What is batrachochytrium salamandrivorans?

Batrachochytrium salamandrivorans (Bsal)

Batrachochytrium salamandrivorans (Bsal), often referred to as the "salamander-eating fungus," is a highly virulent chytrid fungus that causes the disease chytridiomycosis in salamanders and newts. It is a member of the phylum Chytridiomycota and is distinct from Batrachochytrium dendrobatidis (Bd), which primarily affects frogs.

Origin and Spread: Bsal is believed to have originated in East Asia (possibly Southeast Asia) and has been introduced to Europe through the international trade of salamanders, particularly the fire salamander (Salamandra salamandra). The spread of Bsal poses a significant threat to salamander populations worldwide.

Pathogenicity: Bsal infects the skin of salamanders, leading to severe skin lesions, lethargy, and ultimately, high mortality rates in susceptible species. Some Asian salamander species appear to be more resistant to Bsal, acting as potential carriers without showing severe symptoms.

Impact on Salamander Populations: The introduction of Bsal into European populations of Salamandra salamandra has resulted in devastating declines. In some affected areas, populations have experienced near-total collapse. This highlights the fungus's aggressive nature and the vulnerability of certain salamander species.

Diagnosis: Diagnosis of Bsal infection typically involves detecting the fungus's DNA using PCR (polymerase chain reaction) on skin swabs or biopsies from affected salamanders. Histological examination of skin samples can also reveal the presence of the fungal zoospores.

Conservation Efforts: Efforts to mitigate the spread and impact of Bsal include:

  • Biosecurity measures: Implementing strict regulations on the import and export of salamanders to prevent further introductions.
  • Disease surveillance: Monitoring wild salamander populations to detect outbreaks early.
  • Captive breeding programs: Establishing assurance colonies of vulnerable species to safeguard against extinction.
  • Research: Developing potential treatments or strategies to enhance salamander resistance to Bsal.