Batrachochytrium salamandrivorans

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Batrachochytrium salamandrivorans (Bsal) is a fungus that infects the skin of amphibians, especially salamanders and newts. It causes a disease called chytridiomycosis, which damages the skin, disrupts water balance, and can lead to death.

Where it came from and how it spread
Bsal likely originated in East Asia, where salamanders have lived with it for a long time. It was identified in 2013 from a fire salamander in the Netherlands after devastating populations there. It probably reached Europe through the pet trade, spreading to wild populations in several countries.

What it does to salamanders
The fungus erodes the skin, the animal’s main organ for respiration and water regulation. This can cause dehydration, organ failure, and death. In studies, many salamander species in Europe have been highly susceptible, while some Asian salamanders can tolerate infections, and a few frogs and caecilians seem less affected.

Where it has spread in Europe
Bsal has appeared in multiple European countries. It was first detected in the Netherlands in 2012 and has since been found in Belgium, western Germany, Luxembourg, and other areas. In Germany, the disease has caused large declines in salamander populations, especially in the Eifel region. In 2024, a mass die-off was reported in Hesse. Isolated outbreaks have also occurred, such as in Bavaria’s Steigerwald and in Allgäu (2020). A 2018 outbreak in Catalonia, Spain, killed fire salamanders and marbled newts, and some other Spanish reports later turned out to be false positives.

Why this matters for North America
Bsal could threaten many North American salamander species if it arrives. Estimates suggest 80 to 140 North American species could be at risk. In the United States, a 2016 ban on salamander imports was put in place to reduce the risk. Mexico currently has weaker regulations. About a third of the world’s salamander species live in the United States, and a substantial number are already threatened, so preventing introduction is crucial.

About the name
Batrachochytrium combines Greek words for frog and a pot-like structure that holds spores; salamandrivorans means “salamander-eating,” referring to the severe skin damage and rapid death seen in infected salamanders.

What is being done
Scientists and authorities are monitoring outbreaks, limiting trade in salamanders, and studying which species are most at risk. Controlling spread and protecting vulnerable salamander populations are ongoing priorities.

For more information on Bsal and related animal diseases, researchers and conservationists continue to share findings to help protect salamanders and other amphibians.