Snake Fungal Disease (SFD) is now in California

Some symptoms of Snake Fungal Disease – from Lorch, et. al., 2016

Hyphae of Ophidiomyces ophidiicola from University of Toronto

Big myco-ecological news this week, and unfortunately, not in a good way. A recent California Department of Fish and Game Announcement confirms that the rapidly-emerging Snake Fungal Disease (SFD) is now present in California, having been found on a California Kingsnake (Lampropeltis californiae) in the Sierra Foothills.

The causal agent has been shown to be the fungus Ophidiomyces ophidiicola; with symptoms ranging from thickened and lesioned skin, jaw malformation, and behavioral shifts including inability to feed, hibernate, and molt normally. This fungus is thought to be a soil saprobe under normal conditions, but which is perhaps increasingly expressing a pathogenic ecotype in a warming environment (perhaps not directly due to temperatures, but rather their correlates).

SFD has only been recognized for a little over a decade, and until now has been mostly confined to Eastern North America, which obviously makes the extreme western disposition of this new record especially alarming. In eastern North America, some threatened populations of Timber Rattlesnake and Massasauga have been heavily hit by SFD, with high resulting mortality rates. Other snake species susceptible to SFD include Milk Snakes, Black Ratsnakes, garter snakes, Cottonmouth, Black Racer, and quite a few others (see this excellent SFD summary from the USGS).

Although we don’t know whether SFD will become as widespread in the California as it has in the Eastern US, the important ecological role of snakes as predators of rodents (and even as seed dispersers!) in combination with apparent generalized population declines in recent decades suggest we should monitor this situation closely.

Folks should learn the symptoms of SFD and upload photos of potentially affected snakes to iNaturalist.