White noses hit PA brown bats

Biologists have confirmed that bats in Pennsylvania are infected with a mysterious syndrome that has already killed thousands of bats throughout the Northeast over the past two years.

White Nose Syndrome (WNS), so called for the presence of a pale, powdery fungus on the muzzles of infected bats, has hit New York and Vermont bat populations hardest, and it seems to be continuing its march west. The pathology of White Nose Syndrome remains largely unexplained, but infected bats appear to starve to death after exhibiting non-typical behavior, such as flying during the daytime. Some biologists suggest that the fungus is merely a secondary infection that targets the already weakened immune systems of sick bats.

Little brown bats with white noses

Researchers had suspected that the disease was gaining a foothold in Pennsylvania, and confirmation came last week from National Wildlife Health Center in Madison, Wisconsin. DeeAnn Reeder, a comparative ecophysiologist at Bucknell University in Pennsylvania, told The Scientist that bats from an iron mine in central Pennsylvania's Mifflin County had come back from the lab positive for the fungus associated with WNS. Last weekend, news came out that WNS has also stuck bats in New Jersey.

Reeder and some colleagues monitored a large bat colony near Altoona, PA last year -- we wrote about their trip in our October issue -- and found no evidence of WNS. But she says that she's suspected for weeks that WNS was turning up in PA bats.

When I spoke with her yesterday, Reeder had just returned from visiting hibernation sites in Western Pennsylvania, near the border with Ohio, and said that there were no signs of White Nose Syndrome in bats there. "Everything looked great," she said. "We had a site with 6,000 bats, and they all looked clean."

But the bats inhabiting the hibernation site in Mifflin County are worse off. "My sense of it is that [WNS] is increasing in the site," Reeder said. She added that about 150 of the more than 2000 bats that use the mine in the winter likely had WNS. "This site is just classic white nose, and it looks just like New York and Vermont."

While the spread of WSN is worrisome, Reeder said that finding the fungus at what seems to be an early stage of its spread in the state offers researchers an unprecedented opportunity to study its effects on bat populations. "Now we have it, and I think it puts us in a unique position to study the spread of the syndrome within a geographic area," Reeder said.

Reeder said that research is already underway to track "arousal patterns" in hibernating bats. She explained that hibernating bats normally reduce their body temperature for about two weeks, then warm up briefly to "reboot the immune system," before cooling back down. Reeder suspects that hibernating bats with WNS are not conforming to this normal arousal patter, either warming up too frequently of staying warm too long, and burning too many calories. She and a team of biologists have glued temperature loggers to the backs of bats throughout the Northeast to test her hypothesis.

Other research will focus on which climatic conditions favor the fungus and tracking the spread of WNS through upcoming surveys of hibernation sites and by attaching transmitters to both sick and healthy bats.

While little brown bats (Myotis lucifugus) have turned up with WNS most frequently, this is not surprising considering the species' ubiquity. Wildlife managers fear its emergence in less common bats, such as the endangered Indiana bat (Myotis sodalis).

Reeder said that she fully expects WNS to continue moving westward through caves and mines sprinkled throughout West Virginia and Ohio in coming years. "The hope is that enough bats won't get it so that we can rebuild populations."

Related stories:

Nabbing bats' nemesis
[October 2008]

Deadly bat fungus fingered
[30th October 2008]

Photo courtesy of New York Department of Environmental Conservation