ABSTRACT Ophidiomycosis, commonly called snake fungal disease, has been linked to significant morbidity of free-ranging snakes in North America and Europe. Diagnosis of ophidiomycosis currently requires detection of skin lesions via physical exam or characteristic histopathology as well as detection of the causative agent, Ophidiomyces ophidiicola, through quantitative (q)PCR or fungal culture of a skin swab or tissue sample. While reliable, these methods require specialized training, invasive procedures (e.g., biopsy), and several days or weeks to receive results. Additionally, screening entire populations can quickly become costly. A fast, easy-to-use, cost-efficient, and sensitive screening tool is needed to optimize conservation strategies and treatment intervention. Our objective was to investigate the association between skin fluorescence under long-wave ultraviolet (UV) light (365 nm) and the detection of Ophidiomyces ophidiicola DNA using qPCR. Fifty-eight Lake Erie watersnakes (Nerodia sipedon insularum) collected in June of 2018 and 2019 from islands in western Lake Erie, Ottawa County, Ohio, US were visually inspected for skin lesions, photographed under natural light and UV light, and swabbed for qPCR analysis. Fluorescence was highly associated with the presence of skin lesions, and the presence of at least one fluorescent skin lesion was 86% sensitive and 100% specific for identifying animals with apparent ophidiomycosis, with a positive predictive value of 100%. While we recommend performing standard diagnostics along with fluorescence, our study supports the use of visual UV fluorescence identification as a preliminary, affordable, noninvasive, and field-applicable method to screen populations for ophidiomycosis.

Mortality events in eastern box turtles ( Terrapene carolina carolina ) threaten conservation efforts across the species range. These events are often under-diagnosed and, when observed, predictive health factors are unavailable prior to death. At Kickapoo State Park in central Illinois, USA, ranaviruses caused observed mortality events in amphibians and chelonians in 2014 and 2015. Following these outbreaks, eastern box turtles ( n =36) were affixed with radio transmitters and temperature data loggers to obtain repeated location and temperature data from spring 2016–spring 2018. Bimonthly, samples of blood and oral and cloacal swabs were collected to investigate health parameters (hematology and cytokine transcription) and presence of multiple pathogens. Deaths of instrumented turtles occurred in 2016 ( n =5), 2017 ( n =15), and 2018 ( n =2). The largest single die-off occurred in February 2017 ( n =7). Seventeen turtles were necropsied and multiple pathologic processes were identified, most frequently decreased adipose stores ( n =6). Two turtles had pathologic findings consistent with multisystemic inflammation. In addition, infectious pathogens were identified in turtles prior to death, but no single agent was associated with each mortality event. Ranavirus was not detected in any turtle. Hot spot analysis revealed spatial clustering at the center and edges of the study area for body temperature as well as for relative cytokine transcription of interleukin-1 beta, tumor necrosis factor alpha, and interleukin-10 associated with turtle death. Though no single causal factor could be identified, the information from this mortality event can direct future chelonian mortality investigations by providing baseline longitudinal data prior to death and in surviving turtles.