Video: Bonn / EUROBATS Convention, adapted by Jesús Nicolás)
A few days ago, several international consortia that promote the conservation of species published a note that warned that, in a mistaken effort to stop the COVID-19 pandemic, indiscriminate killings of bats are taking place in different parts of the world. Some of these actions have even been promoted by government institutions and authorities.
Bats have never been popular and carry with them a whole series of black legends and superstitions that go back centuries. Their alleged relationship with the appearance of the outbreak of the new coronavirus, which is not proven, has only stigmatized them and served as an excuse for this type of action that has no scientific basis and endangers animals that are already very threatened.
The source of the outbreak is not yet known
“First of all, there is no evidence that bats directly infected humans with COVID-19,” says the note, signed by entities including the Agreement on the Conservation of Bat Populations in Europe (EUROBATS) , dependent on the United Nations. ” Scientific investigations are pointing to a chain of events that may have involved bats, but most likely only through an intermediate animal .” For example, November 2019 is considered the most likely time for the outbreak to appear in humans, and at that time the bats are hibernating and therefore could not be for sale in the live animal market that is indicated as a possible focus of the epidemic.
Second, when it comes to talking about the appearance of SARS-CoV-2, there are two concepts that are being confused very often. One is the epidemiological origin, that is, what was the source of the infection, and another is the evolutionary origin, that is, how and where the virus arose. What we know so far is that SARS-CoV-2 shows a 96.3% genetic resemblance to another coronavirus called Bat-CoV-RaTG13 that was detected years ago in a species of horseshoe bat ( Rhinolophus affinis ) in the province. from Yunnan, southwest China.
“96% homology may seem like a lot, but when we translate that 4% that differentiates both viruses into time, things change,” explains Juan E. Echevarría, virologist at the National Center for Microbiology (Carlos III Health Institute) and Member of the Health Commission of the Spanish Association for the Study and Conservation of Bats (SECEMU). ” This genetic distance between one virus and another corresponds to approximately 40 to 70 years of evolution. That is, if the Bat-CoV-RaTG13 detected in that bat and the SARS-CoV-2 had something to do or were on the same evolutionary line, which is also not known, they would have diverged between 40 and 70 years ago. That is the only proven relationship that exists today between bats and SARS-CoV-2 ”.
The problem is not the animals but our relationship with them
We have already clarified that, currently, there is no evidence that bats can directly transmit COVID-19 to humans. We have also seen that there is currently insufficient evidence to consider bat coronaviruses as the evolutionary ancestor of the new virus, it is only a hypothesis. Now, it is necessary to move on to the following reflection: regardless of the species from which the jump of the new coronavirus to man has occurred, the problem is not the animals, but our relationship with them.
“Even if bats had been the source of infection for humans,” Echevarría continues, “that would not be a reason to stigmatize them either, because the real problem is that we come into direct contact with wild species with which we should not .”
The explosion of the COVID-19 pandemic has revealed that the illegal trafficking of species and their sale in the so-called ‘wet markets’ (with the majority of live animals) in unsanitary and unsanitary conditions facilitate the transmission of new viruses to man . This is one of the mechanisms by which we come into contact with wild species, but the other, and no less relevant, is the degradation of the environment.
Habitat degradation and biodiversity loss threaten our health
“When we destroy a forest, for example, we are forcing the species that live there to occupy other spaces in which we live, and we facilitate contact,” Echevarría explains. In addition, the destruction of habitats also causes the extinction of species, which in turn triggers ecological imbalances with unpredictable consequences. “Some species do not survive the degradation of their environment and when they disappear they leave empty niches that others occupy. Paradoxically, the extinction of some species causes excessive growth in the populations of others and all these processes can also increase the risk of contagion of new diseases ”.
An example of this would be the increase in the incidence of Lyme disease in the US It is thought that some species of wild birds could have been reservoirs of the disease but that, as their populations decrease as a consequence of environmental degradation and increase In parallel, the populations of rodents, which are also vectors and are in closer contact with humans, would have led to the jump.
More pandemics will come
For Echevarría, there are three key conditions for a pandemic to occur. First, have large human populations. On the other hand, the development of means of transporting people and goods from one end of the globe to the other. And finally, close contact with animals. “Right now we are in a period of history where all this occurs with great intensity: the trade in animals and the degradation of the environment are greater than ever, the human population does not stop growing, and the means of transport are very fast and they go very far. None of these phenomena is new, but now all are more intense than ever, so we must expect that pandemics will begin to occur much more frequently ”.
Why keep bats
After clarifying that, we do not really know what the relationship of bats is with the new SARS-CoV-2, nor that no animal is to blame for this pandemic, we have one last question and that is that, beyond its bad reputation and from the legends that circulate about them, bats are animals that play an important ecological role and that bring us many benefits to human society.
“Almost all the species of bats that inhabit Spain are insectivorous, and that means that every night they go out and eat tons of insects that could be pests for crops. Bats save us a lot in pesticides and also in the health risks posed by the abusive use of these compounds ”, Echevarría defends. In addition, part of these insects that are eaten can be vectors of diseases such as malaria or dengue, so they also help to contain their transmission.
Other bats present in tropical and subtropical areas are great seed dispersers, and others, being nectarivores, play an important role as pollinators. “The most paradigmatic case is that of the agave, pollinated by a bat,” explains the expert. ” It is always said that without bats there would be no tequila .”
Bats are natural heritage
Beyond its usefulness for man, we want to end by remembering that species are a good per se . “You have to explain to no one why it is necessary to preserve the Burgos cathedral or a painting by Goya, although they are not useful to us, they are artistic objects and everyone understands that they are heritage”, reflects Echevarría. “The same thing happens with the natural environment, although this seems not to be so present in the collective imagination. The species that live in a territory are natural heritage, and that must be taken care of. In the European context, we are a country that has a lot of biodiversity, we have a very rich natural heritage that we must value and care for. Bats have an exciting biology and they are very particular animals, with a very intense social behavior, they are fascinating. If people knew more about them, they wouldn’t have such a hobby ”.
