Morbidity and mortality in snakes submitted to the Southeastern Cooperative Wildlife Diseases Study from 1977-present

Snake fungal disease (SFD), a potentially fatal fungal infection caused by the fungus Ophidiomyces ophiodiicola (Oo), has been diagnosed throughout the eastern United States and has been associated with population declines in... [ view full abstract ]

Snake fungal disease (SFD), a potentially fatal fungal infection caused by the fungus Ophidiomyces ophiodiicola (Oo), has been diagnosed throughout the eastern United States and has been associated with population declines in some species of rattlesnakes. A retrospective review of snake cases submitted to the Southeastern Cooperative Wildlife Disease Study (SCWDS) in Athens, GA from 1977 to 2015 was performed to further investigate the incidence of SFD as well as other potential causes of morbidity and mortality of snakes in the southeastern United States. Fifty-four reports were reviewed, including 21 carcasses that had complete necropsy examinations. Snake fungal disease was diagnosed in 16/54 (30%) of total snake submissions. Diagnosis of SFD was based upon the presence of characteristic microscopic lesions and detection of the fungus either via fungal culture followed by conventional PCR or real-time PCR. In 11 cases, the detection of Oo was determined retrospectively through real-time PCR testing of archived tissue or samples from paraffin-embedded blocks. Five cases were suspected to be SFD due to the presence of characteristic microscopic lesions without confirmation of the presence of Oo using molecular methods. Snake submissions overall and diagnoses of infectious diseases (predominantly SFD) have markedly increased since 2013. Cases of SFD were documented from GA, FL, WV, NC, KY, and TN in snake species with both terrestrial and aquatic life histories. Non-SFD diagnoses from snake submissions included non-specific bacterial and fungal infections, amebiasis, cryptosporidiosis, trauma, and suspected intoxications with chlorpyrifos and cyanide. Further investigation of causes of morbidity and mortality and ongoing population monitoring are needed to understand the impacts of Oo on free-ranging snake populations.