Chytrid fungus (Batrachochytrium dendrobatidis) has caused the largest infectious disease-driven loss of vertebrate biodiversity ever recorded, with significant animal welfare implications.
Chytrid disease causes a prolonged and distressing death in affected amphibians. Loss of skin function impairs gas exchange and electrolyte regulation, causing cardiovascular failure over days to weeks. The slow progression of the disease means affected animals experience extended suffering. Population collapse removes animals from ecosystems where they play important ecological roles. The welfare of individual amphibians dying from chytrid is rarely considered in conservation discussions focused on species-level outcomes.