Deadly fungus threatens U.S. salamanders

A new type of “chytrid” fungus has escaped from Asia and is killing European fire salamanders. This fungus is known as Bsal (short for Batrachochytrium salamandrivorans) and is closely related to the infamous Bd (Batrachochytrium dendrobatidis) that has been causing massive die-offs of frogs across the globe. But until recently, no one knew if Bsal could infect other species besides fire salamanders. In a recent study, European researchers tested more than 30 species of frogs and salamanders to see which were susceptible to Bsal. Frog lovers finally got a bit of good news – all 10 frog species tested were completely resistant to Bsal. But a very different – and alarming – result emerged when salamanders were infected with the fungus.

The fungus was first discovered when it started killing European fire salamanders, like the one shown here.

Of the 24 salamander species tested, 12 were found to be susceptible to Bsal. As the fungus invaded their skin, these salamanders became unable to maintain a normal balance of water and electrolytes. They became thin and lethargic, and most of them died within weeks. Sadly, this included one of my favorite species, Pleurodeles waltl, a salamander that uses its ribs like spears to attack would-be predators (piercing its own skin in the process).

What does this mean for salamanders in the United States? The study included seven U.S. species – the spotted salamander, marbled salamander, slimy salamander, and spring salamander, all of which were completely resistant to Bsal (hooray!). Lesser sirens, an aquatic salamander found in the southeastern U.S. and Mississippi river basin, became sick but managed to survive with the fungus. But eastern newts and rough-skinned newts weren’t so lucky. These newts, which are very common in the wild, died within 6 weeks of being infected.

So it looks like this new chytrid fungus is bad news for American newts. But what about the other ~165 salamander species living in the U.S.? It’s anyone’s guess, but I’m developing a project to help answer that question. (Philanthropists can email me at terrellk@si.edu).

The new fungus doesn't harm spotted salamanders (left), but quickly kills eastern newts (right).

The new fungus doesn’t harm spotted salamanders (left), but quickly kills eastern newts (right)

While Bsal is definitely cause for concern, there is a silver lining here. The researchers tested about 1,000 frogs and salamanders living in the U.S. and did NOT find Bsal on any of them! So, the good news is that there is still time – we can stop this fungus before it spreads to the United States. What can you do to help? Avoid buying amphibian pets that are imported from outside the U.S., especially species from Europe and Asia. If you do have an amphibian pet, do NOT, under any circumstances, release it into the wild. There are many rescue groups out there that will take unwanted pets, and this will help prevent the spread of Bsal and other diseases.

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