Estimating host species and spatial variation in infection with the fungal pathogen that causes snake fungal disease

Emerging wildlife diseases represent a serious threat to conservation efforts. Impacts of emerging multi-host pathogens can vary greatly among species as well as geographically, and understanding which populations will be at greatest risk is essential for conserving biodiversity. Snake fungal disease (SFD), caused by the fungal pathogen Ophidiomyces ophidiicola, is responsible for lethal infections in snakes and has contributed to the decline of multiple North American snake populations. However, which species are most affected by this disease and how infections vary regionally remains unknown. Here we sampled 44 different species across 14 sites throughout the Southeastern and Mid-Atlantic United States. We found a strong effect of latitude on both pathogen prevalence and severity, with more severe infections at more northern latitudes. We also found high variability in pathogen prevalence and infection severity among species. There was a strong positive relationship between pathogen prevalence and disease severity, suggesting that SFD is not just highly prevalent in some populations but also highly virulent. More broadly, our results support that SFD likely has continued impacts on snake populations with some species experiencing greater disease than others attributed to spatial and host variation.