Houston Chandler

The Orianne Society

Abstract

Houston C. Chandler (hchandler@oriannesociety.org)
Benjamin S. Stegenga
Dirk J. Stevenson
The Orianne Society, Tiger, Georgia

Matthew C. Allender
Ellen Haynes
Emilie Ospina
Wildlife Epidemiology Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois

Ophidiomycosis (snake fungal disease) is an emerging disease caused by the fungus Ophidiomyces ophiodiicola. This fungal pathogen has now been detected in at least 35 snake species from states across the U.S. and has been implicated in population declines of some species. Relatively little is known about ophidiomycosis prevalence, susceptibility of different taxa, and the effects on individual survival. As part of efforts to track the distribution and prevalence of ophidiomycosis, we surveyed for O. ophiodiicola in the snake fauna of southern Georgia from September 1, 2016 through August 11, 2018. Snakes were captured using a variety of techniques, including drift fences, road cruising, and visual encounter surveys. All captured snakes were given a visual inspection for skin lesions consistent with ophidiomycosis and swabbed to test for O. ophiodiicola DNA. We collected 962 swab samples from 786 individual snake encounters and 34 snake species, representing 19 genera and 4 families. A total of 276 snakes (35.1%) had dermal lesions indicative of ophidiomycosis, and 137 snakes (17.4%) tested positive for fungal DNA. A majority (85.4%) of snakes that tested positive for fungal DNA had skin lesions. We tested multiple individuals of all six venomous snakes native to Georgia. At least one individual of all five species in the family Viperidae tested positive, including 28.2% of Cottonmouths (Agkistrodon piscivorus). No Eastern Coral Snakes (Micrurus fulvius) tested positive for ophidiomycosis. Eastern Indigo Snakes (Drymarchon couperi), a federally threatened species, had the second highest prevalence of O. ophiodiicola (43.9%), including cases where infections were negatively impacting the overall health of the individual. Based on a series of generalized linear models, species, month, county, and age were significant factors determining the ophidiomycosis status of snakes in Georgia. Overall, these results provide additional information about the epidemiology of ophidiomycosis, which has important implications for snake conservation.