So Far, No Silver Bullet to Stop Lethal Bat Fungus
Friday, November 8, 2013
Since its appearance in the U.S. seven years ago, white-nose syndrome has decimated bat populations across eastern North America. Scientists say they've determined the culprit--a soil-dwelling fungus called Pseudogymnoascus destructans--and now they're investigating novel ways to stop it, including antifungal bacteria.
JOHN DANKOSKY, HOST:
Next up, a biological threat that is sweeping across eastern North America from Nova Scotia to Ontario, through the Appalachians and the Corn Belt all the way down to Georgia. It's white-nose syndrome, a fungus that is lethal to bats but not to us humans. Some bat species like the northern long-eared bat have been hit so hard that the Fish and Wildlife Service has now called for their listing as an endangered species.
As those casualties pile up, scientists like my next guests are scrambling to find ways to fight the pathogen, sometimes with the fungus' own natural enemies. Winifred Frick is an adjunct professor of ecology and evolutionary biology at the University of California, Santa Cruz. Welcome to SCIENCE FRIDAY, Dr. Frick.
WINIFRED FRICK: Thank you very much. My pleasure to be here.
DANKOSKY: And Chris Cornelison is a post-doctoral research associate at Georgia State University and the U.S. Forest Service in Atlanta. Welcome to SCIENCE FRIDAY, Dr. Cornelison.
CHRIS CORNELISON: Thank you for having me.
DANKOSKY: If you want to join us, 1-800-989-8255 or 1-800-989-TALK as we talk about white-nose syndrome and the die-off of many, many bats. Dr. Frick, you've been studying the pathogen spread. Give us an idea of how you're tracking it and how extensive it is right now.
FRICK: Yeah. So we have been studying white-nose syndrome since it emerged in Albany, New York. We first know it was here from photographs taken by cavers near House Cave in 2006. Our research team is working in collaboration with biologists from state departments of natural resources and the Fish and Wildlife Service.
And what we've been doing is actually going out to the hibernacula, the caves and mines where bats hibernate through the winter, because the fungus only affects the bats while they're in their hibernacula during the winter, and we actually take a sterile Q-Tip and we swab the wing of the bat and we get a DNA sample from that.
And we take that back to the lab and we do some molecular work called a quantitative PCR that basically detects the DNA of the fungus, of the pathogen that causes white-nose syndrome. And so that's how we've been tracking - our research team has been tracking. Of course, there's lots of people involved with the research effort on white-nose syndrome.
And other ways that biologists tell whether white-nose has gotten to a site includes looking for symptoms like bats with white fungus on their faces and bats that are dying at these caves and mines. And the National Wildlife Health Center actually determines whether white-nose got to a site by doing something called histopathology, by looking at the wings and whether the fungus has actually invaded the wing tissue of bats.
DANKOSKY: Yeah. I was just - go ahead. Please.
FRICK: Go for it. I was just going to say, so then you asked about where it was. So we know that the disease is present in about - in 22 different states across North America and five Canadian provinces. And so that includes the whole northeast corridor down through the Appalachian and mid-Atlantic regions. And it's moving west into areas like Tennessee and as far west as Missouri and Illinois.
We're also now detecting the fungus at those frontier sites where, before we see the disease actually manifest. So we've picked up the fact that the pathogen is far west as Iowa and Minnesota and Arkansas.
DANKOSKY: And in the worst-hit places we're talking about 90 percent die-offs of bats, right?
FRICK: In the worst-hit places we're talking about there are no more bats left at some sites; 100 percent die-offs. But, yeah. Where mortality can range, you know, from averages of 70 to 90 percent. Pennsylvania and Virginia have been particularly hard hit and we're seeing 99 percent declines at some sites.
FRICK: For certain species.
DANKOSKY: Chris Cornelison, you've been investigating a bacterium that might be able to fight this white-nose infection. Tell us about it.
CORNELISON: Yeah. So our lab group here at Georgia State is really interested in one particular bacteria, Rhodococcus rhodochrous, and what we've been able to demonstrate, just some preliminary things in the lab so far, where we're able to inhibit the germination of the fungal spores as well as inhibit the radial growth of the mycelia of the fungus in the lab in a contact-independent manner, which we think is pretty exciting. We're hoping to be able to carry this on a little bit farther and hopefully end up providing some tools for disease management.
DANKOSKY: Are you ready to test it out? How much longer is this going to take?
