Chlamydial disease is devastating wild koala populations across Australia, causing painful blindness, reproductive failure, and death in a species already stressed by habitat loss.
Chlamydial disease causes prolonged and severe suffering in koalas. Conjunctivitis progresses from eye discharge to corneal scarring and blindness — a condition that prevents normal feeding in a species requiring precise leaf selection. Urinary tract infection causes constant pain and discharge. Reproductive tract scarring means infected females cannot breed even if they recover — a welfare harm that extends beyond the individual to population viability. The combination of disease and habitat loss creates a compounding welfare crisis. Vaccine development offers hope for population-level disease reduction without the welfare costs of capture and treatment for every individual.