How does amphibian chytridiomycosis affect frogs and other amphibians?

Amphibian chytridiomycosis is a devastating disease caused by the fungus Batrachochytrium dendrobatidis (Bd), which infects the superficial layers of an amphibian's skin.123

The infection begins when free-swimming zoospores encyst on the host's skin and penetrate epidermal cells. As the fungus matures and spreads, it causes significant degradation of the epidermis. This damage disrupts critical physiological processes, specifically the animal's ability to perform gas exchange and maintain electrolyte balance.32

These disruptions lead to a severe osmotic imbalance and a dangerous reduction in sodium and potassium concentrations in the blood plasma. Ultimately, the infected animal succumbs to cardiac arrest. Because this disease has contributed to the extinction or decline of hundreds of species, it represents a major global threat to biodiversity and can trigger wider ecological consequences, such as trophic cascades affecting predators like snakes.32