Towards more zoonoses with risk of new pandemic

WHO’s head of emergencies, Dr. “The interface between humans and animals has become quite unstable,” warns Mike Ryan. “The emergence of the disease and the amplification factors have increased. We just saw it with monkeypox, but not only,” he warns.

Caused by a virus transmitted to humans by infected animals, this monkeypox – “monkeypox” in English – mostly rodents – is the latest example of the proliferation of these zoonoses. Earlier there were MERS-CoV, Ebola, Zika, covid-19… all infectious diseases that vertebrates can transmit to humans. Some even become specifically human, like the coronavirus.

Strong growth for 20 years

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 20-30 years, as humans, who emerged thousands of years ago, intensified their interaction with animals by domesticating animals.

In that question, Marc Eloit, head of the Pathogens Discovery lab at the Institut Pasteur, highlights the “intensification of travel that allows them to spread more rapidly and uncontrollably.”

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

When we destroy forests, we lose animals that naturally regulate viruses and allow them to spread more easily.

Intensification of factory farming therefore increases the risk of pathogens spreading among animals. The wildlife trade 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 lose animals that naturally regulate viruses, which allows them to spread more easily,” explains Benjamin Roche, a biologist at the Research Institute (IRD) who specializes in zoonosis.

Improved surveillance of “urban and wild” animals

A study published in the journal “Nature” at the end of April warned that climate change will force 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 to be able to determine when a pathogen has jumped from one species to another,” says Gregory Albery, an environmental health expert and co-author of the study at Georgetown University in the United States. of your study. “And we should be particularly concerned if the buyer’s host is from the city or is close to people.”

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” 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,” says Marc Eloit of the Institut Pasteur. As we saw with Covid-19, “We are also able to develop vaccines very quickly”.

But “a number of potentially dangerous new diseases are likely to emerge. “We’ll have to be ready,” warns Eric 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.”

Promoting a multidisciplinary approach

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 environment. global ecological situation.

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