Laboratory and Field Testing of Treatments for White Nose Syndrome: Immediate Funding Need for the Northeast

RCN Topic
Factors in Regional Decline of Species of Greatest Conservation Need

Hibernating bats in the NE USA have experienced sudden and dramatic declines over the past three winters due to an emerging infectious disease dubbed “White Nose Syndrome” (WNS). As of January, 2012, new estimates of the number of bats that have died thus far range from 5.7 to 7.7 million, and the causative agent is now known to be the cold-loving fungus Geomyces destructans (Gd). This proposal aims to address these declines by developing and implementing methodologies to combat WNS, which was specifically referenced in the call for proposals. Specific goals include: (1) testing potential treatments for efficacy against cultured Gd (the fungal pathogen associated with WNS) under laboratory conditions, (2) testing potential treatments for safety in healthy bats, and (3) testing potential treatments for efficacy against Gd in hibernating bats.

White-nose Syndrome (WNS), an emerging infectious disease caused by the novel fungus Pseudogymnoascus destructans (Pd), has devastated North American bat populations since its discovery in 2006. The little brown myotis, Myotis lucifugus, once the most common bat in North America, has been especially affected. The goal of this study was to address bat declines by developing and optimizing treatments for WNS. We report the results of two in vitro studies of pharmaceutical/organic compounds and the results of two studies of treatments in control and Pd infected little brown myotis in vivo, performed at the bat research facilities in the Reeder lab at Bucknell University. As has been found by other laboratories, a number of chemical agents, including, from this study 5,7-hexadecadiynoic acid and heptadecanoic acid, are effective at killing or inhibiting the growth of Pseudogymnoascus (but Pichia spent medium (PSM) was not effective). Unfortunately, both systemic and dermatophyte (superficial) fungal infections in humans and animals are notoriously difficult to treat, and often require prolonged chemical application to achieve a cure. Traditional antifungal agents are also known to have relatively high side effect profiles and the use of these drugs in hibernating animals is novel. While treatment with the strong antifungal agent voriconazole was very clearly harmful to bats, trials with subcutaneously terbinafine implants were more promising. We can make no specific treatment recommendations at this time, but rather urge the research community to continue to pursue mitigation options for WNS. Clearly the WNS problem is complex, especially when one considers any sort of treatment option – which will affect the entire cave ecosystem.

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