Washington - A skin-eating fungus that infiltrated Europe through the global wildlife trade is threatening to inflict massive losses on the continent's native salamanders including extinction of whole species and could do the same in North America, scientists say.
An international research team said on Thursday the fungus, first detected in Europe last year, has killed salamanders in the Netherlands and Belgium and is expected soon to reach other European nations. They said it is closely related to another fungus that already has wiped out some amphibian species.
The scientists have found no sign of the fungus in North American amphibians but worry that it is only a matter of time before it surfaces via a pet trade that has funnelled millions of Chinese fire belly newts to the United States.
The researchers tracked the origins and geographical presence of the fungus, Batrachochytrium salamandrivorans, by examining about 5 400 samples accounting for about 150 varieties of amphibians in Europe, Asia, North America and Africa.
They also exposed 35 amphibian species to the fungus to learn which were vulnerable. The study found it can kill numerous kinds of salamanders and newts, a subgroup of the salamander family, but not other amphibians including frogs, toads and snake-like caecilians.
The fungus was discovered by scientists probing a die-off of fire salamanders in the Netherlands. It invades a salamander's skin, an organ vital to its respiratory system, causing ulcers.
"There is little we can do to stop further spread on mainland Europe other than preventing people from moving infected salamanders between countries", said Matthew Fisher, a professor of fungal disease epidemiology at Imperial College London who was one of the researchers.
"If [the fungus] arrives in the USA then millions, if not billions, of salamanders are likely to die and species extinctions may occur."
The findings illustrate the threat posed to native creatures by pathogens spread through the international wildlife trade. Asian salamanders and newts are sold worldwide in huge numbers.
"The uncontrolled trade of animals should be regulated worldwide, and traded animals should be tested for the presence of pathogens that can affect wildlife with special emphasis to prevent introduction of [the fungus] to islands and regions where it is currently absent", said An Martel, a veterinarian at Ghent University in Belgium who led the study.
The fungus appears to have originated in Southeast Asia 30 million years ago, reaching Europe recently through the trade in Asian newts.
Using museum specimens, the scientists determined the fungus was present in amphibians from Thailand, Vietnam and Japan as early as the 19th century without causing disease. That indicates creatures in the region have developed resistance but those from other regions may be highly vulnerable.
University of Maryland ecologist Karen Lips, another of the researchers, underscored the danger in North America, saying, "The impact on our native salamander diversity might be very high because the US is the world's greatest biodiversity 'hot spot' for salamanders. We have more species and families here than anywhere else in the world."