Frogs Develop Resistance to Chytrid Fungus

by Katelynn Fleming

Today, concerns of species going extinct are on top of the list of conservation efforts. However, it is nice to know that some species can bounce back even after species-devastating occurrences.

In the late 1990’s, the fungus nicknamed Bd for its scientific name, Batrachochytrium dendrobatidis, was identified as the culprit of widespread frog death in Panama. It was believed that it even drove some species to extinction. However, researchers have revisited the site and, according to the March 30 article in Science, they have found that frog populations are larger than expected, including species thought to be extinct.

According to the U.S. National Park Service, an amphibian’s skin is critical to its health because it absorbs water and breathes through it. The chytrid fungus inhibits these processes by growing on the skin and eventually depriving the frog of air and water until it dies. The fungus is natural, but normally it grows on dead frogs. The jump to living frogs resulted in the extinction of entire frog species all over the world, a significant and permanent decrease in biodiversity.

According to Science News, researchers who visited the sites tested the fungus and showed that it had not weakened over time, as sometimes happens with pathogens. The modern fungus was still lethal to frogs from captive populations that had been collected before the fungus struck their area, but not to the frogs there today in most species. In a few species, it was still lethal to even modern frogs, further suggesting that some species have developed resistance more than others.

Researchers think that this resistance comes from an increase in skin secretions’ ability to reject the fungus, but applying this hypothesis is hard to do, as a Wired article explains. First and foremost, they still do not have enough information to create a cure that could be applied to the frogs without resistance. If it could be found, the cure could take the form of a solution that could be applied onto their skin to reject the fungus. However, the amphibian microbiome is still little understood and such an approach might cause damage. Researchers have also considered selective breeding to increase the amount of frogs with resistance, but it would result in decreased genetic diversity. It is as yet unknown whether it would be worth the loss.

It is too early to tell for sure whether the population is growing, but the evidence is hopeful. All that can be done for now is try to protect the frogs from polluted water and loss of habitat to give them the best chance they can to survive. If the hope provided by this article proves reality, evolution might just save what humans cannot.

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