You may not notice it, but a relentless fungal disease is plaguing hibernating bats in North America. It’s called White Nose Syndrome and it’s spreading into the Midwest with no signs of stopping. Researchers are concerned the sudden loss of bats could have devastating impacts on agriculture. Illinois has now joined the list of contaminated states.
A group of researchers gather outside an undisclosed abandoned limestone mine an hour north of Normal. They’re gearing up for a two-day census study to see how many bats are hibernating inside. Joe Kath is the Endangered and Threatened Species Manager with the Illinois Department of Natural Resources. He pulls out a map that shows an intricate maze of caverns.
“We basically just go in and start methodically moving through and trying to mark on our maps where we’re at and how many we see per species and that kind of thing,” he says.
The site they’re venturing into tested positive for Geomyces destructans, also known as white nose syndrome, a deadly fungal disease that gets its name from the white fungal growth that develops on the muzzle of infected bats.
“So we wear disposable Tyvek suits, coveralls that get washed in Lysol and really hot water to keep us from spreading the pathogen to new sights if we’re checking on bats in other areas,” says Kate Langwig, a graduate student from the University of California Santa Cruz. She says no outsiders are allowed in. All caves in Illinois are closed to the public. Not for human health, but to slow the spread of the microscopic spores. For now, white nose only affects cave-dwelling, hibernating bats.
“It’s a pretty depressing field to be in especially as you see more and more sights become infected and individuals dying from the disease,” she says.
Langwig is part of a national group of researchers out here today, from California and Colorado to Tennessee. Alan Hicks, from the New York State Department of Environmental Conservation, has seen the destructive effects of white nose first hand.
“It was my crew, we were the first ones who found this disease,” he says.
“Back in 2006?” I ask.
He says he received a call from his team while they conducted a field study at Hales Cave in Albany.
“Said something’s wrong here, there’s dead bats all over the place. Lots of bats. I said, ‘Hundreds?’ He said, ‘Thousands.’ And that was the beginning,” he says.
From New York, White-Nose Syndrome spread across the Eastern part of the U.S. and into Canada. Now, it’s pushing westward. This February, the Illinois Department of Natural Resources confirmed the presence of white nose in four counties: LaSalle, Monroe, Hardin and Pope. Dr. Adam Stern, a Veterinary Pathologist from the University of Illinois, made the diagnosis.
“Histopathology where we look at things under the microscope, we actually see the fungus and we could see it infiltrating into the bat wing,” he says. “One of the more common places.”
Stern says the disease eats away at the bat’s skin and interferes with their metabolism, causing them to use up their fat storage. Infected animals wake early during hibernation because they’re hungry. They leave the cave in the middle of winter in a hopeless search for food, where they either starve or freeze to death.
“It’s essentially going to devastate a cave. If it’s in a cave, it’s going to devastate it to complete eradication of bats in that cave,” says Stern.
Kath says photos of his colleagues inside infected caves in New York and Pennsylvania tell of the grim future awaiting Illinois bats.
“They entered sights and for as far as they could see, they were knee deep in dead bats.”
He says white nose has a mortality rate approaching 100%. Since 2006, the disease has killed nearly six million bats in the eastern third of the U.S. Once it really takes hold in Illinois, Kath says it could push endangered bat species into extinction.
“To realize that we’re facing that in our lifetime for several species, it’s very scary,” he says. “Very scary.”
Its effects won’t be isolated deep inside caves either. Kath says we’ll all notice the decline in bat populations because they’re the ultimate insect predators. In a single night, one brown bat will eat over 3,000 insects and that includes the pests that destroy corn and soybean crops.
“It was estimated that just throughout the greater Midwest alone, that bats save farmers in excess of 3 to 5 billion dollars a year,” says Kath.
Farmers will have to use more pesticides, raising food prices for consumers. Stern calls it a domino effect.
“Insects and insects are vectors for different diseases and we potentially can see increase in other types of diseases because we have more insects,” he says.
It’s bad news all around. A week after the census study at the limestone mine, Kath calls in with disappointing results.
“It was the worst case scenario and nothing that I expected to see in there,” he says. “We encountered massive white nose infection throughout the entire mine.”
When Kath first tested the mine two months ago, he says one bat had white fungus on its muzzle. Now, his crew estimates 60 to 70 percent of bats inside the mine have visible signs of infection.
“This is the last time probably in our lifetime that we will ever see the amount of animals at this site as we saw last week,” he says.
It’s going to be an uphill battle. Joe Kath says he’ll continue to monitor white nose infected sites in Illinois and work with a national network of researchers to try and find a cure. If white nose isn’t contained, then by this time next year, Illinois bats will start disappearing from the landscape, as countless more are killed off by this seemingly unstoppable disease.