These frogs have developed resistance to deadly chytrid fungi

Frogs, like the genus Diasporus, survive a deadly fungus in El Copé, Panama. (Credit: Graziella DiRenzo)

A frog community in Panama may have developed resistance to a deadly fungus that would have put one-third of the world's amphibian population at risk, according to an article published on Wednesday. [Oct. 3] in Ecological applications.

The mushroom is calling Batrachochytrium dendrobatidisor Bd. It is also commonly called chytrid fungus. In 1999, researchers linked the deaths of amphibians, mainly frogs, to specific strains of the fungus, which attack the skin of animals. Frogs use their skin for breathing and the damage caused by Bd can disrupt this function and cause death.

A study from May to Science argued that Bd originated from the Korean peninsula 50 to 120 years ago. The fungus probably has spread around the world via amphibian exports intended for food, traditional medicines and domestic animals.

The question posed by scientists is how to control the Bd, since it is already widespread around the world. In other words, how do you put the genie back in the bottle? The answer could be that you can not. But some or many species may recover by forming resistance to the fungus. And it seems to have happened in this community of frogs in El Cope, Panama.

Hope for infected frog populations

In 2004, 74 species of amphibians were decimated by the Bd El Copé. In four years, 30 species have been extinct and nine at risk, the Ecological applications the paper says.

A team led by researchers from the University of Maryland conducted a field study at El Cope from 2010 to 2014 to examine the extent of BD on the population, composed mainly of frog species . They used a statistical model to assess the dynamics of the disease.

The researchers found that infected animals died at a rate comparable to uninfected animals, suggesting that infected amphibians had developed resistance to the fungus. The study indicates that the survival of infected and uninfected amphibians is around 96%.

Other research teams on amphibians infected with Bd have also seen healings, the paper says. And it is becoming increasingly clear that the virulence of BD is weakening over time, reducing the number of amphibian deaths.

"Our results point to hope for amphibian populations that persist in the face of major threats," says Graziella DiRenzo, currently a postdoctoral fellow at the University of California, Santa Barbara, and lead author of the paper.

"But that does not mean that amphibian populations will regain their abundance before the threat," says DiRenzo, "or that the ecosystem structure has not been compromised."