Chytrid Fungus: Hope for Fighting Deadly Amphibian Disease

Researchers at Oregon State University have discovered a freshwater organism that might help in fighting the chytrid fungus, which is a principal cause for the worldwide amphibian decline. A freshwater species of zooplankton, called Daphnia magna, could provide a tool for biological control of the deadly fungus whose impact, one researcher has called “the most spectacular loss of vertebrate biodiversity due to disease in recorded history.”

Daphnia magna is a variety of water fleas of the genus Daphnia, some species of which are commonly used as food for aquarium fish. It was known that the zooplankton could devour some types of fungi. Oregon researchers wanted to find out whether Daphnia magna could also consume the chytrid fungus that has been devastating amphibian populations worldwide, including Colorado’s endangered boreal toad.

Through extensive research, scientists confirmed that Daphnia magna could consume the free swimming spores of the fungal pathogen. According to lead researcher Julia Buck, an OSU doctoral student in zoology, in an Oregon State University press release:

We feel that biological control offers the best chance to control this fungal disease, and now we have a good candidate for that. Efforts to eradicate this disease have been unsuccessful, but so far no one has attempted biocontrol of the chytrid fungus. That may be the way to go.

Now scientists need to conduct field studies to confirm the zooplankton’s effectiveness in a natural setting. The OSU scientists have found that Daphnia inhabits amphibian breeding sites where chytrid transmission occurs and may be able to stem the unprecedented population declines and extinctions.

For background on the chytrid fungus, please see the video below that we found on the Save the Frogs site, produced by the National Science Foundation:

The Oregon State University research was reported in the journal Biodiversity and Conservation, and was  supported by the National Science Foundation. Click here for the full report.


The Canyon Tree Frog – Guest Post, Allystair D. Jones

We are extremely pleased to feature a guest post by Allystair D. Jones, who studied the canyon tree frog population in Zion National Park, Utah, to determine if the frogs were infected with the chytrid fungus, a disease that is wiping out amphibian populations worldwide. His research will be published by The Utah Academy of Science, Arts and Letters in May 2011. 

Chytridiomycosis is an emerging infectious disease that is plaguing the world and causing the extinction of frogs around the globe. This disease is believed to have come from Africa in 1938 when frogs were sometimes used to diagnose pregnancy. This disease is responsible for the extinction of at least 30 populations of frogs and has found its way into Arizona killing the canyon tree frog (Hyla arenicolor). The Chytrid disease can move very quickly and is transferred through water, contact, or even muddy boots from hikers. My research is aimed at watching the population of canyon tree frogs in Zion National Park and as of the summer of 2009 it appeared this population is safe. 

Photo by Allystair D. Jones

The geography of Zion National Park is very unique. Zion is the middle step in the grand staircase with the Grand Canyon being the first and Bryce Canyon the last. This made locating the frogs often very difficult and technical rappelling and climbing skills were needed. I have been climbing for more than 20 years so I was especially suited for this study. I travelled through the canyons where this frog likes to live and captured, swabbed their bellies with a cotton swab, and released them back to the location that I caught them. I used the prescribed swabbing techniques and noted the location and time of the swab. I then saved the samples for DNA testing. 

Photo by Allystair D. Jones

Photo by Allystair D. Jones

I tested all the samples with a general fungus primer, meaning I tested it to see if there was any fungus at all even if it wasn’t the chytrid fungus. Those that were positive for a fungus were tested for the specific chytrid. The results were very pleasing as none of the samples came up positive for this deadly fungus. This was the first study of this kind done in Zion National Park and during the following year there should be more if the funding keeps up. 

Photo by Allystair D. Jones

It was noted in a review journal article at the beginning of this year (Kilpatrick et al 2010) that to help combat this disease we would need to find a viable population of frogs that are not already infected. I submit this population of frogs to be that population, that if monitored with care may help us gain ground in fighting this deadly disease. We need to increase our efforts to learn about this disease. 

Photo by Allystair D. Jones

Photo by Allystair D. Jones


For more information or comments my email is: ajones67@dmail.dixie.edu

*KILPATRICK, A. M., BRIGGS, C. J. & DASZAK, P. 2010. The ecology and impact of chytridiomycosis: an emerging disease of amphibians. Trends in Ecology & Evolution, 25, 109-118.  


Hope for Frogs in Fight Against Chytrid Fungus

This week  Scientific American reported that researchers in California and Virginia have identified a symbiotic bacteria living on frogs’ skin that protects them from chytrid, a fungal disease contributing to the extinction of one-third of the world’s amphibians.  They discovered this naturally occurring bacteria, toxic to the chytrid fungus, in the skin of mountain yellow-legged frogs and redback salmanders.

The chytrid fungus most likely began in African Clawed frogs, which carry the fungus that causes chytrid, but don’t die from it. In the 1940s these frogs were raised in captivity for pregnancy tests.  Most of the frogs were released once this method was no longer used for the tests. They infected amphibians in the United States and around the world.

So far scientists have not found a way to combat this deadly disease that spreads quickly in amphibian populations. Individual animals can be treated, but not large populations of amphibians.

But in this recent study, frogs inoculated with a solution containing the symbiotic skin bacteria survived. The scientists plan to introduce the bacteria to the wild with with a method called bioaugmentation. They hope to increase naturally occurring bacteria so that it can spread to even more frogs and other amphibians.

This summer the scientists will be conducting tests in isolated areas to ensure that  bioaugmentation will be safe and environmentally friendly. If successful, this might offer the first real hope for warding off the mass exinction of the earth’s amphibians. Good news indeed for our froggy friends!

Mountain Yellow-legged frog