Chytridiomycosis often called chytrid or BD — is a highly infectious fungal disease linked to the widespread decline of more than 200 amphibian species around the world. It is the worst wildlife disease ever recorded in terms of the number of species affected. Chytrid has been particularly disastrous for frogs native to Australia and the Americas, where most species have no resistance to the invasive fungus.

Chytrid is so devastating in part because it depends on water for part of its life cycle — just like frogs and salamanders. Chytrid infects its victims via fungal spores that swim through water and embed themselves in their skin. Once embedded, these spores disrupt the animal’s immune system and eat away at its skin, leading to lethargy, loss of motor function, and eventually a heart attack. Currently, there is no known cure.

Luckily, conservationists are fighting back, creating captive insurance populations for at-risk species and racing to find a path to disease resistance. Learn more about one such effort in Panama in the Wild Hope episode, The Frog Ark.