Combining models of transmission and pathogen growth to determine drivers of white-nose syndrome dynamics
Emerging infectious diseases pose a key threat to wildlife populations. Fungal diseases, which are increasingly recognized as an important threat to both plant and animal species, can be difficult to describe with conventional disease models. Many fungal pathogens have characteristics of both micro- and macroparasites, requiring model frameworks that incorporate elements of both types of pathogens in order to determine drivers of disease dynamics. White-nose syndrome is an emerging fungal disease caused by the pathogen Pseudogymnoascus destructans. The disease has caused widespread declines in bat populations across Eastern North America, and several species are at risk of extinction. Mortality from this disease appears to be driven primarily by infection intensity, with infection prevalence approaching 75% or greater across 6 bat species by the end of hibernation. We adapted integral projection models to examine the disease dynamics of white-nose syndrome at 18 sites across eastern North America. Integral projection models allowed us to seamlessly incorporate environmental drivers of pathogen growth into transmission dynamics.
We found that microclimate conditions of hibernating bats interacted with community composition to drive disease transmission and mortality. Furthermore, timing of infection was critically important in determining disease outcome. These results provide key information needed to mitigate the causes and consequences of this devastating disease.