SA fungus threatens frogs

2005-10-07 13:48

Elise Tempelhoff

Johannesburg - The world's frog populations face extinction because South African spur-toed frogs with a deadly fungus growing on them were exported about 75 years ago to the rest of the world - to be used in pregnancy tests.

Professor Louis du Preez, head of the Africa amphibian research group at the Potchefstroom campus of the University of North West said on Wednesday that this fungus, Batrachochytrium dendrobatidis, was also unknowingly exported in this way.

The World Conservation Union or International Union for Conservation of Nature and Natural Resources (IUCN) identified the fungus together with habitat destruction as the two biggest factors leading to the extinction of 122 of the 5 743 known amphibian species in the past 25 years.

The IUCN designated a group led by Du Preez and a researcher, Dr Cheé Weldon from this university to form a core research group to study factors such as the characteristics, habitat and hosts of the fungus.

This research forms part of the IUCN's comprehensive emergency plan to try to save the world's endangered frogs, salamanders and other endangered amphibians from extinction.

Du Preez said researchers thought there were still a further 2 000 species which had not yet been described.

"But there is a suspicion that the fungus has already wreaked havoc among the undescribed species and that some of them already died out before they could be described."

Weldon says in his thesis they believe that the fungus was exported with the spur-toed frogs, one of the many kinds of frogs in South Africa, to the rest of the world.

Since the 1930s the spur-toed frogs have been exported in large numbers worldwide for use in pregnancy tests. The urine of a woman who may be pregnant is injected into the female spur-toed frog. If the frog began spawning eggs within 24 hours, it was a sign that the woman was pregnant.

Du Preez said South African frogs were fairly immune to the fungus because they had the same habitat.

The Cape river toad is the only one that is rather susceptible to the fungus.

The research team appeals to people who come across dead or sick frogs to phone them at 018 299-2372.

- Beeld