Remember that the vast majority of viruses are exclusive to one species. But with the quantity of viruses circulating, this has left, through all eras, a high number which, by chance of a mutation, became capable of being transmitted to another species. And sometimes to us. The learned name is zoonosis: an infectious disease that has passed from animals to humans. The COVID-19 pandemic is a zoonosis, although we are not yet sure of the animal of origin.
By changing territory, an animal can therefore cross paths with an animal that it would never have met before. Does it increase the chances of cross-species disease transmission? Yes, answer researchers who have built a mathematical model of 3139 species of mammals and the 40,000 viruses – known to date – of which they are the hosts, as well as their current and probable movements, in the next 50 years. Their conclusion is that, in the next 50 years, we can foresee 4500 circumstances where a virus, or even several viruses, could “jump” from one species to another. L’article was published on April 28 in the journal Nature.
Multiple options, multiple risks
Until now, the biologists who had been interested in this question had rather gone there one virus at a time: will it survive such and such an environmental change, does it have mutations that can make it capable of “jumping” to another species.
However, it is with the magnitude of the problem — these 4,500 possibilities — that a warning signal for humans. When the researchers assessed where, in 50 years, these problematic species would have migrated, they found that the vast majority were areas where our cities are expanding. For example, note in the New York Times pathology ecologist Gregory Albery, co-author of the study, a small rodent that until then had little contact with humans, could transmit its virus to a raccoon that lives comfortably in urban areas.
In fact, it has already begun, since the figures of the last century reveal that 60% of the new epidemics that have affected us are zoonoses. The probable result of unprecedented contacts, in the 20th century, between humans and certain animal species, such as the bats of Southeast Asia.
Incidentally, the researchers note, there is concern about the impact of these new viruses on humans, but it should not be forgotten that, for an already fragile animal population, a new virus against which its immune system is not prepared, can have a devastating impact.
Journalist Ed Yong uses the word “pandemicene —we would have entered a “pandemic era,” where large numbers of new hosts will transmit old viruses, and perhaps even new ones. This situation has been created by the collision between two of the impacts that humans have on nature: climate change and loss of habitats for wildlife. And this situation, concludes Yong, is found at the crossroads of three of our existential fears: “climate change, pandemics and the 6th mass extinction of life on Earth. “These three fears are actually the same mega-problem. “As we come out of a pandemic, he warns, we might do well not to underestimate the importance of better prepare for the next…