Scheele's team estimates that the fungus has caused the decline of 501 amphibian species?"about 6.5 percent of the known total. Of these, 90 have been wiped out entirely. Another 124 have fallen by more than 90 percent, and their odds of recovery are slim. Never in recorded history has a single disease burned down so much of the tree of life. "It rewrote our understanding of what disease could do to wildlife," Scheele says.