These parallels have led Dr. Timms to argue 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 actually is really useful for human studies.”
An ancient curse
No one knows how or when koalas first got chlamydia. But the curse is at least centuries old.
In 1798, European explorers reached the mountains of New South Wales and spied a creature that defied description: ear-tufted and spoon-nosed, it peered down stoically from the crooks of towering eucalyptus trees. They compared it to the wombat, the sloth and the monkey. They settled on “native bear” and gave it the genus name Phascolarctos (from the Greek for “leather pouch” and “bear”), spawning the misconception that the koala bear is, in fact, a bear.
“The graveness of the visage,” The Sydney Gazette wrote in 1803, “would seem to indicate a more than ordinary portion of animal sagacity.”
In the late 19th century, the Australian naturalist Ellis Troughton noted that the “quaint and lovable koala” was also particularly susceptible to disease. The animals suffered from an eye ailment similar to pink eye, which he blamed for waves of koala die-offs 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 uteruses riddled with cysts. Many modern scientists now believe those koalas were probably afflicted with the same scourge: chlamydia.
Koalas today have even more to worry about. Dogs, careless drivers and, recently, rampant bushfires have driven their numbers down so far that conservation groups are calling for koalas to be listed as endangered. But chlamydia still reigns supreme: In parts of Queensland, the heart of the epidemic, the disease helped fuel 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 Endeavour. “The figures are 40 percent chlamydia, 30 percent cars, 10 percent dogs,” said Dr. Rosemary Booth, the hospital’s director. “And then the rest is an interesting assortment of what trouble you can get into when you have a small brain and your habitat’s been fragmented.”