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Why is protecting biodiversity key to preventing epidemics?

1.7 million. That is the number of "undiscovered" viruses currently present in mammals and birds. Of these, 827,000 may have the potential to infect humans. So to prevent Covid, Zika, Ebola, Nipah and viruses from ravaging society at a growing rate, there is one critical action we can take: protect nature.

Epidemics affecting humans have been on the rise for several decades. Seventy percent of emerging diseases and almost all pandemics are zoonoses, meaning they are caused by pathogens of animal origin. "The correlation between the appearance of some of these infectious diseases and the degradation of ecosystems by humanity is very clear," notes Hélène Soubelet, director of the Foundation for Research on Biodiversity, based in Paris.

Animal contact

The destruction of natural areas – and therefore of animal habitats – by human activity (deforestation, use of pesticides, rampant urbanization, intensive livestock farming, etc.) is one of the main factors in the development of epidemics. Humans are now coming into contact more often with wild species, and thus with their diseases.

One telling example is Nipah, which emerged in Malaysia in 1998. The natural hosts of this virus include several species of fruit bats. But when their natural habitat was transformed into palm oil plantations, the bats moved to a new area located near fruit trees used to feed farmed pigs. That is how the virus eventually passed to the pigs and then to humans.

"The animal species that adapt best to deteriorated natural environments are also those that retain the most pathogens that may be shared with humans", adds Hélène Soubelet. "For example, mosquitoes thrive in deteriorated environments, especially where there are fewer forests and predators.”
 

“Dilution effect”

On the other hand, some species serve as "dead ends" for pathogens, which means that they are not favorable hosts for their development. And the more numerous and diverse the hosts and non-hosts of a parasite are within a given environment, the lower the infection prevalence in that area (meaning fewer diseases at a given time in a population). This is called the "dilution effect". As a result, this means that pathogens will have a harder time establishing themselves within ecosystems that show greater biodiversity.

That is why it is essential for us to preserve biodiversity and protect wilderness areas. To do this, Hélène Soubelet believes, "we need to create islands where biodiversity can evolve freely, where there is less contact with humans, and where hunting and poaching are not practiced. Moreover, agriculture should be made more sustainable and less harmful to ecosystems". In short, we must preserve the living world to protect living beings.