A little brown bat afflicted with white-nose syndrome. Image credit: Wikimedia Commons
Since 2006, bat populations in the northeastern United States have been decimated by a mysterious condition known as "white-nose syndrome." Caused by a fungus, Geomyces destructans, the syndrome occurs after hibernating bats develop the powdery-white fungal coating around their nose and on their wings. Victims wake and fly from the cave, burning precious fat stores and eventually starving to death.
The syndrome has lead to 90 percent or greater reductions in hibernating populations in some caves and for many species researchers have resigned themselves to predictions of extinction. New reports from Europe, however, indicate that bats across the Atlantic have found a way to live with the fungus without developing the deadly syndrome.Currently, reports from eight countries in Europe have described bats with white mold on their wings and muzzles and four countries—Hungary, Germany, Switzerland, and France—have identified the mold as Geomyces destructans. Despite the presence of the fungus, however, bats in these countries remain healthy.
Complicating matters further is a 1983 report that includes a photograph of a bat in Germany with a "powdery white substance around its muzzle." It goes on to say that several such bats were observed in caves during surveys. If it is, in fact, Geomyces destructans it means that European bats had been contending with the fungus for at least 23 years before it made its first appearance in the United States.
A little brown bat sleeping. Image credit: tuchodi/Flickr
David Blehert, a microbiologist at the US Geological Survey's National Wildlife Health Center, explained:
It will be interesting to see what the situation is in two to three years from now...if the fungus they're seeing now is the same fungus that was anecdotally documented three decades ago, it does suggest that while Geomyces destructans occurs in Europe, white-nose syndrome may not.
Blehert, who led the team that first described the fungus, said that bats in Europe may have coevolved with Geomyces destructans, allowing them to develop an immunity. The absence of white-nose syndrome could also be the result of behavioral differences: European bats tend to hibernate in small groups—with rarely as many as 100 in a single cave—while bats in North America hibernate in groups that number in the thousands or hundreds of thousands.
European Immunity Could Lead to a Vaccine
If European bats have developed immunity to white-nose syndrome, it could help researchers find a way to save bats in North America. One solution would be a vaccine, though this could be too difficult to administer to individual animals.
Other researchers have investigated the use of a spray that could be applied to caves before or during hibernation periods. There is fear, however, that such an application could kill other essential fungi present in caves.
One other approach would involve introducing engineered bacteria that could live on bats and protect them from the fungus.
Whatever method proves finally proves viable, it will have to be refined quickly if it is to have an impact. Every year, more bats are lost and the area affected grows. With some species producing just a single offspring every breeding period, the opportunity for populations to rebound is small.
Indeed, the fight to save northeastern bats is a race against the clock and, even in light of this optimistic news from Europe, time has nearly run out.
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