A small population of eastern massasauga rattlesnakes already in decline shows evidence of debilitating fungal infections, the University of Illinois reported Tuesday.
Researcher Matthew Allender conducted necropsies on dead snakes and identified the pathogen that had killed them as the fungus Chrysosporium.
The fungus plagues portions of the pet reptile industry but is not normally seen in the wild, he said.
"Chrysosporium causes disease in bearded dragons and in other snakes and it's a bad bug," Allender said. "We see it in captive animals worldwide, but we don't typically find it in free-ranging animals."
Chrysosporium also is emerging as a dangerous infection in humans with weakened immune systems, he said.
Allender said he has heard of similar reports of the fungus in other snake populations.
"They seem to be having a similar problem in timber rattlesnakes in New Hampshire and Massachusetts," he said.
The outbreak of a fungal infection in endangered snakes is a "yellow flag" that warrants more study, he said.
"Wildlife diseases and human health are not that different. And often wildlife are our window into a weakened environment that leads to disease in both people and animals."