Friday, June 26, 1998 Published at 18:19 GMT 19:19 UK
Scientists blame fungus for frog deaths
Discovery means scientists can look for a cure
A previously unknown fungus is killing off the world's population of frogs and toads, as Toby Murcott of BBC Science reports.
Scientists have long been puzzled by the dramatic decline in amphibian numbers and the newly-discovered fungus could be the explanation.
However, this global outbreak could actually be spread by the scientists studying the disappearing frogs.
All sorts of theories have been proposed for the decline ranging from global climate change to an increase in the demand for edible frogs' legs.
Now scientists in the United States and Australia have identified a fungus that has infected and killed frogs and toads in Panama, Australia and the United States.
Amphibians breathe through their skin and the fungus grows on the animals' backs and legs, effectively suffocating them.
It is not yet clear whether the fungus is the primary cause of death or whether it only kills frogs and toads weakened by other factors such as pollution.
However, it is certain that the fungus is a global infection and can be transmitted from one frog to another with lethal effect. Just how it has come to be so widespread is unknown.
One rather grim suggestion is that scientists are inadvertantly spreading it themselves.
The discovery of this fungus does mean that scientists can start the difficult job of finding a cure, beginning with animals in zoos and aquariums.
Preventing further reduction of frog and toad populations could also have benefits for human disease - the chemicals produced by many amphibians show great promise as drugs to treat cancers and other diseases.