Frog saunas are helping endangered frogs survive the devastating effects of a deadly fungal disease

Researchers from Macquarie University have used heat to develop a simple and effective way to help endangered frogs survive the devastating effects of a multi-species pandemic.

In collaboration with the University of Melbourne, researchers have delved into the fungal disease chytridiomycosis, which has threatened at least six amphibian species in Australia and threatens dozens more species worldwide.

The findings, published in the journal Nature on June 26, 2024, providing a potential lifeline for rapidly declining populations such as the green and golden bell frog (Litoria aurea), which has disappeared from more than 90% of its native range in Australia.

Dr. Anthony Waddle, a Schmidt Science Fellow at Macquarie University’s Applied BioSciences and lead author of the study, says very few interventions address the impact of the international spread of the disease-causing chytrid fungus (Batrachochytrium dendrobatidis or Bd).

“In the 25 years since chytrid was identified as a major driver of global amphibian population collapse, our results are the first to provide a simple, inexpensive and widely applicable strategy to protect frogs from this disease,” said Dr. Waddle.

Chytridiomycosis (chytrid) usually becomes permanently established once it spreads to a new environment and has caused greater damage to global biodiversity than any other recorded disease or invasive species.

Of the species affected by chytrids worldwide, 90 are extinct or presumed extinct in the wild. Another 124 species have declined in numbers by more than 90%.

Senior author Professor Rick Shine, from Macquarie University’s School of Natural Sciences, says this study has demonstrated a simple intervention that could be easily scaled up, potentially reducing the impact of the deadly chytrid pandemic.

“Chytrid will not disappear, but our behavioral ecology intervention can help endangered amphibians coexist with chytridiomycosis in their ecosystems,” says Professor Shine.

The research team found that artificial ‘hotspot’ shelters built from readily available materials, such as bricks and PVC greenhouses, can allow frogs to quickly ‘bake off’ infections with the chytrid fungus.

When the frogs moved to areas where birds are common, chytrid infections dropped significantly.

“The whole thing is like a mini med spa for frogs,” says Dr. Waddle.

“In these simple little hotspots, frogs can warm their bodies to a temperature that destroys the infections.

The study also found that frogs that survive a chytrid infection can develop a form of acquired immunity, making them more resistant to future infections.

“Reducing mortality rates and increasing their immunity to chytrid is key to protecting amphibians from this disease, which is now endemic around the world,” says Dr. Waddle.

Dr. Waddle says these simple “hotspot” shelters are easy to reproduce, and the strategy can easily be scaled with community involvement.

Professor Lee Skerratt, Professorial Fellow in Wildlife Bioscience at the University of Melbourne, said: “This research has great potential to be extrapolated to other endangered frog species threatened by chytridiomycosis, and demonstrates the value of interdisciplinary and inter-institutional collaboration in the tackling this global problem.”

This content was originally published on The Macquarie University Lighthouse.