Bat to the Future
A 100-year-old bat specimen housed at the National Museum of Natural History in Washington, D.C. may help scientists unravel the mystery behind white-nose syndrome, a disease that has devastated North American bat populations.
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Myotis bechsteinii. Photo by Sam Dyer Ecology.[/caption]
Researchers from the Smithsonian Institution, University of New Hampshire, Bucknell University, and the University of Adelaide in Australia used DNA analysis to detect Pseudogymnoascus destructans, the fungus that causes white-nose syndrome (WNS), on a Bechstein’s bat (Myotis bechsteinii) collected on May 9, 1918 in Forêt de Russy, Centre-Val de Loire, France. The discovery supports the presence of WNS in Europe and Asia more than 100 years ago and shows how ancient specimens can inform modern day research.
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The Smithsonian’s National Museum of Natural History’s biological collections (25 million specimens) preserved in fluids, such as alcohol and formalin, and informally known as the “wet collections.” The facility has the latest technology for the safe use of flammable liquids.[/caption]
Dr. Michael Campana, a computational genomics scientist at the Smithsonian Institution Conservation Biology Institute’s Center for Conservation Genomics, said archived museum collections are critical for studying emerging diseases like white-nose syndrome. As a computational genomics scientist, Campana uses computational and statistical analysis to decipher biology from genome sequences and related data. Campana’s colleague, Carly Muletz-Wolz, also used museum specimens to investigate the historical prevalence of the fungal pathogens Batrachochytrium dendrobatidis and B. salamandrivorans in amphibians, information that has conservation plan implications.
“Without archived specimens from the past, the evolutionary history of an animal or pathogen is inferred, but not confirmed,” Campana said. “Without archived specimens, the genomic history is inferred from limited modern data, limitations that may cause incorrect inferences. By seeing a pathogen’s genetics from the past, you can more accurately infer its evolutionary history.”
Named for the white fungus that is visible primarily on the muzzle of the bat, WNS was first documented in North America during the winter of 2006 in New York state. To date, the disease has killed more than 6 million bats in 31 states and 5 provinces. In the winter months, bats carefully and precisely measure their energy expenditure to survive until spring. Scientists from the University of Wisconsin-Madison and U.S. Geological Survey have hypothesized that P. destructans kills bats by increasing the amount of energy they use during hibernation, thereby inhibiting normal physiological functions.
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White-nose syndrome occurrence map as of August 2017. Map provided by white-nosesyndrome.org, A Coordinated Response to the Devastating Bat Disease.[/caption]
Campana said genetic studies of present day bat specimens and historic samples both inform effective conservation by comparing genetic differences leading to adaptations. Currently, WNS is occurring in multiple bat populations in Europe and Asia, yet the bat populations are not declining as seen in WNS-infected populations in North America. This indicates the presence of disease tolerance mechanisms, whereby the bat host limits the harmful effects of WNS, but does not eliminate the presence of the fungus. The ability of Eurasian bats to survive in the presence of WNS is evidence of a natural, evolutionary adaptation, that can most likely be found in immunity genes.
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Little Brown Bat infected with white-nose syndrome in Greeley Mine, VT. Photo by Marvin Moriarty, USFWS.[/caption]
Dr. Jonathan Reichard, WNS National Assistant Coordinator with the U.S. Fish and Wildlife Service, says the discovery has implications for WNS research in North America.
“The ability of Eurasian bat populations to coexist with WNS suggests adaptive evolution with a possible genetic underpinning for survival,” Reichard says. “We hope that North American bats have the capacity to reach similar equilibrium to survive with the disease.”
Currently, some bats in North America are surviving with WNS while others seem to not contract the disease, but the specific factors leading to their survival are still being investigated.
“If the ability to survive with WNS is from a genetic adaptation that is heritable, North American bats could experience an evolutionary bottleneck and return to a stable or recovering population,” Reichard says. “Work by Dr. Campana and colleagues will help us investigate patterns of resistance and persistence that we are observing both between species and within species in North America. This understanding is critical for focusing our management and research efforts.”
Click here to read the “White-Nose Syndrome Fungus in a 1918 Bat Specimen from France” research letter.
