Experimental reproduction of snake fungal disease by infection of snakes with Ophidiomyces ophiodiicola

In the past decade, snake fungal disease (SFD) has been increasingly recognized as an important emerging disease of wild North American snakes with potential population-level impacts. Until recently, however, a definitive... [ view full abstract ]

In the past decade, snake fungal disease (SFD) has been increasingly recognized as an important emerging disease of wild North American snakes with potential population-level impacts. Until recently, however, a definitive cause of SFD was not known. While the fungus Ophidiomyces ophiodiicola is often present within lesions, the association is correlative and a causative relationship had not been established. The U.S. Geological Survey’s National Wildlife Heath Center experimentally infected captive-bred corn snakes (Pantherophis guttatus) with O. ophiodiicola isolated from a wild snake with SFD. Lesions typical of SFD in wild snakes developed; these included raised, crusted scales, epidermal necrosis with intralesional fungal hyphae, epidermal, dermal and intramuscular inflammation, and fungal granulomas. Re-isolation of the fungus from these lesions was successful, fulfilling Koch’s postulates to establish O. ophiodiicola as a cause of SFD. In addition to developing lesions of SFD, infected snakes exhibited physiological and behavioral changes such as increased shedding frequency, anorexia, and abnormal basking behaviors. By allowing the examination and observation of infected snakes at known time points post-infection, this study contributes to an understanding of disease development that may help to explain SFD as a cause of mortality in wild snakes.