SARS, MERS, Ebola, avian flu, Zika, COVID-19, HIV, monkeypox… Encouraged by our lifestyle, zoonoses, diseases transmitted to man by animals, have multiplied in recent years, making fear the emergence of new pandemics.
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“The interface between humans and animals has become quite unstable,” Dr. Mike Ryan, head of emergencies at the World Health Organization (WHO), said a few days ago. “Disease onset and disease amplification factors have increased,” he said.
We just saw it with monkeypox, but not only, he warned.
This monkey pox – “monkeypox” in English – caused by a virus transmitted to humans by infected animals – most of the time rodents – is the latest example of the multiplication of these zoonoses.
These are infectious diseases that vertebrate animals can transmit to humans. Some even end up becoming specifically human, like Covid-19.
According to the World Organization for Animal Health, approximately 60% of emerging diseases are of zoonotic origin.
Appearing thousands of years ago, since man intensified his interactions with animals by domesticating them, they have seen their frequency increase considerably in the last twenty or thirty years.
In question, “the intensification of travel, which allows them to spread faster and in an uncontrolled manner,” Marc Eloit, head of the Pathogen Discovery laboratory at the Institut Pasteur, told AFP.
By occupying larger and larger areas of the globe, humans are also helping to disrupt the ecosystem and promote the transmission of viruses.
The intensification of factory farming increases the risk of spreading pathogens between animals. The wildlife trade also increases human exposure to the microbes they may carry. Deforestation increases the risk of contact between wildlife, domestic animals, and human populations.
“When we deforest, we reduce biodiversity; we lose animals that naturally regulate viruses, which allows them to spread more easily, ”Benjamin Roche, a biologist at the Research Institute for Development (IRD), a zoonosis specialist, told AFP.
Climate change will also push many animals to flee their ecosystems in search of more habitable land, warned a study published in Nature in late April. However, by mixing more, the species will transmit more of their viruses, promoting the emergence of new diseases potentially transmissible to humans.
“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 a co-author of the study. . “And if the recipient host is urban or close to humans, we should be particularly concerned.”
The study draws a future “network” of viruses that jump from one species to another and grow as the planet warms.
“We now have quick and easy means of investigation that allow us to react quickly in the event of the appearance of new viruses,” said Marc Eloit, from the Institut Pasteur. “We are also able to develop vaccines very quickly,” as we saw with Covid-19.
But “a whole line of new, potentially dangerous diseases are likely to emerge. We will have to be prepared”, warned Eric Fèvre, specialist professor of veterinary infectious diseases at the University of Liverpool (United Kingdom) and the International Livestock Research Institute (Kenya).
This means, according to him, “emphasizing the public health of populations” in the most remote environments and “better studying the ecology of these natural spaces to understand how different species interact.”
Since the early 2000s, the “One Health” concept has been proposed: it promotes a multidisciplinary and global approach to health problems with close links between human health, animal health and the global ecological state.
In 2021, France also launched the international “Prezode” initiative, which aims to prevent the risks of zoonotic emergencies and pandemics by strengthening cooperation with the most affected regions of the world.
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