When researchers found fire salamanders (Salamandra salamandra) in the Netherlands dying at a rapid rate from a skin fungus, they thought the infection looked familiar.

Globally, amphibian numbers are declining in large part due to a chytrid fungus known as Batrachochytrium dendrobatidis or Bd. Bd attacks the skin of its host causing “the outer layers of the epidermis to thicken,” says the Academy’s amphibian expert, Dave Blackburn. “Bd disrupts the function of amphibian’s skin by interfering with electrolyte transport.”

Bd is quick and deadly: its effects may have wiped out more than 200 species of amphibians worldwide.

Similarly, the fire salamanders are dying at a rapid rate. Since first seeing dead animals in the Netherlands in 2010, scientists have observed that the population has fallen to around 10 individuals, less than four per cent of the original numbers.

But the similarities end there. The infected fire salamanders display skin lesions or ulcers and when the animals were tested, they were negative for Bd.

So what gives? According to a paper published last week in the Proceedings of the National Academy of Sciences, a new chytrid fungus.

Batrachochytrium salamandrivorans or Bs is closely related to Bd, but an entirely new chytrid fungus species.

This study is incredibly important, Blackburn says. “It clearly shows three things: 1) Bs is a new species of chytrid, 2) it presents different pathology than Bd (these lesions), and 3) it may have different host specificity.”

Bs, like Bd, doesn’t kill every amphibian it meets. “Midwife toads, Alytes obstetricans, are among the most susceptible of European frogs to Bd,” Blackburn says. But the study researchers infected the toads with new fungus Bs, and they were not susceptible to that fungus.

But the evidence the study provides only brings more questions for Blackburn. “When we think some amphibians around the world were killed by Bd, could it have been something else? Bs? Yet another species of chytrid?”

He gives an example of the thermal range for Bs and Bd. “People trying to predict how Bd spreads and where it would thrive—the fungus may be absent from that location now, but where it might flourish given the right conditions—by modeling where the disease is now with information on climatic conditions. In the past, have we been looking at the thermal range for Bd only or might we have confused some records of Bd with what we now know as Bs? Each may have different thermal conditions and there could be errors to where we’ve predicted that the disease could thrive.”

Testing for the new chytrid fungus also presents a conundrum. Although tests have been developed to screen for Bd, it is not clear whether these might sometimes be detecting Bs instead. The authors of the new study have developed primers to test for Bs, and Blackburn and his lab will obtain these to test animals here at the Academy.

Blackburn and other scientists came back with live frogs from Cameroon earlier this summer. The team hopes to raise and breed the animals here, displaying them for the public. As we reported in a story a few weeks ago, the frogs are part of a new initiative at the Academy focused on amphibian conservation and biodiversity education.

The Cameroonian frogs were screened and tested positive for Bd. They are being treated with a proven microbial solution, but now Blackburn is worried about Bs. “How widespread is Bs?”

And Blackburn has more and more questions… “Does it only affect salamanders? We’ve seen salamander declines in Central America—it looks like Bd, but could it be Bs? We found skin lesions on amphibians in Cameroon with mortality events, Bd was not present when tested. Could we have found Bs, instead?

“How is it spread, is it totally different from Bd? Why are we seeing these now? How is climate change affecting the emergence, spread, and change of prevalence? How do you stop them?

“Bs really opens the door for further research,” Blackburn says.

Image: Didier Descouens/Wikipedia

Two very different Academy scientists traveled to Cameroon together earlier this summer, in search of frogs, in a race to save them.

We’ve cited this scary number on this website before: more than one third of amphibians are at risk of extinction. These species experience many threats, mostly due to human impact, but one clear causes of frog death is the chytrid fungus. Scientists are unsure how it spreads, but the disease it causes quickly kills its victims.

Dave Blackburn, a scientist here at the Academy’s Institute on Biodiversity Science and Sustainability (IBSS), is working with San Francisco State University’s chytrid expert (and Academy fellow), Vance Vredenburg, to learn more about the spread and treatment of chytrid.

Brian Freiermuth works with the Academy’s live animals, mostly herps (amphibians and reptiles), and joined Blackburn on this unusual expedition. The two Academy scientists were joined by other students and colleagues, all looking for and collecting different samples.

“This expedition was exciting because we were conducting a lot of different types of science,” Blackburn, the expedition leader, explains. “We had four grad students with us. Two from UC Berkeley—one of them studies African frogs, the other looks at the larger ecosystem and how many frogs might live at a particular pond. One woman from the University of Texas is studying alkaloids on frogs’ skin and we also had a Cameroonian scientist who studies caecilians on the team. ”

While each team member had a very important role, Freiermuth performed a very crucial and unusual job for this type of expedition—keeping frogs alive during their journey through the country and all the way back home to San Francisco.

