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New Zealand scientists have discovered a cure for a mystery disease that is wiping out the world's frogs - a common antibiotic used in eyedrops.
Millions of frogs have died as a result of chytrid fungal disease, which has spread around the world and has been blamed for the extinction of one-third of the 120 species lost since 1980.
Once infected with the disease, frogs become first torpid and then immobile, usually dying within days.
But researchers have found they can cure frogs of the illness by dipping them in a basic eyedrop solution. The cheap, simple treatment appears to immunise the frogs for life.
The discovery was made by a scientific team led by Associate Professor Russell Poulter of Otago University.
"So you take your frog and put him in a big plastic pot or box, and if it's a big frog, maybe a centimetre of very diluted chloramphenicol solution," Professor Poulter told the Australian Broadcasting Corporation.
"[It] doesn't cause any irritation to the frog at all. They don't know it's there - or care - and it just sort of splashes around in that. It takes a while to clear the chytrid, as is commonly the case with an antibiotic."
Chronically sick frogs could be "brought back almost from the dead" by treatment with chloramphenicol, said fellow researcher Phil Bishop, also from Otago University.
The findings will be presented to an international conference on chytrid and its effects on amphibians in Arizona next week.
But already some scientists are saying the discovery has extremely limited practical use.
While the antibiotic could be used to cure a handful of captured frogs, the fungus still remains rampant in the wild, affecting millions of others.
"The disease is all around the world, so to be really effective you'd have to aerial-spray the entire globe, which is clearly not going to happen," said Associate Professor Jean-Marc Hero of Queensland's Griffith University. "It's not particularly useful in trying to solve the global decline of amphibians. It only cures individual frogs - it won't immunise their offspring."
The only way in which the cure could have a long-term impact was if it was used to clear the disease from a small, isolated population of frogs, for instance on an island, he said.
Chytrid - full name chytridiomycosis - emerged as a serious killer of frogs in the 1980s and 1990s.
Some scientists blame climate change, others blame pesticides.
Said Professor Hero: "We don't know what caused it or why it emerged simultaneously in different parts of the world."
