Bats and COVID

COVID-19 is a zoonotic disease. For the 200+ bats currently in wildlife rehabilitation facilities across Pennsylvania, this presents a threat. Eman Anis, a microbiologist with Penn Vet’s New Bolton Center, is leading a study to test for the presence of SARS-CoV-2 in North American bats, work being done with associate professors Lisa Murphy and Julie Ellis and Pennsylvania Game Commission biologist Greg Turner. 

Because the School of Veterinary Medicine and the Pennsylvania Game Commission began collaborating in 2019 on the Pennsylvania Wildlife Futures Program to address wildlife health problems, they were able to shift quickly to COVID-19 research. Now, the team is developing a rapid diagnostic test using bat guano sent from local wildlife rehabilitation centers. 

The researchers’ goal is to verify that bats held over the winter in rehab facilities will not transmit disease. “When you do these tests, you’re trying to ask questions,” says Murphy. “Can bats harbor it? Do bats in Pennsylvania harbor it?”

Testing the guano of North American bats for COVID-19 ties into Penn Vet’s One Health focus, which recognizes that human, animal, and environmental health are interrelated and that an adverse event in any one of these areas may also adversely impact the others, Murphy says. “With disease, humans, animals, and the environment can all play key roles in transmitting and maintaining harmful pathogens. Identifying the role that each plays can be the first step in understanding how to stop or prevent further harm,” she says.

There is no evidence that North American bat populations currently harbor COVID-19 or other beta-coronaviruses like MERS and SARS, but there is a possibility that humans could transmit disease to bats, Anis says. This would present a public health risk and is one of the impacts her study will mitigate. “We don’t want have another reservoir where they can transfer it back to humans,” she says. 

COVID-19 has the potential to weaken the already precarious health of bat populations, says Turner. Bats have been his main focus for 16 years as populations have declined due to habitat loss and white-nose syndrome, a fungus originating in Europe that thrives in the cold, humid caves and mines that bats use for hibernation. 

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Pennsylvania is home to nine species recognized as resident breeding bats, according to the Game Commission. As bats are able to be a reservoir for most coronavirus strains, they are likely to contract COVID-19 if exposed, Turner says. While the animals are generally able to survive a dormant coronavirus, many North American bats are already stressed due to white-nose syndrome. This presents the risk that the virus would become active and cause an additive mortality factor on top of white-nose syndrome, which has decimated many bat species. 

The Indiana bat is currently the only mammal on the federal list of endangered species in Pennsylvania. “We’re turning the tide, seeing stabilization and maybe even a recovery,” Turner says. “To have something come in now could be catastrophic to these species. What would happen if the bat was immunocompromised from white-nose fungus, would COVID-19 be an additive affect?” 

While bats are often vilified in popular culture, Turner says “they provide numerous services we would miss if they were gone,” he says. “All of the bat species in Pennsylvania and the northeastern part of North America are insectivorous, so they’re eating nothing but insects. Each female little brown bat can consume 4,500 mosquito-sized insects per night.” Bats consume an estimated 900,000 to 1 million insects per bat per year, says Turner, saving Pennsylvania farmers alone an estimated $3 million per year in crop damage and thus reducing the cost of production and the amount of pesticides used. 

By eating insects, bats also prevent the spread of mosquito-borne diseases such as heartworm, encephalitis, West Nile virus, and potentially Zika virus, Turner says. “We also have anecdotal evidence of people in wetland areas that were constantly battling mosquitos until they put up a bat box and had a colony of bats,” he adds.  

Bats are important to agriculture and to the ecosystems they live in, “and they’re already under a considerable amount of pressure,” Murphy says. 

The New Bolton Center team began work on this project at the end of April, and Anis says the team is “very confident that we’ll be able to complete and validate the test and have it up and running soon. Our first goal is to help the rehab populations to release their overwintered bats, and we hope to expand beyond that.” 

The lab, which generally tests diagnostic samples, began guano testing during the pandemic. The team practice “all the needed biosafety and biosecurity measures and follow all of the CDC guidelines,” says Anis. It’s a big challenge she says to work with this “new normal” and being isolated. Having a purpose has helped.

While the current study is targeted to a very specific population and need, it has larger implications, says Murphy. “Why does this matter now? We have an immediate need,” she says. Most wildlife rehabilitation facilities are staffed with volunteers and funded via donations. During the pandemic, most are operating with a skeleton crew and limited financial resources, continuing to feed and care for overwintered bats that are ready to be released into the wild. “To the specific populations of bats in Pennsylvania and people who are caring for them, it really does matter, it matters now, and we have no data” to inform their decisions, Murphy says. “We’re going to address a very specific need, but, in terms of where it can go from there, the ramifications and the benefits, this is only the first step,” Murphy says. 

“In terms of thinking about what animal species may be susceptible to this virus, it doesn’t just stop with bats,” she says, citing evidence that weasels and ferrets are able to contract COVID-19, as can other animals. “This disease is going to be with us, and is going to be a question and a concern for human and animal health for quite some time,” she says. 

Eman Anis is an assistant professor in pathobiology at the University of Pennsylvania School of Veterinary Medicine. 

Julie Ellis is an adjunct associate professor in pathobiology at the University of Pennsylvania School of Veterinary Medicine.

Lisa Murphy is an associate professor of toxicology and director of the Pennsylvania Animal Diagnostic Laboratory System-New Bolton Center at the University of Pennsylvania School of Veterinary Medicine.

Greg Turner is a wildlife biologist with the Pennsylvania Game Commission’s Bureau of Wildlife Management.

This study was made possible with support from the National Wildlife Health Center in Madison, Wisconsin.