Have You Ever Seen Dominoes Set Up to Fall?

A tragedy unfolds for entire ecosystems as humanity unwittingly sets a oendemic off across the globe.

There are hundreds of species of chytrid fungi, and most of them are unobtrusive decomposers. But Bd is an oddball: It has a fanatical taste for the proteins in amphibian skin. In the early 20th century, human activity—such as trade and war—accidentally spread the fungus around the world.
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Some amphibians can tolerate Bd, but in many others, it degrades the animals' permeable skin, which they use to breathe and regulate their water levels. Runaway infections trigger a death spiral that ends in cardiac arrest.

Not only is Bd lethal, it's also devastatingly effective at spreading. While most pathogens target specific hosts, Bd can infect at least 695 species to varying degrees. It also doesn't kill its victims quickly, which increases the odds that the fungus will spread. Species it doesn't kill, such as the American bullfrog, can act as reservoirs.

https://www.nationalgeographic.com/animals/2019/03/amphibian-apocalypse-frogs-salamanders-worst-chytrid-fungus/