Closing a regulatory loophole in laws covering live animal imports into the U.S. could prevent a deadly fungus disease presently killing salamanders in parts of Europe from entering this country, experts say.

A recently identified fungus, Batrachochytrium salamandrivorans, is decimating wild populations of fire salamanders in the forests of the Netherlands.

The fungus, which likely originated in Southeast Asia around 30 million years ago, probably was introduced into Europe by international trade in wild Asian newts, popular pets among amphibian fanciers, researchers say.

A screening of some 1,400 salamander and newts along with frogs at sites in North American and South America showed no trace of the deadly fungus, they report in the journal Science.

But that could change, they say.

Chinese fire belly newts are known to be potential carriers of B. salamandrivorans, and between 2001 and 2009 some 2 million of the creatures were brought into the U.S. for the pet trade, they say.

If any of them were infected -- and it would take just a few animals so affected -- then "it's a question of when, not if, this fungus reaches North America," study co-author Carly Muletz of the University of Maryland says.

Laboratory tests have confirmed the fungus would be lethal to dozens of North American salamander species, the researchers say.

While there are U.S. laws regarding imports of live animals, they are focused on preventing the spread of disease to humans and livestock, rather than protecting native wildlife, says UM amphibian expert Karen Lips, who recently joined with other researchers in briefing Congress on the need to close this regulatory loophole.

"If scientists and policy makers can work together on this, we have a rare opportunity to stop an epidemic from spreading around the globe with potentially deadly effect," says Lips.

A possible threat to North American salamanders could be especially disastrous, as the region is a global hot spot for biodiversity in salamander species, the researchers point out.

More than 150 of the world's 655 identified salamander species make North America their home, they explain.

Scientists aren't sure as yet exactly how B. salamandrivorans kills its infected salamander hosts, although it rapidly invades the animals' skin, known to play a significant role in their respiratory systems.

The researchers say they are aiming at establishing a surveillance network that would monitor wild populations of salamanders and newts for any evidence of the fungus.

"This study captures a pathogen's first steps out of Asia," says Cornell University professor Kelly Zamudio. "The more globalized our world becomes, the more our biodiversity will be challenged by diseases moving into areas where they have never occurred before."