Reducing environmentally mediated transmission to moderate impacts of an emerging wildlife disease

Emerging infectious diseases are a serious threat to wildlife communities, and the ability of pathogens to survive in the environment can exacerbate disease impacts on hosts and increase the likelihood of species extinction. Targeted removal or control of these environmental reservoirs could provide an effective mitigation strategy for reducing disease impacts but is rarely used in wildlife disease control. We examined the effectiveness of managing environmental transmission to reduce impacts of an emerging infectious disease of bats, white-nose syndrome. We used a chemical disinfectant, chlorine dioxide (ClO 2 ), to experimentally reduce Pseudogymnoascus destructans , the fungal pathogen causing WNS, in the environment. We conducted laboratory experiments followed by three years of field trials at four abandoned mines to determine whether ClO 2 could effectively reduce P. destructans in the environment, reduce host infection, and limit population impacts. ClO 2 was effective at killing P. destructans in vitro across a range of concentrations. In field settings, higher concentrations of ClO 2 treatment sufficiently reduced viable P. destructans conidia in the environment. The reduction in the environmental reservoir at treatment sites resulted in lower fungal loads on bats compared to untreated control populations. Survival following treatment was higher in little brown bats ( Myotis lucifugus ), and trended higher for tricolored bats ( Perimyotis subflavus ) compared to untreated sites. These findings support the management of environmental reservoirs as an effective control strategy for wildlife disease and provide a valuable tool for ongoing conservation efforts. More broadly, these results highlight how the intensity of environmental reservoirs can have cascading impacts on host infection and population declines.