How does amphibian chytridiomycosis threaten frogs and other amphibians?

Amphibian chytridiomycosis is a devastating disease caused by the fungus Batrachochytrium dendrobatidis (Bd), which poses a severe threat to global amphibian biodiversity.12

The fungus spreads through free-swimming zoospores that encyst on an amphibian's skin. As the infection progresses, the fungus penetrates the host's epidermal cells and grows into a mature thallus, causing the skin to degrade. This damage disrupts critical physiological processes, specifically gas exchange with the environment and the maintenance of electrolyte balance.13

These disruptions lead to a significant reduction in sodium and potassium concentrations in the blood plasma, ultimately causing the animal to succumb to cardiac arrest. Because amphibians rely on their skin for vital functions, this fungal infection is frequently fatal, contributing to the extinction or population decline of hundreds of species worldwide. Beyond the direct loss of amphibians, these declines can trigger broader trophic cascades, negatively impacting other species that rely on them for food.13