Australian researchers have identified a chemical that can effectively treat chlamydia in koalas without damaging healthy tissue, and it could soon form the base of a new medication.

The discovery could not have come soon enough, with around 70 percent of wild koalas in Australia now infected by the disease, and the local population dropping to a mere 100,000 individuals. Current treatments for koala chlamydia are now in dangerously short supply.

"It's really urgent now that we put a concerted effort into developing this treatment further. Manufacture has stopped, supply has stopped, and it can take years to develop a new drug," said lead researcher Willa Huston, from the University of Technology, Sydney (UTS). 

"We are in a desperate search to find new, effective treatments, and to test other drugs that might help koalas recover from this horrible disease."

Huston and her team came upon the new drug candidate by accident. They've spent the past four years developing a drug to treat the human form of chlamydia, but weren't getting anywhere because of the huge array of antibiotics already on the market for human consumption.

Then, by chance, a researcher working in a lab down the hall told Huston of the plight of the koalas.

"Science is pretty funny. It was pretty much an accident," she told Matt Wordsworth from ABC News. "It was something we were doing for human chlamydia and it just turned out to be the right application at the right time."

With a new, koala-focussed goal in mind, Huston and her colleagues went about testing the drug on tissue samples taken from infected koalas. To their surprise, the drug - called JO146 - effectively wiped out the disease without damaging the animals' healthy tissues.

This is a huge deal, because koalas don't usually respond well to antibiotics due to their ability to break down the toxins inside eucalyptus leaves. Without a specialised treatment, koalas on antibiotics can become emaciated and even die after ingesting certain medications because of the toxin-eating microbes in their stomachs.

Researchers estimate that they only have about two more years' worth of the current medication left, and that's seriously bad news if you're a koala with either the Chlamydia pecorum or Chlamydia pneumoniae strains.

"The first [strain] causes eye disease, including inflammation and discharge, or urogenital disease, including cystitis, urinary incontinence (known as 'wet bottom'), and fibrosis, which can cause infertility," the team explains. "The second strain causes severe respiratory illness."

There's no word yet on how long it will take for Huston's team to turn JO146 into a viable drug for the koalas - they have to go through stringent trials just like new human drugs - but hopefully it will continue to show potential through testing so it can be used in the field in the coming years.

Watch this space.

The team's work was published in Scientific Reportsand you can donate to the project here.

UTS Science is a sponsor of ScienceAlert. Find out more about their research.