Facial Disfiguration Syndrome in Free-Ranging Snakes Throughout the Eastern U.S.: An Emerging Pathogen Associated With Chrysosporium
1Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA; 2Prairie Research Institute, Illinois Natural History Survey, University of Illinois, Champaign, IL, USA; 3Department of Pathobiology College of Veterinary Medicine, University of Illinois, Urbana, IL, USA
With the current rate of declines in global biodiversity, it is apparent that wildlife diseases are serving as additional threats to population declines and potentially species extinctions. Free- ranging Eastern massasaugas (Sistrurus catenatus catenatus) have been reported susceptible to numerous health threats, one of which is a fatal fungal dermatitis. The disease presents as facial disfiguration due to granulomatous dermatitis and osteomyeltits with intralesional fungi. The keratinophilic fungi Chrysosporium has been identified in multiple, but not all cases, and has resulted in 100% observed mortality. The prevalence of Chrysosporium has thus been investigated since 2008. The PCR prevalence in this population was 4.4%, 0%, 1.8%, 0%, and 2.3% in the years 2008 through 2011. In concurrent health assessments, no predictable pattern using hematology, plasma biochemistries, or heavy metal analysis has been observed.
Facial disfiguration without the identification of Chrysosporium has occurred within this population, and highlights the limitations of antemortem diagnosis of this pathogen. Additionally, collaborators have observed a similar disfiguration syndrome in timber rattlesnakes, black rat snakes, and yellow-bellied water snakes from across the eastern US, but have inconsistently identified Chrysosporium. However, a garter snake (Thamnophis spp.) from a separate location in Illinois with similar clinical signs was identified with a Chrysosporium with 100% sequence homology to the massasauga isolate. These additional cases from distinct locales designates that this syndrome is widespread or becoming widespread and should be considered a potential threat to ophidian biodiversity and future studies are needed to truly identify the causative agent or agents.