The chytrid fungus threatens the last epidemiologically naive Neotropical montane amphibian biodiversity hotspot.

The Sierra Nevada de Santa Marta in Colombia is an epidemiologically naive refuge for amphibians, with no evidence of Batrachochytrium dendrobatidis presence despite high suitability.

• Why it matters: Protecting naive refuges is crucial because once virulent B. dendrobatidis lineages establish, eradication is rarely successful, risking extensive amphibian biodiversity loss.
• What they did: Researchers conducted multi-year disease surveillance, population genomic analyses, niche modeling, and infection trials across three endemic amphibian species, focusing on the SNSM.
• The result: Findings show no current B. dendrobatidis infection in SNSM, but the region remains at risk of invasion, threatening 25 endemic amphibian species and emphasizing urgent conservation and biosecurity measures.