CORNELISON: So there's a lot of steps you need to go through when you're talking about biocontrol, particularly in the case of natural caves and the karst environment. A lot of people consider these caves to be biological islands, if you will, where they are home to endemic species of plants and animals and microbes. So any time you're talking about going in and augmenting the ecosystem like that, you have to be very cautious because there are going to be all types of unanticipated negative effects.
And so we want to make sure that we're doing our due diligence to avoid any of these possible consequences. So right now in collaboration with the U.S. Forest Service I'm doing some toxicological assessment of the potential impact on the bats themselves with our control agent and then we're going to do some live trials with infected bats in the lab setting in an artificial hibernacula.
And then, depending on those results, we are going to assess the next step which right now we're looking at something like more similar to real world but not fully out in the environment - something like a converted bunker or an abandoned mine. Something that's not a truly natural cave but will give us a better idea of how this biocontrol agent will translate into the natural environment.
DANKOSKY: I'm John Dankosky and this is SCIENCE FRIDAY from NPR. Dr. Frick, I know one of your grad students is working on a similar project to this, right?
FRICK: That's correct. Yeah. I actually have two graduate students working on this. I have a master's student, Joe Hoyt, who's done some really phenomenal work. Joe has actually worked at the Department of Environmental Conservation in 2006 and 2007 when white-nose syndrome was first discovered. And based off some preliminary work that he did there, he actually discovered that there is a beneficial bacteria that already occurs on the wings of bats, and that it actually - from some preliminary work that he's been doing over the past year in the lab - that it inhibits the growth of the fungus that causes white-nose. So we're actually starting to do some live infection trials as well this fall to test this out, to see if we can augment the microbiome of bats' wings with this beneficial bacteria and see if that can help bats survive infection.
DANKOSKY: We just have a few seconds left, but this fungus has been around in Europe for a lot longer than America. How are the bats over there doing?
FRICK: They're actually doing OK. So, yeah, the fungus is common throughout different species and throughout Europe. And the bats there seem to be able to manage. We don't see massive mortality in Europe the way we see here, but we know that it's the same fungus and then if you put that fungus on our North American bats they will die.
DANKOSKY: Is there anything that people can do to help out if they want to help the bats, Dr. Frick?
FRICK: Absolutely. You know, so there's two really great organizations that people can become members of and they also have funds for donating for supporting white nose syndrome research. Those are Bat Conservation International, which is based in Austin, Texas and the Organization for Bat Conservation, which is based in Michigan.
And both those groups have funds that people could donate money to help support research so that we can try to find treatment and find out as much about this disease as possible, because learning more about it is what's going to help us solve this problem.
DANKOSKY: Dr. Winifred Frick is an adjunct professor of ecology and evolutionary biology at the University of California, Santa Cruz. Thank you so much for joining us.
FRICK: My pleasure.
DANKOSKY: And thanks also to Chris Cornelison, a post-doctoral research associate at Georgia State University and the U.S. Forest Service in Atlanta. Thank you very much.
CORNELISON: My pleasure.
DANKOSKY: One last note before we go today. Clifford Nass, an expert on multitasking and human-computer interactions at Stanford University, died of a heart attack last weekend near Lake Tahoe. Nass was a SciFri alum and we last had him on the show this spring during a live broadcast from Stanford. Here's a clip from that interview.
(SOUNDBITE OF ARCHIVED INTERVIEW)
CLIFFORD NASS: People who multitask all the time can't filter out irrelevancy. They can't manage their working memory. They're chronically distracted. They initiate much larger parts of their brain that are irrelevant to the task at hand, and even - they're even terrible at multitasking. When we ask them to multitask, they're actually worse at it. So they're pretty much mental wrecks.
(SOUNDBITE OF LAUGHTER)
IRA FLATOW, HOST:
NASS: The problem with multitasking is not that we're writing a report on Abraham Lincoln and see pictures of Abraham Lincoln and read words of Abraham Lincoln and see photos of Abraham. The problem is we're doing a report on Abraham Lincoln and tweeting about last night and watching a YouTube video about cats playing the piano, etc. That's where the detriment comes in.
It's extremely healthy for your brain to do integrative things. It's extremely destructive for your brain to do non-integrative things.
FLATOW: So are you fearful about us losing contact with what real life is once these things happen?
NASS: I'm fearful and optimistic. Fearful because technology, media technologies in particular, are incredibly seductive. But optimistic because humans are pretty cool and seem to work their way out of things.
DANKOSKY: That's the late Clifford Nass, communications professor at Stanford. He died at the age of 55, and he will be missed by all of us at SCIENCE FRIDAY. Transcript provided by NPR, Copyright NPR.View this story on npr.org