The fungus that causes white-nose syndrome, a deadly disease of hibernating bats, spreads rapidly by way of bats, then establishes and persists in soil and on walls of underground hibernation sites, according to a study published today.
Findings from the new study, conducted by the U.S. Geological Survey and EcoHealth Alliance, can help scientists and managers in North America better detect and understand the Pseudogymnoascus destructans (Pd) fungus that causes white-nose syndrome, or WNS. Scientists can use the results to determine what, where and when to sample for the fungus as they survey areas for Pd. The results can also help managers assess the effectiveness of disease mitigation efforts.
“First discovered in New York state in 2006, white-nose syndrome has killed millions of agriculturally and environmentally valuable bats, threatening some species with extinction,” said lead author Michelle Verant, who conducted the research while working at the USGS National Wildlife Health Center. Verant now works for the National Park Service. “Our study helps explain natural dynamics of this devastating disease, which is important for effective disease control.”
Hibernacula are dark and cold underground environments, such as caves and mines, in which bats hibernate. For this study, scientists investigated six hibernacula in New York, Kentucky, Tennessee and Wisconsin that represented different stages of WNS progression. They found that bats were the primary means by which Pd was introduced into hibernacula, and that the risk of spread by soil from hibernacula increased over time. They also found a higher probability of detecting Pd on the species known as little brown bats compared to other bat species using the same hibernacula.
Together, these findings can help scientists determine where and how to collect the most useful samples for efficient and early detection of Pd.
“Our results suggest that targeting little brown bats for sampling is the most effective way to detect Pd in a population,” Verant said. “It can take up to a year after Pd is found on bats for the fungus to be accurately and consistently identified in environmental samples from their hibernacula, such as cave sediment or wall surfaces.”
When bats can’t be sampled, however, cave soil is the next best alternative. The scientists found a higher likelihood of detecting Pd in the soil of hibernacula than on cave walls.
"Something else we specifically tested was if temperature differences within a cave influenced the amount of Pd,” said Dr. Kevin Olival, a coauthor from EcoHealth Alliance. “We found that temperature variation did not make a big difference, and that there are unlikely areas of a cave which are Pd-free and thus protective for bats.”
The USGS and the U.S. Fish and Wildlife Service provided funding for this work. The new study is published in the Journal of Applied Ecology.
WNS is not known to affect people, pets or livestock. For more information about WNS, please visit the USGS National Wildlife Health Center, the EcoHealth Alliance and the international coordinated response to WNS websites.
CONTACT: Marisa Lubeck