Kangaroo Island koalas are only ones in Australia without chlamydia and may mean their long-term survival

Kangaroo Island is famous for its landscapes and wildlife — and now it turns out its koalas are just different enough that they may save their species.

PhD candidate Jessica Fabijan from the University of Adelaide, with rescue koala Charlotte. Picture: Tricia Watkinson

Kangaroo Island koalas may hold the key to the long-term survival of the disease-threatened species in Australia, new research by the University of Adelaide has found.

The island’s koalas are chlamydia-free and may be needed to repopulate other declining populations, researcher and PhD student Jessica Fabijan said.

“The impact of chlamydia on populations of koalas in Queensland and NSW is devastating, with high levels of severe disease and death, and common infertility,” Ms Fabijan said.

“This last large, isolated chlamydia-free population holds significant importance as insurance for the future of the species.”

As part of the study, in collaboration with the Environment and Water Department, researchers captured and released 75 koalas from the Mount Lofty Ranges and 170 marsupials from KI. All of the KI koalas tested negative for the chlamydia bacteria and previous records showed there were no definitive cases of the disease in 13,000 examinations.

About 47 per cent of the Mount Lofty koalas tested positive, although the vast majority did not show signs of the disease. Researchers said the KI koalas have remained chlamydia-free because they were an introduced, isolated species.

“To effectively manage the population of koalas across Australia, we need to know the disease prevalence in every state,” Ms Fabijan said.

Adelaide Uni has discovered koalas at KI are the only koalas without Chlamydia in Australia. Jessica Fabijan PHD candidate, School of Animal and Veterinary Sciences, University of Adelaide with rescue koala Charlotte. Picture: Tricia Watkinson

“We know that disease prevalence isn’t as bad (in South Australia) but we know that it’s here — these koalas could be hugely important for the future of koalas across Australia.”

A chlamydia infection is the most significant disease causing death in koalas, and a key factor in koalas being under threat in northeastern Australia.

There are about 50,000 koalas on Kangaroo Island, while in the Mount Lofty Ranges there is estimated to be more than 150,000 koalas.

And a crowd-funding page was launched to support the research — donations can be made at experiment.com/southaustraliankoalas

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