In an era that rejects silos, the One Health concept arises as a unified vision of health, recognizing that the well-being of living beings depends on a healthy environment, and vice versa.
In this article, we will touch on the origins of this philosophy, focusing on its practical applications for safeguarding global health.
Origins and meaning of the One Health concept
Starting from its literal translation, “One Health”, the term “One Health” indicates the close interconnection between human, animal, and environmental health, with inevitable repercussions on collective well-being. Although it emerged in full force only recently, this concept has deeper roots, as we will see shortly.
The birth of the term and its spread
The origins of the One Health vision date back to the nineteenth century, when German physician and pathologist Rudolf Virchow stated: “between animal and human medicine there are no dividing lines, nor should there be.” He thus coined the term “zoonoses” to indicate infectious diseases transmissible between animals and humans.
In more modern times, the One Health philosophy was hinted at in the second half of the twentieth century. During that period, veterinary epidemiologist Calvin Schwabe introduced the term “One Medicine”, uniting veterinary and human medicine, and encouraging mutual and productive collaboration between the two disciplines. Subsequently, in the twenty-first century, this vision evolved, extending also to plants, wildlife, and the geographic areas where they coexist. It was during the SARS-CoV-1 epidemic, between 2002 and 2004, that the term “One Health” became irreversible. At that time, the risks to human health related to zoonoses became strikingly evident. Today, the One Health vision is widely recognized by the World Health Organization (WHO), boasting significant diffusion in the medical-scientific world.
The multidisciplinary approach
The One Health concept takes shape in a multidisciplinary approach aimed at investigating and controlling infectious diseases. The aspects involved include the management of zoonoses and tropical diseases, but also food hygiene, environmental safety, and the fight against antimicrobial resistance. Each macro-area is linked to the others, enabling the sharing of expertise, new evidence, and effective protocols.
Human, animal, and environmental health: an indissoluble bond
The interconnection among living beings, and between living beings and the environment, generates reciprocal risk dynamics. In modern times, these are addressed with this new holistic vision. Below are some examples of such dynamics, with specific reference to zoonoses and environmental issues.
Zoonoses and the risk of new pandemics
Direct (or indirect) contact with infected or carrier animals predisposes humans to infectious risk. Well-documented zoonoses include malaria, caused by a parasite, as well as monkeypox and rabies, both caused by viruses. Generally, zoonoses circulate among animals and can be transmitted to humans, even without “passing” from one human to another. However, when an animal virus mutates, it can develop new infectious capabilities, such as transmitting very efficiently among humans. Significantly, this lays the groundwork for a pandemic, as happened with COVID-19. Recognizing risky interconnections, as well as additional factors that can amplify risk (e.g., human encroachment into animal habitats, wildlife trade, etc.), is a pillar of the One Health approach.
Pollution and climate change
Although the correlation may not be immediately obvious, climate change can impact infection transmission in non-negligible ways. Rising temperatures, for example, lead to migratory flows from areas that become inhospitable, generating greater and more diverse human–animal contacts. Compared to the past, this scenario favors zoonoses and the emergence of new viral variants.
The incompatibility between pollution and health, on the other hand, is known to all. The pathways of impact are multiple and branched. Poisons from industrial production, in particular, can contaminate environmental matrices such as soil, water, and the air we breathe. In turn, chemical contamination disregards borders and accumulates along the food chain, causing diseases and mortality among living beings. Understanding these circumstances, as well as their management, clearly aligns with the One Health paradigm.
Practical examples of applying the One Health model
The theoretical framework of the One Health vision lends itself to various health “challenges.” The examples we will describe show how collaboration among professions and an intersectoral approach can lead to robust and sustainable results.
Control of avian and swine influenza
The management of epidemics is a clear example of how human and animal health professionals must interface to ensure mutual protection. Influenza viruses, specifically, circulate among humans, pigs, and avian species, distinguished by their mutation rate and marked adaptability. Viruses such as H5N1 (avian) and H1N1 (swine) have generated significant epidemic events, requiring more complex, One Health-style control measures. An integrated approach specifically includes the following initiatives:
- Surveillance procedures: professionals carry out active monitoring of at-risk animal groups (e.g., wild birds, pig and poultry farms) to identify new viral strains. This goal leverages, among other things, genetic sequencing techniques.
- Biosecurity: in farming, measures are applied to reduce viral transmission among livestock. These include high hygiene standards and barriers against the entry of wild animals.
- Targeted vaccine development: a key measure, enabled by constant surveillance of circulating strains.
- Collaboration among health authorities: this translates into culling infected livestock, clinical monitoring of potentially exposed people, and vaccination of at-risk livestock.
Managing antimicrobial resistance
Antimicrobial resistance (which also includes antibiotic resistance) is the phenomenon whereby pathogens no longer respond to pharmacological substances designed to neutralize them. This mechanism poses a public health problem, as infections become more difficult to contain. Among other things, it has causes in different but interconnected contexts, aligning with the criteria of the One Health vision. Antimicrobial resistance is caused by the overuse of antibiotics, both in human health (e.g., improper use, excessive prescribing) and in livestock management. In addition, residual antibiotics, excreted from organisms as waste components, end up in effluents and contaminate water and soil, fostering the development of resistance even among environmental microbes. Interventions aimed at containing the phenomenon ultimately include the following points:
- Antibiotic stewardship: ensuring that antibiotics are prescribed and used responsibly and judiciously.
