Adult koalas catch chlamydia just as people do — through sexual transmission — but young koalas can also become infected by eating pap, a nutritious type of faeces, when it is excreted by infected mothers, according to a study published March 12 in the journal Peer J.
The sexually transmitted disease has spread widely among koalas and can cause infertility, further threatening a species already impacted by bushfires, land clearing, and climate change.
But 12 months after launching the trial, Gold Coast's Currumbin Wildlife Hospital believes there is hope for the species after announcing that Cassidy - a koala participating in their research - is pregnant.
The hospital's senior vet, Michael Pyne, said it was extremely encouraging that Cassidy was expecting in an area where chlamydia runs rampant among the koala population.
The hospital admitted almost 500 koalas from the wild last year with 60 per cent of them suffering from the disease.
"It's encouraging that Cassidy is pregnant and negative to chlamydia, not only for the research trial, but for the entire koala species," said Dr Pyne.
"It's still very early stages and too early to say if the vaccine will be a long-term solution, however, Cassidy is making us hopeful."
The hospital has been treating 154 koalas with the vaccine before releasing them back to the wild over the last 12 months.