White-Nose Syndrome Fungus is Worse Than We Thought for Cave Bats

Bat populations are declining across the United States, plagued by a fungus known as white-nose syndrome. Deadly to these mammals, white-nose syndrome can impact entire bat colonies. Now, though, scientists have discovered that the fungus is worse than they realized; there's very little that might stop the organism from spreading further and persisting indefinitely in cave bats.

The fungus itself is called Pseudogymnoascus (Geomyces) destructans. This particular infection strikes bats during their winter hibernation, leaving them weak and susceptible to starvation and secondary infections. It's thought that the fungus first originated in Europe, but was first witnessed in New York in the winter of 2006 to 2007. Since then, it's spread to more than two dozen states and has killed more than 5.5 million bats in the U.S. and Canada. Needless to say, it's crucial for researchesr to learn as much as they can about this fungus in order to hopefully combat it.

In order to learn more about this fungus, the scientists took an in-depth look about the basic biology of the organism. Surprisingly, they found that the fungus is extremely resilient, which spells bad news for bats across North America.

"It can basically live on any complex carbon source, which encompasses insects, undigested insect parts in guano, wood, dead fungi and cave fish," said Daniel Raudabaugh, one of the researchers, in a news release. "We looked at all the different nitrogen sources and found that basically it can grow on all of them. It can grow over a very wide range of pH; it doesn't have trouble in any pH unless it's extremely acidic."

That's not all, either. The researchers found that the fungus can subsist on other proteins and lipids on the bats' actual skin. In addition, it can thrive on glandular secretions. The only real limitation for this organism, besides temperatures above 20 degrees Celsius, has to do with its ability to take up water. Its cells are leaky, which makes it hard for the fungus to absorb water from surfaces, such as dry wood, that have a tendency to cling to moisture. But in the presence of degraded fats or free fatty acids, the fungus can draw up water easily.

"Dan found that P. destructans can live perfectly happily off the remains of most organisms that co-inhabit the caves with the bats," said Andrew Miller, one of the researchers, in a news release. "This means that whether the bats are there or not, it's going to be in the caves for a very long time."

The findings are published in the journal PLOS One.