Koalas have Chlamydia. Yep, you read that right. That’s not some obscure band name or oddball ice breaker (though we’ve had quite a few interesting conversations stem from this fact). No, it’s typically not the same Chlamydia humans get and it usually can’t spread from koalas to humans (or vice versa)…so those rumors a few years back about the One Direction bandmates contracting Chlamydia from koalas in the Australia Zoo were pretty much false. But we’ll talk more about that a little later on!
Native Australian wildlife has been admired by people for thousands of years and arguably one of the most iconic animals is the koala. From eastern aboriginal tribes to modern-day Australian visitors, koalas attract attention globally for their unique lethargic lifestyles and seemingly gluttonous consumption of gum leaves (though many believe they’re stoned out of their minds, that’s not actually the case!). The two biggest things we’ve found people are surprised by when talking about koalas: they’re not bears, they’re marsupials, and yes, they are suffering from a nasty case of Chlamydia. Koalas can be a host for a range of pathogens and parasites including the mite Sarcoptes scabiei (causing mange), koala retrovirus (two types A and B, type B is associated with chlamydial disease), but infection with Chlamydia is arguably the most devastating to koala populations.
Note: Most of the koalas featured in this post are healthy critters, living at the Bonorong Wildlife Sanctuary.
So, what does this mean for unlucky koalas in infected populations? Unfortunately koala populations in southeastern Queensland are experiencing declines and localized extinctions in some areas. These declines led to their conservation status being set to vulnerable, which is just one step away from being listed as endangered. What does it mean for a species to be set as vulnerable? The International Union for Conservation of Nature categorizes a species as vulnerable when it is likely to become endangered unless the conditions which are causing a threat to its survival and reproduction improve.
Several factors are responsible for this current status: loss of habitat, dog attacks, overheating from extreme heat waves, motor vehicle accidents, and disease. Recent research surprisingly has pointed to curing chlamydial disease as one way to stabilize koala populations.
The above photo is of Pinto, a koala being rehabilitated at the Australia Zoo after suffering a broken arm and ruptured eye from getting hit by a car.
Similar to human infection, infection with Chlamydia in most koalas can go without symptoms. This is one way that makes Chlamydia a difficult pathogen to detect among populations in the wild and seemingly facilitates transmission. For those unfortunate individuals, chlamydial infection primarily impacts koalas in three different ways: conjunctivitis that can cause blindness, incontinence and urinary tract infection (commonly called soggy bottom due to brown patches of urine-soaked fur), and cystic reproductive tract disease in females which causes infertility. Warning, graphic images—if interested in seeing the impacts of Chlamydia, check out images in this paper.
Okay, well how did koalas get Chlamydia in the first place? You might have already guessed this, since Chlamydia is a STI (sexually transmitted infection), it can be spread between partners. But more often, it’s transferred between mother and joey. Ready for a disgustingly beautiful biological explanation? Good, me too! Female koalas will bathe their joeys in pap—a specialized form of koala excrement rich in all the mother’s microflora or bacterial community. This includes both the beneficial bacteria the young koala will need to digest eucalyptus leaves, along with any harmful bacteria such as Chlamydia.
As for its origins, that’s a bit up for debate in the scientific community. The leading hypothesis is that it originally spread from infected sheep that European settlers brought to Australia. We’ll just have to wait and see what science can tell us about this in the future!
Yes, and no.
There are two main strains of bacteria that lead to Chlamydia in the marsupials. The more common strain, Chlamydia pecorum, is responsible for most of the outbreak in Queensland and cannot be transmitted to humans.
The second strain, C. pneumoniae, can infect humans if, say, an infected koala were to urinate on someone…though it’s very unlikely. (Next time your friend sends you a cute koala pic, try sharing that!)
Can’t koalas receive antibiotics to get rid of it? Not exactly. See the koala gut has specialized flora to digest eucalyptus—its unique to koalas and allows them to break down eucalyptus leaves, their only form of nutrition. However, some antibiotics can eradicate these bacteria which can have fatal consequences for koalas.
Fortunately there are some antibiotics that can be delivered without killing off all those beneficial eucalyptus degrading bacteria. The downside to this is that koala antibiotics are both costly, and do not always work. Administering antibiotics requires a daily dose for about 45 days—meaning the veterinarian or another caretaker must be staffed and trained to inject the koala. On top of that, apparently there is only one company out there right now that is making the antibiotics.
So, where does that leave us? Well to combat this problem, researchers are working on a vaccine to target the chlamydial disease that would be administered using fewer veterinary resources and is more protective relative to current antibiotic treatment. But the vaccines research is a lengthy process! So…
It’s a little complicated as there are no koalas in Tasmania—other than the ones at the Bonorong Wildlife Sanctuary (more on that in another post). After receiving my Master’s in California, I joined the research group of a university in Queensland who is currently focusing on chlamydial vaccine development for koalas. Koala vaccine trials are expensive (upwards of $1 million AUD), so long story short: someone needs to look at that data and make some sense of it. This brings us back to Tasmania. In Tasmania, I’m joining a research group specializing in mathematical modeling and wildlife disease ecology. By sharing the microbiology results from the group in Queensland with the mathematical savvy Tasmanian group, we can better look at the results from vaccine trials and interpret them in new ways. As a Ph.D. student at both universities, I’ll be advancing vaccine development research one step closer toward a vaccine in koalas.
So there you have it, I’ll be studying in Australia while Chelsea supports me along the way (I seriously couldn’t do it without her) all while sharing a few of our favorite experiences abroad.
Don't miss out on exclusive content
+ get your weekly dose of culture vitamins.