Whole‐room ultraviolet sanitization as a method for the site‐level treatment of Pseudogymnoascus destructans

Abstract

AbstractWhite‐nose syndrome (WNS), a catastrophic fungal disease of hibernating bats, is perpetuated by environmental reservoirs of the fungal pathogen, Pseudogymnoascus destructans. Surviving bats clear infection each summer but are re‐infected upon return to the hibernaculum. Therefore, addressing environmental reservoirs is critical for managing WNS. Ultraviolet (UV) light is known to kill P. destructans in the lab, and whole‐room UV sanitization is a common practice in many commercial settings. However, effective UV treatment at the hibernaculum scale has yet to be confirmed. Importantly, existing standard practices likely require modification for implementation in hibernation sites. Prior to field testing, confirming the ability of UV sanitizers to treat the complex topography of hibernacula, as well as quantifying the effects of such topography on effective treatment times is necessary. Here we use a laboratory setting to investigate the feasibility of whole‐room UV‐C sanitization in treating environmental reservoirs of P. destructans. All trials resulted in mean fungal reductions of 97.3% (range: 91.9‐99.7%) relative to controls. To prepare for future implementation within a hibernaculum, we quantified the effect of distance, emission angle, and incidence angle on UV‐C irradiance delivered to target locations. From these data, we calculated treatment times required for killing P. destructans at the scale of a natural setting. Measurable UV‐C irradiance extended to a maximum distance of 21.3 m. Angles of emission and incidence both reduced irradiance; however, we conclude that ~325 m3 of surface volume could be treated in <2 h. Taken together, UV‐C sanitization may provide a feasible, scalable, and relatively ecologically benign method of reducing P. destructans populations.