Sociality and the transmission of white nose syndrome, an emerging infectious disease of bats
Emerging infectious diseases can have devastating impacts on wildlife and threaten species with extinction. Species differ immensely in sociality, or the tendency to form groups, and this can have important consequences for the transmission of infectious diseases. White-nose syndrome, caused by the fungal pathogen, Pseudogymnoascus destructans, has caused precipitous declines in bat populations across Eastern North America. However, impacts vary considerably among species and populations, and it has been suggested that clustering behavior during hibernation may be contributing to the observed differences in impacts. We measured contact rates among species of bats spanning a gradient of social behavior from solitary to highly gregarious.
We found that clustering behavior was not the primary determinant of contact rates. Some solitarily roosting species had high contact rates and transmission of both the dust and the fungus was just as intense as in highly gregarious species, whereas other solitary species, transmission was much lower. In addition, cross-species transmission was highly prevalent with a large fraction of individuals becoming infected as a result of “spillover” contacts. Variation in contact rates offer a powerful explanation for the impact of pathogens on populations.