- Fewer antibiotics for livestock: instead, favor preventive measures, adhering to hygiene procedures, administering vaccines, and ensuring overall animal welfare.
- Surveillance and monitoring: create comprehensive systems to monitor, among living beings and in the environment, the emergence and spread of resistant microbes.
- Infection prevention and control: maintain basic hygiene in healthcare settings and at all community levels to reduce infection risk and lessen the need for drug treatments.
- Research and development: design new antibiotics, alternative and/or natural treatments, and rapid diagnostic tools to better manage infectious hazards.
One Health and prevention: benefits for society
The One Health vision allows public health to be viewed with a preventive approach rather than one subordinate to already established diseases. This benefits animal and human health, without neglecting other aspects such as economic stability.
Improving food safety
In the One Health vision, food safety is a crucial element. The wholesomeness of food, unsurprisingly, derives from healthy animals and uncontaminated environments, allowing many infectious hazards to be avoided. In this area, the One Health approach includes controlling pathogens at the source (e.g., through vaccination of livestock), reduced use of pesticides and veterinary drugs, and the rise of sustainable agriculture.
In essence, promoting the health of animals and environments also promotes human health. In addition, this helps prevent economic damage resulting from culling livestock and recalling food products.
Environmental monitoring and biodiversity
Biodiversity, understood as the varied array of living forms, can hinder the spread of infections. Scientists attribute this phenomenon to the so-called “dilution effect”, which remains an interesting subject of research today. Specifically, it is suggested that an ecosystem rich in animal species has more diverse hosts for pathogens, and that many of them are poor transmitters of infection. Ultimately, this would prevent pathogens from spreading effectively and reaching humans. Conversely, low biodiversity appears to increase the prevalence of efficient animal hosts (such as bats), favoring species jumps. Clearly, this represents a major issue for public health. Considering these aspects, the One Health approach employs biodiversity conservation and environmental monitoring as prevention tools. The following list outlines the key aspects.
- Monitoring “sentinel” species: some living species can facilitate early identification of infections or environmental contamination, due to a particular, easily observable vulnerability.
- Protection of natural habitats: optimal conservation of environments preserves biodiversity and counters the spread of zoonoses.
- Testing environmental matrices: monitoring the quality aspects of water, soil, and air supports habitat care and the well-being of flora and fauna.
Technologies to support One Health
Although implemented with traditional and effective tools, the One Health vision also leverages technological advancement. Let’s see what this involves in the following sections.
Devices against the spread of viruses in indoor environments
The COVID-19 pandemic highlighted the importance of indoor air and its quality. In the fight against infections and respiratory viruses, the management of indoor environments is an essential aspect, fitting within the broader One Health paradigm. We will describe shortly some technological solutions applicable for this purpose.
- Air filtration: HEPA (High-Efficiency Particulate Air) filters, capable of capturing over 99.97% of airborne particles, are now standard both in conventional air purifiers and in advanced systems for schools, offices, and hospitals.
- Sanitization with far-UVC light: unlike common UV-C light, which is harmful to humans, far-UVC light (at a wavelength of 222 nm) can effectively inactivate pathogens dispersed in bioaerosols without penetrating human tissues. This option facilitates continuous disinfection in shared and public spaces.
- Mechanical ventilation and monitoring: modern devices are equipped with sensors that monitor CO2 values, an indicator of ventilation levels. Such systems can autonomously adjust airflow, bringing in more outside air when occupancy is high. This dilutes the concentration of potential airborne pathogens.
- Electromagnetic waves: cutting-edge solutions, such as the equipment developed by e4life, are based on the emission of microwaves at a specific frequency. These are released into the surrounding environment and impact viruses, damaging their structure irreversibly. These devices are highly effective, as well as safe for human, animal, and environmental health.
Digital tools and artificial intelligence
The One Health approach generates data that require proper processing. There is no shortage, in this regard, of digital tools dedicated to this purpose. The most commonly used applications include those described in the following list.
- Predictive modeling: artificial intelligence algorithms can analyze large amounts of real-time data, such as climate information, epidemiological surveillance records, etc. This enables early detection of pandemic signals. In addition, these systems can generate (or model) hypothetical epidemic spread scenarios in advance.
- Integrated surveillance: dedicated digital platforms enable various health professionals to add new data on infection cases. At the same time, these data are immediately available to other professionals, in a mechanism of continuous sharing.
- Molecular biotechnologies and bioinformatics: available biotechnologies, such as genomic sequencing, allow rapid identification of a potential pathogen, as well as its structural and functional characterization. Bioinformatics, in turn, makes it possible to analyze large and complex datasets, also laying the groundwork for future vaccine tools.
- Telemedicine: remote consultations can increase access to medical support, both in human and veterinary contexts. This is particularly useful in managing infectious cases, limiting human exposure and the spread of infections.
FAQs
What does One Health mean in simple terms?
The term One Health describes the indissoluble link between human, animal, and environmental health. These are no longer considered separately, but as domains that depend on one another.
Which diseases fall under the One Health approach?
The One Health vision can extend to pathological aspects as a whole. Infectious diseases, for example, represent a prominent macro-area among the issues addressed.
Why does WHO promote the One Health concept?
The World Health Organization recognizes the One Health concept for its health implications. This philosophy, in fact, acknowledges the remarkable complexity of the biological world, which is naturally highlighted by the leading authorities in health.
