Skip to main content

Snake fungal disease

Timber rattlesnake with SFD lesion

Timber rattlesnake with SFD lesion.
© Josh Kapfer

Common gartersnake with raised bumps.

Common garter snake with raised bumps, indicative of SFD.
© Erik Wild

Eastern massasauga with swollen mouth

Eastern massasauga with swollen mouth, indicative of SFD.


Snake fungal disease (SFD) is an emerging disease that impacts numerous species of snakes and has been found throughout much of the eastern United States. It is caused by a fungus, Ophidiomyces ophiodiicola, and can cause lumps along the snake’s face, neck and body. In other snakes, skin blisters or scabby areas may be the only sign of disease.

Snake fungal disease has the potential to decimate local snake populations because it can prevent snakes from effectively feeding and drinking and makes them more susceptible to predators

The disease has been found in 14 of Wisconsin’s 21 snake species.

Much is still unknown about SFD and, therefore, several groups have developed FAQs.

Report a snake with signs of this disease

Citizens, researchers and biologists are encouraged to report all snakes with signs of this disease. If you see an infected animal, please note the following:

Help monitor the health of Wisconsin’s wildlife by reporting your sightings of sick or dead snakes to your local DNR office or email the Wisconsin DNR.