When Sick, Bats Isolate

With the COVID-19 pandemic, we have all gotten used to staying home when we feel even slightly sick to keep others safe. We isolate ourselves both for our own good and to protect others. However, a growing concern, given COVID-19’s origin in bats, is whether other mammals, specifically bats, have similar behaviors when sick. According to a recent study led by Kelsey Moreno at Tel Aviv University, the Egyptian fruit bat does have similar sickness behaviors as humans. That is, when sick, they are less active and tend to avoid others.

Egyptian fruit bats are highly social bats that sleep together in clusters during the day. To study whether sick bats change their behavior to avoid transmission, researchers injected bats with lipopolysaccharide, a toxin produced by bacteria that causes an immune response, and tracked the bats’ behaviors. Researchers found that sick bats had a fever and lost weight. They also found that these bats avoided sleeping with the cluster of healthy bats, which they speculated could be to prevent three possibilities: 1) transmitting the disease to other bats, 2) becoming too warm from the bat cluster, which could increase fever, and 3) jostling from the other bats, which could disturb sleep. In addition, the sick bats ate less and did not go out to forage even though healthy bats normally forage every night. This could again either be to avoid transmission to other bat colonies or to preserve energy and rest. 

By studying Egyptian fruit bat sickness behavior, we have gained further insight on what other mammals may do when sick. This study has demonstrated that sick bats will avoid sleeping with healthy bats, but it is still unclear whether this behavior is because the bats are actively trying to prevent transmission or because they are trying to improve their own comfort. Future research will focus on directly assessing which of the speculated possibilities are the true underlying reasons behind these observed behaviors.

Kelsey Moreno is a postdoctoral research fellow at Tel Aviv University. She is currently working with fruit bats and is interested in studying how animals live and interact with one another.

Managing Correspondent: Jenny Zheng

Press Release: https://phys.org/news/2021-06-sick-social-distancing-outbreak-epidemics.html phys.org

Original Article: https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/nyas.14600 Annals of the NEw York Academy of Sciences

Image Credits: https://pixabay.com/photos/flying-dog-zoo-bat-vampire-wing-2623277/?download Pixabay