One of the most worrisome stories on the nature beat these days is the epidemic of white nose syndrome. The mysterious lethal malady, believed to be fungal in origin, has killed an estimated one million bats in the northeastern U.S. since 2006, according to the National Wildlife Health Center. (For more background on white nose, here’s a recent National Geographic News article on the disease.)
The latest reports on the white nose death count at major bat hibernation sites are pretty ominous. In New Jersey, for example, this Daily Record article reports that at Morris County’s Hibernia Mine, where as many as 30,000 bats normally hibernate each winter, a recent count by state wildlife officials found just 1,700 bats alive, a 94 percent decrease. Worse yet, many of those showed signs of the lethal infection, whose trademark is a white residue on the muzzles, ears and flight membranes of stricken bats.
The disease attacks the mammals’ immune systems, causing them to arouse from hibernation prematurely to fight infection, which in turn burns away the fat stores that they need to survive. As a result, many die of starvation.
At least 23 of the 45 bat species in the U.S. are believed to be vulnerable to white nose syndrome, according to microbiologist David Blehert of the US Geological Survey’s National Wildlife Health Center in Madison, WI. As this
as this Associated Press article notes:
One of the most bewildering things about the epidemic is that scientists have still not pinpointed its cause. However, the evidence is growing stronger that it is caused by the fungus that is found on dead and dying bats—a new species called Geomyces destructans, which was discovered in 2008 by
Since then, Blehert has discovered DNA from the fungus in soil samples from caves and mines where bats have developed white nose syndrome, but not in disease-free caves.
Where white nose syndrome came from remains unknown, but scientists have hypothesized that the disease may have been introduced to caves in North America by European cave explorers who inadvertently brought in the pathogen on their clothing or equipment. In a recently published study, French and Irish researchers report that they found G. destructans in a bat in a cave in Périgueux, France.
Scientists are rushing to find a cure for white nose syndrome before it causes a catastrophic decline in the bat population across North America.
Interestingly, one promising antifungal is terbinafine, which is used to treat athlete’s foot and toenail fungus in humans. In Pennsylvania, for example, DeeAnn Reeder, assistant professor of biology at Bucknell University, and Greg Turner, a Pennsylvania Game Commission biologist, are treating bats with both terbinafine and another compound, “agent C,” administered in vapor form, according to an article in the Times-Tribune, a Pennsylvania newspaper.
Reeder already has tested terbinafine successfully in the lab, but whether it will work in the field remains to be seen. However, the epidemic is spreading at such an alarming rate that scientists don’t have the luxury of a gradual rollout.
As the Times-Tribune article notes:
“It’s a known anti-fungal agent, and one of the first obvious things to try,” she said.
The treatment is administered in safe, low-level doses. Some bats have reacted negatively to the treatment, grooming themselves excessively to remove it, Mr. Turner said.
The goal is to see if removing the fungus increases bats’ survival rates, Mr. Turner said. “This will help us provide data as to whether fungus is the causative agent,” he said.
Reeder thinks wildlife officials need to drastically scale up efforts to combat the bat-killing disease, before it’s too late. She told the Times-Tribune that an immediate infusion of $10 million to finance field work is desperately needed.
Meanwhile, this National Geographic News article reports that the National Zoo has accepted 40 endangered Virginia big-eared bats, AKA Corynorhinus townsendii virginianus, in an attempt to create a breeding stock protected from exposure to white nose syndrome.
North County Public Radio recently aired this story about Hale’s Cave, near Albany, NY, were the first bats afflicted with white nose syndrome were discovered in 2006.