Rare frogs are either toughening up or the severity of the fungus credited with their worldwide decline has been exaggerated.
The skin fungus, Batrachochytrium dendrobatidis, was identified in 1998 and blamed for the extinction or population declines of many frogs worldwide, including at least 14 rainforest frogs in Queensland.
At Eungella National Park, outside Mackay, the skin fungus was thought to have led to the extinction of the gastric brooding frog and the near extinction of the Eungella Day frog in 1985-86.
Associate Professor Hamish McCallum, from The University of Queensland's Department of Zoology and Entomology, has written a paper which shows the Eungella Day frog now coexists with the supposedly lethal fungus.
To track the effects of the fungus on the frogs, Associate Professor McCallum and two researchers re-examined 474 preserved toes from six species of frogs, including the Eungella Day frog from Eungella's rainforest streams.
The team found the fungus was present as a stable, localised infection in two of the frog species having no effect on the survival of the Eungella Day frogs.
Associate Professor McCallum said this suggested either the frogs had built a resistance to the fungus or it wasn't the fungus that had killed them in the first place.
He compared the fungus case to the spread of myxomatosis in rabbits when death rates dropped as the disease became less pathogenic and the rabbits more resistant.
There are many theories why frogs are dying around the world such as disease, loss of habitat, pesticides and UV radiation.
Scientists know a frog's skin is important for breathing and regulating water content but know little about the fungus.
"Nobody really knows at the moment exactly how it kills them," Associate Professor McCallum said.
"Lots of people are looking but nobody has actually identified a particular toxin."
He said more research might allow rare frogs to be bred for resistance to the fungus.
He believed the scientific community was recognising that diseases were important to understanding wildlife and this research showed the importance of studying diseases in the wild not just in the laboratory.
The frog research paper, Endemic infection of the amphibian chytrid fungus in a frog community post-decline, will be published in the electronic science journal Public Library of Science.
For more information contact Associate Professor McCallum (phone: 0428 693 712, 07 3365 2450, email: hmccallum@zen.uq.edu.au) or Miguel Holland at UQ Communications (phone: 3365 2619, m.holland@uq.edu.au)
Photo available from UQ photographic librarian Dianna Lilley (phone: 3365 2753, email: d.lilley@uq.edu.au)
