Doctors, veterinarians and ecologists must work hand in hand

Generally and according to the WHO, health is defined as “a state of complete physical, mental and social well-being which does not consist merely of absence from illness or weakness”. From this perspective, health is seen as “human health” and through the prism of diseases that affect humans. This vision of health, although already broad, may therefore seem incomplete in many respects.

What about the interfaces between human, animal and environmental health? Of the importance of biodiversity conservation on the living? The impact of climate change on health? Today, it is undeniable that human health is inextricably linked to animal and plant health as well as to environmental health.

The emergence of HIV, Ebola, zika or even the H1N1 flu, as well as the consequences of air or water pollution, have already shown us that we can not think of human health as an independent bubble with no connection to the rest of the world. The Covid-19 pandemic, in its unprecedented scale, provides a central place for the “One Health” approach, which invites us to blur the boundaries that still exist between human medicine, veterinary medicine, plant biology and ecology.

animal origin

Today, we do not have scientific evidence that accurately explains the origin of the Covid-19 pandemic. But we know that SARS-CoV-2, like 70% of new infectious diseases, has an animal origin. Genetic sequencing data from the virus reveal that the closest known viral precursors to SARS-CoV-2 are coronaviruses circulating in populations of bats of the genus Rhinolophus (horseshoe bat), species endemic in parts of China and Laos. .

The bat had already been identified as the origin of SARS (due to SARS-CoV-1), but also of MERS (due to another very dense coronavirus). However, bats have little contact with humans. We have found an intermediate host, civet in the case of SARS and dromedary in the case of MERS, a host that has not yet been identified in the case of Covid-19.

In addition, if the pandemic is human (that is, it is the result of intense human-to-human transmission of SARS-CoV-2 in all populations of the planet), the fact that many species of mammals (cats), lions, tigers, ferrets, hamsters, deer, etc.) have shown some sensitivity to the virus, either after experimental exposure or in nature, after contact with an infected human.

No less than 663 epizootics (names given to animal epidemics) due to human SARS-CoV-2 had been reported in February 2022 to the World Organization for Animal Health (OIE, headquartered in Paris), with nineteen species from thirty-five countries around the world.

Animals infected by man or woman (this is called reverse zoonoses) can also transmit the virus to other animals and in turn to other men or women. A famous case was Danish mink farms in April 2020. The Mustelids had contracted the virus from humans and transmitted it back to the farmers who cared for them. More than 90% of the minks had then become infected with the virus, which is particularly contagious in this species. 42% had remained asymptomaticthe others with mild forms of the disease.

All the unfortunate rodents (16 million individuals) were killed in an emergency by the Danish authorities, who feared not only new transmissions in humans, but also that the virus mutates to adapt to its host. The fear of building an uncontrolled animal reservoir is due to the risk that it will restart the pandemic and contribute to the emergence of new particularly virulent varieties.

Anthropocene and entropy

The Anthropocene, the new geological epoch we are in today, is characterized by the emergence of man as the most important force of change on Earth that overrides geophysical forces. It creates an unprecedented planetary disorder whose consequences for our health can be dramatic.

Many are the examples. Deforestation has been massive for decades because it is necessary to feed and house nearly 8 billion people on the planet. But this practice, to which is added intensive poaching or even gold panning, has especially helped to create an unprecedented proximity to the wildlife world, resulting in the emergence of zoonoses that are likely to give rise to pandemics.

Should we not rather change the paradigm, think more about upstream prevention and now consider health as a whole?

The same is true of intensive and unregulated animal husbandry in some countries, where the exploited animals can act as viral reservoirs, if not as reinforcing hosts. These are able to multiply the infectious load, even to create microbiological mutations at the origin of strains that are better adapted to humans, sometimes more virulent. They can also develop bacterial resistance to the antibiotics with which they are treated on farms – half of the antibiotics produced on Earth are intended for agriculture.

In addition to zoonoses, we have daily examples of the weight of the consequences of human activity on our health – and on the health of living organisms in general.

We know the effects of air pollution, from asthma attacks to cancers (6 to 11% of lung cancer deaths can be attributed to chronic exposure to fine particles that pollute the atmosphere). We are seeing more and more health consequences of climate change: increase in infectious diseases (malaria, dengue fever, cholera, Rift Valley fever) and respiratory diseases, increased mortality among vulnerable people caused by heat waves … Animals are of course also affected by climate change and air, soil and water pollution.

Another point of view

This vision may seem daunting, but it is no less real and should encourage us to act by thinking of health as a universal common good shared by the living. It’s not a matter of relying on geo-engineering – a term coined by Olivier Boucher, CNRS research director at the Dynamic Meteorological Laboratory, to designate “all the techniques and practices implemented or planned with a large-scale corrective measure of the effects of man-made pressures on the environment”.

In fact, this would be an approach that is likely to contribute to the vicious circle of the Anthropocene. On the contrary, should we not rather change the paradigm, think more upstream prevention and now consider health as a whole, for example by promoting the discourse on co-benefits?

It’s time to change our habits.

Co-benefits are all the interventions that aim to protect the health of living organisms but also of the planet. Active mobility – walking, cycling, using public transport – is thus excellent both for our cardiovascular health and for our CO2 footprint and the quality of the air we breathe.

The co-gain is also the reduction of our consumption of red meat, which helps to combat the risk of cancer and climate change. We know that livestock farming accounts for the majority of greenhouse gas emissions from the agricultural sector, which produces a third of all carbon emissions on the planet.

In addition, livestock requires more deforestation by using water and energy, which we would save by limiting our consumption. Also within our energy choices and our habitat, the change in practice benefits our respiratory health as much as that of the planet. It’s time to change our habits. In addition to the involvement of governments and international organizations, co-benefits place the citizen at the heart of efforts against climate change.

It is therefore urgent in this context that life sciences, humanities and veterinary medicine, climate science and ecology speak and work together to redefine “a new way of inhabiting the world, of learning to curl up in it in order to preserve it and thereby ensure our own survival”as Benjamin Coriat writes in The pandemic, the anthropocene and the common goodreleased in 2020.

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Is it not time to set up an intergovernmental group of experts, like the one who raises the alarm about the climate, and who will be dedicated to this new way of living in the world, who raises the alarm every time the Anthropocene will continue to cross borders? for a respectful cohabitation with the living? Preventing future pandemics will require strong support from public policies with knowledge and expertise in environmental and health issues.

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