White Nose Syndrome: Exactly How it Kills

White nose syndrome (WNS) has been a rampant problem in the United States for nearly a decade, resulting in a decline of many little brown bat colonies by a stunning 90 to 100 percent. However, exactly how this natural epidemic is killing these bats so efficiently remained a mystery, until now.

According to a study recently published in the journal BMC Physiology, researchers have determined the mechanism through which the WNS fungus (Pseudogymnoascus destructans) drains wintering bats of their energy, forcing them to wake early and starve or freeze to death (not unlike in the case of bees and colony collapse disorder).

"This model is exciting for us, because we now have a framework for understanding how the disease functions within a bat," Michelle Verant, a US Geological Survey (USGS) National Wildlife Health Center scientist, explained in a statement. "The mechanisms detailed in this model will be critical for properly timed and effective disease mitigation strategies."

According to the US Fish and Wildlife Service (FWS), the disease was first identified in New York State in late 2006 and has since spread throughout the eastern United States (as far as Mississippi) and Canada. It is characterized by a white fungal infection that covers the muzzle and wings of little brown bats. The fungus saps strength from the wintering bats and, as of July, has killed more than 5.7 million bats since discovered. We will know how many more it has recently killed by the end of this winter. (Scroll to read on...)

In this latest USGS study, Verant and her colleagues determined the amount of energy used by wintering infected and healthy bats by measuring how much fat was burned and at what rate during hibernation. They found that bats with WNS used twice as much energy as healthy bats during hibernation and suffered from potentially life-threatening inhibition of body function.

And while knowing how this disease functions will help, experts are hesitant to help the bats fight what is a completely natural epidemic. Instead, many hope that the bats overcome this disease on their own. Some studies have already shown that the little brown bat is on its way to recovery, having actually changed its social and roosting strategies to avoid rampant spread of infection.

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