By James Gorman, The New York Times, October 30, 2014
An emerging infection similar to one that has caused the extinction of hundreds of frog and toad species around the world is now killing salamanders in Europe and could easily spread to the United States, with disastrous effects, scientists reported Thursday.
Writing in the journal Science, an international team of 27 researchers blamed the spread of the disease on “globalization and a lack of biosecurity” and said the importation of the fire-bellied newt in the pet trade with Asia was the likely cause.
The lead researcher, An Martel of Ghent University in Belgium, said in an interview that both Europe and the United States needed to start screening amphibians in the pet trade. “When animals are traded they should be screened,” Dr. Martel said. “It should involve the world.”
Other scientists agreed. “We need to pay attention to this paper,” said Vance T. Vredenburg of San Francisco State University, one of the scientists who has sounded the alarm about the extinction of hundreds of frog and toad species worldwide over the last four decades.
“We need to think about biosecurity not just in terms of humans and food that we eat and crops that we grow,” he said. “We need to think about functioning ecosystems.”
Dr. Vredenburg is a co-author of a 2008 paper that described the disappearance of frog species as a prime example of what some scientists call the sixth extinction, a mass death of species going on now and caused by humans.
In the case of the frog disappearances, the culprit, a fungus called Batrachochytrium dendrobatidis, was not identified until decades after the extinctions had begun. Where it originated is still not known.
The effects of that fungus, Dr. Vredenburg said, represent “the worst case in recorded history of a single pathogen affecting vertebrates,” causing an “extinction rate 40,000 times higher than in the last 350 million years for amphibians.”
The fungus killing salamanders and newts, Batrachochytrium salamandrivorans, is in the same genus, and also kills animals by infecting the skin. But this time, said Dr. Vredenburg, “We found it early enough to have a chance. The Titanic knows there’s an iceberg out there.”
The United States, as yet untouched by the infection, has the greatest biodiversity of salamanders in the world, and many of the species are already threatened or endangered. The animals are seldom noticed, but are an integral part of forest and aquatic ecosystems, as predators and prey.
One recent study suggested that their decline could affect climate change because the proliferation of some of the creatures they eat could cause greater release of carbon into the atmosphere.
Dr. Martel and other scientists first identified the fungus a year ago, and described its role in the deaths of fire salamanders in Europe. In the new paper, they investigated its origin, presence around the world and the susceptibility of different species to it.
In the lab, the researchers experimentally infected 44 species of salamanders and newts (salamanders live on land, newts in the water). Forty-one, they wrote, “rapidly died.” It did not affect frogs and toads.
Several Asian species were resistant, and molecular biology studies of DNA suggested that there may be a reservoir of the fungus in Asian newts popular in the aquarium trade.
The study found evidence of the fungus in amphibians in Vietnam, Thailand and Japan, where the animals were not affected, and in the Netherlands and Belgium, where it killed numerous populations. Dr. Martel identified the shipping of live newts for the aquarium trade as the way the fungus spread.
James Collins, at Arizona State University, who has studied the spread of fungal disease in frogs, said that further study was needed to prove that the pet trade was the culprit in the disease’s spread, since it was possible that the fungus was wind-borne, or spread by migrating birds.
But, Dr. Collins said, it was clear that the fungus and the lack of screening in the shipping of live animals posed a major threat to salamanders in the United States and Europe. Disease screening exists for threats to agriculture, he said, but not for animals in the pet or aquarium trade.
“When something like Ebola emerges,” he said, international and federal agencies like the World Health Organization or the Centers for Disease Control and Prevention can act. “Something like that is needed,” he said.
Karen R. Lips at the University of Maryland, one of the co-authors of the Science paper, met Thursday with Fish and Wildlife Officials to talk about the new fungus. She said that there were now bills in Congress that could enable the Fish and Wildlife Service to screen for infected wildlife.
“If Congress wanted to, they could take action,” she said.
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A fire salamander showing signs of fungal infection through skin lesions. A study suggests that the fungus, called Batrachochytrium salamandrivorans, may have reached Europe through the pet trade from Asia. Photo: Frank Pasmans/Ghent University.
Writing in the journal Science, an international team of 27 researchers blamed the spread of the disease on “globalization and a lack of biosecurity” and said the importation of the fire-bellied newt in the pet trade with Asia was the likely cause.
The lead researcher, An Martel of Ghent University in Belgium, said in an interview that both Europe and the United States needed to start screening amphibians in the pet trade. “When animals are traded they should be screened,” Dr. Martel said. “It should involve the world.”
Dr. Vredenburg is a co-author of a 2008 paper that described the disappearance of frog species as a prime example of what some scientists call the sixth extinction, a mass death of species going on now and caused by humans.
In the lab, the researchers experimentally infected 44 species of salamanders and newts (salamanders live on land, newts in the water). Forty-one, they wrote, “rapidly died.” It did not affect frogs and toads.
“If Congress wanted to, they could take action,” she said.
