The risks for wildlife living Down Under are plenty. If it’s not a vicious heatwave or a devastating bushfire, it’s a fatal disease (sometimes one plagued by social stigma). Australia's koalas catch chlamydia, their bats harbour Hendra, their devils have facial tumours … oh, and in case you missed it, the saltwater crocs in Oz suffer from herpes.

For humans, herpes means an embarrassing lip sore or an awkward doctor's appointment, but for crocs, the virus can be fatal. These massive reptiles are susceptible to several strains, including one that’s linked to chlamydia and can lead to the eyes and throat filling up with puss, ultimately resulting in suffocation. So, yes, much worse than a cold sore.

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Saltwater crocodile. Image: fvanrenterghem

Herpes in crocs is a relatively recent discovery, but we've known for a while that these reptiles are prone to getting sick. In 2006, a particularly bad outbreak of chlamydia in Australia’s north resulted in the death of thousands of young, farmed crocodiles. And studies from South Africa show that Nile crocs are threatened by a host of diseases, from hepatitis to "winter sores".

This is also not the first time we've seen animals infected with a disease usually associated with human hanky-panky. In fact, many common STDs can be traced back to animal hosts. Gonorrhoea? That probably came from cattle. Syphilis? Possibly sheep. 

Researchers, including the team from Darwin's Centre for Crocodile Research, are on a mission to learn more about the herpes virus in order to figure out how to stop it. Crocs don’t kiss much, so it’s more likely that the reptiles pass on the virus through biting and fighting.

Much like humans, an outbreak can be triggered by stress or environmental factors. "It's like a cold sore. Unless we go through a stressful period, we're always hiding it [in our system],” explains Dr Sally Isberg, managing director of the Centre for Crocodile Research.

So what does herpes mean for Australia’s croc populations in the wild? Well, probably not much. Experts are still trying to figure out if wild salties carry the virus – at this stage, croc herpes poses a threat mostly to the crocodile farming industry, an enterprise with an estimated worth of more than AU$20 million.

But with herpes-related mortality rates as high as 96%, it's certainly not a small problem and researchers are hoping to develop a vaccine in the near future.

Until then, crocs, lay off the biting ...

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At this stage, croc herpes only really poses a threat to the crocodile farming industry. Image: Marcus Södervall

Header image: Peter Nijenhuis