“It did a really huge number on an entire genus of frogs in Central America,” said Marm Kilpatrick, a disease ecologist at the University of California, Santa Cruz (UCSC). The fungus probably caused several species of this harlequin frog (Atelopus) to go extinct, he added.

Chytrid is also largely responsible for endangering California’s mountain yellow-legged frog (Rana muscosa).

"It's the single biggest threat to vertebrate diversity in the world," Kilpatrick said.

The fungus, which seems to attack only amphibians, causes a thickening of the infected amphibian’s skin, preventing the animal from breathing properly and interfering with its electrolyte balance. The infection can eventually lead to cardiac arrest, although some frog species are better able to cope with it than others.

A new study delving into how this fungus spreads has now linked chytrid outbreaks in California—one of the more recent areas experiencing huge amphibian die-offs—to the spread of the African clawed frog (Xenopus laevis).

And the study’s implications could extend far beyond California, providing scientists with a potential road map showing how a devastating infection continues to spread around the world.