Fungal infections contribute to significant morbidity and mortality in reptiles. Emydomyces testavorans is an emerging fungal pathogen associated with ulcerative shell disease in multiple chelonians, including species of conservation concern.1 While E. testavorans morphology, growth, and molecular phylogeny have been described, characteristics of lesion progression are unknown.1 We report the clinical course of E. testavorans infection in a cohort of juvenile alligator snapping turtles (AST; Macrochelys temminckii). Fourteen ASTs presented for evaluation in October 2016 following the death of one animal. Initial clinical signs included paronychia and nail loss (n=9), cutaneous ulceration (n=7), plastron ulceration (n=6), and rhinitis (n=5). E. testavorans was diagnosed using polymerase chain reaction (PCR) and culture, and all turtles tested negative for Ranavirus, herpesvirus, and Mycoplasma sp. Seven turtles died or were euthanized due to progressive clinical signs. Necropsy and histopathology revealed ulcerative dermatitis/rhinitis (n=8) and rare osteomyelitis (n=1), with no other significant findings. Lesions were PCR positive for E. testavorans and were colonized with morphologically consistent fungi. Most clinical signs in survivors resolved within several months; however, over the next 3 years, turtles developed progressive hyperkeratosis with excessive skin and scute shedding, and experienced intermittent cutaneous ulceration of the extremities. All turtles remain E. testavorans PCR positive. This report illustrates that E. testavorans can cause significant cutaneous lesions in ASTs and demonstrates that spontaneous clearance is unlikely. E. testavorans should be considered a pathogen of concern for AST head-starting and reintroduction programs.
The authors thank the veterinary students in the Wildlife Epidemiology Laboratory for their assistance caring for the turtles.
1. Woodburn DB, Miller AN, Allender MC, Maddox CW, Terio KA. Emydomyces testavorans, a new genus and species of onygenalean fungus isolated from shell lesions of freshwater aquatic turtles. J Clin Microbiol. 2019;57(2):e00628–18.