The Fish and Wildlife Service is barring the door against 201 species of salamanders, making it illegal to import them or move them across state lines, the agency announced on Tuesday. Scientists hope the ban will help prevent a devastating outbreak from driving native salamander species extinct.

In 2013, scientists in the Netherlands discovered a species of fungus infecting native fire salamanders. Later research revealed that the fungus, called Batrachochytrium salamandrivorans, or Bsal, was carried by Asian salamanders that were imported into Europe as pets. While the fungus was harmless to the Asian amphibians, it was lethal to the Dutch ones.

Although Bsal has continued to spread in Europe, there is no sign that it has taken hold in the United States. But if the vigorous pet trade goes unchecked, scientists fear that it is only a matter of time before Bsal threatens some of the 190 salamander species that live in the United States. The Fish and Wildlife Service estimated that from 2004 to 2014, nearly 2.5 million live salamanders, representing 59 species, were imported into the United States.

“With the highest biodiversity of salamanders in the world here in the United States, we’re very concerned about the risk this fungus poses,” said David Hoskins, assistant director of the agency’s Fish and Aquatic Conservation Program.