Take Two for January 2, 2013

Scientists race to save endangered frogs from lethal fungus

Panamanian Golden Frog

Amphibian Rescue

Image of a Panamanian Golden Frog.

All over the world, frogs are dying at an alarming rate. From the basins of the Sierra Nevada to Panama, and even extending to Australia and Europe, frog populations have declined as much as 95 percent since 2004 due to a deadly fungus.

Batrachochytrium dendrobatidis, which scientists call “Bd,” is a contagious, lethal fungus that has spread around the globe. The fungus clogs the frogs pores and causes them to die from a heart attack.

Washington Post reporter William Booth – who's reporting on this story as a foreign correspondent – talks about what the fungus is and what biologists are doing to try and stop frogs from becoming extinct.

On how the fungus spread throughout the world:
"Bd has a slow spread, so we don't know exactly when it entered North America, but for example when they went back and looked at samples in Mexico, they realized that the fungus was already there in the 1970s. So if you just look at the Americas it slowly worked its way from Mexico down through Guatemala through the isthmus, then it was in Costa Rica 10 years ago, then it was in Panama 2002, 2003, and now its headed down and has almost reached the Darian pass which is what connects Panama to Colombia. It also has leap frogged down into South America, they've found it in the Amazon and Chile and other places."

 On what the fungus does to the frogs:
"The fungus interrupts the movement of electrolytes and other things across the frog's skin. Frogs are very sensitive animals and their skin is very important, it helps them perspire, many frogs don't drink water they take in water through their skin, so it interferes with their ability to move vitamins and electrolytes and other things across their skin and eventually they'll die of cardiac arrest. So the biologists see really weird things, they'll actually see tens or dozens or hundreds of dead frogs, and in the jungle in Panama you would never see like a bunch of dead frogs, nature would take care of it and you wouldn't find them all along the stream bank. So when it hits a population it hits it quite hard."

On how the fungus has evolved over time:
"There were a couple of papers within the past few months that said the genetics of the Bd organism have been changing, so they co-combine with other funguses they meet, in nature a bacteria or virus or fungus is sort of changing and evolving, so they've found some evidence of that might increase the lethality of the fungus, and they also did some studies where they found that the temperature variation swings up and down more, it tends to be more lethal for frogs, and that temperature variability is what people are seeing from climate change, hotter days, colder days, so it swings up and down."

On what biologists are doing to help stop frog extinction:
"One of the big scientists involved in this is from Berkley, who was one of the people who identified the mechanism of how this fungus actually kills the frog. They call these amphibian arcs and they ran around as fast as they could in 2006, in 2007 and 2008, grabbing frog species that they were seeing being wiped out from the jungle, so they were pulling in several dozen species of frogs,…then pulling them into this laboratory and putting them into what might look like your 12-year-old son's dirty fish tank, so there they are for the last 5 or 6 or 7 years, and they've been trying to figure out how to encourage them to breed and also to keep them alive, since there's no Purina Frog Chow that you can shovel at them. So there's a whole parallel facility raising the stuff to keep these guys alive."

On the difficult road ahead for biologists working on saving frogs from the fungus:
"They need to successfully breed up several hundreds of frogs for each species before they would even attempt to put them back into the wild. We can't put precious, really expensive frogs back into the habitat simply to feed this Bd virus, and have it kill the frogs. There's been some thought of maybe they have a vaccination, there's been some idea that some frogs seem to survive when Bd comes through and maybe its a behavioral thing. Maybe the frog basks in the sun and the Bd fungus can't get going on him or her and so maybe you would take a bunch of frogs and do animal husbandry. You would challenge them with Bd fungus, some would die and some would live, the survivors you would go through a couple of generations to breed them, there's something about them that can beat back the fungus then you would put them back in the wild."


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