The bat is the natural host of the Ebola virus (AFP/Romeo GACAD)
Sras, Mers, Ebola, bird flu, Zika, Covid-19, HIV, monkey pox… Favored by our lifestyle, zoonoses, diseases transmitted from animals to humans have multiplied in recent years, raising fears of the rise of new pandemics has increased .
“The interface between humans and animals has become quite unstable,” said Dr. Mike Ryan, head of emergency room at the World Health Organization (WHO), a few days ago. “Disease incidence and reinforcement factors have increased,” he said.
We’ve just seen it with monkey pox, but not only, he warned.
Charts on symptoms and data available on monkeypox (AFP/)
This monkeypox – “monkeypox” in English – caused by a virus transmitted to humans by infected animals – usually rodents – is the latest example of the multiplication of these zoonoses.
These are infectious diseases that vertebrates can transmit to humans. Some are even becoming specifically human, such as Covid-19.
According to the World Organization for Animal Health, about 60% of emerging diseases are of zoonotic origin.
Appeared thousands of years ago, since humans intensified their interactions with animals by domesticating them, they have seen their frequency increase dramatically over the past twenty or thirty years.
– Deforestation –
The SARS-CoV-2 virus, which causes Covid-19 disease, is housed by bats (AFP/Lionel BONAVENTURE)
In question, “the intensification of travel, which allows them to spread more quickly and in an uncontrolled way”, emphasized AFP Marc Eloit, head of the laboratory for pathogen discovery of the Institut Pasteur.
By occupying ever larger parts of the world, humans are also contributing to disrupting the ecosystem and encouraging the transmission of viruses.
The intensification of intensive livestock farming thus increases the risk of spreading pathogens between animals. The wildlife trade also increases people’s exposure to the microbes they can carry. Deforestation increases the risk of contact between wild animals, domestic animals and human populations.
“When we deforestation, we reduce biodiversity; we lose animals that naturally regulate viruses, making it easier for them to spread,” Benjamin Roche, a biologist at the Research Institute for Development, told AFP. (IRD), specialist in zoonoses.
Climate change will also push many animals to flee their ecosystems for more livable grounds, a study published in Nature in late April warned. However, mixing more will make the species transmit more of their viruses, which will promote the emergence of new diseases that may be transmissible to humans.
The civet cat, intermediate between the bat and the male for transmission of Severe Acute Respiratory Syndrome (SARS) ( AFP / CHAIDEER MAHYUDDIN )
“We need better surveillance in both urban and wild animals so that we can identify when a pathogen has jumped from one species to another,” said Gregory Albery, an environmental health specialist at Georgetown University in the United States and co-author. of the study. “And if the host host is in town or near people, we should be especially concerned.”
– “Be ready” –
The study draws a future “network” of viruses that jump from species to species and grow as the planet warms.
“Today we have easy and fast research methods that allow us to react quickly when new viruses emerge,” reassures Marc Eloit of the Pasteur Institute. “We are also able to develop vaccines very quickly,” as we have seen with the Covid-19.
But “there will probably be a whole host of new diseases, potentially dangerous. We’ll have to be ready,” warned Eric Fèvre, professor specializing in veterinary infectious diseases at the University of Liverpool (UK) and the International Livestock Research Institute (Kenya). .
This means “emphasizing the public health of populations” in the most remote environments, he says, and “studying more closely the ecology of these natural areas to understand how different species interact”.
Since the early 2000s, the “One Health” concept has been put forward: it promotes a multidisciplinary and global approach to health issues with close links between human, animal and environmental health.
France also launched in 2021 the international initiative “Prezode”, which aims to prevent the risks of zoonotic outbreaks and pandemics by strengthening cooperation with the worst affected regions of the world.