Field trial of a probiotic bacteria and a chemical, chitosan, to protect bats from white-nose syndrome

Hoyt, J. R.; Langwig, K. E.; White, J. P.; Kaarakka, H. M.; Redell, J. A.; Parise, K. L.; Frick, W. F.; Foster, J. T.; Kilpatrick, A. M.

doi:10.1101/567826

bioRxiv · 10.1101/567826

Field trial of a probiotic bacteria and a chemical, chitosan, to protect bats from white-nose syndrome

Hoyt, J. R.·Langwig, K. E.·White, J. P.·Kaarakka, H. M.·Redell, J. A.·Parise, K. L.·Frick, W. F.·Foster, J. T.·Kilpatrick, A. M.

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Abstract

Tools for reducing wildlife disease impacts are needed to conserve biodiversity. White-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans, has caused widespread declines in North American bat populations and threatens several species with extinction. Few tools exist for managers to reduce WNS impacts. We tested the efficacy of two treatments, a probiotic bacterium, Pseudomonas fluorescens, and a chemical, chitosan, to reduce impacts of WNS in two simultaneous experiments conducted with caged and free-flying Myotis lucifugus bats at a mine in Wisconsin, USA. In the free-flying experiment, treatment with P. fluorescens increased apparent overwinter survival five-fold compared to the control group (from 8.4% to 46.2%) by delaying emergence of bats from the site by 30 days. Apparent overwinter survival for free-flying chitosan-treated bats was 18.0%, which did not differ significantly from control bats. In the cage experiment, chitosan-treated bats had significantly higher survival until release on March 8 (53%) than control and P. fluorescens-treated bats (both 27%). However, these differences were likely due to within-cage disturbance and not reduced WNS impacts, because chitosan-treated bats actually had significantly higher UV-fluorescence (a measure of disease severity), and body mass, not infection intensity, predicted mortality. Further, few of the bats released from the cage experiment were detected emerging from the mine, indicating that the survival estimates at the time of release did not carryover to overwinter survival. These results suggest that treatment of bats may reduce WNS mortality, but additional measures are needed to prevent declines.

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Hoyt, J. R., Langwig, K. E., White, J. P., Kaarakka, H. M., Redell, J. A., Parise, K. L., Frick, W. F., Foster, J. T., Kilpatrick, A. M.. 2019-03-05. Field trial of a probiotic bacteria and a chemical, chitosan, to protect bats from white-nose syndrome. https://doi.org/10.1101/567826

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