A big brown bat, which is used an ambassador at the Center for Wildlife in York because it has permanent injuries, is one of the bats from the center used in the Tufts study. Photo courtesy of the Center for Wildlife

Many scientists believe the coronavirus pandemic originated with a bat in China. But in a twist, biologists in Maine and New England are more concerned about bats contracting the virus from humans.

That is why four Maine wildlife rehabilitation centers this fall joined others across New England in sending samples from injured bats to the Cummings School of Veterinary Medicine at Tufts University in Boston, to help researches there better understand the potential for human-to-animal transmission of the virus.

Using samples from bats around the Northeast, Tufts researchers are trying to understand whether bats and other animals can contract COVID-19 from humans. The threat to bat populations in North America could be catastrophic, said Kaitlin Sawatzki, the Tufts animal surveillance coordinator working on the coronavirus epidemiological research and surveillance study.

As of mid-December, Tufts had tested 235 wildlife animals representing 24 species. But bats are the focus because of a dramatic decline in their numbers in the Northeast due to white-nose syndrome. So far, Tufts has tested 188 bats, including 19 from Maine.

Tufts also has tested 842 domestic or agricultural animals representing 14 species.

All the wildlife tests searching for active or very recent infections came back negative. There were positive antibody tests from domestic pets, but none from wildlife tests. (So far, no Maine domestic animals are part of the study.)

According to the U.S. Centers for Disease Control and Prevention, the novel coronavirus first appeared in China and may have been passed to a person from an animal sold at an open-air market. But many biologists believe it may have started earlier – and was first passed from a bat in China to an animal that later was sold at such a market.

“You hear a lot that people are scared of bats in New England, that they’ll give them COVID,” Sawatzki said. “That is not the risk. It’s much more a danger to the bats.

“Bats are almost certainly the origin of this virus. But it’s not yet known if (North American) bats are able to be infected at all. But even if there’s a low probability of transmission, the risk to our bat populations could be huge because they are already struggling with white-nose syndrome. It could be brown bats are totally resistant – we would love to know that. On the other hand, maybe they are susceptible.”

White-nose syndrome, caused by a fungus, which was first discovered in New York in 2006 and in Maine in 2011. White-nose syndrome has caused bat populations across the Northeast to decline as much as 90 percent, according to the Maine Department of Inland Fisheries and Wildlife.

Wildlife Specialist Sam Cox at the Center for Wildlife uses COVID-19 personal protective equipment as she checks on an injured little brown bat that recently was found by the side of a road. Photo courtesy of the Center for Wildlife

Bats play an important role in balancing ecosystems. Because bats feed on mosquitoes, they help prevent mosquito-borne illnesses such as West Nile virus or Eastern equine encephalitis. Bats also provide pest control for farmers. For example, the more than 1 million little brown bats in the Northeast that died from white-nose syndrome would have removed between 700 and 1,300 metric tons of insects annually, according to DIF&W.

Even though a relatively small number of people handle bats, most being biologists or wildlife rehabilitators, Sawatzki said humans pose a significant threat to bats because they’ve played a part in spreading white-nose syndrome by carrying the fungus from bat colonies on their clothing and shoes.

“Humans and bats overlap in a lot of spaces, even in rural and urban environments,” Sawatzki said. “In many parts of New England, bats live in man-made structures and dwellings, from old barns to home attics. Anytime we share space, even when we don’t want to, there is an unknown risk of reverse zoonotic transmission.”

Because wildlife rehabilitators have unusually close contact with bats, these wildlife professionals are being used in the study to show if bat populations face an even greater risk during the pandemic. 

Shevenell Webb, Maine’s furbearer and small mammal biologist, said that the species of bats in China are different from the roughly 40 species in the United States, including the eight species in Maine.

“You can’t assume that the bat that carried the coronavirus in China is the same as the bats here,” Webb said. “But we don’t know if it’s a credible risk. And the populations already are impacted by white-nose syndrome and are susceptible to further decline if it’s susceptible to the disease. It’s a possibility.”

At the outset of the pandemic, DIF&W suspended researchers and wildlife rehabilitators from handling bats, in order to protect the bats. The state revamped protocols used by wildlife rehabilitators handling bats, and this summer allowed just four rehabilitation centers in Maine to care for injured bats. Work on bats by researchers was completely suspended and is currently under review.

In June, Tufts began to test samples from bats, with most coming from Vermont and Massachusetts. Soon thereafter, four Maine wildlife rehabilitators in York, Limington, Auburn and Mount Desert joined the study, by agreeing to send swab samples from bats and rehabilitators to Tufts to test for the virus. 

Researchers elsewhere have found that dogs, cats and other animals in captivity, such as tigers and lions, can contract the virus. But Sawatzki said it’s unknown if domestic animals or those in captivity with the virus can pass it to humans.

A COVID-19 infection was found recently in a wild mink in Utah – presenting one of the first observations of natural infection in a wild animal in the United States, Sawatzki said.

As of Friday, the Center for Wildlife in York had submitted 10 bat samples to Tufts, including six injured bats and four ambassador or non-releasable bats. The negative tests were a good sign for the rehabilitators.

“That’s excellent news because it means the precautions and protocols we’re taking to help protect the bats from possibly contracting the virus are working,” said Karen Lesinski, the center’s senior wildlife specialist.


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