Australian scientists, including a team at CSIRO, were first to identify a fungus as the cause of mass frog declines in Australia and Panama.
Identifying a killer
Australia's frog populations, along with those in other countries, have been disappearing over the last 20 years.
The loss of frogs is very serious as they play an important role in ecosystems. Scientists regard this as being one of the most significant global biodiversity problems facing us today.
Researchers from CSIRO’s Australian Animal Heath Laboratory (AAHL) in Geelong, Victoria, and James Cook University in Townsville, Queensland, were first to find the new fungus — now called the chytrid fungus (Batrachochytrium dendrobatidis) — in ten frog species. In laboratory trials, CSIRO researchers showed that the fungus can kill frogs.
The areas where this fungus has been found include areas that are 'pristine'. Frog population crashes have been observed in relatively untouched areas of tropical Queensland rainforest. Similar sudden declines have occurred in protected mountainous rainforest areas in Central and South America.
Research has shown that the fungus invades the keratin layer of the frog's skin, but exactly how it kills the frog is still not known.
In 2000 the Amphibian Disease research team were awarded a CSIRO medal.
Tadpoles only have keratin in their mouths, so while they may carry the fungus, they do not succumb to it. But once they metamorphose into a frog, the fungus can take hold and kill the frog.
New diagnostic tests
Scientists at CSIRO’s Australian Animal Health Laboratory (AAHL) developed diagnostic assays and sampling techniques that enable the rapid detection of the fungus.
The researchers developed immunohistochemical, molecular and electron microscopy tests for the fungus, along with a range of sampling assays. Using wash water or swabs, tadpoles and frogs can be tested for infection, with the sampling assays detecting even low levels of fungus zoospores.
These tests have been transferred to laboratories in Australia, the United Kingdom, United States, and Canada. A workshop was held at AAHL in April 2005, in an effort to standardise the chytrid fungus diagnostic procedures used throughout the world.
This research outcome can enhance the management of the disease. Geographical regions can now be monitored for the presence or absence of infected animals.
Research team
The initial discovery that the chytrid fungus was killing frogs was due to the collaboration of scientists with different areas of expertise, and from different countries. The research team included:
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Dr Lee Berger, formerly with CSIRO, now with James Cook University, Townsville, Queensland
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Dr Alex Hyatt, CSIRO Livestock Industries, AAHL, Geelong, Victoria
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Dr Rick Speare, James Cook University, Townsville, Queensland
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Dr Andrew Cunningham, Institute of Zoology, London, UK
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Dr Peter Daszak, Consortium for Conservation Medicine, New York, NY, USA
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Dr David Green, NIH, Maryland, USA
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Dr Karen Lips, University of South Illinois, USA
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Dr Keith McDonald, Queensland Department of Environment, Brisbane, Queensland
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Mr Harry Hines, Queensland Department of Environment, Brisbane, Queensland.
Learn more about the Australian Animal Health Laboratory (AAHL).
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