Koalas are thought to be a source of the original spillover of chlamydia pneumonia to humans; and are known to be heavily infected with immortal intracellular pathogens, including chlamydia pneumonia and chlamydia pecorum. The infectious burden in koalas is damaging fertility, limiting lifespan, and threatening koalas with extinction. Tasmanian devils are similarly heavily infected with immortal intracellular pathogens, and similarly threatened with extinction. When Tasmanian devils bite each other, during courting or battle, the animals can transmit an aggressive form…..