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The disappearance of the wild world facilitates epidemics

By Maria Antonia Serge

Since the onset of the Coronavirus, many people have insisted that epidemics have always existed, citing “the Spanish Flu”, the black death (or bubonic plague), and SARS. But does the number of epidemics tend to decrease or increase?

Since the turn of the century, the number of people affected by infectious diseases has decreased thanks to our high-performance healthcare system. The decrease begins with the appearance of vaccines and antibiotics, and is mainly due to public health and hygiene. In the United States, the number of infected people, for example, decreased by 95% between 1900 and 1980 [1]. However, the number of epidemics is increasing. Worldwide, the number of epidemics has multiplied by more than 10 between 1940 and today [1].

But why are infectious diseases on the rise?

Due to the loss of biodiversity, an infectious disease is transmitted, in most cases, from wild animals to domestic animals, to humans, with pet often acting as a bridge. The natural world has been invaded by domestic animals and wild species that rely on humans, such as mosquitoes; the bond between the wild and the domestic world has intensified. Many studies have shown that the destruction of natural habitats increases the risk of infections. It is estimated that about 20% of the risk of swamping in places of severe deforestation is due to international trade in export products, which involve deforestation, for the production of timber, tobacco, cocoa, coffee and cotton [1].

But what is the impact of the sharp increase in domestic animals?  In biomass, for example, cows weigh more than humans. In order to raise and feed these animals, we need lands that occupy natural habitats: 70% of agricultural land is dedicated to industrial farming, for the production of proteins of animal origin [1]. These animals create more than 200 billion tons of excrement per year, these excrements, added to the harmful substances, contaminate soils and water, feeding the spread of diseases [1].

Does loss of biodiversity mean loss of health?

BIODIVERSITY is “The fruit of billions of years of evolution, shaped by natural processes and, increasingly, by the influence of humans. It forms the web of life of which we are an integral part and upon which we so fully depend. It also encompasses the variety of ecosystems such as those that occur in deserts, forests, wetlands, mountains, lakes, rivers, and agricultural landscapes. In each ecosystem, living creatures, including humans, form a community, interacting with one another and with the air, water, and soil around them” [3]. 

HEALTH is “A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. The enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being without distinction of race, religion, political belief, economic or social condition” [4]. 

From Living Planet Report 2020

One million species are threatened with extinction. More than 60% of wild animals have seen their populations regress since the 1970s [2]. Numerous pathogen regulation systems have altered. We are witnessing a decrease in important predators, such as lynxes and wolves, which control populations of small mammals, such as rodents, which are carriers of different microbes or of ticks that are also vectors. These predators, which control the abundance of rodents, reduce the transmission of pathogens. The interactions between living beings lose their dynamic equilibrium within a perturbed ecosystem, and with these also the resilience of ecological systems. We have created a “pathosystem”, human destroys the resilience necessary for nature and our health.

We are faced with an ultimatum, given to us by the wild world. These epidemics are yet another alarm signal, perhaps it would be necessary to start acting on the causes, rather than continuing to deal with the consequences. Do you think that this time, that we have been directly touched, we will definitely change course? realizing that by destroying our home we also destroy ourselves?


[1] Marianne, French newspaper, article by Serge Morand, researcher at the CNRS-CIRAD, health ecologist and field parasitologist;

[2] WWF (2020) Living Planet Report 2020 – Bending the curve of biodiversity loss. Almond, R.E.A., Grooten M. and Petersen, T. (Eds). WWF, Gland, Switzerland;

[3] D., Arthington, A. H., Gessner, M. O., Kawabata, Z.-I., Knowler, D. J., et al. (2006). Freshwater biodiversity: importance, threats, status and conservation challenges. Biological Reviews 81:163-182. doi: 10.1017/ s1464793105006;

[4] WWF/ZSL. (2020). The Living Planet Index database.


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