Infectious diseases can have devastating effects on host populations, and the presence of an environmental pathogen reservoir can exacerbate disease impacts by preventing pathogen fadeout and facilitating sustained transmission independent of affected hosts. Environmental reservoir dynamics are driven by both the reservoir input from infected hosts as well as pathogen survival and persistence under various environmental conditions. Here we examine environmental factors and shedding of the fungal pathogen, Pseudogymnoascus destructans, that causes white-nose syndrome in bats, from a range of different host species and environments. P. destructans is known to persist for long periods of time in the environment, which can result in widespread infection and mortality. We collected over 8,000 samples from bat roosts in subterranean environments from 60 sites over an 8-year period during P. destructans invasion of the Midwestern, United States.
Results/Conclusions
We observed differential pathogen shedding into the environment by species. Two species, Eptesicus fuscus and Myotis sodalis, disproportionally contributed more pathogen to the environmental reservoir given their level of infection compared to other species present in the community. However, two other species that had higher infection intensity, contributed cumulatively more pathogen to the environmental reservoir. We also found that fungal loads were significantly lower in areas of the environment with low moisture levels, which was conserved across species roosting location and temperatures. Additionally, we found that crevices in hibernacula served as pathogen hot spots and had significantly higher fungal contamination than non-crevice type substrate. Our results show that species-dependent pathogen shedding and abiotic conditions interact to drive the extent of the environmental reservoir, which ultimately determines the population and species level impacts.