Asian fungus puts salamanders in Europe at risk

BERLIN - Europe's salamanders could be decimated by a flesh-eating alien species that has wreaked havoc in some parts of the continent, scientists say in a study published on April 19.

Researchers who examined the impact of the invasive fungus native to Asia on fire salamanders in Belgium and the Netherlands found it to be lethal and almost impossible to eradicate.

The study, published in the journal Nature Research, provides a warning to North America, where the fungus hasn't yet taken hold.

"Prevention of introduction is the most important control measure available against the disease," says co-author An Martel, a veterinarian at Belgium's University of Ghent, who specializes in wildlife diseases.

The B salamandrivorans fungus, which likely was imported to Europe by the pet trade, causes skin ulcers, eating the salamander's skin and making it susceptible to secondary bacterial infections.

Martel and her colleagues began studying the effect of the fungus in early 2014, four years after it was first recorded in Europe. Within six months, the population of fire salamanders at the site in Robertville, Belgium, had shrunk to a tenth of its original size. Two years later about 1 percent of the distinctive yellow-and-black patterned amphibians had survived, the study says.

Sexually mature salamanders appeared to be prone to becoming infected with the fungus, preventing them from producing new generations. Furthermore, researchers found the fungus was able to form spores with thick walls that allowed it to survive for longer and spread further. Other amphibian species were also susceptible.

Finally, infected animals failed to develop an immune response that might allow some of the salamander population to survive and prevail against its new foe, which has been detected in the Netherlands, Belgium and Germany. Conservationists in the United States are monitoring wetlands for signs of the fungus.

"For highly susceptible species like fire salamanders, there are no available mitigation measures," Martel says. "Classical measures to control animal diseases such as vaccination and repopulation will not be successful since there is no immunity buildup in these species and eradication of the fungus from the ecosystem is unlikely."

In a separate comment published by Nature, Matthew C. Fisher, an expert in fungal epidemiology at Imperial College London who wasn't involved in the study, backs the researchers' suggestion that the only way to save Europe's salamanders may be to keep a healthy population in captivity at least until a cure is found.

"It is unclear how (the fungus) can be combated in the wild beyond establishing 'amphibian arks' to safeguard susceptible species as the infection marches onwards," says Fisher.

Associated Press