More than 200 frogs, toads, and other amphibian species around the world are threatened by a lethal skin disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Last year, a related pathogen was discovered decimating populations of fire salamanders in the Netherlands and Belgium. The new microscopic killer, known as B. salamandrivorans (Bs), is only the second known species of its kind found to infect vertebrate hosts.