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Does treating koala chlamydia hurt their gut microbes?

Joeys might not be getting the bacteria they need to break down toxic eucalyptus. (EPA/ROLAND WEIHRAUCH)
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Treating koalas for chlamydia might be hurting their overall health. A group of researchers is crowdfunding a project to take a close look at fecal samples from the adorable critters in the hopes of uncovering any negative consequences to antibiotic treatment.

In case you're not aware, a lot of koalas have chlamydia. Yes, chlamydia, the STI. It's a different strain than humans get, but it's a lot more devastating to the population: Experts estimate that around half of the 80,000 koalas in Australia have the infection, which can cause blindness, infertility, and even death. Even little joeys can get it from breastfeeding, if their mothers are infected.

[Australia is low on koala food and may need to kill some of the iconic creatures]

To fight the spread, animal caretakers collect sick koalas and treat them with broad-spectrum antibiotics before releasing them back into the wild. But Scientific American reports that the treatments might have unintended consequences. From Scientific American:

But some researchers are now worried that these powerful drugs are wrecking koalas' gut microbiotas—in particular the microbes that digest otherwise toxic eucalyptus leaves, koalas' only food source. "Koalas represent a fascinating case study of a rare extreme in mammals—where we know specific functions of the microbiome that are required for survival," says Jonathan Eisen, an evolutionary biologist at the University of California, Davis.

So basically, we might be curing one devastating infection but crippling koalas from digesting the only food they eat. And that's especially unfortunate for little joeys. Baby koalas are weaned off milk with something called pap. It's basically their mom's feces, but it's full of extra nutrients to help them grow. Unfortunately, mama koalas who've been treated for chlamydia might not have the right bacteria in their pap to make a healthy joey -- one that can digest eucalyptus.

[Why giant pandas have to eat and poop all day]

Katie Dahlhausen (one of Eisen's doctoral students) is leading an Indiegogo campaign with the noble goal of studying koala poop. With the $3,400 she and her team hope to raise, Dahlhausen will look for Tannin-Protein-Complex-Degrading Enterobacteria -- the bacteria koalas use to break down eucalyptus -- in the waste of female koalas who've had chlamydia, both with and without treatment. Then she'll see how their joeys fare on the stuff, and whether or not mom's who lack the right bacteria are able to raise healthy babies.

If you donate $200, you get a koala onesie. Just FYI.

For now, simply stopping chlamydia treatment isn't an option. The infection poses too great a risk to the koala population. But if projects like this one show that broad spectrum antibiotics are doing more harm than good, researchers may be able to find more targeted therapies that leave the gut microbiota unscathed.

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