Big leap in understanding frog threat

May 25, 2011
A Green and Golden Bell Frog, one of the species affected by this parasite.

(PhysOrg.com) -- University of Sydney researchers have identified two new parasite species causing disease among endangered Australian frogs. They say they are most likely native, overturning a commonly held view they were introduced with cane toads in 1935.

The parasites have so far been found in 10 , including the iconic Green and Golden Bell Frog, the Southern Bell Frog and even the Yellow Spotted Bell Frog - a species presumed extinct for 30 years until recently.

These singled-celled myxosporean parasites have been identified in bell since 1997, says Ashlie Hartigan, a PhD student leading the research with Dr. Jan Šlapeta from the Faculty of Veterinary Science, David Phalen, Director of the University of Sydney's Wildlife Health and Conservation Center, and Karrie Rose from the Australian Registry of Wildlife Health.

"Infected lose weight, are lethargic, and some can't move their back legs, making them more vulnerable to predators," Hartigan says. "Infection could also be reducing the number of tadpoles that become adults, with affected tadpoles more likely to delay metamorphosis and die from liver disease."

The singled-celled myxosporean parasites under an electron microscope.

When Hartigan and colleagues genotyped parasites from frogs and collected in New South Wales and Queensland and compared them to myxosporea from South American cane toads, they found that the Australian parasites were distinct from the South American species. This debunks the theory the parasites came to Australia with cane .

"We are 99 percent sure the cane toad did not bring it in," says Hartigan, whose research was recently published in a leading science journal PLoS ONE.

But the cane toad is not completely off the hook. "Our data suggests these parasites recently spread across eastern Australia from their original source," Hartigan said. "While the spread may have occurred by a number of means, it is possible that by infecting the invasive Cane Toad the parasite has spread faster and further as a result."

Hartigan says frogs are under increasing threat of disease, and global losses can be attributed to different pathogens. Frogs are bio-indicator species, she says: "The presence of frogs in a habitat indicates good environmental health."

"If we can learn more about the life cycle of these , how they are spread, and identify other potential hosts, we will be able to screen frogs for infection and control the spread to captive breeding populations and threatened populations in the wild."

Explore further: Science casts light on sex in the orchard

More information: www.plosone.org/article/info%3… journal.pone.0018871

Provided by University of Sydney

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Aussie meat ants may be invasive cane toad's Achilles' heel

Mar 30, 2009

Ecologists in Australia have discovered that cane toads are far more susceptible to being killed and eaten by meat ants than native frogs. Their research - published in the British Ecological Society's journal Functional Ec ...

Frogs with disease-resistance genes may escape extinction

Jul 16, 2008

As frog populations die off around the world, researchers have identified certain genes that can help the amphibians develop resistance to harmful bacteria and disease. The discovery may provide new strategies to protect ...

Recommended for you

'Divide and rule'—raven politics

6 hours ago

Mythology has attributed many supernatural features to ravens. Studies on the cognitive abilities of ravens have indeed revealed that they are exceptionally intelligent. Ravens live in complex social groups ...

Science casts light on sex in the orchard

Oct 30, 2014

Persimmons are among the small club of plants with separate sexes—individual trees are either male or female. Now scientists at the University of California, Davis, and Kyoto University in Japan have discovered ...

Four new dragon millipedes found in China

Oct 30, 2014

A team of speleobiologists from the South China Agriculture University and the Russian Academy of Sciences have described four new species of the dragon millipedes from southern China, two of which seem to ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.