Even before bushfires in 2019 and 2020 began driving koalas dangerously close to extinction, experts estimated that there were only about 329,000 left in Australia, which represents an average of a 24 percent decline in populations over the past three generations.
“It’s very difficult to estimate koala populations, even at the best of times,” Adams-Hosking tells National Geographic, “Some populations are becoming locally extinct and others are doing just fine.”
Koalas are today threatened by land development, food degradation, eucalyptus tree loss, drought, dog attacks, and chlamydia. The latter poses perhaps the greatest threat.
In koalas, chlamydia flare ups are extreme, leading to severe inflammation, massive cysts and scarring of the reproductive tract. In the worst cases, animals cannot urinate without great pain, and develop an acrid, smoky smell, The New York Times reports.
The strain of chlamydia koalas are afflicted with is similar to that which infects humans through sexual contact, as it has a tiny, highly conserved genome with just 900 active genes. It is technically not the same disease though it can be passed on in the same manner.
As a study in Nature reveals, 40% of the 1,000 individuals arriving annually in New South Wales and Queensland wildlife hospitals have untreatable late-stage chlamydia and cannot be rehabilitated.
Researchers tracking the population of koalas south of Brisbanen in an area known as the “Koala Coast” found that 52% of the koalas observed showed chlamydia-like symptoms, another study reported.
Research backed by the Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) finds that 61% of koalas in Victoria’s South Gippsland region are carriers of the chlamydia bacteria, representing one of the highest prevalence rates that has been observed in a population.
Lead researcher Dr Faye Wedrowicz told BuzzFeed News that her team decided to look at koalas in the region because they may hold the secret to preserving future koalas.
“The South Gippsland koala population is unique in Victoria because it’s got quite high genetic diversity,” Wedrowicz said.
Though chlamydia doesn’t directly kill koalas, it renders them infertile means koalas could become extinct in as little as a few decades.
The good news is, there is a vaccine. The bad news is, the cure can be as deadly as the disease.
Special bacteria deep inside a koala’s intestines help the animal subsist off eucalyptus, which is otherwise toxic. The chlamydia antibiotics wipes out this bacteria, too.
In a 2019 study published in PLOS ONE, Dr. Peter Timms, Dr. Rosemary Booth and team treated five koalas with antibiotics. Those koalas later had to be euthanized “due to gastrointestinal complications, resulting in muscle wasting and dehydration.”
The only known solution to this fatal side-effect is fecal transplants in a not-always-successful effort to restore the essential microbiota.
For the past decade, Dr. Peter Timms, one of the lead researchers on the study, has worked to create a better a vaccine.
“Rather than treat animals once they are already sick, a widespread vaccine would protect koalas from any future sexual encounter and from passing the infection from mother to newborn,” The New York Times reports.
According to ABC Science, trials of the vaccine have shown that it is safe for koalas, takes effect within 60 days, and protects against the chlamydia bacteria for the entire reproductive lifespan. The next step is optimizing it for use in the field.
A successful vaccine trial is one thing, but treatment is quite another. As National Geographic reports, handling infected wild koalas can stress them on top of their poor health, so alternatives are sought after whenever possible.
“Any time you handle [a wild] animal, a certain amount of stress will decrease their immune function,” says Dalen Agnew, associate professor in the department of Pathobiology and Diagnostic Investigation at Michigan State University.
Koalas are considered vulnerable to extinction but not yet endangered despite dwindling numbers, Nat Geo reports. Were the Australian government to grant this classification, koalas would be subsequently protected from some of their most pressing threats such as habitat destruction, and programs aimed at curing the chlamydia outbreak could see increased funding.
About 40% of Australian female koalas are now infertile, all because of this insidious disease. Join others in asking Australias Federal Environment Minister to elevate koalas to endangered status and ensure they receive the resources necessary to avert their extinction.
Click below to make a difference.
Help Rescue Animals
Provide food and vital supplies to shelter pets at The Animal Rescue Site for free! →