A Chinese policeman observes a civet in its cage at the Wuhan market, May 26, 2003. – AFP
- Tribune, conference, decryption … With Covid-19, calls for the adoption of the “One Health” concept multiply, both from international organizations such as the WHO and from groups of researchers or institutes, such as ANSES .
- One Health emphasizes the interdependence between animal, human and environmental health, and invites researchers specializing in these various themes to work together to better anticipate future pandemics.
- Simple on paper, but much more complex to apply in reality?
Human and animal health, same fight… The Covid-19, probably caused by a virus of animal origin, is a new invitation to no longer dissociate the two. The stakes are high and moreover go well beyond the framework of the current pandemic. The
influenza, the
HIV,
Ebola… 60% of human infectious diseases are zoonoses, these diseases transmitted naturally between vertebrate animals to humans, and vice versa. And 75% of emerging diseases affecting humans are of animal origin.
Impossible, therefore, to take them separately. This is what the concept advocates “One Health” [« Une seule santé »], which even invites to add into the equation the health of the ecosystems in which animals and humans evolve.
A tool to be institutionalized as quickly as possible to prevent new epidemics? Calls have multiplied in this direction in recent months. Both from international public health organizations,
WHO in the lead, that of
collectives of researchers or research institutes. This Wednesday again,
National Agency for National Food Safety (ANSES) devoted the morning to describing the close links between animal and human health.
But what are we talking about with One Health? What are the challenges of such an approach? 20 minutes make the point.
Are we discovering the links between human health and animal health with the Covid-19 pandemic?
Far from there. Gilles Salvat, Deputy Director General for Research, ANSES, dates back to Antiquity, recalling that “the first studies on human health were for many studies compared between humans and animals”. “These links between doctors, veterinarians, biologists were very close until the 19th century, before gradually weakening”, regrets Muriel Vayssier-Taussat, head of the
animal health department at INRAE. “Medicine has always dominated other sciences and in the world of research, interdisciplinarity is not emphasized. You have to be the great specialist ”, noted Delphine Destoumieux-Garzon, research director at CNRS last August.
in The world.
Yann Voituron, researcher at Ecology laboratory of natural and anthropized hydrosystems (CNRS, University of Lyon), nonetheless describes, since the 1980s, attempts to reconnect between human and animal health. “It is in particular the concept” One medicine “, encouraging to link the human health and those of the farm animals, he describes. Then, in the 1990s, the approach was extended to wild animals before arriving, in 2008, at the “One Health” concept, which adds a layer by integrating the health of ecosystems. “
Why are human, animal and ecosystem health inseparable?
“Because they live on the same planet, humans and animals share a certain number of infectious diseases”, summarizes Gilles Salvat. These pathogens can be bacteria, viruses, parasites transmitted either directly to humans, during contact between animals and humans, or indirectly through food or by a vector such as the mosquito, which transmits malaria by its bite.
This coevolution between these diseases, man and animals began through hunting, then domestication. All these zoonoses do not give rise to pandemics like the one we are currently experiencing. The worrying observation, all the same, is that their resurgence and their emergence have accelerated for a century. The growth of the world population and our lifestyles are no strangers to it. “Human intrusions into preserved environments endowed with great biodiversity – for the search for bushmeat or the exploitation of forest resources – increase contacts and therefore the risk of transmission of pathogens”, begins Gilles Salvat. “Deforestation – in particular to gain new agricultural land – also has the effect of unbalancing ecosystems,” adds Muriel Vayssier-Taussat. Wild species then seek new territories and approach human populations, again increasing the probabilities of contact. “
Climate change is also having a grain of salt. “For example, it influences the distribution of zoonotic vectors [notamment des insectes] by promoting their ascent from South to North, or modifying the routes of migratory species which are themselves sometimes carriers of pathogenic agents, ”continues Gilles Salvat. Finally, add globalization, which allows certain zoonoses to spread across the planet in just a few weeks.
How can the “One Health” concept help prevent future pandemics?
The bet of One health is that of “interdisciplinarity” … In short, breaking down the barriers between human medicine, veterinary medicine and environmental sciences. For a better understanding and better management of animal reservoirs of infectious agents, but also of their routes of transmission and adaptation to humans.
If One health did not prevent the Covid-19 pandemic, it has not remained an empty shell since 2008. And has initial successes to its credit. Epidemiological surveillance networks bringing together researchers, veterinarians and doctors have thus contributed to preventing the introduction of avian influenza in 2016 in the Caribbean and to monitor
epizootics [épidémies qui frappent les animaux] of
foot-and-mouth fevers and of
rift valley fever in the Indian Ocean area in 2019, illustrated a group of researchers in a forum at the
World last November.
A concept still too embryonic?
While interdisciplinary research programs have emerged in the case of the One Health approach – starting with EJP One Health, coordinated by ANSES – the concept can still gain momentum. “A strong stake is that of training, estimates Yann Voituron. In particular in the course of medicine, where it would be necessary to include much more notions on evolutionary biology and the biology of ecosystems… ”
Another major challenge is to inject this concept into the political sphere. In the boxes, there is in particular this idea, carried by France, to create a “Haut Conseil One Health”. On the model of the Intergovernmental Panel on Climate Change (IPCC), this committee of experts from different disciplines would have the task of “providing, from the first alert, the data and recommendations that political leaders need to stop emerging pandemics ”.
For Muriel Vayssier-Taussat and Yann Voituron, we should go even further by questioning the potential impacts of all policies on animal and environmental health. And by extension on human health. “There is a lot of talk at the moment about the agro-ecological transition. With this concern to leave more animals outside, to promote biodiversity, illustrates Muriel Vayssier-Taussat. This is very good, but taking this direction requires imagining the impacts that this could have in terms of public health, and thus setting up surveillance or solutions to anticipate possible problems. “