The global amphibian trade spread the lethal chytrid fungus, which is decimating frogs around the planet, and it now looks like it may have created the disease in the first place.
The team behind this finding are calling for an amphibian quarantine to help slow the disease’s spread.
Rhys Farrer of Imperial College London and colleagues sequenced the genomes of 20 samples of the offending fungus, Batrachochytrium dendrobatidis (Bd), collected in Europe, Africa, North and South America and Australia.
They found that 16 of the 20 samples were genetically identical, belonging to a single strain called BdGPL that had spread to all five continents. Tests on tadpoles also revealed that the strain was extremely virulent.
BdGPL’s genome showed that it had formed when two strains mated, some time in the past 100 years. The best and simplest explanation is that 20th-century trade, which shipped amphibians all over the world, enabled the mating, says Farrer’s supervisor Matthew Fisher.
“We’ve got to restrict trade, or at least make sure that amphibians are not contaminated,” says Fisher. One approach would be for countries to quarantine all imported amphibians and only allow them to stay if they are uninfected.
Last redoubts
When it emerged that trade was spreading chytrid, the World Organisation for Animal Health made the disease notifiable, meaning that countries must report whether they have it or not. But that doesn’t stop it spreading. » Read more: Frog-killer disease was born in trade
