Determinants of within bat hibernacula: implications for surveillance and management of white-nose syndrome.

1. Fungal diseases are an emerging global problem affecting human health, food security and biodiversity. Ability of many fungal pathogens to persist within environmental reservoirs can increase extinction risks for host species and presents challenges for disease control. Understanding factors that regulate pathogen spread and persistence in these reservoirs is critical for effective disease management. 2. White-nose syndrome (WNS) is a disease of hibernating bats caused by (), a fungus that establishes persistent environmental reservoirs within bat hibernacula, which contribute to seasonal disease transmission dynamics in bats. However, host and environmental factors influencing distribution of within these reservoirs are unknown. 3. We used model selection on longitudinally collected field data to test multiple hypotheses describing presence-absence and abundance of in environmental substrates and on bats within hibernacula at different stages of WNS. 4. First detection of in the environment lagged up to one year after first detection on bats within that hibernaculum. Once detected, the probability of detecting within environmental samples from a hibernaculum increased over time and was higher in sediment compared to wall surfaces. Temperature had marginal effects on the distribution of . For bats, prevalence and abundance of were highest on and on bats with visible signs of WNS. 5. . Our results indicate that distribution of () within a hibernaculum is driven primarily by bats with delayed establishment of environmental reservoirs. Thus, collection of samples from , or from sediment if bats cannot be sampled, should be prioritized to improve detection probabilities for surveillance. Long-term persistence of in sediment suggests that disease management for white-nose syndrome should address risks of sustained transmission from environmental reservoirs.