Study provides new clues to killer frog disease

There are some unexpected results from a new study that may change the way scientists fight the epidemic.

The disease chytridiomycosis has led to the decline or extinction of over 500 species of salamanders.

"However, not all amphibian species are susceptible to chytridiomycosis, and some species and populations that underwent initial declines are surviving or increasing, despite the continued presence of the pathogen."

Australian lace-lid frog populations were wiped out in upland sites and remained absent, while the waterfall frog had the same experience but began recolonising upland sites. The stony creek frog did not fall at any elevation.

The reasons for the differences between species and populations are not entirely clear, but the differences may be due to differences in the organisms that live on the frog.

Four Australian frog species from the same area had different responses to chytridiomycosis, according to scientists.

They found that different frog species have different microbiomes.

The species with the lowest ability to recover was lace-lids. It matches what other studies have found.

It was surprising that lace-lids had high levels of anti-fungalbacteria that are thought to protect against chytridiomycosis. The people with the highest levels of chytridiomycosis were also the people with the highest levels of anti-fungalbacteria.

Despite the fact that lace-lid populations have not recovered, the Australian lace-lid frog and the waterfall frog have the highest abundance of anti-fungalbacteria.

Scientists have more questions and a variety of answers from the findings.

It is possible that the presence of the fungus that causes chytridiomycosis actually causes anti-fungalbacteria to thrive, or that there is some other factor in the frog's environment that favors both thebacteria and the pathogen. The only way to survive high infections is to have high levels of anti-fungalbacteria.

The research has implications.

In laboratory trials, seeding infections with anti-fungalbacteria can reduce mortality and allow the frog to clear the infections.

It's considered a promising strategy to mitigate the disease in wild populations. According to our results, this strategy may not work unless a diverse range ofbacteria is used, and they may need to be tailored for each frog species.

More information: Donald T. McKnight et al, The interplay of fungal and bacterial microbiomes on rainforest frogs following a disease outbreak, Ecosphere (2022). DOI: 10.1002/ecs2.4037 Journal information: Ecosphere