event that could then inform satellite detection and deployment of targeted vaccination to prevent spillover in humans.
We need to have more joint research efforts that aim to achieve a deeper understanding of cross-species disease transmission and comparative medicine. The communication barrier between human and veterinary medicine, agronomy and ecology, environmental science and evolutionary science may be removed by integrating sufficient understanding of other disciplines and multidisciplinary approaches. New interdisciplinary journals, conferences and allied health networks can facilitate this reciprocal communication. Additionally, ecology and evolution training should be supported and included in medical, veterinary, and agronomic training.
Research is frequently led by the direction of the available funding. Public Research & Innovation bodies need to invest in translational research that crosses disciplines as well as incentivise and invest in joint research labs and lab equipment/exercises. Funding can go into shared public-private partnerships to develop and evaluate new diagnostic methods and vaccines in order to prevent diseases that cross between species.
The rise of One Health embodies our long-standing efforts to bring humans, animals and the environment closer together and break down barriers between human and more-than-human disciplines. One Health can be part of the collective response to a set of highly complex concerns which extend across traditional disciplinary boundaries — over environmental damage, scarce resources, food availability and health.
It can be a holistic way to re-imagine health in the 21st century.