Koalas Get A Shot At Survival As World-First Chlamydia Vaccine Gets Approval

Great news for koalas in Australia: a new chlamydia vaccine has officially been approved by Australia’s Veterinary Medicine Regulator (yay!). 

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Developed over more than a decade at the University of the Sunshine Coast (UniSC) as part of a global collaborative effort, the vaccine is designed to protect the tree huggers from chlamydia, a bacterial infection that’s been devastating their populations for decades. Chlamydia spreads rapidly among wild populations, causing painful urinary tract infections, infertility, blindness, and even death. But now, a breakthrough single-dose vaccine could turn the tide for the species.

“[We were] determined to do the hard yards to move from research to this vital next stage – a high-quality, veterinary-approved product that can now be used in wildlife hospitals, veterinary clinics and in the field to protect the nation’s most at-risk koalas,” said Professor Peter Timms, lead researcher of the UniSC team, in a statement. “Some individual wild colonies, where infection rate can be as high as 70 percent, are edging closer to extinction every day.”

Up to this point, antibiotics were the go-to treatment for koalas infected with chlamydia. But these drugs come with a big downside: they can destroy the gut bacteria in koalas that are required to digest eucalyptus leaves, their only food source. This disruption can lead to starvation and sometimes even death. On top of that, antibiotics don’t reliably stop reinfection, leaving koala populations at ongoing risk.

“We knew a single-dose vaccine – without the need for a booster - was the answer to reducing the rapid, devastating spread of this disease, which accounts for as much as half of koala deaths across wild populations,” said Professor Timms.

Developing this vaccine wasn’t an easy and quick process. 

“The vaccine has been trialed on hundreds of wild koalas, others in captivity and wildlife hospitals, and over multiple generations,” said Dr Sam Philips, senior researcher at UniSC, who led the longest and largest study on wild koalas.

A decade of clinical investigations, including the above study, has shown that this vaccine is not only safe but also effective at protecting koalas from chlamydia.

“This study found it reduced the likelihood of koalas developing symptoms of chlamydia during breeding age and decreased mortality from the disease in wild populations by at least 65 percent,” explained Dr Phillips.

Phillips added that the new vaccine targets the major outer membrane protein of Chlamydia pecorum, the strain affecting koalas. It offers protection by cutting down infection rates, stopping the disease from developing into full-blown symptoms, and in some cases, it can reverse signs of illness that have already appeared. 

Although we are now equipped with this powerful new tool to combat a disease that has long threatened the survival of koalas, researchers emphasize the need for further funding and support.

“We are also continuing to refine the product and conduct ongoing research to ensure the vaccine’s long-term success,” said Professor Timms. “Every contribution will go towards vaccinating at-risk koalas and to help reverse the alarming impacts of this disease.”

This development not only holds promise for iconic Aussie koalas but also serves as a model for wildlife disease management worldwide.