How Can Bats Carry So Many Viruses?

Written By: Angela Hu

Scientists think the current coronavirus originates from bats – in a comparison of genetic sequences, the virus and horseshoe bats have a 96% match. Bats also carry 130 other viruses, yet they never seem to be affected. Why not?

Turns out, it has to do with how bats are the only flying mammal. Their body temperatures will spike and their heart rate speed up during flight, and their immune systems deal with this stress by making special molecules to repair cell damage. This gives them very strong immune systems. Bats also don’t overreact to infections, meaning they are less likely to become ill. 

In a new study, scientists used cells grown in a lab to study viruses. They found that when two bat viruses infected monkey and bat cells, the monkey cells were completely destroyed while more of the bat cells survived. Using mathematical simulations, they also found that viruses in bats have a high rate of cell-to-cell spreading. This means the virus can more easily combat the quick defences and antiviral properties of bat cells. In humans, where we don’t have an as strong immune system, these viruses cause great damage. 

Not only can viruses easily pass between bats as they group in huge colonies, but bats can live for more than 30 years. Bats and humans have a lot of contact. Scientists think that insect-eating bats were the source of the Ebola outbreak, which is just one example of the impact they can have on humans. However, it is important to remember that bats are important. They eat insects, pollinate plants, and do other vital tasks.

Moving Forward

We can’t immediately create drugs or vaccines for the many different pathogens, so we should study interactions between bats and humans to see how we can stop contagion. For example, humans in bat’s habitats can cause stress. This can lead to more saliva and waste which carry viruses, which is why conservation is important.

For the future, I think it will be interesting to see if we can find similarly strong immune systems in animals such as rodents. In addition, how will scientists be able to learn from their immune systems? Perhaps one day, we will no longer be as affected by bat viruses.