Why did you want to address the topic of pandemics in a book and a documentary*?
I have been working on this for a long time the link between health and the environmentlike in my movies and books our daily poisonthat treat endocrine disruptorsWhere The world according to Monsanto, where I show the impact of pesticides on soil, air and water. But I never got close the issue of biodiversity as a pillar of health. Is reading an article in the New York Times titled “We made the coronavirus epidemic “at the end of January 2020, just before the first confinement, that I discovered the existence of a multitude of studies showing the relationship between biodiversity and healthon the one hand, and between destruction of biodiversity and emergence of pandemics, on the other hand. I got in touch with a hundred scientists – virologists, biologists, infectiologists, anthropologists, etc –, I selected 62 for the book and about fifteen for the film. They all claim to belong to a new discipline, health ecology and sharing a holistic view of health.
How did you choose the scientists you interviewed?
My first contact, Serge Morand, is a CNRS parasitologist who works in Thailand. He put me in touch with some of his colleagues, who have in common be independent scientists working for the general interest, with no particular interests. An independent scientist is someone whose remuneration does not depend on the results of their studies. Prevents interest conflicts…
How did you make the link between the health crisis and the biodiversity crisis?
O biodiversity is very rich in tropical regions, mainly in what remains of primary forests, which shelter a great diversity of animals, plants, but also microorganisms, including pathogens, potentially dangerous for humans. We could say that the solution is to scrape the the tropical forestsand exterminate the three main reservoirs of pathogens, namely rodents, primates and bats. But scientists have shown that if we did that, we would get the opposite result! In a study published in 2014, Serge Morand compared Southeast Asia deforestation map from 1950 to 2008, to endangered species and to the 120 infectious foci during the same period. The three cards overlap! Hence your conclusion:The more we deforest, the more we reduce biodiversity, especially animal biodiversity, and the more we have zoonoses, these diseases transmitted from animals to humans. This is called the pandemic factory. “
Global warming: biodiversity threatened, our nutrition too
Can you enlighten us about the relationship between deforestation and pandemics?
Deforestation is the main factor in the emergence of diseases, especially in tropical areas. We deforest to explore mining, timber, breeding, soy monocultures intended for intensive European agriculture or oil palm plantations. During these activities, humans enter virgin spaces, where they disturb the balance that prevailed between the components of biodiversity, for example, forcing certain animals to move. This intrusion brings them into contact with infectious agentswho have lived there since the dawn of time without posing a danger, because they were not adapted infect humans. We now know that the AIDS virus, which is a zoonosis and of which chimpanzees are the reservoir, emerged during deforestation in Africa. This is the same for Ebola, a bat virus, which infected great apes and later humans through consumption of wild animal meat.
In addition to deforestation, are there other emergency factors?
A virus of animal origin never jumps directly to humans. It needs an intermediate host, a wild or domestic animal, that allows it to adapt. The The Nipah virus, which appeared in 1998, illustrates the mechanisms at work. O Deforestation on the island of Borneo to establish palm oil monocultures forced the bats to flee. Scientists have shown that stress causes a drop in the immune system of flying mammals, which suddenly begin to excrete – in urine or excrement – the viruses they carry. These can soil fruits, eaten by monkeys, as was the case with Ebola. In my story, the fruit bats fell back on the back of Malaysia, where mango trees are grown above intensive outdoor swine farms. They ate the mangoes, defecated on the pigs, which began to drop like flies. The pigs contaminated the farm workers. Ironically, Malaysia is a Muslim country that doesn’t eat pigs. The animals were destined for export. They took the boat to Singapore, where the virus reached slaughterhouse workers because it is 35% deadly. In this example, we find the recurring factors that govern the emergence of infectious diseases: deforestation, intensive agriculture, which plays the role of amplifier, and globalization, which allows viruses to reach the other side of the world. .
How is Lyme disease related to human activities?
Two American scientists, Keesing and Ostfeldwho have been working on this disease for more than thirty years have discovered a little-known ecological mechanism: the dilution effect. they showed that the fragmentation of forests, by roads or crop fields, leads to the disappearance of predators like foxes or lynxes, who no longer have enough space to live. This causes the proliferation of a kind of rodents, the white-footed mouse, which is the reservoir of the bacteria responsible for Lyme disease. However, ticks, which are born without being infected by the bacteria, have a 95% chance of acquiring it if they feed on the blood of this mouse. If there is high animal diversity, the tick may bite a skunk, squirrel, bird or deer, which are hosts incapable of transmitting the bacteria. Thus, the more biodiversity there is, the more diluted the risk of tick infection. On the other hand, if biodiversity is reduced, the risk of humans becoming infected increases. The mechanism of the dilution effect has been confirmed for many vector-borne diseases, transmitted, for example, by mosquitoes. As I say, with a little self-mockery, Biodiversity is not an extra soul for boho-ecologists-on-bike, it actually plays a role in regulating the risk of infection.
Lyme, ambush co-infections
Is there a correlation between biodiversity loss and pathogen virulence?
The intensive breeding of genetically uniform animals plays the role of amplifying viruses from wild fauna. This is often seen with the flu. The dilution effect was also observed for plants in monocultures. As explained in my book agronomist Christian Lannou de Inrae, in a wheat field, the uniformity of cultivated species favors the proliferation and virulence of the fungus responsible for rust. Same phenomenon in tree monocultures. In all cases, biodiversity is the best antidote to the emergence of infectious pandemics.
What main message do you want to convey?
I think it’s urgent review our relationship with the environment, rethink our agricultural and economic models. If governments took the right steps, it would be good for the climate, biodiversity and health in general. Humanity is on a Titanic descending the glacier. When it sinks, there will be no boat to escape. Even for the richest 1% on the planet, who are at the helm… No one will survive the destruction of biodiversity, which is our common home.