Chytridiomycosis, caused by two fungal pathogens, has driven dozens of amphibian species extinct and causes significant welfare suffering in affected populations.
Amphibian chytrid disease causes significant individual welfare suffering before death. The fungi disrupt amphibian skin function - which regulates ion transport in these semi-permeable animals - causing electrolyte imbalance leading to cardiac arrest. The disease progression involves weeks of declining function before death. The extraordinary scale of species loss - chytridiomycosis has driven the largest documented disease-caused vertebrate extinction event in history - means the aggregate welfare harm is immense. Captive assurance colonies represent a welfare and conservation lifeline but are resource-intensive.