Fighting the Frog Killer: Ending the Chytrid Fungus Crisis with More Fungus

For more than 20 years, the chytrid fungus has been wreaking havoc on frog populations all over the globe, wiping approximately 200 species to extinction including 90 percent of the endemic mountain yellow-legged frogs. The origin of the killer fungus is a mystery, but scientists are up in arms to fight the deadly fungus, using none other than high doses of the fungus itself.

Yes, it's a battle of fungus versus itself, as scientists have decided to boost the immunity of frogs by pumping up large amounts of the fungus to their bodies, NPR reports.

Tagged as “the worst infectious disease ever recorded among vertebrates," the chytrid fungus (Phylum Chytridiomycota), according to Amphibian Ark, thrive in water or moist environments and feed on rotting organic matter.

When a frog is infected with Chytridiomycosis, the disease caused by the fungus, its skin will have large amounts of keratin making it thick and tough. For amphibians like frogs, having tough skin is deadly because they absorb water and other nutrients via their skin. The disease could cause the frog's heart to stop, leading to death.

"The skin is a really important part of the frog. They breathe through their skin underwater," Jessie Bushell, director of conservation at the San Francisco Zoo, told NPR.

Bushnell is part of a search and rescue experiments of mountain yellow-legged frogs, where she and scientists from the San Francisco Zoo and Oakland Zoo are rearing this species with booster immunity by slowly exposing each frog with small amounts of the chytrid fungus.

Bushnell believes that by infecting the frogs and familiarizing them with the fungus in the lab, there's a higher chance that they can fight the chytrid fungus when they encounter them in the wild. In the experiment, she lets the frog get sick to introduce the fungus to its immune system and figure out a way on how to defend it. Then, she gives them an anti-fungal treatment just when the animal is in the nick of death.

"It's the best chance that we know how to give them," said Roland Knapp, a biologist with UC Santa Barbara, adding that it may seem "a bit crazy" but the method have showed promising results.

Knapp says that in order to save the population of the mountain yellow-legged frogs, they have to find a way to maintain that these frogs survive until evolution plays out.

"We're staring at what could be the extinction of a significant fraction of the world's amphibians. So if we can do something to reverse that, even for a few species here and there, we should try to do that," Knapp said.