COS 171-2 - Snake Fungal Disease: Estimating the impacts of an emerging multi-host pathogen across a Southeastern gradient

Abstract: Conserving biodiversity is a significant challenge in the Anthropocene. Wildlife species are under numerous threats including habitat loss, changing climate, invasive species, pollution, and infectious diseases. Emerging wildlife diseases can pose a major problem as they typically go undetected until they cause substantial declines for the affected species, sometimes leading to population extirpations and extinction events. Snake fungal disease (SFD) is an emerging disease caused by the fungal pathogen Ophidiomyces ophidiicola (Oo), responsible for lethal infections and has contributed to the decline of some North American snake populations. Host infection rates appear highly variable among species and across the landscape, however little is known about differences in infection, transmission, and host responses to SFD within snake communities. To investigate the dynamics of this pathogen, we collected epidermal and lesion swabs from 41 species from a total of 11 sites in Virginia, North Carolina, South Carolina, Georgia, Florida, and Louisiana. With the objectives of predicting host species susceptibility and to determine the factors that contribute to variation in SFD infection among species. We sampled a total of 486 snakes to examine variation in prevalence over time among species and locations. For individuals with skin lesions, we quantified infection severity by recording the number of lesions, location on the body, size, and type as well as the animal’s morphological measurements were taken to quantify infection severity.
We found that Oo was highly prevalent in some species (Farancia erytrogramma, Nerodia erythrogaster and Nerodia taxispilota ( >70-75%)). While other species within these communities had much lower prevalence including Agkistrodon piscivorus and Pantherophis alleghaniensis. Many snakes showed evidence of severe Oo infections, particularly F. erytrogramma, with lesions covering a large fraction of the body. Infection prevalence was also highly variable among sites and we detected a strong effect of latitude with more southern sites having significantly lower prevalence. Generally, prevalence reduced through spring into summer and pathogen clearance occurred faster at more southern latitudes.