Coronavirus, monkey pox, Ebola… Why scientists are studying French bats to better understand zoonoses

Coronavirus research continues. We may never know the precise origin of Sars-Cov2, the virus behind the Covid-19 pandemic, but what is certain is that it all started with a bat. So, to anticipate the next epidemics, researchers are actively studying these animals.

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And for that, no need to go to China. Meriadeg Le Gouil takes us to Pontchateau, near Saint-Nazaire, in Loire-Atlantique. At nightfall, a few minutes of walking, climbing in the brambles in the light of headlamps with this virologist from the University of Caen, affiliated with Inserm, and you enter a huge cave. “It’s an old gallery that dates from the war in which the bats nest. We’re going to have three or four species that will meet here”explains the researcher.

You have understood, we are far, very far from the image of the scientist in the white coat in a very clean lab. Meriadeg Le Gouil dragged his rain boots and his headlamp for years in the caves of Asia and Africa to study bats, but not only. “I realized that there were also a lot of coronaviruses in our bats. We have 36 different species in Francedetails the scientist. We also have horseshoe bats – the ones we are talking about a lot at the moment for Sars-Cov2.”

“To study the mechanisms and the evolution of these viruses, we can very well do it in our latitudes”

Meriadeg Le Gouil, virologist from the University of Caen

at franceinfo

With a veterinary colleague, Meriadeg Le Gouil begins to install the traps, large nets in which the bats will tangle their wings. “We catch them when they go to look for food and there, it’s a crossing point”, specifies the virologist. It does not miss: a few moments later, a specimen gets stuck in the net, squealing. This is “a small male who is probably not of the year, not too young”, specifies Meriadeg Le Gouil, before detailing the protocol: “We put him in a cotton bag. We will take samples from him to do genetics. And then to search for coronaviruses in particular.”

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Indeed, bats are mostly carriers of coronaviruses, hosts, natural reservoirs of these viruses. “We make them chew on a swab to collect some saliva and cells from the mouth. In general, they have very good teeth, so we put on gloves”slips the specialist.

The animals are then released, because the idea is to follow them over several years in their natural state. The virologist details the objectives of the project: “We can study how these viruses work in bats or with bats, how these viruses interact with their hosts, how they are transmitted, how they evolve, at what speed, what are the causes of their appearance, their disappearance, their change…” He also hopes “to better understand how the viruses they harbor can pass from one species to another”, it is “a parameter which is very important”he assures. “What are the conditions that allow its viruses to emerge into a new species or pass into a new species – what is called zoonautical transmission, it means when a virus changes species”specifies Meriadeg Le Gouil.

We now know: Covid-19 is a zoonosis – a virus was transmitted to humans by animals. Ebola, but also malaria, chikungunya and, more recently, monkey pox are also zoonoses. Scientists are also seeing, in fact, more and more emergences and re-emergences of these viruses, explains Dr Muriel Vayssier-Taussat, from INRAE, the Research Institute for Agriculture, Food and Agriculture. ‘environment.

“It is estimated that 60% of infectious diseases in humans come from animals and that for emerging infectious diseases, three quarters have an animal origin”, says the researcher. So many reasons to study these zoonoses: if there are more and more humans on Earth, by enlarging cities, the habitat of animals is upset and there are therefore more and more interactions between species.

To deal with these zoonoses, a concept is developing and is increasingly put forward by the international scientific community: the approach One Health, “single health”. Clearly, the health of animals and that of humans are interdependent, and if we study and protect the health of animals, we also protect humans, and vice versa.

France has thus just released specific research budgets. Because the key to understanding future pandemics may be nestled in our French caves.