Snake Fungal Disease in Virginia: Estimating the effects of Ophidiomyces ophiodiicola on snakes in a coastal ecosystem

Background/Question/Methods

Emerging infectious diseases are an important threat to wildlife communities, resulting in declines of once abundant species and species extinctions. Snake fungal disease (SFD) is an emerging disease caused by the fungal pathogen Ophidiomyces ophiodiicola (Oo) that can cause lethal infections and has contributed to the decline of North American snake populations. Differences in susceptibility among species may play a key role in SFD dynamics, however little is known about differential infection and responses to SFD within snake communities. In addition, recent observations of unusual mortality events in rare aquatic species, like the rainbow snake (Farancia erytrogramma), have suggested that cryptic pathogen spread may be commonly occuring. We investigated the dynamics of this pathogen in the coastal Southeastern US. To assess capture and sample snakes, we created 20 coverboard arrays across sites and collected capture data and epidermal swabs for 10 species over two years.

Results/Conclusions

We found that Oo was highly prevalent in coastal snake communities. Rainbow snakes (Farancia erytrogramma), Red Bellied Watersnakes (Nerodia erythrogaster) and Brown Watersnakes (Nerodia taxispilota) had >70-75% Oo prevalence. Several other species within snake communities had lower prevalence including the Northern Cottonmouth (Agkistrodon piscivorus) and Eastern Ratsnake (Pantherophis alleghaniensis). Many snakes showed evidence of severe Oo infections during capture events, with lesions covering much of the face and body. These results suggest that Oo may be a persistent threat to coastal snake communities, and more research is needed to determine the underlying causes of this epizootic.