Researchers Begin to Unravel Mystery Fungus Killing Bats

A mysterious plague is wiping out cave-dwelling bats in Pennsylvania and much of the eastern US. They include endangered Indiana bats just when it seemed their numbers were rebounding. As the epidemic white nose syndrome spreads, scientists are working frantically to find the cause. The Allegheny Front's Deborah Weisberg traveled deep underground for the story, the first in our series, Protecting Pennsylvania's Wildlife.

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OPEN: A mysterious plague is wiping out cave-dwelling bats in Pennsylvania and much of the eastern US. They include endangered Indiana bats just when it seemed their numbers were rebounding. As the epidemic white nose syndrome spreads, scientists are working frantically to find the cause. Here's The Allegheny Front's Deborah Wiesberg with the story, the first in our series, Protecting Pennsylvania's Wildlife.

Weisberg: (Nat sound of background voices...this isn't fashion show) A team of scientists zip themselves (zipping) into the kind of moon suits you'd expect to see on a space mission, as they prepare to go half a mile deep into an old Fayette County mine to study bats.

Reeder:(outside clay mine) We were in here in January and everything looked really clean, this portion of the state seems so far unaffected - so this is a control site for several white nose studies.

Weisberg: Dee Ann Reeder is an eco-physiologist from Bucknell University. She's suited up to avoid tracking the white nose fungus from affected sites into this clean mine. Given how rampant white nose has become, there's a moratorium on recreational caving, and even scientists are taking extra precautions.

Reeder: It's nice to have sites, and it's sort of refreshing to walk into sites where bats look good. It's been sort of a depressing winter to go into most of our primary field sites where most of the bats are in horrible condition and we're finding carcasses on the ground and carcasses floating in the water, and just bats gone.

Weisberg: Reeder's colleague is Greg Turner - an endangered mammals specialist with the Pennsylvania Game Commission.

Turner: We'll enter in and head down to where the colder temps are to where the bats are at, you guys ready?

(sound of footsteps)

Weisberg: On this sunny spring day, they and their team crawl through the narrow entrance of the mine, where wood beams from a century ago sag under the weight of the mountain. It's spring and the bats will soon be leaving this hibernaculum where they hibernate over the winter. Pregnant females travel to maternity colonies a hundred miles away. Other bats head to trees and barns. Wearing miners' lamps, Reeder and Turner begin probing their way through a series of dark tunnels into rooms where bats hang by their feet in huge clusters.

Turner: There's a cluster right here. It's about 12 inches by about 24 inches. There's probably about 250-300 bats right here.

Weisberg: Turner and Reeder have their eyes peeled for specific bats - those they outfitted with tiny plastic data loggers last year. They record body temperatures and could give important clues about how often the bats are waking up. Healthy bats arouse every couple of weeks to reboot their immune systems but bats with white nose are warming up too frequently for reasons scientists don't understand.

Reeder: We found one of our little browns wearing a data logger...looks like a little red back pack right there in this cluster. So Greg will use this pole extender. He'll wrap duct tape on the end and put it up under the bat and raise it up and we can just pull it down.

Weisberg: Turner works quickly capturing bats and recording information. As the bats arouse, they make squeaking sounds.

Turner: It's in the middle of cluster and it's number 20, data logger 20.

Weisberg: Turner places the bats into a cloth bag (sound of bag being zipped) and hands it to someone who runs it outside where other researchers wait to assess the animals' health. Some will be processed and returned to the mine, others euthanized and dissected. Their blood and organs studied for immune competence. So far, Reeder is pleased with what she sees.

Reeder: I don't see any signs of white nose...their body condition looks good. It's great. It's a nice refreshing break from white nose sites which are just depressing, really sad and tragic.

Weisberg: The next day, though, is a different story.

(Sound of hiking through brush)

Weisberg: The team hikes through a forest in Mifflin County to Aikens cave where white nose has already been discovered. They crawl through the narrow entrance, pick their way over ice-covered rocks, and find sick bats huddled in crevices and clinging to walls.

Turner: One of the symptoms is roost location. They're shifting to cold areas in the very front of the cave, some displaying fungus around the wings, the wings and the forearms there.

Weisberg: Turner and veterinarian Jesse Fallon pluck bats from the walls of the cave then carry them to a field lab outside. Fallon is from Virginia Tech. White nose was just discovered in his state. He's here to collect blood and tissue samples from affected bats.

Fallon: We're trying to find out, confirm that the causative agent is indeed a fungus and not something else and we're trying to understand the disease syndrome better. It's hard to implement a management plan when you don't know what the causative agent is.

sounds of Fallon's instruments)

Weisberg: Fallon snips off a bat's head (snipping) to collect blood.

Turner: It's really the only way to collect blood from such a small animal. This guy's about the size of the last knuckle of my thumb. He weighs a little more than a standard US nickel.

Weisberg: Fallon uses tweezers to extract tiny organs like the heart, liver and lungs.

Fallon: So this is a lung lobe...we'll send this off for viral isolation.

Weisberg: Each body part goes into a baggie and then a cooler of ice for the long drive back to Virginia Tech. Although fungus is the obvious sign of white nose syndrome, there are others too.

Fallon: One of key clinical signs of bats that are going to die of white nose is they run out of most of their fat stores. Normally in this little brown like the ones yesterday is there'd be a whole bunch of subcutaneous fat pockets, very little there.

Weisberg: Affected bats also can be seen flying outside in the middle of winter, an indication they're arousing at abnormal times. It alarmed Jessica Wilt, who lives near Aikens cave and contacted researchers this past winter when she saw bats outside in the middle of the day.

Wilt: It's unfortunate because we really like the bats. They keep away the bugs and they're an endangered species here. So we're really sad to hear that that might be their downfall.

Weisberg: Although Wilt is eager for answers, scientists so far have none. White nose was first discovered in New England two years ago and has spread like wildfire through many Eastern states. It has claimed hundreds of thousands of bats including two rare species, the small-footed bat and the Indiana bat. But as they watch the death toll mount, Reeder and her colleagues have only theories.

Reeder: One of those is there's some sort of pathogen. The most likely culprit is the fungus associated with white nose. Another is that there's some sort of environmental contaminant like a pesticide residue that could be contributing and that one has been largely discounted at this point. Third is bats are losing weight and starving to death and that could be because they're arousing too frequently during the winter. And the fourth one is all of the above. This is a synergy of multiple causal factors that are coming together and hitting the bats all at one time.

Weisberg: Reeder says she's becoming convinced white nose syndrome is an emerging infectious disease. That the fungus isn't a secondary infection but rather the primary pathogen. One that could wipe out all cave-dwelling bats and wreak havoc on the eco-system since bats control insects and in parts of the world they pollinate plants.

Reeder: They're really sophisticated exquisitely evolved organisms completely in tune with their natural environment and so tightly balanced and always on the edge.

Weisberg: And while bats have survived mining, loss of habitat, wind farms and other impacts to their environment, Reeder says they're no match for white nose syndrome whatever it may turn out to be. Pennsylvania scientists just received more than $1 million to come up with an answer sooner. For the Allegheny Front, I'm Deborah Weisberg.