A geologist at the Museum of Natural History in Madrid discovered the fungus, which belongs to the common Geotrichum family, on CDs brought back from the central American state of Belize.

Experts say it is unusual but not unknown for a fungus to attack manmade substances like plastics.

Javier Garcia-Guinea, head of Geology at the museum, said he believed it was the first documented case of a fungus attacking CDs.

Similar reports were coming in from around the world, he said.

"This year we received many e-mails from Panama, Costa Rica and Guatemala describing similar cases in tropical countries," Dr Garcia-Guinea told the BBC.

Fungus 'widespread'

Marc Valls, a biologist at Spain's National Centre for Biotechnology, warned people not to be alarmed. He said the fungus would only attack CDs under certain conditions.

"Even though this fungus is widespread it could only develop on a CD in high humidity and high temperature, which is not the case most of the time," Mr Valls told the BBC.

And he said there was a positive side to the story - the ability of micro-organisms to degrade manmade products could help in waste disposal.

"Nature is very clever and, for all the materials that we design, sooner or later they will be degraded by some organism."