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Snake Fungal Disease

Snake fungal disease (SFD) results from a skin infection that has been documented only in snakes. Historically, reports of snakes with skin infections of unknown origin have been sporadic. Recently, the number of reported cases of skin infections in snakes has increased substantially.

Examples of Snake Fungal Disease (SFD)
Examples of Snake Fungal Disease (SFD). 

SFD, confirmed in numerous species of snakes, is caused by the fungus Ophidiomyces ophiodiicola. As of August 2017,  O. ophiodiicola has been detected in at least 23 States and one Canadian Province. However, researchers suspect that SFD may be more widely distributed than these documented cases suggest, because efforts to monitor the health of many snake populations are limited. Snake fungal disease may also be underreported in populations where it affects snakes infrequently or in species that develop less severe illness. Signs of SFD include

  • crusted or ulcerated scales,
  • nodules (that is, abnormal bumps) under the skin, and
  • facial disfiguration that can be quite severe, leading to emaciation and death.


USGS Contributions to Understanding Snake Fungal Disease

Scientists at the USGS are recognized leaders in advancing understanding of SFD. Specific contributions
by USGS researchers include:

  • Establishing that O. ophiodiicola is the cause of SFD;
  • Developing laboratory methods to detect O. ophiodiicola;
  • Studying the development and disease progression of SFD in captive snakes;
  • Diagnosing SFD in snakes submitted by partner agencies to the National Wildlife Health Center;
  • Coordinating field surveillance to monitor SFD infections in new populations or species;
  • Establishing the past extent and geographic distribution of SFD and projecting its future course;
  • Identifying other fungi, bacteria, or viruses that may independently cause skin infections in snakes or contribute to development of SFD; and
  • Examining how SFD alters the behavior and survival of infected snakes to better understand the how the disease affects populations.

--Snake Fungal Disease in North America: U.S. Geological Survey Updates