Before entering the second enclosure, Fontaine changes into fresh gear to avoid any contamination. Here, the real work awaits. Another 10 bats live here, who not only need to be fed and watered but also have their wings swabbed. This group of bats is being trialled with the probiotic cocktail that Cheeptham and Xu developed. It’s Fontaine’s job to see if the probiotic can survive on living bats.
For the summers of 2018 and 2019, Fontaine lived and breathed this trial, driving to and from his home in Kamloops and the B.C. Wildlife Park on the outskirts of town each day to care for the animals.
“It was a lot of responsibility,” he says. “I didn’t want to let anyone down.”
To apply the probiotic onto bats, the team eventually settled on the idea of mixing the bacteria into sterile water or combining freeze-dried probiotics with clay and spraying it into bat boxes. Once it is in the bat boxes, it transfers onto the bats themselves, merging with the bacteria that naturally live on their skin. Then, Fontaine (along with the team’s advising veterinarians) could monitor and test the bats to ensure that the probiotic was safe for the animals. No adverse effects were found.
In September 2019, Fontaine began testing the probiotic on hibernating bats. The research team didn’t have the money to purchase a specialized hibernation fridge, so Cheeptham went to Costco and bought a wine cooler. Setting its temperature to five degrees Celsius and its humidity at 90 per cent, Fontaine installed a camera so he could keep an eye on his test subjects, then put several Yuma myotis in the fridge. He then slowly took away their food, forcing the bats’ instincts to kick in. “Like, ‘Hey, I can’t scavenge any more food. I need to hibernate,’” said Fontaine.
It turned out that the cool and moist environment that bats hibernate in was also the environment in which the probiotic thrived. Not only did it stay on their wings, but it also reproduced. This meant that if bats have the probiotic on their bodies going into hibernation, even if it was just a small amount, it has the potential to increase. The probiotic was showing promise as a defence against white-nose syndrome.
It was time to see if it would work in the wild.
At the same time that Fontaine was carrying out his trials, Leah Rensel, a grad student at the University of British Columbia Okanagan, was establishing baseline data for five little brown bat and Yuma myotis communities in the Greater Vancouver area, including at Alice Lake Provincial Park. In August 2019, the team sprayed their first maternity roost (a bat box where bats spend the summers raising their young) with the probiotic. The following year, COVID-19 caused a snag in their field work, because they needed to ensure that they didn’t introduce the virus to B.C.’s bats. But the project was too urgent to stall for too long.
“We just kept thinking, ‘At any moment, white-nose syndrome fungus could show up in the province,’” said Lausen. When going into the field, bat biologists masked up, took COVID antigen tests, and could no longer carpool to the field sites. A few months later than they would have liked, they sprayed all five sites with the probiotic.
Work was back on track the following year. Each spring since, the team has sprayed three of the five (two are control sites) summertime colonies’ roosts with the probiotic. Every year, the swabs the researchers (including Mithcell and Currie) collected have confirmed that bats have flown off to their winter hibernating spots with it on their bodies. These same bats have not yet tested positive for white-nose syndrome, nor has the fungus been found in these sites.
In the east of North America, Lausen said that white-nose followed a predictable pattern. “You get the fungus. Within two years, you’ve got the disease. And within another year, you’ve got a mass die-off. That’s not at all the pattern we’re seeing here,” she said.
But this isn’t yet a cause for celebration.
The threat of the fungus has made it clear how little is known about bats. Before white-nose hit North America, bat populations were stable. With their survival taken for granted, little funding was available to research these animals. As a result, basic knowledge about bats, such as how the same species vary across ecosystems, why their immune system staves off most viruses, or even where they roost in trees is poorly known. If humans hope to understand how these animals are affected by anthropogenic changes beyond the white-nose crisis, says Lausen, this knowledge is needed.
Bats face a multitude of threats: forestry clears away important bat habitats, wind turbines built in migratory pathways have put some species at serious risk and increased pesticide use and insect decline is also a substantial—though not yet measurable—threat.