Did you wash your caving suit? Cavers’ role in the potential spread of \u3cem\u3ePseudogymnoascus destructans\u3c/em\u3e, the causative agent of White-Nose Disease

Abstract

White-Nose Disease (WND) has killed millions of hibernating bats in the US and Canada. Its causative agent, the fungus Pseudogymnoascus destructans was introduced to North America, but is native to Europe and Asia, where it is not associated with mass mortality. Although it is nearly impossible to eradicate an emerging wildlife disease, research on P. destructans spread mechanisms can aid in prevention of new introductions and development of better environmental management strategies. It is of particular importance to quantify the potential role of people visiting caves (cavers, tourists, bat researchers, etc.) whom inadvertently move P. destructans spores between sites, and to limit spread, particularly to areas where the fungus is absent. In the course of two consecutive field seasons, samples were collected from the equipment before and after work in Bulgarian caves where P. destructans is present. Viable P. destructans spores were isolated from field equipment after nearly 100% of cave visits, irrespective of the season. Results from lab experiments show the pathogen’s spores can remain viable on pieces of contaminated caving equipment under room temperature for at least 25 days, with no significant reduction in germination rates. This is concerning evidence indicating the potential for movement of viable P. destructans spores across countries and continents. Results further demonstrated that any type of regular washing can successfully remove the majority of P. destructans spores from several fabric types. Brushing complemented by washing in a ‘washing machine’ was slightly more effective than brushing alone, while a washing temperature of 50°C was more effective than temperatures of 30 and 40°C. However, none of the methods herein tested fully removed P. destructans and hence they are not a substitute for decontamination. Since many cavers forgo washing equipment after surveys, and bat workers often visit several underground sites per day during monitoring activities without cleaning equipment in between sites, it is essential to raise awareness on this subject and introduce hygienic protocols for the prevention of pathogen pollution in underground sites