Koalas are listed as Endangered in eastern Australia, facing simultaneous threats from habitat loss, vehicle strikes, dog attacks, and a chlamydia epidemic that causes blindness and infertility.
Koalas with chlamydia experience chronic pain from urinary tract infections and progressive vision loss that impairs their ability to navigate, find food, and avoid predators. Treatment with antibiotics disrupts the gut microbiome that koalas depend on to detoxify eucalyptus leaves, creating a treatment dilemma. Vehicle-struck koalas suffer traumatic injuries requiring intensive veterinary care, and survivors are released into increasingly degraded habitat with smaller eucalyptus groves. The combination of disease, habitat loss, and traumatic mortality creates a population under siege from multiple simultaneous welfare threats.