For Southeastern Magazine’s Spring 2020 issue, we sat down with Assistant Professor of Biological Sciences Dr. Teague O’Mara to discuss his extensive research on bats—including their movements and impacts on ecosystems and people. Since that short time ago, the rapid rise of the COVID-19 pandemic has ushered in a wave of questions and concerns over the potential link between the virus’s origins and these small flying mammals.
To address this, we asked O’Mara to explain from a scientific standpoint the real connection between bats and COVID-19.
While there are a lot of uncertainties about COVID-19, the origin of this virus is commonly thought to be from bats. But is this necessarily true?
At the outset of this current pandemic, scientists were able to quickly and effectively sequence the genome of the SARS-CoV-2 virus that causes COVID-19. Thanks to broad efforts by the One Health Institute, the CDC, WHO, and others that have tried to document different types of viruses across the world, we’ve found the most closely related virus. This virus was isolated from an insect-feeding horseshoe bat and
called RaTG13.
These two viruses separated from each other approximately 50 years ago. This means that despite its recent outbreak, SARS-CoV-2 didn’t appear overnight; it has been spending time in another species since it left bats and before it infected humans.
SARS-CoV-2 didn’t jump directly from bats to humans, but we don’t know what the intermediate host is yet. It is curious that the spike protein that lets the virus enter human cells is much more similar to a coronavirus from a Malayan pangolin (a relative of the armadillo and anteaters) than any other bat virus, even though the entire SARS-CoV-2 genome is more similar to the bat virus. So, the origin of COVID-19 is still under active investigation.
But why are the new viruses that seem to have massive effects on humans so closely associated with bats? Recent work has shown that bats don’t necessarily harbor more viruses than other animals. There are over 1,400 species of bats (25 percent of all mammals), and the number of viruses any group of mammals has is proportional to the number of species in that group.
Bats are often linked (sometimes very weakly) to outbreaks of new infections. This is likely because bats have supercharged immune systems. They are able to master a wide range of infections, largely due to their ability to minimize their inflammatory response and seek and destroy DNA damaging free radicals in a way that no dose of antioxidant foods could even come close to handling. This makes understanding their immune systems and inflammatory control incredibly interesting to try and harness the molecular mechanisms they’ve come by naturally for our own health. It is also why we find antibodies that show bat immune systems have seen the virus, but there are no actual active viruses. Viruses that find their way into bat species and do manage to make a living must compensate for this incredible immune system.
Occasionally when a virus manages to escape from bats into an intermediate host, amplify and mutate, and then come in contact with humans, these zoonotic infections can be dramatic because we have not had a long evolutionary history with the virus. Measles, which had its origins in a cow virus, is one such virus that is well known.
Regardless of which animal species a zoonotic virus comes from, when viruses jump from animals to humans it’s almost always because of humans encroaching on them, not because they have invaded our space. Bats control our pest insects, pollinate the plants that give us tequila, and disperse seeds across the landscape—all for free. The incredible adaptations of their immune systems might also give us answers to longer, healthier lives. But to allow all of this to happen, it is important that we take care in how we treat them and provide them with enough space to do their work.
