April 2, 2009

Amphibians may develop fungus immunity

A U.S. study suggests amphibians might be able to develop immunity to the fatal fungus disease that is reducing the Earth's amphibian populations.

Jonathan Richmond of the U.S. Geological Survey and colleagues said they discovered individual amphibians can develop both acquired and innate immunity to the fungal disease chytridiomycosis, which is caused by the fungus Batrachochytrium dendrobatidis.

The researchers said scientists should broaden their studies of chytridiomycosis to include so-called acquired immunity, because that might improve predictive models of the disease's spread and suggest ways to protect threatened frog and toad populations.

Richmond and colleagues studied two species of New Zealand frogs infected with the disease but when treated with the antimicrobial drug chloramphenicol, were later resistant to re-infection with the fungus.

They said other studies indicate North American toads that survived after being first exposed to the fungus in dry conditions survived longer when re-infected in wet conditions than did toads that were exposed only in wet conditions.

The research appears in the journal BioScience.