Frog trade linked to emergence of killer fungus
28 November 2011
The global trade in frogs, toads and other amphibians may have accidentally helped create and spread the deadly fungal disease, chytridiomycosis.
An international team of scientists, led by Dr Matthew Fisher (Public Health), found that the trade may have let non-lethal strains of the chytrid fungus from different parts of the world come into contact with each other. This means they’ve exchanged genes in a process called recombination, creating a new and lethal strain which has decimated frog populations around the world in recent years.
“It’s likely that the amphibian trade has allowed different populations of the fungus to come into contact with each other, allowing recombination to occur,” said Rhys Farrer from the School of Public Health at Imperial and the Institute of Zoology, who was the lead author of the study, published in Proceedings of the National Academy of Sciences. “This has created a hypervirulent strain leading to losses in amphibian biodiversity,” he added.
The chytrid fungus, Batrachochytrium dendrobatidis (Bd), infects the skin of amphibians like frogs, toads, salamanders and newts. The disease has caused many amphibian populations around the world to decline and over 200 species are suspected to have become extinct as a result. In Central America alone, chytridiomycosis has led to the loss of up to 40 per cent of wild amphibians including the Panamanian golden frog.
Despite much research on the disease, scientists have struggled to figure out where it came from or explain how it spread. The problem is even more puzzling because some amphibians coexist alongside Bd with no sign of disease. “This strongly suggests there may be more than one type of strain of chytrid fungus,” said Mr Farrer.
— Adapted from a news release issued by the Natural Environment Research Council