Species at Risk

"I've seen [fungal infection] it go [infected snakes] really, really rapidly."
"[What makes a species susceptible ...?] The trait is being a snake. [The study represents] 'a call to arms' to monitor the potentially devastating infection]."
Frank Burbrink, curator, American Museum of Natural History, New York

"People started being on the lookout [with the realization that snakes were being seen in wider geographic areas infected by the fungus]."
"[It could turn out] that what we're looking at is the tip of the iceberg of this disease. [New analysis] supports the notion that no species is safe."
"Let's start doing our homework, so if the sky does start falling, we can respond quickly."
Jeffrey Lorch, microbiologist, U.S. Geological Survey, National Wildlife Health Center, Madison, Wisconsin

Eastern racer (Coluber constrictor) showing signs of fungal skin infection. Obvious external abnormalities are an opaque infected eye (spectacle), roughened crusty scales on the chin, and several discolored roughened scales on the side of neck. Snake captured in Volusia County, Florida, in January 2013 (case 24266). Photograph by D.E. Green, USGS National Wildlife Health Center

From the far northern edge of timber rattlesnakes' habitat in New Hampshire came a report eleven years ago of a discovery of an isolated winter den of the snakes which had undergone a population crash. Signs of inbreeding were detected, but on examination it was also found that skin lesions called hibernation blisters (or hibernation sores) afflicted the snakes. These discoveries alerted the attention of biologists.

And then similar instances of snake populations being afflicted began popping up in Massachusetts, followed by massasauga rattlesnakes in Illinois were also identified as suffering from this mysterious malady. The fungus causing the lesions, Ophidiomyces ophiodiicola, was identified as the culprit by 2009, found to infect over two dozen species of snakes in the United States. Snakes sometimes made a swift recovery from the fungal infection, while others died.

A conservation biologist at the University of Maryland, Karen Lips, collaborated with Drs. Burbrink and Lorch to undertake an analysis of the situation. That study reached the conclusion that vulnerability to the fungal infection was common to all snake species. The research reached its conclusion based on a mathematical analysis of 23 wild-infected species in the United States and two in Europe in a  study of their evolutionary relationships.

Northern water snake (Nerodia sipedon) with crusty and thickened scales overlaying raised blisters as a result of a fungal skin infection, captured from island in western Lake Erie, Ohio, in August 2009 (case 22747). Photograph by D.E. Green, USGS National Wildlife Health Center.

The three scientists likened this devastating fungal threat to the existence of snakes to the calamitous fungal infection that has been killing bats, exposed to the virus causing white nose syndrome, as well as other fungal diseases laying waste to frog and salamander populations. White nose syndrome, a fungal disease that appears to have emanated out of Europe has caused millions of bats in North America to die.

Center for Biological Diversity

Since the late 1990s, millions of frogs have succumbed to Chytrid fungi, utterly devastating some frog populations. As a result, salamander species have been banned from import into the United States since a Chytrid fungus represents a threat to them, too. The ultimate damage to these wildlife populations can only be theorized. These are creatures, particularly snakes, that are averse to showing themselves.

Because they remain largely hidden it can be difficult to study them closely and the effect this newly identified disease has on snake populations. Some snakes are seen to survive the fungus, shedding their skin. On the other hand, the fungus is capable of burrowing under the skin, and thus becoming fatal. Moreover, it seems likely that the fungus can live in soil for a period of time, seeking a host to infect.

According to Dr. Lorch, reports of lesions resembling the fungal infection can be dated back to the 1950s and evidence of the disease found in captive snakes go back to around 1980. Although the fungus may be native to North America, it has been discovered to be present in wild snakes in Europe. Now that biologists have been alerted, the hope is that more monitoring of snake populations and allied research may answer more questions.

The hope is that snakes will turn out to be more resistant to the infection than bats or frogs have proven to be, to the fungal diseases that have laid waste to their populations.