One of his biggest challenges was temperature since air conditioning isn’t always available or reliable in the country. “Keeping frogs alive for weeks at a time in less than ideal conditions in multiple locations isn’t easy,” says Freiermuth.  “Transporting the frogs from remote areas is hard to do because you don’t have any way to keep them cool in the vehicles, which get very warm during while traveling. I packed a large number of gel packs in our Styrofoam transport box and packed the frogs in individual vials. I also set the frogs up in cages in the field, and fed them until we would move to another location.”

Blackburn and Freiermuth also worked out cozy travel back to the US for the frogs. The amphibians were allowed in the cabin on Air France.

The frogs are now in quarantine here at the Academy, and will make their home in the Steinhart Aquarium by the end of this year, on display for visitors to see. The frogs were chosen because the Steinhart biologists believe they will do well in captivity but also because these are species of conservation concern for which we know little of their biology.

And they are here for a more important mission, too. The Cameroonian frogs are part of a new initiative at the Academy focused on amphibian conservation and biodiversity education. “This new initiative will enable us to figure out aspects of the biology of these many animals that we know so little about,” Blackburn says. The idea is that the more we know, the more we can protect and sustain populations.

“One basic goal of our work at the Academy is to better understand the conditions necessary for reproduction: breeding preferences (where are the eggs laid?), tadpole biology (what type of water quality do they require?), and requirements to get through metamorphosis (how long do they take to get to metamorphose, how long do they live, how long until they first reproduce, etc.),” Blackburn continues. “We can learn more about all of the species we collected in Cameroon: Cardioglossa pulchra, Cardioglossa gracilis, Hyperolius riggenbachi, Hyperolius ademetzi and Xenopus longipes.”

Science Today will follow up with two videos this fall: one on our new initiative and one on the fight against the deadly chytrid fungus. In the meantime, you can see some of Freiermuth’s amazing photos from the Cameroon expedition here.

Image: Brian Freiermuth

This week, UC Berkeley announced the amazing growth of its project, AmphibiaWeb, an online catalogue of the world’s amphibians created to encourage more field monitoring and lab studies of the threatened animals.

David Wake, an Academy fellow from UC Berkeley, started the project in 2000 because amphibians were declining at a terrifying rate and he was concerned we’d lose species we didn’t even know existed. “In 1985, there were a handful of amphibian biologists in the whole world,” he says. “Now, the numbers [of scientists] have increased dramatically, and we are getting to the ends of the earth.”

The Academy’s amphibian biologist Dave Blackburn has contributed to AmphibiaWeb for about ten years and recently became more involved in expanding the project. “I joined the steering committee nearly three years ago. I actively work as part of a team on issues related to the systematics displayed on AmphibiaWeb, but, perhaps more importantly, am actively invested in ways of improving our services, such as an iPhone app (available for download now, but major improvement coming soon!), summary diagrams of evolutionary relationships among amphibian groups, and general ideas for improving the content for diverse viewers.”

The more viewers the better. Earlier this summer, the International Union for the Conservation of Nature and Natural Resources (IUCN) assessed that about 41 percent of amphibian species are at risk of extinction, and some are already extinct. These charismatic creatures are disappearing for many reasons—a warming Earth, increasing population, widespread use of pesticides and a deadly fungus.

But AmphibiaWeb is succeeding! With only about 4000 species known in 1985, AmphibiaWeb now boasts 7,000 species! Woo-hoo! (Fist-pump or –bump!)

Now that’s something to sing about! “An undergraduate researcher assisting with AmphibiaWeb suggested the idea of a song when it came to celebrating the scientific description of the 7,000th amphibian,” Dave explains. “We’ve known since early this year that we’d probably hit number 7,000 some time in the summer based on the rate of descriptions of new species over the past few years. I happen to have a good friend (Conor Loughridge, performing as The Wiggly Tendrils) from college that writes songs for a living. We asked if he would be willing to help us out, and when he said yes, Conor and I worked together on content for the song (though the rest was left up to him to make it catchy and fun!).

“The general idea is to simply catch attention,” Dave adds. “The idea is to highlight the excellent work done by amphibian biologists around the world and the fact that we are still in a crisis. We are losing many populations and species of amphibians around the world due to climate change, habitat degradation and destruction, disease and pollution. In some cases, we’ve lost them before we even knew they existed.”

What a great way to spread the news! Is the tune stuck in your head yet? Pass it along!

Image: Alessandro Catenazzi