Fungal Shell Disease Associated with Emydomyces testavorans in a Zoo Collection of Western Pond Turtles (Actinemys marmorata)
American Association of Zoo Veterinarians Conference 2019
Geoffrey R. Browning1,2, MS, DVM; Louden Wright1,2,3, DVM; Ray F. Wack1,2,4, DVM, DACZM, DECZM (Zoo Health Management); Jenessa L. Gjeltema1,2,4, DVM, DACZM
1Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, USA; 2Sacramento Zoo, Sacramento, CA, USA; 3San Diego Zoo Global, San Diego, CA, USA; 4Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
Abstract
A novel onygenalean fungus, Emydomyces testavorans, has recently been isolated from shell lesions of both free-ranging aquatic turtles and those under human care, including western pond turtles (Actinemys marmorata) in conservation programs.1 This case series describes the clinical presentation, diagnosis, and treatment of both early and later-stage lesions in a group of zoo-housed western pond turtles. Thirteen 3-month to 2-year-old western pond turtles presented for superficial carapacial lesions characterized by keratin disruption, including depigmentation, flaking, thinning, and less commonly full-thickness necrotic lesions extending into underlying bone. Fungal culture and polymerase chain reaction (PCR) with sequencing for Emydomyces species were positive. Other diagnostics included bacterial culture, histopathology, hematology, biochemistry, radiography, and computed tomography. Management of this disease involved debridement of lesions when indicated and topical treatment with betadine and terbinafine, which helped to resolve clinical signs after 3–16 months of treatment. Following this, six approximately 3- to 17-year-old adult western pond turtles developed new lesions ranging from keratin depigmentation to deeper ulcerative lesions, which were positive for Emydomyces testavorans on fungal culture, PCR, and fungal sequencing. Clinical signs improved with a combination of topical therapy and debridement. The clinical findings, diagnostic and therapeutic approach outlined in this case series can aid clinicians in recognition and diagnosis of subtle lesions in early stages of disease and the management of more severe cases associated with this fungus in aquatic turtles. Further research is necessary to determine optimal treatment protocols and potential risk factors for this disease.
Acknowledgments
The authors thank Matt McKim and the reptile keeper team at the Sacramento Zoo for their support and the Western Pond Turtle Conservation Fund at the Sacramento Zoo for funding support.
Literature Cited
1. Woodburn DB, Miller AN, Allender MC, Maddox WC, Terio A. Emydomyces testavorans, a new genus and species of onygenalean fungus isolated from shell lesions of freshwater aquatic turtles. J Clin Microbiol. 2019;57:e00628–618.