#chytrid

From the article:

For the first time in nearly two decades, Panama’s forest streams are once again home to flashes of bright yellow. The Panamanian golden frog (Atelopus zeteki) is being reintroduced to the wild 17 years after a fungal epidemic wiped it out in its native habitat. The return follows years of captive breeding, disease research, and carefully staged release trials aimed at navigating one of the most destructive wildlife pathogens ever recorded. [...] The golden frog is not the only species benefiting from these efforts. In the past year, PARC successfully reintroduced three additional species: the crowned tree frog (Tripion spinosus), Pratt’s rocket frog (Colostethus pratti), and the lemur leaf frog (Agalychnis lemur). Each release contributes to a growing body of knowledge about amphibian conservation in the age of chytrid fungus.

I teared up hearing this news. As someone deeply enmeshed in reptile and amphibian conservation for my entire adult life, the terror of chytrid has always loomed large. I have a close friend who is currently researching it, we talk about its conservation impacts frequently.

Golden frogs have been the poster child for chytrid extinction for so long. I remember always looking out for them at conservation facilities and thinking "this species literally only exists because we refused to just let them go extinct". To know that some of them are back in the wild already is overwhelming. Though I know we have made huge leaps in our understanding of chytrid, it is such a vicious disease that I don't think I was even sure I would live to see golden frogs return to Panama.

Many of the world’s most beloved frogs and amphibians are headed for extinction, but inside “The Ark” in Panama, some of those threatened species are given a fighting chance. Using innovative technology and breakthrough genetics, researchers have ignited a cadre of solutions to save these rare and cherished species.

The Ark at the Smithsonian Tropical Research Institute in Panama houses hundreds of large, captive communities of frogs, some of which no longer exist in the wild. Here, scientists hope to bring these species back from the brink of extinction and solve the world’s worst wildlife pandemic: an amphibian-killing fungus known as chytrid.

Scientists feared this frog was extinct. No one had seen a Sehuencas water frog in the wild since 2008. Just one “lonely” survivor, nicknamed Romeo, remained in captivity. A fungal disease has been wiping out frog populations worldwide, and scientists suspected it had killed off this one, too. But after 10 years searching Bolivian mountain forests for the long-lost amphibians, scientists have finally turned up a tiny group of five.

“It’s just incredible,” says herpetologist Robin Moore. A herpetologist studies reptiles and amphibians. Moore is the communications director at Global Wildlife Conservation in Austin, Texas. He was among the scientists who announced the rediscovery of this species on January 15.

Sehuencas water frogs (Telmatobius yuracare) live only in the Bolivian mountain cloud forests, where the climate is moist and cool. And that’s where researchers found the five. Unfortunately, this frog’s native habitat also provides the ideal conditions for the growth of a fungal infection with an ungainly name: chytridiomycosis (Kih-TRIH-dee-oh-my-KOH-sis). Most scientists just refer to it (and the fungus that causes it) as chytrid (KIH-trid).

The disease has killed off most Sehuencas water frogs. It was believed to have eliminated them all. Why the five newfound animals survived remains a mystery. “It could be that this small population has immunity,” Moore says. A genetic difference might make them resistant to the fungus. Or there might be something special about their environment, such as an unusually warm patch of cloud forest.

It could also just be luck. “Many species of frogs that disappeared for years — decades in some cases — have been seen again later,” says Karen Lips. She’s an ecologist at the University of Maryland in College Park. For example, Ecuador’s marsupial horned frog was missing for more than 10 years. In December 2018, researchers announced they had rediscovered it.

Sehuencas water frogs live only in cool mountain streams, where chytrid fungus easily grows. That makes scientists wonder how a lucky few survived.

CREDIT: R. MOORE

Reappearances can happen for several reasons, Lips says. There might be changes in the frogs, the fungus or the environment. “The simplest explanation is that once most of the frogs are gone, the fungus declines,” she says. With fewer hosts to infect, the disease can die off, too. Any surviving frogs can then slowly rebound until, years later, one hops in front of scientists.

The five newfound Sehuencas water frogs raise hopes that even more are still hiding in the wild. They also offer researchers a chance to help the species recover. Scientists have taken the five back to the lab. There, the frogs will breed and make more frogs that can later be returned to the forest.

There’s currently no good way to get rid of the deadly chytrid fungus in the wild. So scientists are eager to study frogs that have survived exposure to the disease, Moore says. They could offer clues to how the animals pulled through.