Some snake populations appear at-risk from spreading fungal pathogen
First the chytrid fungus started killing amphibians, then white-nose syndrome emerged to devastate bat populations, and now, there’s Ophidiomyces ophiodiicola, a snake-killing fungus that appears to be much more widespread than thought, according to new research from the U.S. Geological Survey.
The USGS report concluded the fungus is present in at least 20 eastern states and in many snake species not previously known to harbor the fungus. These findings increase the total number of confirmed susceptible snake species to 30. Snakes affected by Snake Fungal Disease include the threatened eastern massasauga rattlesnake. The research also shows that SFD infections are often mild, but there are unknown factors that cause outbreaks of severe skin disease and death.
“Some snake populations in the eastern and midwestern U.S. could eventually face extinction as a result of SFD,” said Jeff Lorch, a USGS scientist and the lead author of the report. “Our new findings increase our understanding of the geographic extent, species susceptibility and manner of development of this disease. These results will offer important clues regarding how to manage SFD.”
Snakes are valuable because they prey upon pests that damage agricultural crops and rodents that can carry disease, and they serve as food for many other animals. SFD, which first gained attention in the U.S. in 2006, produces thickened skin, ulcers, blisters and emaciation in infected snakes.
The USGS scientists, in collaboration with the Wisconsin and Minnesota Departments of Natural Resources, also captured 206 snakes from Minnesota and Wisconsin during late April to late May in 2013-2015, after the snakes emerged from hibernation. Forty-one percent of the captured snakes had skin lesions similar to those associated with SFD, and almost all of the lesions were relatively mild. Over half of the samples tested from these snakes were positive for the O. ophiodiicola fungus.
“Our findings suggest that O. ophiodiicola most often causes mild, non-lethal skin lesions in snakes, which gives us hope that snakes may be able to clear some infections,” Lorch said. “However, we still need to determine why these mild infections are becoming more severe and fatal in certain areas.”
The study is published in the journal Philosophical Transactions of the Royal Society B. For more information about USGS wildlife disease research, please visit the USGS National Wildlife Health Center website. Information about SFD is also available on the USGS Wetland and Aquatic Research Center website.