From Africa to the Americas, frogs and other amphibians are vanishing from the planet at an alarming rate. Not since the dinosaurs has the world seen such a rapid extinction. In the past few decades, as many as 130 species of frogs and other amphibians may have been wiped out. Right now, one-third to one-half of the world's amphibian species are threatened. Climate change, pollution and a silent killer — chytrid fungus — are the main suspects in the mass disappearance. Chytrid fungus is currently unstoppable and untreatable in the wild. The World Conservation Union calls it the worst infectious disease ever recorded among vertebrates.