Bats are a group of nocturnal mammals capable of flight. They are a diverse group of mammals with about 1200 known species and are distributed globally. They have consistently been feared and misrepresented. Today, bats are in the news globally and for the wrong reasons. With the Covid-19 pandemic getting almost all countries observing some kind of a lockdown, people's fears have been stoked. Bats are unfortunately at the receiving end. People are constantly exposed to misinformation peddled on various fora claiming that bats are dangerous, blood sucking creatures, and carry a host of diseases including the Covid-19 virus. Expectedly, people now want to chase bats away and cut down trees.
It is at an inopportune moment that several news outlets recently chose to report a study which had found coronavirus in bats from south India. The study was conducted by a team of researchers based out of the National Institute of Virology and the Indian Council for Medical Research and led by Dr Pragya Yadav. The paper, published in a special issue of the Indian Journal of Medical Research, mentions “coronavirus” in the title but the entire paper is a much needed exploratory research on viruses in bats and they confirm the presence of bat coronavirus (BtCov). This has nothing to do with the Covid-19 that has put the world into a tailspin.
Are bats responsible for coronavirus?
The fact of the matter is, bats, like any other animals, are a reservoir to a host of potentially disease-causing pathogens. These pathogens would have evolved host specificity and do not have the ability to affect other hosts directly. However, historically, there have been incidents of pathogens jumping from one species to another and this phenomenon is called a “spillover effect”. Some examples of diseases which jumped on to humans are: Human Immuno Virus (HIV), Middle Eastern Respiratory Syndrome (MERS), Nipah, Severe Acute Respiratory Syndrome (SARS), and Ebola.
While the native host of some of these diseases are suspected to be bats, the disease almost always jumped to humans via an intermediary species. In fact, preliminary research suggests that the Covid-19 virus jumped to humans via pangolins, which are illegally and extensively traded across south and southeast Asia. The field of research dealing with such diseases is aptly called Emerging Infectious Diseases. To catch a disease before it emerges, one has to screen native fauna for pathogens and this is exactly what Dr Yadav and team have accomplished.
Why do diseases spill over?
In our myopic pursuit of development, we have gone about destroying forests, laying roads and railway lines in forests, building dams, or encroaching upon wilderness areas. All this results in irreversible habitat degradation, leading to a reduction in ecological complexity. Added to this, we rampantly trade wildlife for food or for pets despite such activities being illegal under several international laws and conventions such as the CITES (Convention on International Trade of Endangered Species). Such actions expose humans to wildlife contact, providing ample opportunities for a disease to spill over to humans. It is ironic and a matter of profound sadness that the environment ministry of the Indian government, recently cleared several projects which will further fragment forests while in the midst of a lockdown caused by a pandemic which spread because of such actions elsewhere.
The other factor is the burgeoning populations of humans. This has led to the reduction in natural areas and increase in crowded cities and towns. If people do not maintain basic hygiene, diseases will tear through populations and cripple us all. Until and unless we stop damaging the ecosystem, there will always be novel diseases that spill over to humans. Despite this harsh truth, we conveniently blame the bats for our mistakes.
Can bats and humans co-exist?
Bats typically live in deep and dark caves. But they also live in our cities and in ancient temples as long as they can find a dark corner somewhere. Many of the bats we see hanging from trees belong to a group called fruit bats. They congregate in large colonies and at night, they leave the roost, going in different directions in search of food. Similar behaviour is exhibited by other insectivorous bats. They too, roost during the day and leave at night in search of insects. Rohit Chakravarty, a bat-researcher says that “Many
species of bats have lived alongside humans, and in fact, thrived in human-modified habitats. For example, my neighbourhood in Nagpur has small insectivorous bats such as the Pipistrelles hiding somewhere in cracks, crevices or, in pipelines.”
Rohit is a graduate student at the Leibniz Institute for Zoo and Wildlife Research, Germany. “We have always lived with bats and have largely been disease-free. Our most familiar species, the Indian Flying Fox is a reservoir of the Nipah virus. Other species of flying foxes and related species are reservoirs of Hendra virus, Marburg virus, and probably Ebola in Australia and Africa respectively. Nipah is known to transmit through contaminated fruits and plant sap. To co-exist with flying foxes, we simply need to follow basic hygiene rules, including but not limited to not eating fallen fruits and probably also keep pets away from flying fox roosts," he clarified.
Can we live in a world without bats?
Bats are a critical link in ecosystem functioning. They provide us several services, free of charge. Bats are excellent pollinators. Many of the fruit bats visit flowers to suck nectar and end up pollinating several commercial crops such as Mango and Guava. They are also crucial in dispersing seeds. Bats often sally into fruiting trees, take a fruit and fly to a nearby tree where they eat the fruit pulp in peace, dropping the seed down. The seeds eventually germinate and grow into trees.
Some of the commonly encountered species of fruit bats are Leschenault’s fruit bat (Rousettus leschenaultii); greater short nosed fruit bat (Cynopterus sphinx), and Indian flying fox (Pteropus giganticus). Bats also eat insects and pests to crops and the common insectivorous bats are Indian pipistrelle (Pipistrellus coromandra) and Schnieder’s round leaf bat (Hipposideros speoris). Imagine a world without bats? It would be overrun with insects and very little fruits to eat!
What can we do to save bats?
Perhaps the best thing for us to do is simply let bats be. In our rush for comforts, we have forgotten the fact that we do not survive in isolation. Every species on earth forms an important cog in the wheel of life. One place to start is to simply acknowledge the presence of bats and their importance. The next logical step is to learn more about them and share facts to dispel myths. Given a chance, one could also sit and observe them and appreciate their beauty. Indians have a phenomenal tolerance to wildlife and this tolerance needs to extend to bats. Is it that we install a bat-deity, similar to the scores of animals depicted in our places of worship?. If we saw bats as gods and value them for the services they render to us, we might start to respect them, protect them and perhaps, begin to cherish their company.