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 explained, so it's difficult to determine whether Bd infections in the countries are newly expanding. It will be critical, he said, "to see how Bd prevalence is changing through time, because this is key to understanding the ultimate outcome of the disease."
If Bd has been in Asia for a long time, researchers would like to know why amphibians there have managed to co-exist with a fungus that has proved so destructive elsewhere. It is possible, for instance, that Asian amphibians might bear some sort of bacterial protection against Bd in their skins.
Other scientists are analyzing the genes of the Bd fungus collected globally, Vredenburg said, "to find out whether strains from different parts of the world also differ in their virulence."
Vredenburg said the possibility of another wave of extinctions highlights the need to follow the Asian survey with further research to answer all of these questions.
And if Asia is on the brink of a chytrid epidemic, Vredenburg and colleagues think it might start in the Philippines. "The prevalence and intensity of Bd infection is much higher here than anywhere else in Asia," he said. "Bd in the Philippines today looks similar to Bd in early outbreaks in California and South and Central America."
"This study is the first important step to understanding Bd in Asia," Vredenburg said. "It provides a solid foundation that future studies can build upon."
Link to Original Article: Swei A, et al. (2011) Is Chytridiomycosis an Emerging Infectious Disease in Asia? PLoS ONE 6(8): e23179. doi:10.1371/journal.pone.0023179