Fighting a disease in bats

Mar 29, 2012

This week, we’ll hear about a devastating disease afflicting bat populations across the country, and learn about the hazards of ignoring the issue. KBIA’s Kyle Deas followed two researchers working on stemming the spread of the disease, and has this story. 

I’m standing in the mouth of a cave in mid-Missouri; I can’t t tell you exactly which cave. I’m with two cave biologists from the Missouri Department of Conservation: Tony Elliott and Shelly Colatskie. 

We’re wearing these makeshift hazmat suits that look like a supervillain costume put together by a kid for Halloween: a disposable blue jumpsuit, dishwashing gloves, knee-high rubber wading boots and a helmet with a lamp on it.

Inside the gate the cave widens into a high-ceilinged chamber, and in the cracks in the roof are bats. Tony and Shelley get to work.

So, why are we in this cave? Why the gate, and the secrecy? And why the makeshift hazmat suits?

The answer to those questions is all the same: white-nose syndrome. White-nose syndrome is a disease that’s been quietly decimating bat populations for the last five years. It’s caused by a fungus, geomyces destructans, that found its way - probably on the boot of an avid caver – from a cave in Europe to a cave in Schoharie County, in upstate New York, where it was first discovered in 2007.

From that one cave in New York the disease radiated relentlessly outward: first to the rest of New England; then into Pennsylvania and north into Ontario and Quebec; down along the Appalachians to North Carolina and Virginia; then over to the cave-rich Tennessee, Kentucky, and Missouri. Though no bats have yet been confirmed to have the disease in Missouri, the fungus has been found at several cave sites.

White-nose manifests as a growth on the muzzles and wings of bats. The discomfort of the fungus causes bats to wake too frequently from hibernation, and they starve. Or fly out of the cave into weather far too cold to survive.

Ann Froschauer works for the US Fish and Wildlife Service. She’s the national communications coordinator on white-nose syndrome. Part of her job is to visit caves hit by white-nose, where the mortality rate is often as high as 95 percent.

“It’s not a very pleasant sight. Aside from just the physical appearance of the fungus growing on the bat’s wings and muzzles, there seems to be some impact to the neurological systems as well,” Froschauer said. “So oftentimes these bats are behaving very oddly. They’re crawling around on the snow and ice and on the rocks. It doesn’t seem to be a pleasant quick way to die.”

So, the cynical question here is: why should we care? Bats are not the most lovable of creatures. So what’s in this for us?

Well, there’s the obvious answer – that it’s tragic to see yet another species vanish from the planet, right in front of our eyes, for reasons we imperfectly understand and cannot control. 

But there are other, more selfish answers, too.

Justin Boyles is a researcher at the University of Tennessee, and has been studying the economic impacts of white-nose syndrome for the last few years. According to him, bats play a little-recognized role in pest control.

“They are basically the only natural predators on nighttime flying insects. Most crop pests are nighttime flying insects, or have some life stage where they are a nighttime flying insect,” said Boyles. “So really, short of pesticides, bats are the only control on a lot of those pests.” 

Putting an exact number on the economic impact of white-nose is tough. Because we never had accurate counts of bat populations before the disease, it’s tough to know what impact their disappearance would have.

The estimates of how much white-nose could cost farmers range between 3 and 50 billion dollars a year. Boyles thinks it’ll be somewhere in the middle – maybe $20 billion a year, taking into account both the amount that farmers would have to spend on pesticides and the value of the crops they could lose.

“When you look at the numbers at a local scale, they’re not huge,” said Boyles. “But when we extrapolate them to the millions of acres of cropland that were talking about, the numbers get pretty big, pretty quickly.”

What’s more, Boyles says that due to the slow reproductive rate of bats, it could take hundreds of years for their populations to rebound

So let’s go back to that cave in mid-Missouri, and to those questions I asked at the beginning of this story. We’re in the cave looking for the bats infected with white-nose. The gate is there to keep intrepid cavers from spreading the fungus, and the secrecy is to keep them from trying to get past it. And the hazmat suits are the last inadequate defense against the disease, an acknowledgement that if we can’t cure white-nose, we might at least be able to slow its spread.

Luckily, the bats in this cave look normal. But listening to Elliott and Colatskie, it’s tough to see them as anything less than sentries in the watchtower, waiting for an invasion they absolutely know is coming.

“It makes us happy that it’s not here yet,” said Elliott. “We still expect it to arrive. It’s not moving as quick these last two winters as we thought it was going to. It gives us more time to figure out a solution, or for nature to come into a balance, and maybe deal with it, somehow.”

Elliott and Colatskie will be finishing up their cave surveys in the next few weeks. Only after they’re all finished will they know if they’ve gotten another year to prepare. Meanwhile, white-nose was just found for the first time in a cave in Alabama on March 1; that’s the southernmost appearance of the disease so far.