Spread of snake fungal disease mirrors bat-killing white-nose syndrome
U.S. Geological Survey scientists said they’ve identified the fungus that’s been taking a toll on snake populations in parts of the U.S. and warned that global warming could put more snakes at risk.
The fungal disease killing snakes has some eerie similarities to white-nose syndrome, which has wiped out bat populations across the eastern half of the U.S. The snake and bat pathogens emerged in North America in the mid-2000s. Both are moving from east to west across the United States and into parts of Canada.In the wild, most snakes respond to the fungis fungus (Ophidiomyces ophiodiicola) by repeatedly molting 15 to 20 days after exposure. In lab tests, the scientists said they observed some potentially lethal behaviors that could increase snakes’s risk for predation or starvation in the wild. For example, infected snakes rested in exposed areas of their cages and some snakes were reluctant to eat. The uninfected snakes acted normally.
“These behaviors are uncharacteristic of healthy snakes and demonstrate how SFD can put snakes at risk in the wild,” said Jeffrey Lorch, a USGS National Wildlife Health Center scientist and the lead author of the study. “Climate change could promote growth of O. ophidiodiicola and hinder recovery from SFD because snake immunity is highly dependent on environmental conditions.”
Wild snakes are valuable because they consume pests that damage agricultural crops, prey on rodents that can carry disease and serve as food for many predatory animals. However, some snake populations in the midwestern and eastern United States have declined since 2006 as a result of is the definitive cause of the skin infections in snakes known as snake fungal disease.
“The loss of certain snake species in eastern North America could have widespread negative impacts on ecosystems,” Lorch said. “Pinpointing the SFD-causing fungus can help conserve snake populations threatened by this disease.”
The scientists infected eight healthy captive-bred corn snakes with O. ophiodiicola in the laboratory. Within days after exposure to the fungus, all snakes developed swelling followed by lesions identical to those observed in wild snakes with SFD.
These lesions contained the same fungus to which the animals were exposed. Snakes that were not infected in the laboratory did not develop lesions and did not harbor O. ophiodiicola.
O. ophiodiicola has consistently been found on snakes with SFD, but this new study is the first to prove that the fungus is the actual cause of the disease. The USGS has confirmed SFD in at least seven species of snakes in nine states: Illinois, Florida, Massachusetts, Minnesota, New Jersey, New York, Ohio, Tennessee and Wisconsin.
For more information on SFD, please visit the USGS National Wildlife Health Center website.