Sometime around 2008, a mysterious disease started killing off the Netherlands’ fire salamanders. Three years later, 96 percent were dead.The disease turned out to be Batrachochytrium salamandrivorans (Bsal), a relative of the chytrid fungus Batrachochytrium dendrobatidis (Bd) that has been implicated in the decline or extinction of some 200 frog species around the world.Scientists think Bsal originated in Asia and spread to Europe through the pet trade. And they believe it’s only matter of time before it gets to the U.S. – the world’s hotspot of salamander diversity, where nearly half of all species may be susceptible.Now, scientists are in a race against time to find the fungus as soon as possible after it gets here in the hopes that quickly enacted quarantines may stop, or at least slow, its spread. It’s like searching for a needle in a haystack — except the needle is invisible and the hay stretches for thousands of miles. Oh, and there may not actually be a needle at all. Such is the hunt for the salamander-killing fungus Batrachochytrium salamandrivorans in the United States. Its spherical spores, which feed on salamanders’ skin, are too small to see without a microscope. And they could be in any corner of the country; while known outbreaks of the pathogen remain isolated in Europe, research indicates that so-called Bsal is spreading through the international pet trade. Most Bsal researchers believe it’s only a matter of time until the emergent pathogen invades North America. And when it arrives, minimizing the impact on U.S. salamanders will hinge on early detection, they say. The longer the pathogen lingers surreptitiously, the further it will spread, and the more species it will infect and ultimately kill as a result. And so scientists have been out searching in droves. Hundreds of regions have been tested. Thousands of salamanders have been scanned for infection. Now even the public is involved. But are these efforts sufficient to find the pathogen before a catastrophic die-off gets underway? A familiar fungus The threat of Bsal is a painful déjà vu for amphibian biologists, who for decades have been battling its closest relative, Bd (also known as chytrid fungus), which is implicated in the decline or extinction of some 200 species of frogs.