Volume 35
Issue 2
Little brown bat with WNS 0046734 Credit Michael Schirmacher
Symptoms of White-nose Syndrome include white fuzzy growths of the
Pseudogymnoascus destructans fungus as seen on the chin of this little
brown bat. Photo: Michael Schirmacher

Looking back, I can remember exactly where I was when I saw the first images of what would come to be known as White-nose Syndrome (WNS). I was sitting in a computer lab at the Smithsonian Tropical Research Institute in Panama. It was the dry season in the tropics, but winter in North America. Those first images came through a few different email strings. Each email asked, Does anyone know what this white, fuzzy growth is? After scanning the comments, I remember squinting at the photos and quickly disregarding them. I didnt know what that growth was, and the problem seemed half a world away from me. And at the time, it was. Little did I know, almost 10 years later, WNS would be such a big part of my life. The first photos of WNS are from 2006. With the devastating news that the disease has jumped from the east coast to the west, recently having been confirmed in the state of Washington, its time to reflect on what weve learned, where we are now and where we need to go.

When White-nose Syndrome (WNS) first emerged in New England, the fungus didnt even have a name. We didnt know if it was a native fungus that mutated to cause this destruction, or if it came from someplace else. We now know that WNS is caused by the cold- loving fungus, Pseudogymnoascus destructans. The fungus is not native to North America and was accidentally introduced here. European researchers, with the support of Bat Conservation International (BCI), have been using genetic techniques to determine where this fungus came from. Last year, we learned that the fungus most likely came from Western Europeperhaps France, or Germany, or Luxembourg.

More astonishing, this year, we learned that the fungus is present not just in Europe, but in China as well. Since European and Asian bats have not suffered the devastating population declines that our North American bats have, it appears that the fungus has been present there for millennia. Consequently, it is likely that Eurasian bats have evolved a resistance to WNS over that time.

When we first started seeing dead bats at hibernation sites, we didnt know if WNS would affect all of our bats or not. Now, we know that WNS affects different species of bats in different ways. Today, the disease has been confirmed in seven species of hibernating bats. Five additional species have been confirmed for the fungus, but have never developed the disease. Three species of bats appear to be most sensitive to WNS: the little brown bat (Myotis lucifugus), the northern long-eared bat (Myotis septentrionalis) and the tri-colored bat (Perimyotis subflavus). These three species of bats bear the brunt of the devastation from WNS, suffering population collapses across their ranges. Other species, such as the big brown bat (Eptesicus fuscus), the eastern small-footed bat (Myotis leibii), and the endangered Indiana bat (Myotis sodalis) are also impacted by WNS, but not to the same degree. And there are surprising anomalies. The endangered gray bat (Myotis grisescens) can develop the disease, but doesnt appear to suffer fatalities. Clearly, we still have much to learn about the subtleties of WNS.

In the early years, everyone felt helpless. This fungus, this disease, was destroying our hibernating bats, and it seemed there was nothing we could do. But a few years ago, we became more hopeful. BCI began to focus our support on potential treatmentstools that controlled the growth of the fungus. The first treatment that BCI fundedthe naturally-occurring fungus Rhodococcus rhodochrous DAP 96253continues to show promise in its development. Researchers at Georgia State University and the U.S. Forest Service have conducted treatment trials on bats in the lab and in the field in Kentucky and Missouri. The trials are ongoing and the data are being analyzed. We hope the efficacy in the field is as positive as the efficacy in the lab environment.

In 2014, BCI and the Tennessee Chapter of The Nature Conservancy (TNC) supported a truly cutting-edge research project. The U.S. Forest Service is investigating the use of gene silencing to control the effects of WNS. The approach uses gene finding and gene editing techniques to downregulate the genes (i.e., to decrease the production of specific gene products) that are so destructive to our bats.

This [gene editing] technology gives us the ability to understand the pathogen better than ever before, said Dr. Daniel Lindner, a mycologist and principal investigator for this line of research. Once we understand at a molecular level how this fungus causes WNS, it will give us a chance to design tools to help defeat the fungus. Our ability to understand exactly how pathogens cause disease is one of the most powerful weapons we have against diseases like WNS.

Last year, BCI and TNC selected another promising treatment tool to test: a naturally-occurring probiotic. Initial laboratory research showed it could reduce WNS lesions and mortality. Now, it is being tested in the field in Wisconsin. The research proposal came from a team at the University of California, Santa Cruz and included BCIs new Senior Director of Conservation Science, Dr. Winifred Frick.

Finding treatment solutions for WNS is very challenging, but is urgently needed, said Frick. Field trials that test whether we can find ways to help bats with WNS survive through the winter is an important step toward protecting bats from the devastating impacts of this disease. When the stakes are as high as possible extinction, we have to get creative and try our best to find solutions.

There is currently no silver bullet for improving bat survival from WNS. It is critical that we develop several tools in our toolbox to fight against this disease. Multiple tools will be needed, given that so many different species are impacted by WNS, and impacted in different ways, across a large landscape.

White-Nose Syndrome
A northern long-eared bat carcass shows evidence of White-nose
Syndrome. Photo: Michael Schirmacher

WNS, or the fungus, are now present in 31 states and five Canadian provinces. In the last month, it has leapt from the Midwest to Washington state. The Washington specimen has been confirmed as a local bat, which indicates that we humans are most likely responsible for its recent spread. We must redouble our commitment to decontamination, especially in our Western states. We need to focus on minimizing the spread of this fungus, increasing surveillance and ramping up our investment in potential treatments.

The next few years are critical in our fight against WNS. The establishment of this new epicenter now threatens up to 16 Western bat species. New strategies in the fight against WNS must be developed and implemented. It is more important than ever that we create and deploy tools that minimize the impact from WNS. Looking ahead, I hope the steps weve taken to combat WNS are not in vain. Decades from now, I hope that our work will keep the night skies alive with the bats we are passionate about protecting