salamandrivorosis

Salamandrivorosis, commonly referred to as Bsal disease, is a lethal fungal infection of salamanders and newts caused by the chytrid fungus Batrachochytrium salamandrivorans. Like other chytridiomycete infections, it targets keratinized skin, a critical barrier for amphibians, and can disrupt osmoregulation and water balance, often leading to rapid deterioration and death in affected individuals.

The pathogen produces motile zoospores in aquatic environments and forms sporangia within the outer skin layers of hosts. Transmission occurs through direct contact between animals, as well as via contaminated water, substrate, or equipment. Susceptibility varies by species and population; several European salamander species exhibit high vulnerability, while some individuals or species may show lower susceptibility or act as asymptomatic carriers.

Since its first documented emergence in Europe in the early 2010s among traded salamanders, salamandrivorosis has been associated with declines in wild populations in multiple countries and has been identified as a major threat to native salamanders in several regions. The ongoing risk is linked to international trade in live salamanders and to the potential movement of contaminated materials between habitats.

Diagnosis relies on molecular assays, primarily quantitative PCR testing of skin swabs, supported by histopathology. Clinical signs include lethargy, reduced feeding, abnormal shedding or skin lesions, excess mucus, and rapid, often fatal decline in individual health.

Management emphasizes prevention and biosecurity rather than cure in wild populations. Measures include quarantine and testing of traded animals, strict decontamination of equipment and enclosures, and regulatory restrictions on movement of salamanders. In captive settings, antifungal treatments may be used for individual animals, but there is no reliable cure for wild populations.