What is a zoonosis? – Numerama

Zoonoses are diseases transmitted from animals to humans. The phenomenon is at the heart of the news due to the pandemic and the ecological crisis.

We know that the covid-related pandemic is probably the result of a zoonosis. But, what exactly does this term mean? What ecological and medical challenges does it represent — today and in the future?

What is a zoonosis?

A zoonosis is a disease or infection naturally transmitted from animals to humans. », Explains the site of the World Health Organization. Clearly, if an animal infects a human being, the transmission is a zoonosis. This can concern a virus, but also a bacterium.

Several diseases are of zoonotic origin:

  • salmonellosis
  • Avian and swine flu
  • Campylobacteriosis
  • Ebola
  • Rabies
  • Hepatitis E
  • Several coronaviruses
  • And many others: more than 200 diseases are listed among the zoonoses…

The AIDS virus, HIV, started out as a zoonosis before mutating and establishing itself permanently in humans. Other zoonoses, such as Ebola, cause recurring epidemics. The SARS-CoV-2 coronavirus, for its part, has caused the covid pandemic since its emergence in humans at the end of 2019.

The SARS-CoV-2 coronavirus is most likely of zoonotic origin. // Source: Pixabay

The ecological crisis and zoonoses

Zoonoses are not disconnected from the ecological crisis. The more humanity encroaches on the natural habitat of wild animals, the more it exploits them, the greater the risk of zoonotic transmission.

As shown in particular by a study published in 2020, the number of emerging zoonotic diseases has increased in recent decades, at the same time as the human exploitation of ecosystems. ” The spread of viruses from animals is a direct result of our actions regarding wildlife and their habitat “, explained the director of this work, Christine Kreuder Johnson. “ These actions simultaneously threaten the survival of species and increase the risk of spread. »

Another link between the ecological crisis and zoonoses: the melting of the ice. In the permafrost, there is a whole virological and bacteriological reservoir, which is preserved there like in a freezer. In the event of melting – caused by climate change in our time – these pathogens can contaminate animals… and potentially humans then by zoonosis. This is why a 2022 study warns of the risks of a future pandemic from the Arctic.

To listen: our podcast “The 6th extinction”

To deepen the ecological issues of our era with notes of hope, discover the first episode of our podcast dedicated to the threats to life: The 6th extinction. Available on all listening platforms or the player below.


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