It would be hard to find someone more enthusiastic about bats than Amy Wray. She’s so fascinated by these winged mammals that she has devoted her academic career to studying and understanding them.
A doctoral student of wildlife ecology, Wray’s expertise lies at the intersection of wildlife diseases and the food web. Her master’s thesis research focused on the feeding habits and pathogens of common vampire bats in Guatemala, and now she’s using next-generation DNA sequencing and other methods to study the diets of insect-eating bats in Wisconsin.
One thing Wray has come to understand through her research is that bats play a vital role in our ecosystem. It wouldn’t function well without them. Despite such a crucial benefit, bats still spook some people out.
Some of that fear stems from bats’ reputation as disease carriers. This concerns Wray, especially in a post-COVID-19 world, because it may lead to needless harm to bats when many species are already struggling with habitat loss and diminished food supply, among other challenges. Here she offers answers to frequently asked questions about bats, their role (and that of humans) in viral outbreaks, and how conservation can be a solution.
Did SARS-CoV-2, the virus that causes the disease called COVID-19, come from bats?
At this point, the origin of SARS-CoV-2 is not totally clear, but several studies have shown that the virus is similar — though not identical — to a virus found in particular species of horseshoe bat. It is possible that an intermediate host (another animal species, possibly an animal that comes into contact with humans more frequently) could also have been involved.
Disease spillover from wildlife is not the fault of the animals themselves, rather, it is often a result of various human activities. For example, animal markets that bring together many wild and domestic animal species that previously have never been in contact with each other can create a situation where a new disease is likely to emerge. Additionally, the destruction or degradation of habitat can cause wild animals to become stressed, to change their movement patterns, or to come into contact with humans more frequently, which also leads to the increased risk of zoonotic disease emergence.
Why do so many diseases come from bats?
There has been a long-standing debate in biology over whether bats are special in their ability to host viruses and other pathogen-causing microbes. When bats fly, their body temperature increases, so some studies have suggested that flight may limit infections in a way that is similar to the fever response in other mammals. Other studies have suggested that bats may have a unique immune system.
However, it is extremely important to note that bats are a super diverse group (there are an estimated 1,411 species as of October 2019), so perhaps it seems like a lot of emerging diseases come from bats simply because there are a lot of different types of bats. Additionally, a lot of research that involves pathogen discovery — including studies searching for novel coronaviruses — tends to focus on bats, so there could also be an element of research bias in terms of which animals are studied more frequently.
Can I get COVID-19 from a bat? Should I be worried if I find a bat in my house?
Not all bat species carry human coronaviruses. Specifically, SARS-like coronaviruses have been most commonly detected among several species in the horseshoe bat family (Rhinolophidae). Horseshoe bats, so-called because they have uniquely shaped noses, do not live in the Americas. Different coronaviruses have also occasionally been found in other bat families (which include some bat species that do live in the Americas), but most of those viruses are not closely related to human pathogens.
We still do not definitively know the origin of SARS-CoV-2 at this time, but it is clear that people are almost always infected with SARS-CoV-2 by other people rather than through direct contact with wild animals. In North America, springtime is upon us, and it’s a common time of year for people to find bats in their house. If you do find a bat in your house, do not touch or handle it. Instead, try turning off the lights and opening a window, and it will probably leave on its own.
Although bats can carry diseases — just like all animals (including humans) — when they are left alone and undisturbed, they are not dangerous. And there is no reason to fear bats. In fact, bats in North America have experienced drastic population declines due to a fungal disease called white-nose syndrome, which was probably introduced to their habitat by humans.
Many bat species also provide important ecosystem services, such as pollinating plants, reducing crop pests, and dispersing seeds, so protecting them has many benefits for humans. Conservation of bats and other wildlife offers an effective and well-documented solution for reducing the risk of zoonotic disease emergence.