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Koala Bears Suffer From Chlamydia Epidemic But Docs Fight Back with Ultrasound

August 07, 2014

Koalas have it rough. Cars and dogs kill some 4,000 of the tree-climbing Aussie icons every year. Now the entire koala population, which could number anywhere between 50,000 to 100,000, is at risk from another, unlikely villain: chlamydia.

Although koalas fall prey to strains of chlamydia bacteria that are only related to the type that causes the sexually transmitted disease in humans, the illness can lead to conjunctivitis, blindness, urinary and reproductive tract infections, infertility, pneumonia, and death. In some parts of Australia, up to 90 percent of the koala population is infected. The disease strikes koalas living in the wild as well as in zoos.

Although the disease can be treated, it is difficult to diagnose. As a result, koalas can live with an undetected infection for a long time, suffer serious damage to their organs, and spread it to other animals. But Australian veterinarians and biologists are fighting back.


Researchers at the Featherdale Wildlife Park in Sydney are working with GE Healthcare to catch chlamydia infections in koalas early. “It turns out that koalas look remarkably like humans when you put them under an ultrasound,” says Fiona Mildren, GE Healthcare’s regional clinical marketing manager for general imaging ultrasound. “In koalas with chlamydia, you see a thickening of the bladder wall, similar to what you see in people when they have a urinary tract infection.”

A recent study published in the journal of the Australian Veterinary Association said ultrasound can be an effective tool for spotting the disease early. That could give vets more time to treat the animals and stem the spread of the disease.


Mildren says that the hardest part of scanning koalas is getting them to keep still. The procedure is painless and simple, and keepers are developing a special perch to make the scan less intrusive for the animal.

“What we learn about preventing or treating diseases will ultimately also help the populations in the wild,” says Chad Staples, senior curator at Featherdale. “If we’re not careful, koalas will become extinct. The more we can learn about how to treat and prevent threats like chlamydia, the more chance we have to save them.”