Researchers at Vanderbilt University have identified an alternative to a sometimes toxic therapy that protects frogs in zoos from a deadly fungal infection that has been destroying the amphibian populations worldwide. Their research is published ahead of print in Applied and Environmental Microbiology.
The fungal disease, chytridiomycosis, has been decimating frogs all over the world. At present, nothing can help amphibians in the wild, but zoos currently rely on the often-toxic itraconazole to eradicate the disease from infected amphibians they wish to acquire.
To preserve the most at risk amphibians, zoos have been acquiring "founding populations" of species threatened by chytridiomycosis, which is caused by the fungus, Batrachochytrium dendrobatidis.
"Some species, such as the Panamanian Golden Frog, are nearly extinct in nature, and doing well only in zoos," says Louise Rollins-Smith, a researcher on the study. "Facilities which house multiple amphibian species need safe treatments to protect their valuable colonies."
Brian Gratwicke, a conservation biologist with the National Zoo, describes the difficulties zoos face in treating the creatures. The animals must go through 10 days of immersion in an itraconazole solution.
"Itraconazole is a fairly expensive drug, and depending on the species we treat we can see a very high mortality rate," says Gratwicke. "An alternative treatment would be very helpful."
In the study, Rollins-Smith and colleagues, of Vanderbilt University, Nashville, TN, tested two potential alternatives, chloramphenicol, and amphotericin B. Although both drugs reduced B. dendrobatidis infection, neither could eradicate it. But amphotericin B had a critical advantage over chloramphenicol.
The investigators found that chloramphenicol can cause major changes in the community of microbes inhabiting amphibian skin, while amphotericin B does not, says Rollins-Smit
|Contact: Jim Sliwa|
American Society for Microbiology