Environmental stress increasing infectious disease in amphibians

Environmental Research Web: Climate change, habitat destruction, pollution and invasive species are all involved in the global crisis of amphibian declines and extinctions, researchers suggest in a new analysis, but increasingly these forces are causing actual mortality in the form of infectious disease.

Amphibians are now, and always have been hosts for a wide range of infectious organisms, including viruses, bacteria and fungi, scientists said in a review published in Philosophical Transactions of the Royal Society B.

But in recent decades, disease seems to have taken a more prominent role in causing mortality. Because of multiple stresses, many induced by humans, amphibians now succumb to diseases they may historically have been better able to resist or tolerate.

"There's more and more evidence of the role of disease in the biodiversity crisis, in both amphibians and other types of animals," said Andrew Blaustein, a distinguished professor of zoology at Oregon State University and author of the recent analysis.

"It's normal for animals to deal with infectious organisms, often many of them simultaneously," he said. "But in the face of pollution, a reduced immune response, climate change, evolving pathogens and many other stresses in such a short period of time, many species now simply can't survive."...

Frog's eye close up, shot by Ren West, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license