White-Nose Syndrome Disease Severity and a Comparison of Diagnostic Methods
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White-nose syndrome is caused by the fungus Pseudogymnoascus destructans and has killed millions of hibernating bats in North America but the pathophysiology of the disease remains poorly understood. Our objectives were to (1) assess non-destructive diagnostic methods for P. destructans infection compared to histopathology, the current gold-standard, and (2) to evaluate potential metrics of disease severity. We used data from three captive inoculation experiments involving 181 little brown bats (Myotis lucifugus) to compare histopathology, quantitative PCR (qPCR), and ultraviolet fluorescence as diagnostic methods of P. destructans infection. To assess disease severity, we considered two histology metrics (wing area with fungal hyphae, area of dermal necrosis), P. destructans fungal load (qPCR), ultraviolet fluorescence, and blood chemistry (hematocrit, sodium, glucose, pCO2, and bicarbonate). Quantitative PCR was most effective for early detection of P. destructans, while all three methods were comparable in severe infections. Correlations among hyphae and necrosis scores, qPCR, ultraviolet fluorescence, blood chemistry, and hibernation duration indicate a multi-stage pattern of disease. Disruptions of homeostasis occurred rapidly in late hibernation. Our results provide valuable information about the use of non-destructive techniques for monitoring, and provide novel insight into the pathophysiology of white-nose syndrome, with implications for developing and implementing potential mitigation strategies.
Keywordsblood chemistry histopathology Myotis lucifugus non-destructive methods PCR Pseudogymnoascus destructans ultraviolet fluorescence
We thank the animal care staff (Monique Burmester, Paula Mason, Melanie Weiss), imaging specialists (Ian Shirley, Chris Stuart), and necropsy team (Marnie Zimmer, Crystal Rainbow) at the Western College of Veterinary Medicine for their support and technical expertise throughout these studies. We also thank Katy Parise, Nicolette Janke, and Kevin Drees at the Center for Microbial Genetics and Genomics at Northern Arizona State University for molecular diagnostics. Funding was provided by the United States Fish and Wildlife Service, Canada Foundation for Innovation, Manitoba Research and Innovation Fund, Natural Sciences and Engineering Research Council of Canada, the German Academic Exchange Service (DAAD), and NSF grant DEB-1115895.
All applicable institutional and/or national guidelines for the care and use of animals were followed. Collection of wild bats was approved under permits from Manitoba Conservation (Permits WB11145 and WB13148) and experiments were approved by the University of Saskatchewan Committee on Animal Care and Supply (Protocol #20100120).
- Frick WF, Puechmaille SJ, Hoyt JR, Nickel BA, Langwig KE, Foster JT, Barlow KE, Bartonicka T, Feller D, Haarsma AJ, Herzog C, Horacek I, van der Kooij J, Mulkens B, Petrov B, Reynolds R, Rodrigues L, Stihler CW, Turner GG, Kilpatrick AM (2015) Disease alters macroecological patterns of North American bats. Global Ecology and Biogeography 24: 741 – 749.CrossRefGoogle Scholar
- Langwig KW, Frick WF, Reynolds R, Parise KL, Drees KP, Hoyt JR, Cheng TL, Kunz TH, Foster JT, Kilpatrick AM (2015a) Host and pathogen ecology drive the seasonal dynamics of a fungal disease, white-nose syndrome. Proceedings of the Royal Society B: Biological Sciences 282: 20142335.CrossRefPubMedPubMedCentralGoogle Scholar
- R Core Team (2014) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org/.
- Reeder DM, Frank CL, Turner GG, Meteyer CU, Kurta A, Britzke ER, Vodzak ME, Darling SR, Stihler CW, Hicks AC, Jacob R, Grieneisen LE, Brownlee SA, Muller LK, Blehert DS (2012) Frequent arousal from hibernation linked to severity of infection and mortality in bats with white-nose syndrome. PLOS One 7: e38920.CrossRefPubMedPubMedCentralGoogle Scholar
- Turner GG, Meteyer CU, Barton H, Gumbs JF, Reeder DM, Overton B, Bandouchova H, Bartonička T, Martínková N, Pikula J, Blehert DS (2014) Nonlethal screening of bat-wing skin with the use of ultraviolet fluorescence to detect lesions indicative of white-nose syndrome. Journal of Wildlife Diseases 50: 566 – 573.CrossRefPubMedGoogle Scholar
- United States Geological Survey, National Wildlife Health Center (2014) Updated WNS case definitions. https://www.whitenosesyndrome.org/resource/revised-case-definitions-white-nose-syndrome-11252014. Accessed 29 July 2015.
- Warnecke L, Turner JM, Bollinger TK, Lorch JM, Misra V, Cryan PM, Wibbelt G, Blehert DS, Willis CKR (2012) Inoculation of bats with European Geomyces destructans supports the novel pathogen hypothesis for the origin of white-nose syndrome. Proceedings of the National Academy of Sciences 109: 6999 – 7003.CrossRefGoogle Scholar