These frogs evolve to survive a deadly mushroom that tries to stop their hearts

Two decades ago, scientists discovered a kind of archaic fungus infecting frogs in Central America. called Batrachochytrium dendrobatidis, or fungus, the fungus appeared to be a rare and devastating threat: it altered the skin chemistry of infected hosts, depriving them of their ability to drink water and absorb electrolytes through their skin, eventually stopping their heart. He was blind, able to jump easily between frog species and kill almost all his hosts.

In a white paper published in 2007, the International Union for the Conservation of Nature (IUCN) wrote that because of the fungus (and human activity that allowed it to spread throughout the world), "the crisis The world of amphibian extinction and its current dynamics are the worst we have ever seen, "adding," This is the worst infectious disease ever recorded among vertebrates in terms of number of species affected and its propensity for disease. lead to extinction ".

A new document offers good news: a tropical site has shown that frog ecosystems can adapt to the fungus. Some infected species die and those who survive the infection – probably because they have evolved to become resistant to its fungus. effects, and because the fungus itself has become less lethal. [7 Iconic Animals Humans Are Driving to Extinction]

In an article published yesterday (October 3) in the journal Ecological Applications, researchers described how they had studied tropical frogs in a region of Panama called El Cope, about 0.8 square kilometers (2 square kilometers) . Between 2010 and 2014, researchers slowly wandered around the area, picking up frogs and wiping them for signs of the fungus. They divided the areas into 20 by 20 square meters, carefully recording frogs of each species in each square and indicating whether they were infected or not.

While nearly half of the region's frog species were extinct when the epidemic reached El Cope in 2004, between 2010 and 2014, the remaining populations appeared to have stabilized, discovered researchers. The infected frogs seemed to survive longer, fewer frogs were infected and the researchers did not find the type of dramatic decline in the population that occurred during the initial hatch.

"Our results are really promising because they lead us to conclude that the El Copé frog community is stabilizing and not falling into extinction," said University biologist Graziella DiRenzo. from California to Santa Barbara, and lead author of the article, in a report. "This is a big problem with chytrids around the world, and before this study, we knew very little about the communities that survive an epidemic, and in some areas it's still a black box."

The general outlook for frogs is not good, noted researchers, describing the daily reality of frogs in the region as "sinister" in the newspaper. But they showed that things could be much worse.

"Our study found that, even though there are many infected individuals, about 98% of them are at very low levels," said Karen Lips, a biologist at the University of Toronto. 39, University of Maryland and co-author of the newspaper, the statement. "We know that early on, several species played a key role in spreading the infection, like Mary Typhoid, but some of these species have now disappeared, so the ecosystem is totally different.This is almost not comparable to what it was before. "

The long-term prospects for frogs are unclear, whether in Panama or elsewhere. However, Lips said: "If enough species of frogs in a given place can survive and persist, then hope that someday a new vibrant frog community will replace what has been lost."

Originally posted on Live Science.