Frog-Killing Plague Is ‘Most Deadly’ Disease Known To Science

The 'Batrachochytrium dendrobatidis' microbes are causing a significant decline in various amphibian populations.

A Waxy Tree Frog rests on a zookeeper's hand.
Dan Kitwood / Getty Images

The 'Batrachochytrium dendrobatidis' microbes are causing a significant decline in various amphibian populations.

A study published in Science on Thursday is the first worldwide analysis of an amphibian fungus that has been killing frogs for decades, and it doesn’t bode well: the plague is worse than previously believed. As The New York Times reports, populations of more than 500 species of amphibians — previously believed to be just 200 — have been significantly decreasing as a result of the outbreak. Not only that, but at least 90 species have likely been wiped out, which is a larger number than earlier estimates.

Wendy Palen, a biologist at Simon Fraser University and co-author of a commentary paired with the study, addressed the results.

“That’s fairly seismic. It now earns the moniker of the most deadly pathogen known to science.”

As per Wired, scientists knew that the Batrachochytrium dendrobatidis microbes — Bd, for short — were a threat. Previous research revealed that two species of the fungi have the ability to infect amphibian skin, which inhibits its ability to respire and absorb water.

Bd was first spotted back in the 1970s when researchers noticed certain frog populations on a fast decline, which led to some species going extinct in the 1980s. And since the frogs were living in clean, healthy habitats far from deforestation and pollution, it was puzzling.

Fast forward to the late 1990s and scientists discovered that Bd was affecting frogs in Panama and Australia. Although it began popping up in other countries, scientists believe that Bd came from the Korean Peninsula, since amphibians from Asia appear to be immune to the disease. It is likely that Bd made its way to other countries through the pet trade.

Infected amphibians transmit the disease via spores that float in water or by contact with other animals. After infection, the disease makes its way through their skin cells and proliferates.

But it’s not all bad news: the new review also suggests that the decline in amphibian populations peaked in the 1980s, and an increased understanding of the fungi could help curb its deadly effects.

Benjamin Scheele, an ecologist at Australian National University and lead author of the recent study, spoke about the data.

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“We’ve learned, and we’re dealing with it better. I guess the question is always, ‘Are we doing enough?’ And that’s debatable.”

Daniel Greenberg, co-author of the Science commentary, added that Bd-infected frogs could make their way into the pet trade and infect a large number of vulnerable amphibians.

“It could be a meltdown of the ecosystems over there.”

“It’s just Russian roulette, with moving pathogens around the world,” Scheele added.