This lungless species of salamander, Ensatina, is common along the West Coast, an area vulnerable to the Bsal pathogen. (Tiffany Yap)

A known killer is on its way to the United States, and government officials recently put out a warning to alert the public. When the feared fungus known as Bsal lands on the backs of newts and salamanders destined for the pet trade, scientists predict that lots of wild salamanders are expected to die.

This isn’t some unfounded alarm for scientists at the U.S. Geological Survey, who wrote a report published recently in Royal Society Open Science. The skin-eating Batrachochytrium salamandrivorans —  meaning “salamander devourer” — has killed repeatedly. By the time it was discovered three years ago in the Netherlands, only 10 of that country’s once abundant fire salamanders were left.

“Bsal is decimating wild salamander populations in Europe and could emerge in the U.S. through the captive amphibian trade,” the USGS said in a statement announcing the study. Behind dogs, cats, rabbits, turtles, snakes and various reptiles, salamanders ranked pretty high among pets in demand. 

The pathogen hitches a ride on the bodies of the bright-colored, sensitive amphibians and makes its way into the wild when one escapes or is taken outdoors to places that wild salamanders inhabit. It’s expected to reach the United States even after the U.S. Fish and Wildlife Service moved to ban salamander imports in January.

The Feb. 17 study, led by USGS researcher Katherine Richgels, examined areas where the fungus could thrive and determined that the mortality risk is highest in Mid-Atlantic states, such as Maryland, Delaware, Pennsylvania, New Jersey and New York. “The Eastern U.S. has the highest diversity of salamanders in the world, and the introduction of this new pathogen is likely to be devastating,” Richgels said. “Our findings can help with early Bsal detections by highlighting high-risk areas.”

The Pacific Coast and the Appalachian Mountains are also likely “to have significant population declines due to high concentrations of diverse salamander species and mild climates that are well suited to Bsal growth,” the study said. Some scientists are urging lawmakers to ban salamander imports to protect amphibians in the Americas.

One study last year showed that Bsal can be reduced with heat treatment and anti-fungal creams when infected salamanders are discovered. Bsal thrives and kills quickly when temperatures are 59 degrees Fahrenheit, but it is less effective when they reach 68 degrees.

Why is the disappearance of slimy little salamanders around the world and in the United States a cause for concern? They are part of a web of life that continues to vanish, along with bees, monarch butterflies, bats, frogs and even snakes. The impacts of these losses from a deadly mix of disease, competitive invasive species, climate change and pesticides is unknown.


Spotted salamander have been a focal species for amphibian monitoring at ​the USGS ​Patuxent ​Wildlife Research Center ​in Laurel, Md., for years. (Evan H.C. Grant/USGS)​

When Bsal was ravaging salamanders in the Netherlands in 2013, a USGS study reported that frogs, toads and salamanders were vanishing from the American landscape at an alarming pace. The report estimated that seven species — including Colorado’s boreal toad and Nevada’s yellow-legged frog — faced population drops of 50 percent if their rate of decline held steady for seven years.

“It’s a loss of biodiversity. You lose them, and you can’t get them back. That seems like a problem,” Michael J. Adams, a research ecologist for USGS and the lead author of that study, said at the time.

The findings of the current study were announced in part to help wildlife managers protect already declining amphibians in the United States from a coming threat that could ensure the grim predictions of the earlier report. USGS researchers said biologists should heed the warning and work to detect the fungus early.

Bsal would be one of the most significant disease threats to animals since the white-nose syndrome hit bats. In the United States, there isn’t a more lethal pathogen than white-nose, which has killed at least 7 million bats of at least seven species since it was first detected in New York about a decade ago, and it is continuing to spread south and west.

It’s an eerie fungus that creeps on bats as they hibernate in large communities in caves and mines, then attacks their tissue. Biologists are still struggling to understand it, let alone cure it. The same can be said of Bsal.


An endangered Shenandoah salamander rests in Virginia’s Shenandoah National Park. (USGS)

“Amphibians are the most endangered vertebrates in the world,” Richgels said. “Disease risk assessments like ours can help managers prevent and mitigate losses of vulnerable U.S. salamanders.”  

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