🦬 One Health
Understanding how the environment is intimately tied to our well-being is crucial to tackling the health problems of the future.
Imagine a world today where hospitals are overrun with patients infected with rabies. People are dying from the deadly disease, yet the focus is on treating the disease rather than finding the root cause. Once the link to the root cause, pet dogs, is found, there is a blanket ban on owning pet dogs and all living ones are culled to control the spread of the disease. After this, it makes a comeback due to the disease spreading from another vector, rats.
Thankfully, most of the world is not living in the fear of rabies. This was possible not just due to treatment of the disease when patients fell ill. In fact, the story is far from it. Collaboration of many different sectors was involved to vaccinate dogs against rabies, educate people about the disease and how they can avoid getting it, and surveillance of the disease in both humans and animals. This is one of the many success stories of the One Health approach.
What is One Health?
The One Health approach recognizes that the health of humans, animals and ecosystems are interconnected. It is an interdisciplinary approach that brings multiple disciplines (medicine, veterinary medicine, environmental science and etc.) to work together at the local, national and global levels to attain optimal health for people, animals and the environment. Health challenges that can be tackled using the One Health approach include communicable diseases (particularly zoonotic diseases), food security and sustainable practices in agriculture. Some of these are explained in further detail below.
Role of One Health in Preventing Communicable Diseases
Typically, we think about communicable diseases as those that can be spread between humans. While that is true, communicable diseases also include those that could be spread between humans and animals and vice versa. These groups of diseases are also known as zoonotic infectious diseases (ZIDs). ZIDs can be caused by bacterial, viral or parasitic pathogens and can be transmitted from wild animals or domestic animals, which includes pets, livestock and poultry. The reasons for the spread of zoonotic diseases are not just limited to the consumption of animal products but also include human activities such as deforestation, urbanization, and local and global travel. All these factors have led to ZIDs making up about 60% of all known human pathogens.
One Health recognizes that ZIDs cannot be controlled just by human or animal interventions. Rather, a holistic approach is required that addresses ecological, biological and environmental factors that drive their transmission. Furthermore, One Health recognizes that ZIDs can have significant harmful effects on human health, animal health and the environment. For example, a flea-borne Murine Typhus is caused by a bacteria called Rickettsia typhi. It is a ZID that typically affects wildlife, like rats and opossums, and can spread to domestic animals, like cats, and humans. While the impact on human and animal health is clear in this case, there is also a potential underlying impact on the environment as the unnatural deaths of a species can lead to an imbalance in the food chain and disrupt essential ecological processes. By taking a One Health approach, a coordinated response can address the health and economic impacts of ZIDs on all three sectors.
Role of One Health in Food Security
A major issue in food security has been the lack of cross-sectoral collaboration across the food chain. As a result, this has hampered disease prevention dramatically. In fact, One Health was largely initiated due to the global outbreaks of avian influenza in the early 2000s, which affected human health as well as the global supply chains of poultry. This accelerated efforts towards a cross-sectoral approach that linked human and animal health, resulting in the creation of the One Health approach.
Today, One Health initiatives have gained support among key national and global policymakers including the World Health Organization (WHO), the United Nations Food and Agricultural Organization (FAO), the United States Centre for Disease Control (CDC) and the European Union with the One Health European Joint Programme (OHEJP). These organizations work together to deal with a multitude of issues, with food security as a key agenda.
Role of One Health in Sustainability
Sustainability has recently emerged to be one of the newer focuses of One Health. Particularly, One Health looks at the unsustainable farming practices which can lead to deforestation, soil degradation and pollution. These would then lead to poorer animal and human health and harm to the environment. It can also contribute to the spread of ZIDs with the increased proximity between wild animals and the humans involved.
An unsustainable farming practice is the overuse of antibiotics in poultry and livestock, which has inadvertently led to antimicrobial resistance (AMR) in pathogens and makes them harder to treat when they spread to humans. In fact, a large number of ZIDs make up WHO’s antibiotic-resistant "priority pathogens", which are 12 families of bacteria that pose the greatest threat to human health. However, promoting alternative methods, such as segregating livestock and ensuring cleaner living spaces for them, require additional resources which not all farmers may be able to afford, especially considering that for the farmers, antibiotics is a cost-effective method to keep their livestock healthy. Therefore, legislation and incentives would play a key role in promoting sustainable farming practices among farmers.
Role of One Health in Preventive Healthcare
From this point of the article, it should be quite obvious that One Health can play a large role in preventive healthcare. Rather than treating diseases when they reach humans, One Health looks at identifying and addressing the root cause of diseases, such as environmental factors and animal-to-human transmission. This can lead to more effective prevention strategies, such as improving sanitation and hygiene practices or implementing measures such as vaccination programs for both humans and animals, including livestock and poultry. With a focus on sustainability, resilient processes and healthcare systems can also be proliferated through One Health.
By working together across different sectors locally and globally, health equity can be promoted, particularly in marginalized communities where access to healthcare and information may be limited. For instance, while Ebola is found mainly in some African countries, it poses a threat to other countries, including affluent ones in other parts of the world. By working together with the One Health approach in mind, countries and organizations have worked together to not only eradicate Ebola in communities but also worked towards preventing further outbreaks, such as by reducing the interaction between wild bats, a reservoir for the Ebola virus, and humans. This was done through numerous means which included education or providing safer food options, especially in poorer communities.
Overall, One Health can play a large part in improving human health, animal health and the environment by acknowledging that these three sectors are interlinked. COVID-19 was a great reminder of the interconnectedness of the three sectors, and how a One Health approach for potential emerging infectious diseases could have prevented the pandemic. The preventive healthcare ideology is embedded in One Health one way or the other and is something that should be pushed locally and globally to prevent future epidemics and pandemics while also promoting sustainability.
Hi, I'm Mayank Goel, a Master of Public Health (MPH) student at Imperial College London and a Bioengineering Graduate from Nanyang Technological University. | LinkedIn