Australia is trying to vaccinate all of its koalas against chlamydia

• Australia is conducting a chlamydia vaccine trail among koalas in the country.
• The sexually transmitted disease widely affects koalas and can cause infertility in the animals.

Australia is rolling out a chlamydia vaccine trial among koalas in the country.

About 400 koalas will be vaccinated as part of the trial, and researchers told Reuters that they hope the vaccine will help the animals survive longer as a species.

While the disease is often sexually transmitted, it can be transmitted from mothers to their babies as well.

"It is a cruel disease that causes debilitating conjunctivitis, bladder infections and at times, infertility," Amber Gillett, a veterinarian and coordinator of research at the Australia Zoo Wildlife Hospital Wildlife, told Reuters.

The vaccine trial is being led by the University of the Sunshine Coast.

Peter Timms, a professor of microbiology at the school, told The Guardian that the vaccine had already been tested in 250 koalas in eight smaller trials.

He said that the vaccine is safe and that it can reduce infection levels.

"You can't really easily give antibiotics to koalas," Timms said. "People do, but it upsets their gut bacteria, and they need their gut bacteria to digest eucalyptus leaves."

"Unfortunately 10 or even 20% of animals that go through the [Australia Zoo] wildlife hospital come back to the hospital," he added. "In a lot of cases, if you just treat them with antibiotics, they often come back with chlamydial disease again."

The Australian Koala Foundation, an independent non-profit group, told Reuters in September that it estimates that Australia has lost about 30% of its koala population over the last three years.

The group said droughts, bushfires, and loss of habitats all played factors in the loss of population.

It estimates that there less than 58,000 koalas left in Australia.