Over the course of a day in June 2013, some 200,000 wood frog tadpoles perished in a pond in Brunswick, Maine. It was a grim scene: Researchers report blood loss from throats and legs, as well as tadpoles whose skin had shed.
Bowdoin College biologist Nathaniel Wheelwright didn't have to travel far to make this harrowing discovery - the pond was in his backyard, the Associated Press reports. Wheelwright's postmortem analysis revealed evidence of ranavirus, a disease responsible for mass deaths of amphibians around the globe.
But this is only the second time ranavirus has been recorded in Maine - and, as Wheelwright and his Univeristy of Tennessee colleagues write, may be "the largest and most rapid event reported in amphibians" associated with the illness. Ranavirus can spread by transmission from frog to frog (including from pets to wild amphibians), or may disperse through waterways.
Tipped off to ranavirus' spread, the researchers call for increased vigilance of amphibian health in the area. And across the U.S. amphibians are faring poorly, facing not only ranavirus but a fungal disease called chytrid, as well as shrinking wetlands.
A 2013 PLOS ONE study found amphibian populations declining at a rate of 3.7 percent each year. "Now, more than ever, we need to confront amphibian declines in the U.S. and take actions to conserve our incredible frog and salamander biodiversity," said Brian Gratwicke, an amphibian expert with the Smithsonian Conservation Biology Institute, in a statement accompanying the study.