These parallels have Timms argued that koalas could serve as a "missing link" in the search for a human vaccine. "The koala is more than just a fancy animal model," he said. "It's really useful for human studies."
An ancient curse
Nobody knows how or when koalas got chlamydia for the first time. But the curse is at least centuries old.
In 1798 European explorers reached the mountains of New South Wales and spotted a creature that defied description: ear tufts and spoon nose stoically looked down from the crooks of towering eucalyptus trees. They compared it to the wombat, the sloth and the monkey. They chose "native bear" and gave it the generic name Phascolarctos (from the Greek for "leather pouch" and "bear"), which caused the misunderstanding that the koala bear is actually a bear.
"The seriousness of the face," wrote the Sydney Gazette in 1803, "seems to indicate a more than ordinary part of the ingenuity of the animals."
In the late 19th century, Australian naturalist Ellis Troughton found that the “picturesque and lovable koala” was also particularly susceptible to disease. The animals suffered from an eye disease similar to the pink eye, which he blamed for waves of koala deaths in the 1890s and 1900s. At the same time, the anatomist J.P. Hill found that koalas from Queensland and New South Wales often had ovaries and uterus with cysts. Many modern scientists today believe that these koalas were probably affected by the same scourge: chlamydia.
Koalas have to worry even more today. Dogs, carefree drivers and recently rampant bushfires have reduced their numbers to such an extent that conservation groups are demanding that koalas be classified as endangered. But chlamydia still prevails: in parts of Queensland, the heart of the epidemic, the disease has contributed to an 80 percent decline over two decades.
The disease is also the one that most often sends koalas to the Australia Zoo Wildlife Hospital, the country's busiest wildlife hospital located 30 miles north of Endeavor. "The numbers are 40 percent chlamydia, 30 percent cars, 10 percent dogs," said Dr. Rosemary Booth, the director of the hospital. "And then the rest is an interesting set of problems that you can get into if you have a small brain and your living space is fragmented."