First wild koalas caught and vaccinated against chlamydia

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A koala rests in a branch at a Koala Park in Sydney, Australia on Friday, 5 May 2023. In a groundbreaking field trial, Australian scientists are vaccinating wild Koalas in New South Wales against chlamydia. The goal is to test the effectiveness of a vaccine against chlamydia, a disease that can cause blindness, infertility, and even death.

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A koala is seen eating gum leaves in a Sydney koala-park on Friday, 5 May 2023. In a groundbreaking field trial, Australian scientists are vaccinating wild Koalas in New South Wales against chlamydia. The goal is to test the effectiveness of a vaccine against chlamydia, a disease that can cause blindness, infertility, and even death.

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On Nov. 15, 2022, Samuel Phillips poses in the Laboratory at the University of the Sunshine Coast, Sippy Downs in Queensland, Australia. The lab is making UniSC Koala Chlamydia vaccination doses for trials of wildlife vaccines. In an ambitious field test, Australian scientists are vaccinating koalas in the wild against chlamydia. Phillips, a scientist who developed the vaccine, said that it was killing koalas as they could not climb trees for food or to escape predators. Females may also become infertile. (Ton Steward/Samuel Phillips, via AP).

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A koala rests in a branch at a Koala Park in Sydney, Australia on Friday, 5 May 2023. In a groundbreaking field trial, Australian scientists are vaccinating wild Koalas in New South Wales against chlamydia. The goal is to test the effectiveness of a vaccine against a disease that can cause blindness, infertility, and death.

Mark Baker/AP

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A selfie is taken by a visitor with a Koala in a koala-park in Sydney, Australia on Friday, 5 May 2023. In a groundbreaking field trial, Australian scientists are vaccinating wild Koalas in New South Wales against chlamydia. The goal is to test the effectiveness of a vaccine against a disease that can cause blindness, infertility, and death.

Mark Baker/AP

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A koala rests in a branch at a Koala Park in Sydney, Australia on Friday, 5 May 2023. In a groundbreaking field trial, Australian scientists are vaccinating wild Koalas in New South Wales against chlamydia. The goal is to test the effectiveness of a vaccine against a disease that can cause blindness, infertility, and death.

Mark Baker/AP

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A koala is seen eating gum leaves in a Sydney, Australia koala-park on Friday, 5 May 2023. In a groundbreaking field trial, Australian scientists are vaccinating wild Koalas in New South Wales against chlamydia. The goal is to test the effectiveness of a vaccine against a disease that can cause blindness, infertility, and death.

Mark Baker/AP

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In an ambitious field test in New South Wales, Australian scientists are vaccinating wild Koalas against Chlamydia.

The goal is to test the effectiveness of a new method that can protect marsupials from a disease that has caused blindness, infertility, and even death.

The vaccine is killing koalas as they are unable to climb trees for food or to escape predators. Females can also become infertile.

Scientists' first goal is to capture, vaccinate, and monitor about half of the Koala population of Northern Rivers in New South Wales. This means that they will need to vaccinate around 50 animals.

Safety and effectiveness of the

single-shot vaccine,

The vaccine, which was designed for koalas specifically, had been tested on a few hundred animals that were brought to wildlife rehabilitation centers with other ailments.

Scientists are now trying to determine the effect of vaccinating wild koalas. Phillips said, 'We are trying to determine what percentage of koalas needs to be vaccinated to reduce disease and infection.'

The first koalas have been caught and vaccinated since March. It is estimated that the vaccination effort will last for about three months.

Researchers use binoculars for spotting koalas on eucalyptus tree trunks, and then build circular enclosures with doors around the base of trees. After a few days or hours, the koalas eventually descend from the tree they were on to reach the leaves of another. They then fall into the traps.

It's difficult to mistake a koala for any other animal -- they're easy to spot.' Jodie Wakeman is the clinical and veterinary director of Friends of the Koala. This nonprofit runs a wildlife clinic where the koalas come to be vaccinated.

Wakeman said that after a checkup to ensure the animals' health, researchers inject anesthesia, and then administer shots of vaccine. They keep them under observation 24 hours later to confirm they have no side effects.

It is important to protect healthy koalas from chlamydia.

The researchers mark the backs of the koalas before releasing them with a pink dye to make sure the same animals don't get caught again.

Scientists placed the cage of the first vaccinated Koala at the base a tree on 9 March and opened the door. She quickly emerged from the cage and ran up the trunk of the tree.

The Koala is an iconic Australian marsupial, just like the wombat and kangaroo. Koalas spend the majority of their time sleeping and eating in eucalyptus tree trunks. Their paws are equipped with two opposing thumbs that help them climb and grasp.

The wild koala population in Australia has declined dramatically over the last two decades.

In February last year, the Australian federal government declared that koalas were 'endangered in eastern New South Wales and Queensland, as well as the Australian Capital Territory.

According to the government of New South Wales' 2020 assessment, disease, habitat destruction and road accidents could lead to the extinction of koalas by 2050.

Scientists estimate that around half of the wild koalas living in Queensland have chlamydia.

Scientists weigh the risks of the vaccine against the spread of disease. Multiple government agencies, including Australia's Agriculture Department and New South Wales Planning and Environment Department, approved the trial.

Scientists believe that chlamydia was first contracted by koalas from the feces and urine of sheep or cattle infected with the disease. It is then spread sexually or from mother to child.

Koalas are not as easily treated by antibiotics. While chlamydia in humans and livestock can be treated, the same isn't true for koalas.

Mathew Crowther is a conservation biologist from the University of Sydney. He said that the 'complex microbes' in the stomachs of the koalas were designed to neutralize the toxins found in the eucalyptus leaf, which is their primary food source. Their digestive systems are also able to neutralize certain medicines, so they do not respond well to anti-biotics.

Crowther has monitored a koala population in northern New South Wales, Australia for over a decade. In 2008, 10% animals were found to be infected by chlamydia. Today, that rate has risen to 80%.

"It has been devastating -- there is very, very little fertility," he said. "You barely see any babies."

Crowther said that the other threats to koalas, such as habitat destruction due to land clearing, and climate-adjusted wildfires, may cause them stress, weaken their immune system, and make them more susceptible for diseases, including chlamydia.

Rebecca Johnson, who is now the chief scientist of the Smithsonian National Museum of Natural History, Washington, D.C., led the Koala Genome Consortium, an Australian consortium, before. She described the experience as heartbreaking, having seen the effects of the illness up close.

Johnson recalled that a necropsy performed on a koala who had advanced chlamydia and was euthanized showed that her ovaries were completely covered in cysts, as well as intestines filled with hard lumps of food. This indicated that she could not digest food properly. She was clearly infertile and in severe pain.

Only a few scientists have attempted to capture and inoculate wildlife that is endangered for conservation. Scientists began vaccinating Hawaiian monks seals in 2016 against a deadly morbillivirus strain. Biologists in Brazil started vaccinating golden lion-tamarins for yellow fever two and a half year ago.

Jacob Negrey is a biologist from Wake Forest University School of Medicine. Conservation biologists are currently arguing over whether the vaccine should be used more frequently.

Johnson, of the Smithsonian Institute, said that the benefits for koalas are likely to be greater than the risks. 'Vaccination requires a lot of resources. Koalas are found in the trees.

"But because the effects are so debilitating I think it is totally worth it."

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