Scientific Leap Uncovers Native Reason For Amphibian Declines
Thursday 28th June 2012
Scientific Leap Uncovers Native Reason For Amphibian Declines
Booroolong Frog

Scientists have uncovered two parasite species, related to jellyfish, which is causing deaths amongst endangered Australian Frogs.

The deadly myxosporean parasites have been killing 10 native frog species, including the iconic Green and Golden Bell Frog, endangered Booroolong Frog and Yellow Spotted Bell Frog, which was thought to be extinct until recently.

The parasites were once thought to be South American and bought to Australia with the arrival of Cane Toads in 1935, but the new scientific evidence suggests these parasites are in fact native.

Taronga’s Dr. Karrie Rose, who heads up the Australian Registry of Wildlife Health, says:  Our investigations of Cane Toads in Hawaii, where frogs were originally collected and shipped to Australia from, were free of the parasites. 

Dr. Karrie Rose (L) and Dr. Cheryl Sangster (R)

“But the dastardly Cane Toad isn’t off the hook. They didn’t bring the disease to our shores, but they’ve certainly helped spread it throughout Australia at an advanced and terrifying rate.” 

The parasites tend to live in the brains and livers of infected frogs and symptoms include loss of body weight, lethargy and an inability to move their back legs, making them vulnerable to predator attack.

“It may also reduce the number of tadpoles which reach adulthood, a devastating impact since frog species worldwide are suffering the biggest species extinction rates since the age of dinosaurs,” said Dr. Rose.

 “These findings are really significant in understanding why we are losing so many frog species and things to consider as we fight against the very real threat of frog extinction.”

Since the 1980’s frog species around the globe have been dying at an alarming rate. More than 30% of the world’s amphibian species compared to 25% of mammals and 12% of birds are threatened. Australia has already lost three frog species and approximately 165 of the world’s known amphibian species may already be extinct.

“The explanations for the extinctions have been numerous, including habitat destruction, pollution and pesticides,” said Dr. Rose.

“In recent years, the deadly Chytrid Fungus has been blamed for wiping out frogs, but now it seems that other pathogens like these parasites have played a major role in amphibian declines.”

“Although there’s quite a bit of surveillance work done to monitor Australian frogs for Chytrid fungus, the tests used are so specific for the fungus that the parasites would not be detected.“


“Few wild frogs receive a thorough diagnostic investigation each year, and it’s only through the vigilance of the Australian Registry of Wildlife Health that we were able to detect these unusual and emerging diseases, providing conservationists with extra armoury to fight extinction,” said Dr. Rose.

This ground breaking research was a collaborative project between the University of Sydney and the Taronga funded Australian Registry of Wildlife Health, a national body dedicated to investigating emerging and developing wildlife disease.

Taronga is committed to amphibian conservation working on five amphibian projects to safeguard a future for native species. They include Conservation Breeding Programs for the critically endangered Southern Corroboree Frog, Northern Corroboree Frog, Booroolong Frogs, Yellow Spotted Bell Frogs and the iconic Green and Golden Bell Frogs.