HOST FACTORS AND TESTING MODALITY AGREEMENT ASSOCIATED WITH OPHIDIOMYCES INFECTION IN A FREE-RANGING SNAKE POPULATION...

Snake fungal disease (SFD) is an emerging mycotic disease caused by Ophidiomyces ophiodiicola, and has been demonstrated to impact snake populations of conservation concern in the United States negatively. Although Ophidiomyces has been shown to affect diverse taxa and to have a broad distribution, host factors associated with infected individuals and optimal testing protocols are not yet well characterized. The purpose of this study was to evaluate host factors and agreement across testing modalities associated with Ophidiomyces infection in a free-ranging snake population in southeast Ohio. Wild-caught snakes were swabbed and biopsied to test for Ophidiomyces via quantitative polymerase chain reaction (qPCR), culture, and histopathology. The host parameters assessed were species, sex, snout-vent length, body weight, month captured, and presence of gross skin lesions. A total of 8/30 individuals across three species-Black Racers (Coluber constrictor), Grey Ratsnakes (Pantherophis spiloides), and Eastern Gartersnakes (Thamnophis sirtalis sirtalis)-tested positive via at least one testing modality for Ophidiomyces infection. There were no associations between sex, snout-vent length, or weight and Ophidiomyces infection status. A higher proportion of individuals with gross lesions tested positive for Ophidiomyces than those without gross lesions, and most individuals that tested positive were caught in April or May. A low level of agreement was observed across testing modalities. Swab qPCR identified the most Ophidiomyces-positive individuals, and fungal culture identified the fewest at 0 individuals. Although there are limitations associated with a sample size of 30, these findings support the potential of this pathogen to infect individuals broadly across species and size, highlighting the relevance of this disease for snake conservation efforts. They also suggest that although little agreement was observed across test modalities, the concurrent use of multiple modalities is a more sensitive method for characterizing prevalence and distribution of Ophidiomyces.