Towards more “zoonoses”, with the risk of new pandemics

“The human-animal interface has become quite unstable,” said Dr. Mike Ryan, head of the World Health Organization (WHO) Emergency Department, a few days ago. “Disease causing and amplifying factors have increased,” he said. We just saw it in monkeypox, but not only, he warned.

This monkeypox, caused by a virus transmitted to humans from infected animals, mostly rodents, is the latest example of the proliferation of these zoonoses.

These are infectious diseases that can be transmitted from vertebrates to humans. Some are even becoming specifically human, like Covid-19.

According to the World Organization for Animal Health, about 60% of emerging diseases are zoonotic in origin.

They appeared thousands of years ago, since humans intensified their interactions with animals by domesticating them, and their frequency has increased greatly over the last twenty or thirty years.

The disturbed ecosystem

In question is “the intensification of travel, which allows them to spread faster and more uncontrolled,” stressed Marc Eloit, head of the laboratory for the detection of pathogens at the Pasteur Institute, to AFP.

By occupying ever-increasing areas of the earth, humans are also helping to disrupt ecosystems and promote virus transmission.

The intensification of factory farming thus increases the risk of transmission of pathogens between animals. The wildlife trade also increases human exposure to the microbes they may carry. Deforestation increases the risk of contact between wild animals, domestic animals and human populations.

“If we cut down forests, we reduce biodiversity; We are losing animals that regulate viruses naturally, which allows them to spread more easily,” Benjamin Roche, a biologist at the Research Institute for Development (IRD), specialist in zoonoses, explained to AFP.

Climate change will also force many animals to flee their ecosystems for more livable lands, warned a study published in Nature in late April. However, by mixing more, the species will transmit more of their viruses, which will encourage the emergence of new diseases potentially transmissible to humans.

“We need improved surveillance in both urban and wild animals so we can determine when a pathogen has jumped from one species to another,” said Gregory Albery, an environmental health specialist at the University of Georgetown in the United States and Study co-author. And if the receiving host is in the city or near people, we have to be especially worried. »

” Be ready ”

The study depicts a future “network” of viruses hopping from species to species, growing as the planet warms.

“Today, we have simple and rapid means of investigation that allow us to react quickly to the emergence of new viruses,” assures Marc Eloit of the Pasteur Institute. “We are also able to develop vaccines very quickly,” as we saw with Covid-19.

But “there’s likely to be a whole host of new diseases emerging that are potentially dangerous. We must be ready,” warned Éric Fèvre, Professor of Veterinary Infectious Diseases at the University of Liverpool (UK) and the International Livestock Research Institute (Kenya).

This means, he says, “focusing on the public health of populations” in the most remote environments and “better studying the ecology of these natural areas to understand how different species interact.”

The “One Health” concept has been propagated since the early 2000s: it promotes a multidisciplinary and global approach to health issues with close links between human, animal and environmental health.

In 2021, France also launched the international initiative “Prezode”, which aims to prevent the risks of zoonoses and pandemics by strengthening cooperation with the most affected regions of the world.

Daniel Lawler

and Isabelle TOURNE/AFP

“The human-animal interface has become quite unstable,” said Dr. Mike Ryan, head of the World Health Organization (WHO) Emergency Department, a few days ago. “Disease causing and amplifying factors have increased,” he said. We just saw it in monkeypox, but not…

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