There's a lot of concern about the health of koala populations in Australia - and the disease the koalas are carrying is one that's considered taboo in human society.
It's chlamydia.
Yes, in a way it is funny. I mean, who would believe that these cute, fuzzy-eared creatures would have such high rates of a sexually-transmitted disease? They hardly seem promiscuous. Or overtly sexual.
It was actually The Colbert Report that inspired us to write an article about chlamydia in koalas. Stephen Colbert, a political satirist on Comedy Central, introduced the issue to the world in a recent segment. So we had to follow up. I mean, we couldn't have the world thinking what he suggested, right?
Ok, back? Now for the real science, starting with the basics. Chlamydia is spread via sexual contact just as it is among humans, but also between mother and offspring. And it's already in 50-80% of Australia's koala population. Symptoms of chlamydia in koalas may include eye infections (as seen below) and infertility. Though chlamydia itself isn't thought to cause death directly, it may diminsh the koala's ability to handle stressful activities, minor infections, or recover from injury.
Imagine this from an urban koala's perspective. You're trying to move from one patch of eucalyptus trees to another- and to do so, you have to go through some pretty rough neighborhoods, across roads, and through a couple of dog-infested backyards. A bit dangerous at the best of times, right? And on top of that, you've got an eye infection, your immune system isn't working properly, and you're getting really tired from all the exertion. You might make some bad choices, or be less likely to get yourself out of danger.
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| an infected koala |
Scientists want to better understand how chlamydia is spread in koalas, what symptoms it causes, and ultimately how to stop it. But what really baffles scientists is that chlamydia seems to affect different koalas in different ways. For example, koalas living in urban areas (like Brisbane, or the Gold Coast) seem to show more symptoms to chlamydia infection than koalas in non-urban areas. Are there different strains of the disease? Or do koalas that are routinely stressed-out just get sicker?
Outside urban areas, such as at our St Bees Island research site (shown below), koalas have carried the disease for a long time. But despite the prevalence of chlamydia, the St Bees koala population is healthy and fertile. And it doesn't seem to show all the outward signs of illness that characterises the koalas living in the Brisbane metropolitan area. This would seem to support the idea that chronic stress influences how chlamydia is expressed in koalas - the stress of living in a degraded, dangerous, human-modified area.
It makes me wonder if we might learn a lesson or two from these stressed urban koalas...
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| Our St Bees Island study site, where koalas are healthy (and researchers are happy) |
Currently, researchers are trying to figure out how to solve the chlyamydia problem in koalas. There's been lots of talk of a vaccine, but the reality is that vaccines are a) very expensive to develop, b) difficult to administer to wild animals, and c) it's unclear if a vaccine would actually improve koala health over their range.
Chlamydia is undoubtedly a problem for some koalas, but we suspect that it's the stressful lifestyle experienced by those koalas in urban areas that makes them more susceptible to serious infection and death. Our research objective is to identify what environmental factors cause a benign chlamydia infection to become overtly symptomatic and life-threatening. Then, once we understand these triggers we can better manage them in koala habitats.
So what can you do to help koalas?
Well, firstly I just want to assure you that if you come to Australia and cuddle a koala or two - you are not going to get chlamydia.
Now that we've got that out of the way ... of course we recommend supporting koala research! You can donate to our research group directly. We're a team of researchers based at the University of Queensland, and we are the foremost experts on koala ecology and conservation in Australia (so we know what we're doing, and we spend donations wisely).
Otherwise, it's up to people who live in Australia to protect native habitat and to make urban environments as koala-friendly as possible. Which means setting aside blocks of native forest; designing housing developments to maximise bushland; providing safe ways for koalas to cross roadways; and locking up domestic dogs at night.
Written by Amanda Niehaus, PhD, on behalf of the Koala Ecology Group
