An international team of researchers has completed the first major survey in Asia of a deadly fungus that has wiped out more than 200 species of amphibians worldwide. The massive survey could help scientists zero in on why the fungus has been unusually devastating in many parts of the globe -- and why Asian amphibians have so far been spared the same dramatic declines.
The disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis or Bd, is the culprit behind amphibian extinctions in Central, South and North America, Australia and Europe. The new Asian survey of the fungus, which was published Aug. 16 in the journal PLoS One, shows that Bd is prevalent at very low levels in the region.
Asia is home to a highly diverse set of amphibian species, and potentially could be vulnerable to Bd. But Vance Vredenburg, assistant professor of biology, said very little is known about the fungus and its impact on the health of amphibians in Asia.
"That's why we're excited about this first really big survey," said Vredenburg, who led the research team. "If you look at chytrid worldwide, Asia's been the black hole in our data."
From 2001 to 2009, Vredenburg and his colleagues surveyed more than 3,000 amphibians -- mostly frogs -- from 15 Asian countries, swabbing the toe webbing, thigh and abdomen of the animals to pick up any signs of Bd, which infects the skin of amphibians.
They found that the prevalence of Bd was very low throughout the region, appearing in only 2.35 percent of the frogs. The Philippines, Kyrgyzstan, Laos, Indonesia, Malaysia and South Korea were the only countries with any Bd infection.
The survey suggests that Bd is either emerging in Asia, or may have been in Asia at low levels for a long time or that some other factor is preventing Bd "from fully invading Asian amphibians," the researchers write.
Each site in the study was only surveyed once, Vredenburg explain
|Contact: Elaine Bible|
San Francisco State University