Scientists in Panama Searching for a Cure for Deadly Amphibian Disease
By Yessenia Soto
The Smithsonian Tropical Research Institute facilities in Panama are home to precious collections of endangered amphibians that, in a few years, might be the only survivors among their kind. These amphibians live amid among biologists and scientists who are urgently seeking ways to breed them in captivity and safeguard them from a disease that is devastating them in the wild.
Beginning in the 1930s, African clawed frogs (Xenopus laevis) were sent around the world for use in pregnancy tests and laboratory experiments. Devastating consequences ensued due to the fact that they are carriers of a fungus called Batrachochytrium dendrobatidis, which produces a lethal and highly infectious disease commonly called chytridiomycosis. The fungus has quickly spread in North America, Central America, South America, Europe, and Australia, and today is considered to be the main cause of the extinction of more than 120 amphibian species since 1980, the largest decline to have occurred among all species of wildlife.
"When an amphibian is infected with the fungus, it has two options - die or survive. But, those that survive become infected and spread the disease to other individuals," explains Brian Gratwicke, Smithsonian Conservation Biology Institute biologist and international coordinator of the Amphibian Rescue and Conservation Project of Panama.
Panama was the last country in Central America to be attacked by the fungus. Its presence dates back to 1996, but initially, no action was taken to fight it because it was not clear that the fungus was the culprit of the amphibian declines. However, an alarm was set off as it began to spread, because the country is an amphibian biodiversity hotspot, holding more than 200 species. It is estimated that chytrid is advancing at a rate of 18 miles (30 km) per year, decimating the majority of the amphibian populations in its path. A group of 25 to 50 species in the eastern part of the country is now at high risk for extinction.
In response to this threat, Gratwicke's team began working in 2009 to minimize the loss of endangered amphibians, while simultaneously pursuing the ambitious goal of finding a cure for chytrid.
So far, scientists' main tool to combat species disappearances caused by chytrid is to establish captive "insurance colonies" to safeguard amphibian populations against local extinctions. This effort is being led by the International Union for the Conservation of Nature's "Amphibian Ark" project.
To establish these insurance colonies, specialists go on rescue expeditions to collect individuals of endangered species. At least 40 unrelated individuals from each species must be collected as wild founders to ensure their genetic integrity. They are then bred in captivity and kept in isolation so that they do not run the risk of contracting the disease. The long-term goal is to eventually reintroduce them into the wild once there is a cure.
Roberto Ibáñez, the project's director in Panama, explains that the team hopes to preserve at least 20 species of amphibians using insurance colonies, making it the most ambitious effort currently underway in Latin America. So far, the team has managed to set up insurance colonies for six species - Atelopus certus, Atelopus glyphus, Gastrotheca cornuta, Hemiphractus fasciatus, Strabomantis bufoniformis, and Anotheca spinosa.
According to Ibáñez, the project's biggest challenge is finding the 40 individuals to establish each colony. For example, in one case they only managed to find four individuals of a species. It is not possible to use such a small number in captive breeding, as they would create a population with low genetic variability. Another challenge is to breed amphibians in sufficient numbers to maintain stable populations.
Concurrently with the project's captive breeding efforts, another segment of the team is conducting research and laboratory tests to find a cure for chytridiomycosis. Tests have been done with a bacterium discovered by researchers at James Madison University in the United States, which produces antimycotic chemicals that inhibit the fungus. The tests consist of giving infected amphibians a dose of these bacteria, which should grow into the skin and ward off the fungus. The bacterium has been used with some species of amphibians in the United States, says Gratwicke, but it did not work during the first experiments done with the Panamanian golden frog (Atelopus zeteki). The project is currently making a second attempt with a Panamanian bacterium that also inhibits the fungus. If successful, it could be the gateway to finding a cure.
"If we find the cure, our project will have an enormous effect on the world," said Gratwicke. "Even if we fail, we will also have succeeded in drawing a lot of attention to this crisis. The idea of the Amphibian Ark will have been validated by the successful creation of insurance colonies, and all of the invaluable local capacity that was built in Panama will remain."
Thanks to the project, the government of Panama has passed laws that recognize the decline of amphibian populations and the importance of taking action. It is also hoped that the National Environmental Authority of Panama (ANAM) will soon publish a national plan for the conservation of amphibians that incorporates much of the work done under this initiative.
Another major achievement is the establishment of Golden Frog Day, officially celebrated for the first time on August 14, 2011, with about five hundred people attending. The project has also raised awareness about the chytrid crisis through an online community of thousands of followers on Facebook and Twitter. In addition, the project has received 70 local and international volunteers.
If a cure is found, all captive amphibians could be released back into their natural habitats, gradually restoring populations the fungus has affected. If the cure is not found, amphibians will continue to wait at the Smithsonian, where facilities are now being expanded to accommodate the growing number of individuals that need to be rescued.