Originally published in Spanish on the official website of the Pontifical Catholic University of Chile.

Given the recent report of the first case of avian flu in Chile, it is imperative to prevent another epidemiological event such as the coronavirus pandemic. The key seems to be to integrate the health of people, animals and the environment. This is the approach known as ‘One Health’, initially developed by researchers at the US university UC Davis. This institution is seeking to strengthen its collaboration with the Catholic University on this issue.

More than three years after its emergence, COVID-19 continues to be classified as a global pandemic. According to the statistics centre Our World in Data, in March 2023, the total number of people infected with this virus exceeded 687 million, reaching 66% of the world’s population. The total number of deaths globally, according to the same source, stands at 6.8 million people.

Fortunately, advances in medical science, together with various measures adopted by governments, have meant that since the beginning of 2022, the statistics for deaths, hospitalisations and critical beds have gradually stopped rising.

Although the coronavirus continues to be a significant public health problem, we have managed to slow the spread of the pandemic. But are we prepared for a new epidemiological event?

Years before the emergence of COVID-19, various scientists, such as Vaclav Smil, David Quammen and Robert Webster, were already warning about the possible emergence of a virus capable of causing a pandemic with devastating consequences for the world. Even businessman Bill Gates gave a TED talk in 2015, in which he criticised the lack of policies to prepare for a possible pandemic.

Identifying the origins of the coronavirus can give us insight into how to deal with a new scenario like this. In 2021, the World Health Organisation (WHO) concluded in a report that SARS-Cov-2 had a natural origin and that there was ‘no evidence’ that it originated in a laboratory. The main hypothesis is that the virus originated in an animal—probably a bat—that came into direct contact with a human being, placing the coronavirus in the category of ‘zoonosis’ or a disease that is transmitted from animals to humans.

Currently, more than two hundred types of zoonotic diseases are known, some of which have left their dark mark on world history, such as the ‘Plague of Justinian’—probably caused by the bubonic plague—the Black Death, smallpox, Ebola, and Zika. There are also infections originating in animals that have already been eradicated or can be prevented through vaccination or other methods, such as the SARS epidemic in 2002 and MERS in 2012.

Epidemiological surveillance must be integrated, meaning that it must incorporate all components related to diseases from a human, animal, and environmental perspective. In this way, areas of greatest risk for the emergence of new diseases can be identified, which may originate from pristine environments or highly urbanised cities. In both cases, comprehensive epidemiological surveillance must be carried out in conjunction with public policies to identify pathogens that could cause a future pandemic,» says Fernando Mardones, professor of Veterinary Epidemiology and One Health at the School of Veterinary Medicine.

Despite this, there are currently several factors that are contributing in a worrying way to the emergence of new zoonotic diseases, including: increased demand for meat, unsustainable intensification of agriculture, increased use and exploitation of wild species, unsustainable use of natural resources, and climate change.

Zoonoses and pandemics are among the greatest global health challenges. And since complex problems require complex solutions, in 1976 Calvin Schwabe, a veterinary epidemiologist at UC Davis who would later be named the ‘father of modern veterinary epidemiology,’ thought about the need to define a holistic health framework to prevent and respond to future outbreaks and pandemics.

This is how Schwabe coined the term ‘One Health,’ an integrated and unifying approach that recognises the close link and interdependence between the health of people, domestic and wild animals, plants and the wider environment. It is from this new approach that UC Davis began important work to establish the concept internationally, becoming a leader in the field. Currently, the UC Davis School of Veterinary Medicine ranks first worldwide in the QS Ranking (2022).

«Professor Calvin Schwabe and UC Davis are pioneers in One Health. In 2016, when Schwabe passed away, the legacy of his work began to be seen, with a movement gaining momentum to promote this paradigm as a global commitment in academia», says Professor Mardones.

One Health offers a collaborative, multisectoral, and transdisciplinary approach, with the goal of achieving optimal health indicators, addressing the collective need for clean water, energy, and air, food safety and security, climate change actions, and contributing to sustainable development.

Although the concept has existed for several decades, it was not until recent years that the approach gained prominence, promoted by the tripartite alliance between the World Health Organisation (WHO), the World Organisation for Animal Health (OIE) and the Food and Agriculture Organisation of the United Nations (FAO). Since 2021, the United Nations Environment Programme (UNEP) has joined this crusade under the auspices of the High-Level Panel of Experts on the One Health Approach (OHHLEP), as the only approach to prevent and respond to future outbreaks and pandemics, including the current COVID-19 pandemic.