Towards more zoonoses, with the risk of new pandemics

Towards more zoonoses, with the risk of new pandemics

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Paris (AFP) – Sras, Mers, Ebola, bird flu, zika, Covid-19, HIV, monkeypox … Favored by our lifestyles, zoonoses, diseases transmitted to humans by animals, have multiplied in recent years, raising concerns about the emergence of new pandemics.

“The human-animal interface has become quite unstable,” said Dr. Mike Ryan, head of emergencies at the World Health Organization (WHO), a few days ago. “Disease emergence and amplification factors have increased,” he said.

He has just been seen with monkeypox, but not only that, he warned.

This monkeypox – a monkeypox – caused by a virus transmitted to humans by infected animals – most often rodents – is the latest example of the proliferation of these zoonoses.

Smallpox John SAEKI AFP

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, about 60% of emerging diseases are of zoonotic origin.

Appearing thousands of years ago, since humans intensified their interactions with animals by domesticating them, they have seen their frequency greatly increase over the last twenty or thirty years.


At issue is “the intensification of travel, which allows them to spread more quickly and uncontrollably,” Marc Eloit, head of the Pathogen Discovery Laboratory at the Institut Pasteur, told AFP.

SARS-CoV-2 virus, which causes Covid-19 disease, is harbored by the bat
SARS-CoV-2 virus, which causes Covid-19 disease, is harbored by the bat Lionel BONAVENTURE AFP / Archives

By occupying larger areas of the globe, humans are also helping to disrupt the ecosystem and promote the transmission of viruses.

The intensification of industrial livestock farming thus increases the risk of the spread of pathogens among animals. The wildlife trade also increases human exposure to the microbes they are likely to carry. Deforestation, on the other hand, 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, making it easier for them to spread,” Benjamin Roche, a biologist at the Development Research Institute, told AFP. (IRD), zoonoses specialist.

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

“We need improved surveillance in both urban and wildlife, so we can identify when a pathogen has passed 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 receiving host is urban or close to humans, we should be particularly concerned.”

Owl, intermediate between bat and human for the transmission of Severe Acute Respiratory Syndrome (SARS)
Owl, intermediate between bat and human for the transmission of Severe Acute Respiratory Syndrome (SARS) CHAIDEER MAHYUDDIN AFP / Archives

“Be ready”

The study draws a future “network” of viruses jumping from species to species, and growing as the planet warms.

“We now have easy and quick means of investigation that allow us to react quickly in the event of new viruses,” said Marc Eloit of the Pasteur Institute. “We are also able to develop vaccines very quickly,” as we have seen with Covid-19.

But “a whole new line of disease is likely to emerge, potentially dangerous. We need to be prepared,” warned Eric Fèvre, a professor of veterinary infectious diseases at the University of Liverpool (UK) and International Livestock. Research Institute (Kenya).

This means, he said, “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 emphasized: it promotes a multidisciplinary and comprehensive approach to health issues with close links between human health, animal health and health. global ecological status.

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

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