Towards more “zoonosis” with risk of new pandemic

A few days ago, the World Health Organization (WHO) head of emergencies Dr. “The interface between humans and animals has become quite unstable,” said Mike Ryan. “Disease emergence and amplification factors increased,” he said. We’ve just seen it with monkeypox, but not only, he warned.

Caused by a virus transmitted to humans by infected animals – mostly rodents – this monkeypox – “monkeypox” in English – is the latest example of the proliferation of these zoonoses.

These are infectious diseases that vertebrate animals can transmit to humans. Some even become specifically human, such as Covid-19.

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

They have seen their frequency increase drastically in the last two or three decades, as man, who appeared thousands of years ago, intensified his interaction with animals by domesticating animals.

Degraded ecosystem

AFP Marc Eloit, head of the Institut Pasteur Pathogen Discovery Laboratory, highlighted the “intensification of travel that allows for a faster and uncontrolled spread of travel” when it comes to it.

Humans are also contributing to disrupting the ecosystem and promoting the transmission of viruses by invading increasingly large areas of the globe.

Intensification of factory farming therefore increases the risk of pathogens spreading among animals. Trade with wild animals also increases people’s exposure to germs they can carry. Deforestation increases the risk of contact between wildlife, domestic animals and human populations.

“When we destroy forests, we reduce biodiversity; We are losing animals that naturally regulate viruses and allow them to spread more easily,” explained AFP Benjamin Roche, a biologist and zoonosis expert at the Development Research Institute (IRD).

A study published in Nature at the end of April warned that climate change will also push many animals to flee their ecosystems for more habitable land. However, the more the species mixes, the more it will transmit its viruses, resulting in the emergence of new diseases that can potentially infect humans.

“We need enhanced surveillance in both urban and wild animals before we can identify when a pathogen has jumped from one species to another,” said Gregory Albery, an environmental health expert at Georgetown University in the United States and co-author of the study. . And if the buyer’s host is in the city or near people, we should be particularly concerned. »

” Be ready ”

The study charts a future “web” 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 if new viruses appear,” said Marc Eloit of the Pasteur Institute. As we saw with Covid-19, “We can also develop vaccines very quickly”.

But “a number of potentially dangerous new diseases are likely to emerge. We will need to be ready,” warned Éric Fèvre, professor specializing in veterinary infectious diseases at the University of Liverpool (UK) and the International Livestock Research Institute (Kenya).

According to him, this means “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.”

Since the early 2000s, the concept of “One Health” has been put forward: it promotes a multidisciplinary and global approach to health problems, with close links between human health, animal health and the global ecological situation.

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

Daniel Lawler

and Isabelle TOURNÉ/AFP

A few days ago, the World Health Organization (WHO) head of emergencies Dr. “The interface between humans and animals has become quite unstable,” said Mike Ryan. “Disease emergence and amplification factors increased,” he said. We just saw it with monkey pox, but…