What is the relationship between COVID-19, monkeypox and Ebola? All are outbreaks of emerging viruses associated with “zoonoses”. These diseases and infections have spread in the 21st century to some extent, with or without treatment and are somewhat dangerous to humans. Everything indicates that things are not about to improve. 20 minutes It tells you all about this large family of viruses.
What are zoonotic diseases?
We call “zoonoses” all diseases transmitted to humans by animals. Hence, the list includes Sars, Mers, Ebola, and bird flu, as well as Zika, COVID-19, HIV, and even monkeypox. As for the “monkeypox” virus, it is transmitted by infected animals, most often rodents. As for MERS, it comes from camels in Saudi Arabia where it was first discovered in 2012.
Bats are the natural host of Ebola, first identified in 1976 in the Democratic Republic of the Congo. Marburg disease, which causes severe hemorrhagic fever, was identified in 1967 in Germany and Yugoslavia after work on green monkeys. Finally, Zika, chikungunya and dengue are transmitted by mosquitoes and explode in Latin America in 2015.
So these are originally infectious diseases that vertebrates can transmit to humans, but some end up being human specifically, like Covid-19 that’s transmitted between humans. According to the World Organization for Animal Health, about 60% of emerging diseases are of zoonotic origin.
Why is there more and more?
If it is animals that transmit zoonotic diseases to humans, it is not their fault, but the fault of man and, more precisely, their way of life. They appeared thousands of years ago, since humans have intensified their interaction with animals by domesticating them, they have seen their frequency increase dramatically over the past twenty or thirty years. “The relationship between humans and animals has become quite unstable,” says Dr. Mike Ryan, Director of Emergencies at the World Health Organization (WHO). “The factors for the emergence and amplification of the disease have increased,” he said.
In the question, “the intensification of travel, which allows them to spread more quickly and in an uncontrolled way,” emphasizes Mark Elwett, head of the Pathogen Detection Laboratory at the Pasteur Institute. But also the intensification of factory farming, which increases the risk of pathogens spreading among animals. Trade in wild animals also increases human exposure to the microbes they may carry.
Deforestation increases the risks of contact between wildlife, pets, and human populations. “When we deforestation, we reduce biodiversity; we’re losing animals that naturally regulate viruses, allowing them to spread more easily,” explains Benjamin Roche, a biologist at the Research Institute for Development (IRD) who specializes in zoonoses.
A study published in the journal Nature at the end of April warned that climate change will prompt many animals to flee their ecosystems in search of more livable land. However, by mixing, species will transmit more of their viruses, which will promote the emergence of new diseases potentially transmitted to humans.
What are the risks to humanity?
“Today we have quick and easy investigation tools that allow us to respond quickly if new viruses emerge,” reassures Mark Elwett, of the Pasteur Institute. “We are also able to develop vaccines very quickly,” as we have seen with Covid-19.
But a whole host of new, potentially dangerous diseases are likely to emerge. You have to be prepared,” warns Eric Pfeffer, professor specializing in veterinary infectious diseases at the University of Liverpool (UK) and at the International Livestock Research Institute (Kenya). This means, according to him, “a focus on the overall health of the population” in remote and “Studying the ecology of these natural areas better 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 issues with close links between human health, animal health and the global environmental state. In 2021, France also launched the international “Prezode” initiative, which aims to prevent the risks of the emergence of zoonoses and epidemics by strengthening cooperation with the most affected regions of the world.