are among people According to the Pan American Health Organization, chlamydia is the most common sexually transmitted disease. If left untreated, the disease can lead to serious consequences such as infertility or ectopic pregnancies, where a fertilized egg grows outside the uterus. But uncomplicated cases are usually curable with antibiotics within a few days or weeks.

Again, this applies to humans. But we’re not the only ones dealing with chlamydia.

The koala, one of Australia’s symbols, can also contract chlamydia if it comes into contact with the feces of infected sheep or cattle. The venereal disease is then transmitted from mother to child or passed on when two animals mate. Once marsupials have chlamydia, they are usually much worse off than humans.

“The disease kills koalas because they get so sick they can’t climb trees to get food or to escape predators. And females can become infertile,” said Samuel Phillips, a microbiologist at the University of the Sunshine Coast in Queensland, Australia, the AP news agency.

Dying Koalas are bad enough. But for the dwindling number of animals – the Australian Koala Foundation estimated in 2022 that there are fewer than 58,000 koalas left in the wild – infertility is just as big a problem.

That’s why Australian researchers have now started a vaccination campaign against chlamydia among koalas in the state of New South Wales. The aim is to find out whether the specially developed koala vaccine, which only requires one dose, protects the animals from the dangerous disease. In addition to infertility and death, chlamydia can also cause blindness in koalas.

A safe vaccine for koalas

A research team wants to vaccinate half of the koalas in the Northern Rivers region of New South Wales – that’s about 50 animals. The vaccine has already been used on a few hundred koalas that were previously donated to wildlife rescue centers. The researchers therefore know that the vaccine is effective and does not harm the animals. However, they cannot yet say exactly how many koalas need to be vaccinated to create group immunity.

“We want to find out what percentage of koalas we need to vaccinate to significantly reduce contagion and disease,” Phillips said.

Catch koalas for vaccination

To do this, however, the researchers first have to capture their objects. This may not sound too difficult at first. Anyone who has ever seen a koala knows that they are not one of the most agile animals. Koalas don’t escape the researchers in a rush, but they spend most of their time high up in eucalyptus trees.

So the researchers keep an eye out for the koalas there. Once they spot an animal, they set up a trellis around the tree, with a door leading to a cage. And then patience is required.

After a few hours, or sometimes days, the koala climbs down the tree and into the cage. He is then taken to a wildlife hospital where he is anesthetized, vaccinated and then kept under surveillance for 24 hours.

Finally, the researchers put a pink mark on the back of the vaccinated koala so that they don’t catch the same animal twice.

Koalas: Endangered as of 2022

A vaccination campaign like this in a wild population is an absolute rarity. Not only is it difficult to capture the animals. During the action, the animals can also be injured or harmed by the stress. In this case, however, the researchers were willing to take the risk. Finally the Situation of koalas dramatic.

According to scientific estimates, around half of all wild koalas in Queensland, a state on the east coast of Australia, already have chlamydia. And in February 2022 The Australian government classified koalas as critically endangered.

The tightening, from endangered to endangered, applies to the koalas in Queensland, New South Wales and the Australian Capital Territory around the capital Canberra.

“Long droughts followed by summer wildfires, disease, urbanization and habitat loss over the past twenty years” led to the decision to list koalas as a critically endangered species, then Australian Environment Minister Sussan Ley said in 2022.

Stress increases the risk of chlamydia

All of these threats make koalas even more susceptible to chlamydia, which is why vaccination is so important, experts say. Because: Factors such as bush fires and loss of habitat stress the animals. This weakens their immune systems, which in turn makes them more likely to contract diseases.

The vaccination campaign in New South Wales is in full swing. The first vaccinated koala was released back into the wild on March 9, and researchers plan to vaccinate half of all koalas in the region within three months.